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diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* rendering object to wrap rendering objects that should be scrollable */
+
+#include "nsGfxScrollFrame.h"
+
+#include "mozilla/layers/LayersTypes.h"
+#include "nsIXULRuntime.h"
+#include "base/compiler_specific.h"
+#include "DisplayItemClip.h"
+#include "nsCOMPtr.h"
+#include "nsIContentViewer.h"
+#include "nsPresContext.h"
+#include "nsView.h"
+#include "nsViewportInfo.h"
+#include "nsContainerFrame.h"
+#include "nsGkAtoms.h"
+#include "nsNameSpaceManager.h"
+#include "mozilla/intl/BidiEmbeddingLevel.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "nsFontMetrics.h"
+#include "mozilla/dom/NodeInfo.h"
+#include "nsScrollbarFrame.h"
+#include "nsINode.h"
+#include "nsIScrollbarMediator.h"
+#include "nsITextControlFrame.h"
+#include "nsILayoutHistoryState.h"
+#include "nsNodeInfoManager.h"
+#include "nsContentCreatorFunctions.h"
+#include "nsStyleTransformMatrix.h"
+#include "mozilla/PresState.h"
+#include "nsContentUtils.h"
+#include "nsDisplayList.h"
+#include "nsHTMLDocument.h"
+#include "nsLayoutUtils.h"
+#include "nsBidiPresUtils.h"
+#include "nsBidiUtils.h"
+#include "nsDocShell.h"
+#include "mozilla/ContentEvents.h"
+#include "mozilla/DisplayPortUtils.h"
+#include "mozilla/EventDispatcher.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/ScrollbarPreferences.h"
+#include "mozilla/ScrollingMetrics.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/StaticPrefs_toolkit.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/SVGOuterSVGFrame.h"
+#include "mozilla/ViewportUtils.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/HTMLMarqueeElement.h"
+#include "mozilla/dom/ScrollTimeline.h"
+#include <stdint.h>
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/Telemetry.h"
+#include "nsSubDocumentFrame.h"
+#include "mozilla/Attributes.h"
+#include "ScrollbarActivity.h"
+#include "nsRefreshDriver.h"
+#include "nsStyleConsts.h"
+#include "nsIScrollPositionListener.h"
+#include "StickyScrollContainer.h"
+#include "nsIFrameInlines.h"
+#include "gfxPlatform.h"
+#include "mozilla/StaticPrefs_apz.h"
+#include "mozilla/StaticPrefs_general.h"
+#include "mozilla/StaticPrefs_layers.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_mousewheel.h"
+#include "mozilla/ToString.h"
+#include "ScrollAnimationPhysics.h"
+#include "ScrollAnimationBezierPhysics.h"
+#include "ScrollAnimationMSDPhysics.h"
+#include "ScrollSnap.h"
+#include "UnitTransforms.h"
+#include "nsSliderFrame.h"
+#include "ViewportFrame.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/layers/APZCCallbackHelper.h"
+#include "mozilla/layers/APZPublicUtils.h"
+#include "mozilla/layers/AxisPhysicsModel.h"
+#include "mozilla/layers/AxisPhysicsMSDModel.h"
+#include "mozilla/layers/ScrollingInteractionContext.h"
+#include "mozilla/layers/ScrollLinkedEffectDetector.h"
+#include "mozilla/Unused.h"
+#include "MobileViewportManager.h"
+#include "VisualViewport.h"
+#include "WindowRenderer.h"
+#include <algorithm>
+#include <cstdlib> // for std::abs(int/long)
+#include <cmath> // for std::abs(float/double)
+#include <tuple> // for std::tie
+
+static mozilla::LazyLogModule sApzPaintSkipLog("apz.paintskip");
+#define PAINT_SKIP_LOG(...) \
+ MOZ_LOG(sApzPaintSkipLog, LogLevel::Debug, (__VA_ARGS__))
+static mozilla::LazyLogModule sScrollRestoreLog("scrollrestore");
+#define SCROLLRESTORE_LOG(...) \
+ MOZ_LOG(sScrollRestoreLog, LogLevel::Debug, (__VA_ARGS__))
+static mozilla::LazyLogModule sRootScrollbarsLog("rootscrollbars");
+#define ROOT_SCROLLBAR_LOG(...) \
+ if (mIsRoot) { \
+ MOZ_LOG(sRootScrollbarsLog, LogLevel::Debug, (__VA_ARGS__)); \
+ }
+static mozilla::LazyLogModule sDisplayportLog("apz.displayport");
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+using namespace mozilla::layers;
+using namespace mozilla::layout;
+using nsStyleTransformMatrix::TransformReferenceBox;
+
+static ScrollDirections GetOverflowChange(const nsRect& aCurScrolledRect,
+ const nsRect& aPrevScrolledRect) {
+ ScrollDirections result;
+ if (aPrevScrolledRect.x != aCurScrolledRect.x ||
+ aPrevScrolledRect.width != aCurScrolledRect.width) {
+ result += ScrollDirection::eHorizontal;
+ }
+ if (aPrevScrolledRect.y != aCurScrolledRect.y ||
+ aPrevScrolledRect.height != aCurScrolledRect.height) {
+ result += ScrollDirection::eVertical;
+ }
+ return result;
+}
+
+/**
+ * This class handles the dispatching of scroll events to content.
+ *
+ * Scroll events are posted to the refresh driver via
+ * nsRefreshDriver::PostScrollEvent(), and they are fired during a refresh
+ * driver tick, after running requestAnimationFrame callbacks but before
+ * the style flush. This allows rAF callbacks to perform scrolling and have
+ * that scrolling be reflected on the same refresh driver tick, while at
+ * the same time allowing scroll event listeners to make style changes and
+ * have those style changes be reflected on the same refresh driver tick.
+ *
+ * ScrollEvents cannot be refresh observers, because none of the existing
+ * categories of refresh observers (FlushType::Style, FlushType::Layout,
+ * and FlushType::Display) are run at the desired time in a refresh driver
+ * tick. They behave similarly to refresh observers in that their presence
+ * causes the refresh driver to tick.
+ *
+ * ScrollEvents are one-shot runnables; the refresh driver drops them after
+ * running them.
+ */
+class nsHTMLScrollFrame::ScrollEvent : public Runnable {
+ public:
+ NS_DECL_NSIRUNNABLE
+ explicit ScrollEvent(nsHTMLScrollFrame* aHelper, bool aDelayed);
+ void Revoke() { mHelper = nullptr; }
+
+ private:
+ nsHTMLScrollFrame* mHelper;
+};
+
+class nsHTMLScrollFrame::ScrollEndEvent : public Runnable {
+ public:
+ NS_DECL_NSIRUNNABLE
+ explicit ScrollEndEvent(nsHTMLScrollFrame* aHelper);
+ void Revoke() { mHelper = nullptr; }
+
+ private:
+ nsHTMLScrollFrame* mHelper;
+};
+
+class nsHTMLScrollFrame::AsyncScrollPortEvent : public Runnable {
+ public:
+ NS_DECL_NSIRUNNABLE
+ explicit AsyncScrollPortEvent(nsHTMLScrollFrame* helper)
+ : Runnable("nsHTMLScrollFrame::AsyncScrollPortEvent"), mHelper(helper) {}
+ void Revoke() { mHelper = nullptr; }
+
+ private:
+ nsHTMLScrollFrame* mHelper;
+};
+
+class nsHTMLScrollFrame::ScrolledAreaEvent : public Runnable {
+ public:
+ NS_DECL_NSIRUNNABLE
+ explicit ScrolledAreaEvent(nsHTMLScrollFrame* helper)
+ : Runnable("nsHTMLScrollFrame::ScrolledAreaEvent"), mHelper(helper) {}
+ void Revoke() { mHelper = nullptr; }
+
+ private:
+ nsHTMLScrollFrame* mHelper;
+};
+
+//----------------------------------------------------------------------
+
+//----------nsHTMLScrollFrame-------------------------------------------
+
+class ScrollFrameActivityTracker final
+ : public nsExpirationTracker<nsHTMLScrollFrame, 4> {
+ public:
+ // Wait for 3-4s between scrolls before we remove our layers.
+ // That's 4 generations of 1s each.
+ enum { TIMEOUT_MS = 1000 };
+ explicit ScrollFrameActivityTracker(nsIEventTarget* aEventTarget)
+ : nsExpirationTracker<nsHTMLScrollFrame, 4>(
+ TIMEOUT_MS, "ScrollFrameActivityTracker", aEventTarget) {}
+ ~ScrollFrameActivityTracker() { AgeAllGenerations(); }
+
+ virtual void NotifyExpired(nsHTMLScrollFrame* aObject) override {
+ RemoveObject(aObject);
+ aObject->MarkNotRecentlyScrolled();
+ }
+};
+static StaticAutoPtr<ScrollFrameActivityTracker> gScrollFrameActivityTracker;
+
+nsHTMLScrollFrame* NS_NewHTMLScrollFrame(PresShell* aPresShell,
+ ComputedStyle* aStyle, bool aIsRoot) {
+ return new (aPresShell)
+ nsHTMLScrollFrame(aStyle, aPresShell->GetPresContext(), aIsRoot);
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsHTMLScrollFrame)
+
+nsHTMLScrollFrame::nsHTMLScrollFrame(ComputedStyle* aStyle,
+ nsPresContext* aPresContext,
+ nsIFrame::ClassID aID, bool aIsRoot)
+ : nsContainerFrame(aStyle, aPresContext, aID),
+ mHScrollbarBox(nullptr),
+ mVScrollbarBox(nullptr),
+ mScrolledFrame(nullptr),
+ mScrollCornerBox(nullptr),
+ mResizerBox(nullptr),
+ mReferenceFrameDuringPainting(nullptr),
+ mAsyncScroll(nullptr),
+ mAsyncSmoothMSDScroll(nullptr),
+ mLastScrollOrigin(ScrollOrigin::None),
+ mDestination(0, 0),
+ mRestorePos(-1, -1),
+ mLastPos(-1, -1),
+ mApzScrollPos(0, 0),
+ mLastUpdateFramesPos(-1, -1),
+ mDisplayPortAtLastFrameUpdate(),
+ mScrollParentID(mozilla::layers::ScrollableLayerGuid::NULL_SCROLL_ID),
+ mAnchor(this),
+ mCurrentAPZScrollAnimationType(APZScrollAnimationType::No),
+ mIsFirstScrollableFrameSequenceNumber(Nothing()),
+ mInScrollingGesture(InScrollingGesture::No),
+ mAllowScrollOriginDowngrade(false),
+ mHadDisplayPortAtLastFrameUpdate(false),
+ mHasVerticalScrollbar(false),
+ mHasHorizontalScrollbar(false),
+ mOnlyNeedVScrollbarToScrollVVInsideLV(false),
+ mOnlyNeedHScrollbarToScrollVVInsideLV(false),
+ mFrameIsUpdatingScrollbar(false),
+ mDidHistoryRestore(false),
+ mIsRoot(aIsRoot),
+ mSuppressScrollbarUpdate(false),
+ mSkippedScrollbarLayout(false),
+ mHadNonInitialReflow(false),
+ mFirstReflow(true),
+ mHorizontalOverflow(false),
+ mVerticalOverflow(false),
+ mPostedReflowCallback(false),
+ mMayHaveDirtyFixedChildren(false),
+ mUpdateScrollbarAttributes(false),
+ mHasBeenScrolledRecently(false),
+ mWillBuildScrollableLayer(false),
+ mIsParentToActiveScrollFrames(false),
+ mHasBeenScrolled(false),
+ mIgnoreMomentumScroll(false),
+ mTransformingByAPZ(false),
+ mScrollableByAPZ(false),
+ mZoomableByAPZ(false),
+ mHasOutOfFlowContentInsideFilter(false),
+ mSuppressScrollbarRepaints(false),
+ mIsUsingMinimumScaleSize(false),
+ mMinimumScaleSizeChanged(false),
+ mProcessingScrollEvent(false),
+ mApzAnimationRequested(false),
+ mApzAnimationTriggeredByScriptRequested(false),
+ mReclampVVOffsetInReflowFinished(false),
+ mMayScheduleScrollAnimations(false),
+#ifdef MOZ_WIDGET_ANDROID
+ mHasVerticalOverflowForDynamicToolbar(false),
+#endif
+ mVelocityQueue(PresContext()) {
+ AppendScrollUpdate(ScrollPositionUpdate::NewScrollframe(nsPoint()));
+
+ if (UsesOverlayScrollbars()) {
+ mScrollbarActivity = new ScrollbarActivity(this);
+ }
+
+ if (mIsRoot) {
+ mZoomableByAPZ = PresShell()->GetZoomableByAPZ();
+ }
+}
+
+nsHTMLScrollFrame::~nsHTMLScrollFrame() = default;
+
+void nsHTMLScrollFrame::ScrollbarActivityStarted() const {
+ if (mScrollbarActivity) {
+ mScrollbarActivity->ActivityStarted();
+ }
+}
+
+void nsHTMLScrollFrame::ScrollbarActivityStopped() const {
+ if (mScrollbarActivity) {
+ mScrollbarActivity->ActivityStopped();
+ }
+}
+
+void nsHTMLScrollFrame::Destroy(DestroyContext& aContext) {
+ DestroyAbsoluteFrames(aContext);
+ if (mIsRoot) {
+ PresShell()->ResetVisualViewportOffset();
+ }
+
+ mAnchor.Destroy();
+
+ if (mScrollbarActivity) {
+ mScrollbarActivity->Destroy();
+ mScrollbarActivity = nullptr;
+ }
+
+ // Unbind the content created in CreateAnonymousContent later...
+ aContext.AddAnonymousContent(mHScrollbarContent.forget());
+ aContext.AddAnonymousContent(mVScrollbarContent.forget());
+ aContext.AddAnonymousContent(mScrollCornerContent.forget());
+ aContext.AddAnonymousContent(mResizerContent.forget());
+
+ if (mPostedReflowCallback) {
+ PresShell()->CancelReflowCallback(this);
+ mPostedReflowCallback = false;
+ }
+
+ if (mDisplayPortExpiryTimer) {
+ mDisplayPortExpiryTimer->Cancel();
+ mDisplayPortExpiryTimer = nullptr;
+ }
+ if (mActivityExpirationState.IsTracked()) {
+ gScrollFrameActivityTracker->RemoveObject(this);
+ }
+ if (gScrollFrameActivityTracker && gScrollFrameActivityTracker->IsEmpty()) {
+ gScrollFrameActivityTracker = nullptr;
+ }
+
+ if (mScrollActivityTimer) {
+ mScrollActivityTimer->Cancel();
+ mScrollActivityTimer = nullptr;
+ }
+ RemoveObservers();
+ if (mScrollEvent) {
+ mScrollEvent->Revoke();
+ }
+ if (mScrollEndEvent) {
+ mScrollEndEvent->Revoke();
+ }
+ nsContainerFrame::Destroy(aContext);
+}
+
+void nsHTMLScrollFrame::SetInitialChildList(ChildListID aListID,
+ nsFrameList&& aChildList) {
+ nsContainerFrame::SetInitialChildList(aListID, std::move(aChildList));
+ ReloadChildFrames();
+}
+
+void nsHTMLScrollFrame::AppendFrames(ChildListID aListID,
+ nsFrameList&& aFrameList) {
+ NS_ASSERTION(aListID == FrameChildListID::Principal,
+ "Only main list supported");
+ mFrames.AppendFrames(nullptr, std::move(aFrameList));
+ ReloadChildFrames();
+}
+
+void nsHTMLScrollFrame::InsertFrames(ChildListID aListID, nsIFrame* aPrevFrame,
+ const nsLineList::iterator* aPrevFrameLine,
+ nsFrameList&& aFrameList) {
+ NS_ASSERTION(aListID == FrameChildListID::Principal,
+ "Only main list supported");
+ NS_ASSERTION(!aPrevFrame || aPrevFrame->GetParent() == this,
+ "inserting after sibling frame with different parent");
+ mFrames.InsertFrames(nullptr, aPrevFrame, std::move(aFrameList));
+ ReloadChildFrames();
+}
+
+void nsHTMLScrollFrame::RemoveFrame(DestroyContext& aContext,
+ ChildListID aListID, nsIFrame* aOldFrame) {
+ NS_ASSERTION(aListID == FrameChildListID::Principal,
+ "Only main list supported");
+ mFrames.DestroyFrame(aContext, aOldFrame);
+ ReloadChildFrames();
+}
+
+/**
+ HTML scrolling implementation
+
+ All other things being equal, we prefer layouts with fewer scrollbars showing.
+*/
+
+namespace mozilla {
+
+enum class ShowScrollbar : uint8_t {
+ Auto,
+ Always,
+ // Never is a misnomer. We can still get a scrollbar if we need to scroll the
+ // visual viewport inside the layout viewport. Thus this enum is best thought
+ // of as value used by layout, which does not know about the visual viewport.
+ // The visual viewport does not affect any layout sizes, so this is sound.
+ Never,
+};
+
+static ShowScrollbar ShouldShowScrollbar(StyleOverflow aOverflow) {
+ switch (aOverflow) {
+ case StyleOverflow::Scroll:
+ return ShowScrollbar::Always;
+ case StyleOverflow::Hidden:
+ return ShowScrollbar::Never;
+ default:
+ case StyleOverflow::Auto:
+ return ShowScrollbar::Auto;
+ }
+}
+
+struct MOZ_STACK_CLASS ScrollReflowInput {
+ // === Filled in by the constructor. Members in this section shouldn't change
+ // their values after the constructor. ===
+ const ReflowInput& mReflowInput;
+ ShowScrollbar mHScrollbar;
+ // If the horizontal scrollbar is allowed (even if mHScrollbar ==
+ // ShowScrollbar::Never) provided that it is for scrolling the visual viewport
+ // inside the layout viewport only.
+ bool mHScrollbarAllowedForScrollingVVInsideLV = true;
+ ShowScrollbar mVScrollbar;
+ // If the vertical scrollbar is allowed (even if mVScrollbar ==
+ // ShowScrollbar::Never) provided that it is for scrolling the visual viewport
+ // inside the layout viewport only.
+ bool mVScrollbarAllowedForScrollingVVInsideLV = true;
+ nsMargin mComputedBorder;
+
+ // === Filled in by ReflowScrolledFrame ===
+ OverflowAreas mContentsOverflowAreas;
+ // The scrollbar gutter sizes used in the most recent reflow of
+ // mScrolledFrame. The writing-mode is the same as the scroll
+ // container.
+ LogicalMargin mScrollbarGutterFromLastReflow;
+ // True if the most recent reflow of mScrolledFrame is with the
+ // horizontal scrollbar.
+ bool mReflowedContentsWithHScrollbar = false;
+ // True if the most recent reflow of mScrolledFrame is with the
+ // vertical scrollbar.
+ bool mReflowedContentsWithVScrollbar = false;
+
+ // === Filled in when TryLayout succeeds ===
+ // The size of the inside-border area
+ nsSize mInsideBorderSize;
+ // Whether we decided to show the horizontal scrollbar in the most recent
+ // TryLayout.
+ bool mShowHScrollbar = false;
+ // Whether we decided to show the vertical scrollbar in the most recent
+ // TryLayout.
+ bool mShowVScrollbar = false;
+ // If mShow(H|V)Scrollbar is true then
+ // mOnlyNeed(V|H)ScrollbarToScrollVVInsideLV indicates if the only reason we
+ // need that scrollbar is to scroll the visual viewport inside the layout
+ // viewport. These scrollbars are special in that even if they are layout
+ // scrollbars they do not take up any layout space.
+ bool mOnlyNeedHScrollbarToScrollVVInsideLV = false;
+ bool mOnlyNeedVScrollbarToScrollVVInsideLV = false;
+
+ ScrollReflowInput(nsHTMLScrollFrame* aFrame, const ReflowInput& aReflowInput);
+
+ nscoord VScrollbarMinHeight() const { return mVScrollbarPrefSize.height; }
+ nscoord VScrollbarPrefWidth() const { return mVScrollbarPrefSize.width; }
+ nscoord HScrollbarMinWidth() const { return mHScrollbarPrefSize.width; }
+ nscoord HScrollbarPrefHeight() const { return mHScrollbarPrefSize.height; }
+
+ // Returns the sizes occupied by the scrollbar gutters. If aShowVScroll or
+ // aShowHScroll is true, the sizes occupied by the scrollbars are also
+ // included.
+ nsMargin ScrollbarGutter(bool aShowVScrollbar, bool aShowHScrollbar,
+ bool aScrollbarOnRight) const {
+ if (mOverlayScrollbars) {
+ return mScrollbarGutter;
+ }
+ nsMargin gutter = mScrollbarGutter;
+ if (aShowVScrollbar && gutter.right == 0 && gutter.left == 0) {
+ const nscoord w = VScrollbarPrefWidth();
+ if (aScrollbarOnRight) {
+ gutter.right = w;
+ } else {
+ gutter.left = w;
+ }
+ }
+ if (aShowHScrollbar && gutter.bottom == 0) {
+ // The horizontal scrollbar is always at the bottom side.
+ gutter.bottom = HScrollbarPrefHeight();
+ }
+ return gutter;
+ }
+
+ bool OverlayScrollbars() const { return mOverlayScrollbars; }
+
+ private:
+ // Filled in by the constructor. Put variables here to keep them unchanged
+ // after initializing them in the constructor.
+ nsSize mVScrollbarPrefSize;
+ nsSize mHScrollbarPrefSize;
+ bool mOverlayScrollbars = false;
+ // The scrollbar gutter sizes resolved from the scrollbar-gutter and
+ // scrollbar-width property.
+ nsMargin mScrollbarGutter;
+};
+
+ScrollReflowInput::ScrollReflowInput(nsHTMLScrollFrame* aFrame,
+ const ReflowInput& aReflowInput)
+ : mReflowInput(aReflowInput),
+ mComputedBorder(aReflowInput.ComputedPhysicalBorderPadding() -
+ aReflowInput.ComputedPhysicalPadding()),
+ mScrollbarGutterFromLastReflow(aFrame->GetWritingMode()) {
+ ScrollStyles styles = aFrame->GetScrollStyles();
+ mHScrollbar = ShouldShowScrollbar(styles.mHorizontal);
+ mVScrollbar = ShouldShowScrollbar(styles.mVertical);
+ mOverlayScrollbars = aFrame->UsesOverlayScrollbars();
+
+ if (nsScrollbarFrame* scrollbar = aFrame->GetScrollbarBox(false)) {
+ scrollbar->SetScrollbarMediatorContent(mReflowInput.mFrame->GetContent());
+ mHScrollbarPrefSize = scrollbar->ScrollbarMinSize();
+ // A zero minimum size is a bug with non-overlay scrollbars. That means
+ // we'll always try to place the scrollbar, even if it will ultimately not
+ // fit, see bug 1809630. XUL collapsing is the exception because the
+ // front-end uses it.
+ MOZ_ASSERT(mHScrollbarPrefSize.width && mHScrollbarPrefSize.height,
+ "Shouldn't have a zero horizontal scrollbar-size");
+ } else {
+ mHScrollbar = ShowScrollbar::Never;
+ mHScrollbarAllowedForScrollingVVInsideLV = false;
+ }
+ if (nsScrollbarFrame* scrollbar = aFrame->GetScrollbarBox(true)) {
+ scrollbar->SetScrollbarMediatorContent(mReflowInput.mFrame->GetContent());
+ mVScrollbarPrefSize = scrollbar->ScrollbarMinSize();
+ // See above.
+ MOZ_ASSERT(mVScrollbarPrefSize.width && mVScrollbarPrefSize.height,
+ "Shouldn't have a zero vertical scrollbar-size");
+ } else {
+ mVScrollbar = ShowScrollbar::Never;
+ mVScrollbarAllowedForScrollingVVInsideLV = false;
+ }
+
+ const auto* scrollbarStyle =
+ nsLayoutUtils::StyleForScrollbar(mReflowInput.mFrame);
+ // Hide the scrollbar when the scrollbar-width is set to none.
+ //
+ // Note: In some cases this is unnecessary, because scrollbar-width:none
+ // makes us suppress scrollbars in CreateAnonymousContent. But if this frame
+ // initially had a non-'none' scrollbar-width and dynamically changed to
+ // 'none', then we'll need to handle it here.
+ if (scrollbarStyle->StyleUIReset()->ScrollbarWidth() ==
+ StyleScrollbarWidth::None) {
+ mHScrollbar = ShowScrollbar::Never;
+ mHScrollbarAllowedForScrollingVVInsideLV = false;
+ mVScrollbar = ShowScrollbar::Never;
+ mVScrollbarAllowedForScrollingVVInsideLV = false;
+ } else if (const auto& scrollbarGutterStyle =
+ scrollbarStyle->StyleDisplay()->mScrollbarGutter;
+ scrollbarGutterStyle && !mOverlayScrollbars) {
+ const auto stable =
+ bool(scrollbarGutterStyle & StyleScrollbarGutter::STABLE);
+ const auto bothEdges =
+ bool(scrollbarGutterStyle & StyleScrollbarGutter::BOTH_EDGES);
+
+ if (mReflowInput.GetWritingMode().IsVertical()) {
+ const nscoord h = HScrollbarPrefHeight();
+ if (bothEdges) {
+ mScrollbarGutter.top = mScrollbarGutter.bottom = h;
+ } else if (stable) {
+ // The horizontal scrollbar gutter is always at the bottom side.
+ mScrollbarGutter.bottom = h;
+ }
+ } else {
+ const nscoord w = VScrollbarPrefWidth();
+ if (bothEdges) {
+ mScrollbarGutter.left = mScrollbarGutter.right = w;
+ } else if (stable) {
+ if (aFrame->IsScrollbarOnRight()) {
+ mScrollbarGutter.right = w;
+ } else {
+ mScrollbarGutter.left = w;
+ }
+ }
+ }
+ }
+}
+
+} // namespace mozilla
+
+// XXXldb Can this go away?
+static nsSize ComputeInsideBorderSize(const ScrollReflowInput& aState,
+ const nsSize& aDesiredInsideBorderSize) {
+ // aDesiredInsideBorderSize is the frame size; i.e., it includes
+ // borders and padding (but the scrolled child doesn't have
+ // borders). The scrolled child has the same padding as us.
+ nscoord contentWidth = aState.mReflowInput.ComputedWidth();
+ if (contentWidth == NS_UNCONSTRAINEDSIZE) {
+ contentWidth = aDesiredInsideBorderSize.width -
+ aState.mReflowInput.ComputedPhysicalPadding().LeftRight();
+ }
+ nscoord contentHeight = aState.mReflowInput.ComputedHeight();
+ if (contentHeight == NS_UNCONSTRAINEDSIZE) {
+ contentHeight = aDesiredInsideBorderSize.height -
+ aState.mReflowInput.ComputedPhysicalPadding().TopBottom();
+ }
+
+ contentWidth = aState.mReflowInput.ApplyMinMaxWidth(contentWidth);
+ contentHeight = aState.mReflowInput.ApplyMinMaxHeight(contentHeight);
+ return nsSize(
+ contentWidth + aState.mReflowInput.ComputedPhysicalPadding().LeftRight(),
+ contentHeight +
+ aState.mReflowInput.ComputedPhysicalPadding().TopBottom());
+}
+
+/**
+ * Assuming that we know the metrics for our wrapped frame and
+ * whether the horizontal and/or vertical scrollbars are present,
+ * compute the resulting layout and return true if the layout is
+ * consistent. If the layout is consistent then we fill in the
+ * computed fields of the ScrollReflowInput.
+ *
+ * The layout is consistent when both scrollbars are showing if and only
+ * if they should be showing. A horizontal scrollbar should be showing if all
+ * following conditions are met:
+ * 1) the style is not HIDDEN
+ * 2) our inside-border height is at least the scrollbar height (i.e., the
+ * scrollbar fits vertically)
+ * 3) the style is SCROLL, or the kid's overflow-area XMost is
+ * greater than the scrollport width
+ *
+ * @param aForce if true, then we just assume the layout is consistent.
+ */
+bool nsHTMLScrollFrame::TryLayout(ScrollReflowInput& aState,
+ ReflowOutput* aKidMetrics,
+ bool aAssumeHScroll, bool aAssumeVScroll,
+ bool aForce) {
+ if ((aState.mVScrollbar == ShowScrollbar::Never && aAssumeVScroll) ||
+ (aState.mHScrollbar == ShowScrollbar::Never && aAssumeHScroll)) {
+ NS_ASSERTION(!aForce, "Shouldn't be forcing a hidden scrollbar to show!");
+ return false;
+ }
+
+ const auto wm = GetWritingMode();
+ const nsMargin scrollbarGutter = aState.ScrollbarGutter(
+ aAssumeVScroll, aAssumeHScroll, IsScrollbarOnRight());
+ const LogicalMargin logicalScrollbarGutter(wm, scrollbarGutter);
+
+ const bool inlineEndsGutterChanged =
+ aState.mScrollbarGutterFromLastReflow.IStartEnd(wm) !=
+ logicalScrollbarGutter.IStartEnd(wm);
+ const bool blockEndsGutterChanged =
+ aState.mScrollbarGutterFromLastReflow.BStartEnd(wm) !=
+ logicalScrollbarGutter.BStartEnd(wm);
+ const bool shouldReflowScrolledFrame =
+ inlineEndsGutterChanged ||
+ (blockEndsGutterChanged && ScrolledContentDependsOnBSize(aState));
+
+ if (shouldReflowScrolledFrame) {
+ if (blockEndsGutterChanged) {
+ nsLayoutUtils::MarkIntrinsicISizesDirtyIfDependentOnBSize(mScrolledFrame);
+ }
+ aKidMetrics->mOverflowAreas.Clear();
+ ROOT_SCROLLBAR_LOG(
+ "TryLayout reflowing scrolled frame with scrollbars h=%d, v=%d\n",
+ aAssumeHScroll, aAssumeVScroll);
+ ReflowScrolledFrame(aState, aAssumeHScroll, aAssumeVScroll, aKidMetrics);
+ }
+
+ const nsSize scrollbarGutterSize(scrollbarGutter.LeftRight(),
+ scrollbarGutter.TopBottom());
+
+ // First, compute our inside-border size and scrollport size
+ // XXXldb Can we depend more on ComputeSize here?
+ nsSize kidSize = GetContainSizeAxes().ContainSize(
+ aKidMetrics->PhysicalSize(), *aState.mReflowInput.mFrame);
+ const nsSize desiredInsideBorderSize = kidSize + scrollbarGutterSize;
+ aState.mInsideBorderSize =
+ ComputeInsideBorderSize(aState, desiredInsideBorderSize);
+
+ nsSize layoutSize =
+ mIsUsingMinimumScaleSize ? mMinimumScaleSize : aState.mInsideBorderSize;
+
+ const nsSize scrollPortSize =
+ Max(nsSize(0, 0), layoutSize - scrollbarGutterSize);
+ if (mIsUsingMinimumScaleSize) {
+ mICBSize =
+ Max(nsSize(0, 0), aState.mInsideBorderSize - scrollbarGutterSize);
+ }
+
+ nsSize visualViewportSize = scrollPortSize;
+ ROOT_SCROLLBAR_LOG("TryLayout with VV %s\n",
+ ToString(visualViewportSize).c_str());
+ mozilla::PresShell* presShell = PresShell();
+ // Note: we check for a non-null MobileViepwortManager here, but ideally we
+ // should be able to drop that clause as well. It's just that in some cases
+ // with extension popups the composition size comes back as stale, because
+ // the content viewer is only resized after the popup contents are reflowed.
+ // That case also happens to have no APZ and no MVM, so we use that as a
+ // way to detect the scenario. Bug 1648669 tracks removing this clause.
+ if (mIsRoot && presShell->GetMobileViewportManager()) {
+ visualViewportSize = nsLayoutUtils::CalculateCompositionSizeForFrame(
+ this, false, &layoutSize);
+ visualViewportSize =
+ Max(nsSize(0, 0), visualViewportSize - scrollbarGutterSize);
+
+ float resolution = presShell->GetResolution();
+ visualViewportSize.width /= resolution;
+ visualViewportSize.height /= resolution;
+ ROOT_SCROLLBAR_LOG("TryLayout now with VV %s\n",
+ ToString(visualViewportSize).c_str());
+ }
+
+ nsRect overflowRect = aState.mContentsOverflowAreas.ScrollableOverflow();
+ // If the content height expanded by the minimum-scale will be taller than
+ // the scrollable overflow area, we need to expand the area here to tell
+ // properly whether we need to render the overlay vertical scrollbar.
+ // NOTE: This expanded size should NOT be used for non-overley scrollbars
+ // cases since putting the vertical non-overlay scrollbar will make the
+ // content width narrow a little bit, which in turn the minimum scale value
+ // becomes a bit bigger than before, then the vertical scrollbar is no longer
+ // needed, which means the content width becomes the original width, then the
+ // minimum-scale is changed to the original one, and so forth.
+ if (UsesOverlayScrollbars() && mIsUsingMinimumScaleSize &&
+ mMinimumScaleSize.height > overflowRect.YMost()) {
+ overflowRect.height += mMinimumScaleSize.height - overflowRect.YMost();
+ }
+ nsRect scrolledRect =
+ GetUnsnappedScrolledRectInternal(overflowRect, scrollPortSize);
+ ROOT_SCROLLBAR_LOG(
+ "TryLayout scrolledRect:%s overflowRect:%s scrollportSize:%s\n",
+ ToString(scrolledRect).c_str(), ToString(overflowRect).c_str(),
+ ToString(scrollPortSize).c_str());
+ nscoord oneDevPixel = PresContext()->DevPixelsToAppUnits(1);
+
+ bool showHScrollbar = aAssumeHScroll;
+ bool showVScrollbar = aAssumeVScroll;
+ if (!aForce) {
+ nsSize sizeToCompare = visualViewportSize;
+ if (gfxPlatform::UseDesktopZoomingScrollbars()) {
+ sizeToCompare = scrollPortSize;
+ }
+
+ // No need to compute showHScrollbar if we got ShowScrollbar::Never.
+ if (aState.mHScrollbar != ShowScrollbar::Never) {
+ showHScrollbar =
+ aState.mHScrollbar == ShowScrollbar::Always ||
+ scrolledRect.XMost() >= sizeToCompare.width + oneDevPixel ||
+ scrolledRect.x <= -oneDevPixel;
+ // TODO(emilio): This should probably check this scrollbar's minimum size
+ // in both axes, for consistency?
+ if (aState.mHScrollbar == ShowScrollbar::Auto &&
+ scrollPortSize.width < aState.HScrollbarMinWidth()) {
+ showHScrollbar = false;
+ }
+ ROOT_SCROLLBAR_LOG("TryLayout wants H Scrollbar: %d =? %d\n",
+ showHScrollbar, aAssumeHScroll);
+ }
+
+ // No need to compute showVScrollbar if we got ShowScrollbar::Never.
+ if (aState.mVScrollbar != ShowScrollbar::Never) {
+ showVScrollbar =
+ aState.mVScrollbar == ShowScrollbar::Always ||
+ scrolledRect.YMost() >= sizeToCompare.height + oneDevPixel ||
+ scrolledRect.y <= -oneDevPixel;
+ // TODO(emilio): This should probably check this scrollbar's minimum size
+ // in both axes, for consistency?
+ if (aState.mVScrollbar == ShowScrollbar::Auto &&
+ scrollPortSize.height < aState.VScrollbarMinHeight()) {
+ showVScrollbar = false;
+ }
+ ROOT_SCROLLBAR_LOG("TryLayout wants V Scrollbar: %d =? %d\n",
+ showVScrollbar, aAssumeVScroll);
+ }
+
+ if (showHScrollbar != aAssumeHScroll || showVScrollbar != aAssumeVScroll) {
+ const nsMargin wantedScrollbarGutter = aState.ScrollbarGutter(
+ showVScrollbar, showHScrollbar, IsScrollbarOnRight());
+ // We report an inconsistent layout only when the desired visibility of
+ // the scrollbars can change the size of the scrollbar gutters.
+ if (scrollbarGutter != wantedScrollbarGutter) {
+ return false;
+ }
+ }
+ }
+
+ // If we reach here, the layout is consistent. Record the desired visibility
+ // of the scrollbars.
+ aState.mShowHScrollbar = showHScrollbar;
+ aState.mShowVScrollbar = showVScrollbar;
+ const nsPoint scrollPortOrigin(
+ aState.mComputedBorder.left + scrollbarGutter.left,
+ aState.mComputedBorder.top + scrollbarGutter.top);
+ SetScrollPort(nsRect(scrollPortOrigin, scrollPortSize));
+
+ if (mIsRoot && gfxPlatform::UseDesktopZoomingScrollbars()) {
+ bool vvChanged = true;
+ const bool overlay = aState.OverlayScrollbars();
+ // This loop can run at most twice since we can only add a scrollbar once.
+ // At this point we've already decided that this layout is consistent so we
+ // will return true. Scrollbars added here never take up layout space even
+ // if they are layout scrollbars so any changes made here will not make us
+ // return false.
+ while (vvChanged) {
+ vvChanged = false;
+ if (!aState.mShowHScrollbar &&
+ aState.mHScrollbarAllowedForScrollingVVInsideLV) {
+ if (ScrollPort().width >= visualViewportSize.width + oneDevPixel &&
+ (overlay ||
+ visualViewportSize.width >= aState.HScrollbarMinWidth())) {
+ vvChanged = true;
+ if (!overlay) {
+ visualViewportSize.height -= aState.HScrollbarPrefHeight();
+ }
+ aState.mShowHScrollbar = true;
+ aState.mOnlyNeedHScrollbarToScrollVVInsideLV = true;
+ ROOT_SCROLLBAR_LOG("TryLayout added H scrollbar for VV, VV now %s\n",
+ ToString(visualViewportSize).c_str());
+ }
+ }
+
+ if (!aState.mShowVScrollbar &&
+ aState.mVScrollbarAllowedForScrollingVVInsideLV) {
+ if (ScrollPort().height >= visualViewportSize.height + oneDevPixel &&
+ (overlay ||
+ visualViewportSize.height >= aState.VScrollbarMinHeight())) {
+ vvChanged = true;
+ if (!overlay) {
+ visualViewportSize.width -= aState.VScrollbarPrefWidth();
+ }
+ aState.mShowVScrollbar = true;
+ aState.mOnlyNeedVScrollbarToScrollVVInsideLV = true;
+ ROOT_SCROLLBAR_LOG("TryLayout added V scrollbar for VV, VV now %s\n",
+ ToString(visualViewportSize).c_str());
+ }
+ }
+ }
+ }
+
+ return true;
+}
+
+bool nsHTMLScrollFrame::ScrolledContentDependsOnBSize(
+ const ScrollReflowInput& aState) const {
+ return mScrolledFrame->HasAnyStateBits(
+ NS_FRAME_CONTAINS_RELATIVE_BSIZE |
+ NS_FRAME_DESCENDANT_INTRINSIC_ISIZE_DEPENDS_ON_BSIZE) ||
+ aState.mReflowInput.ComputedBSize() != NS_UNCONSTRAINEDSIZE ||
+ aState.mReflowInput.ComputedMinBSize() > 0 ||
+ aState.mReflowInput.ComputedMaxBSize() != NS_UNCONSTRAINEDSIZE;
+}
+
+void nsHTMLScrollFrame::ReflowScrolledFrame(ScrollReflowInput& aState,
+ bool aAssumeHScroll,
+ bool aAssumeVScroll,
+ ReflowOutput* aMetrics) {
+ const WritingMode wm = GetWritingMode();
+
+ // these could be NS_UNCONSTRAINEDSIZE ... std::min arithmetic should
+ // be OK
+ LogicalMargin padding = aState.mReflowInput.ComputedLogicalPadding(wm);
+ nscoord availISize =
+ aState.mReflowInput.ComputedISize() + padding.IStartEnd(wm);
+
+ nscoord computedBSize = aState.mReflowInput.ComputedBSize();
+ nscoord computedMinBSize = aState.mReflowInput.ComputedMinBSize();
+ nscoord computedMaxBSize = aState.mReflowInput.ComputedMaxBSize();
+ if (!ShouldPropagateComputedBSizeToScrolledContent()) {
+ computedBSize = NS_UNCONSTRAINEDSIZE;
+ computedMinBSize = 0;
+ computedMaxBSize = NS_UNCONSTRAINEDSIZE;
+ }
+
+ const LogicalMargin scrollbarGutter(
+ wm, aState.ScrollbarGutter(aAssumeVScroll, aAssumeHScroll,
+ IsScrollbarOnRight()));
+ if (const nscoord inlineEndsGutter = scrollbarGutter.IStartEnd(wm);
+ inlineEndsGutter > 0) {
+ availISize = std::max(0, availISize - inlineEndsGutter);
+ }
+ if (const nscoord blockEndsGutter = scrollbarGutter.BStartEnd(wm);
+ blockEndsGutter > 0) {
+ if (computedBSize != NS_UNCONSTRAINEDSIZE) {
+ computedBSize = std::max(0, computedBSize - blockEndsGutter);
+ }
+ computedMinBSize = std::max(0, computedMinBSize - blockEndsGutter);
+ if (computedMaxBSize != NS_UNCONSTRAINEDSIZE) {
+ computedMaxBSize = std::max(0, computedMaxBSize - blockEndsGutter);
+ }
+ }
+
+ nsPresContext* presContext = PresContext();
+
+ // Pass InitFlags::CallerWillInit so we can pass in the correct padding.
+ ReflowInput kidReflowInput(presContext, aState.mReflowInput, mScrolledFrame,
+ LogicalSize(wm, availISize, NS_UNCONSTRAINEDSIZE),
+ Nothing(), ReflowInput::InitFlag::CallerWillInit);
+ const WritingMode kidWM = kidReflowInput.GetWritingMode();
+ kidReflowInput.Init(presContext, Nothing(), Nothing(),
+ Some(padding.ConvertTo(kidWM, wm)));
+ kidReflowInput.mFlags.mAssumingHScrollbar = aAssumeHScroll;
+ kidReflowInput.mFlags.mAssumingVScrollbar = aAssumeVScroll;
+ kidReflowInput.mFlags.mTreatBSizeAsIndefinite =
+ aState.mReflowInput.mFlags.mTreatBSizeAsIndefinite;
+ kidReflowInput.SetComputedBSize(computedBSize);
+ kidReflowInput.SetComputedMinBSize(computedMinBSize);
+ kidReflowInput.SetComputedMaxBSize(computedMaxBSize);
+ if (aState.mReflowInput.IsBResizeForWM(kidWM)) {
+ kidReflowInput.SetBResize(true);
+ }
+ if (aState.mReflowInput.IsBResizeForPercentagesForWM(kidWM)) {
+ kidReflowInput.mFlags.mIsBResizeForPercentages = true;
+ }
+
+ // Temporarily set mHasHorizontalScrollbar/mHasVerticalScrollbar to
+ // reflect our assumptions while we reflow the child.
+ bool didHaveHorizontalScrollbar = mHasHorizontalScrollbar;
+ bool didHaveVerticalScrollbar = mHasVerticalScrollbar;
+ mHasHorizontalScrollbar = aAssumeHScroll;
+ mHasVerticalScrollbar = aAssumeVScroll;
+
+ nsReflowStatus status;
+ // No need to pass a true container-size to ReflowChild or
+ // FinishReflowChild, because it's only used there when positioning
+ // the frame (i.e. if ReflowChildFlags::NoMoveFrame isn't set)
+ const nsSize dummyContainerSize;
+ ReflowChild(mScrolledFrame, presContext, *aMetrics, kidReflowInput, wm,
+ LogicalPoint(wm), dummyContainerSize,
+ ReflowChildFlags::NoMoveFrame, status);
+
+ mHasHorizontalScrollbar = didHaveHorizontalScrollbar;
+ mHasVerticalScrollbar = didHaveVerticalScrollbar;
+
+ // Don't resize or position the view (if any) because we're going to resize
+ // it to the correct size anyway in PlaceScrollArea. Allowing it to
+ // resize here would size it to the natural height of the frame,
+ // which will usually be different from the scrollport height;
+ // invalidating the difference will cause unnecessary repainting.
+ FinishReflowChild(
+ mScrolledFrame, presContext, *aMetrics, &kidReflowInput, wm,
+ LogicalPoint(wm), dummyContainerSize,
+ ReflowChildFlags::NoMoveFrame | ReflowChildFlags::NoSizeView);
+
+ if (mScrolledFrame->HasAnyStateBits(NS_FRAME_CONTAINS_RELATIVE_BSIZE)) {
+ // Propagate NS_FRAME_CONTAINS_RELATIVE_BSIZE from our inner scrolled frame
+ // to ourselves so that our containing block is aware of it.
+ //
+ // Note: If the scrolled frame has any child whose block-size depends on the
+ // containing block's block-size, the NS_FRAME_CONTAINS_RELATIVE_BSIZE bit
+ // is set on the scrolled frame when initializing the child's ReflowInput in
+ // ReflowInput::InitResizeFlags(). Therefore, we propagate the bit here
+ // after we reflowed the scrolled frame.
+ AddStateBits(NS_FRAME_CONTAINS_RELATIVE_BSIZE);
+ }
+
+ // XXX Some frames (e.g. nsFrameFrame, nsTextFrame) don't
+ // bother setting their mOverflowArea. This is wrong because every frame
+ // should always set mOverflowArea. In fact nsFrameFrame doesn't
+ // support the 'outline' property because of this. Rather than fix the
+ // world right now, just fix up the overflow area if necessary. Note that we
+ // don't check HasOverflowRect() because it could be set even though the
+ // overflow area doesn't include the frame bounds.
+ aMetrics->UnionOverflowAreasWithDesiredBounds();
+
+ auto* disp = StyleDisplay();
+ if (MOZ_UNLIKELY(disp->mOverflowClipBoxInline ==
+ StyleOverflowClipBox::ContentBox)) {
+ // The scrolled frame is scrollable in the inline axis with
+ // `overflow-clip-box:content-box`. To prevent its content from being
+ // clipped at the scroll container's padding edges, we inflate its
+ // children's scrollable overflow area with its inline padding, and union
+ // its scrollable overflow area with its children's inflated scrollable
+ // overflow area.
+ OverflowAreas childOverflow;
+ mScrolledFrame->UnionChildOverflow(childOverflow);
+ nsRect childScrollableOverflow = childOverflow.ScrollableOverflow();
+
+ const LogicalMargin inlinePadding =
+ padding.ApplySkipSides(LogicalSides(wm, eLogicalSideBitsBBoth));
+ childScrollableOverflow.Inflate(inlinePadding.GetPhysicalMargin(wm));
+
+ nsRect& so = aMetrics->ScrollableOverflow();
+ so = so.UnionEdges(childScrollableOverflow);
+ }
+
+ aState.mContentsOverflowAreas = aMetrics->mOverflowAreas;
+ aState.mScrollbarGutterFromLastReflow = scrollbarGutter;
+ aState.mReflowedContentsWithHScrollbar = aAssumeHScroll;
+ aState.mReflowedContentsWithVScrollbar = aAssumeVScroll;
+}
+
+bool nsHTMLScrollFrame::GuessHScrollbarNeeded(const ScrollReflowInput& aState) {
+ if (aState.mHScrollbar != ShowScrollbar::Auto) {
+ // no guessing required
+ return aState.mHScrollbar == ShowScrollbar::Always;
+ }
+ // We only care about scrollbars that might take up space when trying to guess
+ // if we need a scrollbar, so we ignore scrollbars only created to scroll the
+ // visual viewport inside the layout viewport because they take up no layout
+ // space.
+ return mHasHorizontalScrollbar && !mOnlyNeedHScrollbarToScrollVVInsideLV;
+}
+
+bool nsHTMLScrollFrame::GuessVScrollbarNeeded(const ScrollReflowInput& aState) {
+ if (aState.mVScrollbar != ShowScrollbar::Auto) {
+ // no guessing required
+ return aState.mVScrollbar == ShowScrollbar::Always;
+ }
+
+ // If we've had at least one non-initial reflow, then just assume
+ // the state of the vertical scrollbar will be what we determined
+ // last time.
+ if (mHadNonInitialReflow) {
+ // We only care about scrollbars that might take up space when trying to
+ // guess if we need a scrollbar, so we ignore scrollbars only created to
+ // scroll the visual viewport inside the layout viewport because they take
+ // up no layout space.
+ return mHasVerticalScrollbar && !mOnlyNeedVScrollbarToScrollVVInsideLV;
+ }
+
+ // If this is the initial reflow, guess false because usually
+ // we have very little content by then.
+ if (InInitialReflow()) return false;
+
+ if (mIsRoot) {
+ nsIFrame* f = mScrolledFrame->PrincipalChildList().FirstChild();
+ if (f && f->IsSVGOuterSVGFrame() &&
+ static_cast<SVGOuterSVGFrame*>(f)->VerticalScrollbarNotNeeded()) {
+ // Common SVG case - avoid a bad guess.
+ return false;
+ }
+ // Assume that there will be a scrollbar; it seems to me
+ // that 'most pages' do have a scrollbar, and anyway, it's cheaper
+ // to do an extra reflow for the pages that *don't* need a
+ // scrollbar (because on average they will have less content).
+ return true;
+ }
+
+ // For non-viewports, just guess that we don't need a scrollbar.
+ // XXX I wonder if statistically this is the right idea; I'm
+ // basically guessing that there are a lot of overflow:auto DIVs
+ // that get their intrinsic size and don't overflow
+ return false;
+}
+
+bool nsHTMLScrollFrame::InInitialReflow() const {
+ // We're in an initial reflow if NS_FRAME_FIRST_REFLOW is set, unless we're a
+ // root scrollframe. In that case we want to skip this clause altogether.
+ // The guess here is that there are lots of overflow:auto divs out there that
+ // end up auto-sizing so they don't overflow, and that the root basically
+ // always needs a scrollbar if it did last time we loaded this page (good
+ // assumption, because our initial reflow is no longer synchronous).
+ return !mIsRoot && HasAnyStateBits(NS_FRAME_FIRST_REFLOW);
+}
+
+void nsHTMLScrollFrame::ReflowContents(ScrollReflowInput& aState,
+ const ReflowOutput& aDesiredSize) {
+ const WritingMode desiredWm = aDesiredSize.GetWritingMode();
+ ReflowOutput kidDesiredSize(desiredWm);
+ ReflowScrolledFrame(aState, GuessHScrollbarNeeded(aState),
+ GuessVScrollbarNeeded(aState), &kidDesiredSize);
+
+ // There's an important special case ... if the child appears to fit
+ // in the inside-border rect (but overflows the scrollport), we
+ // should try laying it out without a vertical scrollbar. It will
+ // usually fit because making the available-width wider will not
+ // normally make the child taller. (The only situation I can think
+ // of is when you have a line containing %-width inline replaced
+ // elements whose percentages sum to more than 100%, so increasing
+ // the available width makes the line break where it was fitting
+ // before.) If we don't treat this case specially, then we will
+ // decide that showing scrollbars is OK because the content
+ // overflows when we're showing scrollbars and we won't try to
+ // remove the vertical scrollbar.
+
+ // Detecting when we enter this special case is important for when
+ // people design layouts that exactly fit the container "most of the
+ // time".
+
+ // XXX Is this check really sufficient to catch all the incremental cases
+ // where the ideal case doesn't have a scrollbar?
+ if ((aState.mReflowedContentsWithHScrollbar ||
+ aState.mReflowedContentsWithVScrollbar) &&
+ aState.mVScrollbar != ShowScrollbar::Always &&
+ aState.mHScrollbar != ShowScrollbar::Always) {
+ nsSize kidSize = GetContainSizeAxes().ContainSize(
+ kidDesiredSize.PhysicalSize(), *aState.mReflowInput.mFrame);
+ nsSize insideBorderSize = ComputeInsideBorderSize(aState, kidSize);
+ nsRect scrolledRect = GetUnsnappedScrolledRectInternal(
+ kidDesiredSize.ScrollableOverflow(), insideBorderSize);
+ if (nsRect(nsPoint(0, 0), insideBorderSize).Contains(scrolledRect)) {
+ // Let's pretend we had no scrollbars coming in here
+ kidDesiredSize.mOverflowAreas.Clear();
+ ReflowScrolledFrame(aState, false, false, &kidDesiredSize);
+ }
+ }
+
+ if (IsRootScrollFrameOfDocument()) {
+ UpdateMinimumScaleSize(aState.mContentsOverflowAreas.ScrollableOverflow(),
+ kidDesiredSize.PhysicalSize());
+ }
+
+ // Try vertical scrollbar settings that leave the vertical scrollbar
+ // unchanged. Do this first because changing the vertical scrollbar setting is
+ // expensive, forcing a reflow always.
+
+ // Try leaving the horizontal scrollbar unchanged first. This will be more
+ // efficient.
+ ROOT_SCROLLBAR_LOG("Trying layout1 with %d, %d\n",
+ aState.mReflowedContentsWithHScrollbar,
+ aState.mReflowedContentsWithVScrollbar);
+ if (TryLayout(aState, &kidDesiredSize, aState.mReflowedContentsWithHScrollbar,
+ aState.mReflowedContentsWithVScrollbar, false)) {
+ return;
+ }
+ ROOT_SCROLLBAR_LOG("Trying layout2 with %d, %d\n",
+ !aState.mReflowedContentsWithHScrollbar,
+ aState.mReflowedContentsWithVScrollbar);
+ if (TryLayout(aState, &kidDesiredSize,
+ !aState.mReflowedContentsWithHScrollbar,
+ aState.mReflowedContentsWithVScrollbar, false)) {
+ return;
+ }
+
+ // OK, now try toggling the vertical scrollbar. The performance advantage
+ // of trying the status-quo horizontal scrollbar state
+ // does not exist here (we'll have to reflow due to the vertical scrollbar
+ // change), so always try no horizontal scrollbar first.
+ bool newVScrollbarState = !aState.mReflowedContentsWithVScrollbar;
+ ROOT_SCROLLBAR_LOG("Trying layout3 with %d, %d\n", false, newVScrollbarState);
+ if (TryLayout(aState, &kidDesiredSize, false, newVScrollbarState, false)) {
+ return;
+ }
+ ROOT_SCROLLBAR_LOG("Trying layout4 with %d, %d\n", true, newVScrollbarState);
+ if (TryLayout(aState, &kidDesiredSize, true, newVScrollbarState, false)) {
+ return;
+ }
+
+ // OK, we're out of ideas. Try again enabling whatever scrollbars we can
+ // enable and force the layout to stick even if it's inconsistent.
+ // This just happens sometimes.
+ ROOT_SCROLLBAR_LOG("Giving up, adding both scrollbars...\n");
+ TryLayout(aState, &kidDesiredSize, aState.mHScrollbar != ShowScrollbar::Never,
+ aState.mVScrollbar != ShowScrollbar::Never, true);
+}
+
+void nsHTMLScrollFrame::PlaceScrollArea(ScrollReflowInput& aState,
+ const nsPoint& aScrollPosition) {
+ nsIFrame* scrolledFrame = mScrolledFrame;
+ // Set the x,y of the scrolled frame to the correct value
+ scrolledFrame->SetPosition(ScrollPort().TopLeft() - aScrollPosition);
+
+ // Recompute our scrollable overflow, taking perspective children into
+ // account. Note that this only recomputes the overflow areas stored on the
+ // helper (which are used to compute scrollable length and scrollbar thumb
+ // sizes) but not the overflow areas stored on the frame. This seems to work
+ // for now, but it's possible that we may need to update both in the future.
+ AdjustForPerspective(aState.mContentsOverflowAreas.ScrollableOverflow());
+
+ // Preserve the width or height of empty rects
+ const nsSize portSize = ScrollPort().Size();
+ nsRect scrolledRect = GetUnsnappedScrolledRectInternal(
+ aState.mContentsOverflowAreas.ScrollableOverflow(), portSize);
+ nsRect scrolledArea =
+ scrolledRect.UnionEdges(nsRect(nsPoint(0, 0), portSize));
+
+ // Store the new overflow area. Note that this changes where an outline
+ // of the scrolled frame would be painted, but scrolled frames can't have
+ // outlines (the outline would go on this scrollframe instead).
+ // Using FinishAndStoreOverflow is needed so the overflow rect gets set
+ // correctly. It also messes with the overflow rect in the 'clip' case, but
+ // scrolled frames can't have 'overflow' either.
+ // This needs to happen before SyncFrameViewAfterReflow so
+ // HasOverflowRect() will return the correct value.
+ OverflowAreas overflow(scrolledArea, scrolledArea);
+ scrolledFrame->FinishAndStoreOverflow(overflow, scrolledFrame->GetSize());
+
+ // Note that making the view *exactly* the size of the scrolled area
+ // is critical, since the view scrolling code uses the size of the
+ // scrolled view to clamp scroll requests.
+ // Normally the scrolledFrame won't have a view but in some cases it
+ // might create its own.
+ nsContainerFrame::SyncFrameViewAfterReflow(
+ scrolledFrame->PresContext(), scrolledFrame, scrolledFrame->GetView(),
+ scrolledArea, ReflowChildFlags::Default);
+}
+
+nscoord nsHTMLScrollFrame::IntrinsicScrollbarGutterSizeAtInlineEdges(
+ gfxContext* aRenderingContext) {
+ const bool isVerticalWM = GetWritingMode().IsVertical();
+ nsScrollbarFrame* inlineEndScrollbarBox =
+ isVerticalWM ? mHScrollbarBox : mVScrollbarBox;
+ if (!inlineEndScrollbarBox) {
+ // No scrollbar box frame means no intrinsic size.
+ return 0;
+ }
+
+ if (PresContext()->UseOverlayScrollbars()) {
+ return 0;
+ }
+
+ const auto* styleForScrollbar = nsLayoutUtils::StyleForScrollbar(this);
+ if (styleForScrollbar->StyleUIReset()->ScrollbarWidth() ==
+ StyleScrollbarWidth::None) {
+ // Scrollbar shouldn't appear at all with "scrollbar-width: none".
+ return 0;
+ }
+
+ const auto& styleScrollbarGutter =
+ styleForScrollbar->StyleDisplay()->mScrollbarGutter;
+ ScrollStyles ss = GetScrollStyles();
+ const StyleOverflow& inlineEndStyleOverflow =
+ isVerticalWM ? ss.mHorizontal : ss.mVertical;
+
+ // Return the scrollbar-gutter size only if we have "overflow:scroll" or
+ // non-auto "scrollbar-gutter", so early-return here if the conditions aren't
+ // satisfied.
+ if (inlineEndStyleOverflow != StyleOverflow::Scroll &&
+ styleScrollbarGutter == StyleScrollbarGutter::AUTO) {
+ return 0;
+ }
+
+ // No need to worry about reflow depth here since it's just for scrollbars.
+ nsSize scrollbarPrefSize = inlineEndScrollbarBox->ScrollbarMinSize();
+ const nscoord scrollbarSize =
+ isVerticalWM ? scrollbarPrefSize.height : scrollbarPrefSize.width;
+ const auto bothEdges =
+ bool(styleScrollbarGutter & StyleScrollbarGutter::BOTH_EDGES);
+ return bothEdges ? scrollbarSize * 2 : scrollbarSize;
+}
+
+// Legacy, this sucks!
+static bool IsMarqueeScrollbox(const nsIFrame& aScrollFrame) {
+ if (!aScrollFrame.GetContent()) {
+ return false;
+ }
+ if (MOZ_LIKELY(!aScrollFrame.GetContent()->HasBeenInUAWidget())) {
+ return false;
+ }
+ MOZ_ASSERT(aScrollFrame.GetParent() &&
+ aScrollFrame.GetParent()->GetContent());
+ return aScrollFrame.GetParent() &&
+ HTMLMarqueeElement::FromNodeOrNull(
+ aScrollFrame.GetParent()->GetContent());
+}
+
+/* virtual */
+nscoord nsHTMLScrollFrame::GetMinISize(gfxContext* aRenderingContext) {
+ nscoord result = [&] {
+ if (const Maybe<nscoord> containISize = ContainIntrinsicISize()) {
+ return *containISize;
+ }
+ if (MOZ_UNLIKELY(IsMarqueeScrollbox(*this))) {
+ return 0;
+ }
+ return mScrolledFrame->GetMinISize(aRenderingContext);
+ }();
+
+ DISPLAY_MIN_INLINE_SIZE(this, result);
+ return result + IntrinsicScrollbarGutterSizeAtInlineEdges(aRenderingContext);
+}
+
+/* virtual */
+nscoord nsHTMLScrollFrame::GetPrefISize(gfxContext* aRenderingContext) {
+ const Maybe<nscoord> containISize = ContainIntrinsicISize();
+ nscoord result = containISize
+ ? *containISize
+ : mScrolledFrame->GetPrefISize(aRenderingContext);
+ DISPLAY_PREF_INLINE_SIZE(this, result);
+ return NSCoordSaturatingAdd(
+ result, IntrinsicScrollbarGutterSizeAtInlineEdges(aRenderingContext));
+}
+
+// When we have perspective set on the outer scroll frame, and transformed
+// children (possibly with preserve-3d) then the effective transform on the
+// child depends on the offset to the scroll frame, which changes as we scroll.
+// This perspective transform can cause the element to move relative to the
+// scrolled inner frame, which would cause the scrollable length changes during
+// scrolling if we didn't account for it. Since we don't want scrollHeight/Width
+// and the size of scrollbar thumbs to change during scrolling, we compute the
+// scrollable overflow by determining the scroll position at which the child
+// becomes completely visible within the scrollport rather than using the union
+// of the overflow areas at their current position.
+static void GetScrollableOverflowForPerspective(
+ nsIFrame* aScrolledFrame, nsIFrame* aCurrentFrame, const nsRect aScrollPort,
+ nsPoint aOffset, nsRect& aScrolledFrameOverflowArea) {
+ // Iterate over all children except pop-ups.
+ for (const auto& [list, listID] : aCurrentFrame->ChildLists()) {
+ if (listID == FrameChildListID::Popup) {
+ continue;
+ }
+
+ for (nsIFrame* child : list) {
+ nsPoint offset = aOffset;
+
+ // When we reach a direct child of the scroll, then we record the offset
+ // to convert from that frame's coordinate into the scroll frame's
+ // coordinates. Preserve-3d descendant frames use the same offset as their
+ // ancestors, since TransformRect already converts us into the coordinate
+ // space of the preserve-3d root.
+ if (aScrolledFrame == aCurrentFrame) {
+ offset = child->GetPosition();
+ }
+
+ if (child->Extend3DContext()) {
+ // If we're a preserve-3d frame, then recurse and include our
+ // descendants since overflow of preserve-3d frames is only included
+ // in the post-transform overflow area of the preserve-3d root frame.
+ GetScrollableOverflowForPerspective(aScrolledFrame, child, aScrollPort,
+ offset, aScrolledFrameOverflowArea);
+ }
+
+ // If we're transformed, then we want to consider the possibility that
+ // this frame might move relative to the scrolled frame when scrolling.
+ // For preserve-3d, leaf frames have correct overflow rects relative to
+ // themselves. preserve-3d 'nodes' (intermediate frames and the root) have
+ // only their untransformed children included in their overflow relative
+ // to self, which is what we want to include here.
+ if (child->IsTransformed()) {
+ // Compute the overflow rect for this leaf transform frame in the
+ // coordinate space of the scrolled frame.
+ nsPoint scrollPos = aScrolledFrame->GetPosition();
+ nsRect preScroll, postScroll;
+ {
+ // TODO: Can we reuse the reference box?
+ TransformReferenceBox refBox(child);
+ preScroll = nsDisplayTransform::TransformRect(
+ child->ScrollableOverflowRectRelativeToSelf(), child, refBox);
+ }
+
+ // Temporarily override the scroll position of the scrolled frame by
+ // 10 CSS pixels, and then recompute what the overflow rect would be.
+ // This scroll position may not be valid, but that shouldn't matter
+ // for our calculations.
+ {
+ aScrolledFrame->SetPosition(scrollPos + nsPoint(600, 600));
+ TransformReferenceBox refBox(child);
+ postScroll = nsDisplayTransform::TransformRect(
+ child->ScrollableOverflowRectRelativeToSelf(), child, refBox);
+ aScrolledFrame->SetPosition(scrollPos);
+ }
+
+ // Compute how many app units the overflow rects moves by when we adjust
+ // the scroll position by 1 app unit.
+ double rightDelta =
+ (postScroll.XMost() - preScroll.XMost() + 600.0) / 600.0;
+ double bottomDelta =
+ (postScroll.YMost() - preScroll.YMost() + 600.0) / 600.0;
+
+ // We can't ever have negative scrolling.
+ NS_ASSERTION(rightDelta > 0.0f && bottomDelta > 0.0f,
+ "Scrolling can't be reversed!");
+
+ // Move preScroll into the coordinate space of the scrollport.
+ preScroll += offset + scrollPos;
+
+ // For each of the four edges of preScroll, figure out how far they
+ // extend beyond the scrollport. Ignore negative values since that means
+ // that side is already scrolled in to view and we don't need to add
+ // overflow to account for it.
+ nsMargin overhang(std::max(0, aScrollPort.Y() - preScroll.Y()),
+ std::max(0, preScroll.XMost() - aScrollPort.XMost()),
+ std::max(0, preScroll.YMost() - aScrollPort.YMost()),
+ std::max(0, aScrollPort.X() - preScroll.X()));
+
+ // Scale according to rightDelta/bottomDelta to adjust for the different
+ // scroll rates.
+ overhang.top = NSCoordSaturatingMultiply(
+ overhang.top, static_cast<float>(1 / bottomDelta));
+ overhang.right = NSCoordSaturatingMultiply(
+ overhang.right, static_cast<float>(1 / rightDelta));
+ overhang.bottom = NSCoordSaturatingMultiply(
+ overhang.bottom, static_cast<float>(1 / bottomDelta));
+ overhang.left = NSCoordSaturatingMultiply(
+ overhang.left, static_cast<float>(1 / rightDelta));
+
+ // Take the minimum overflow rect that would allow the current scroll
+ // position, using the size of the scroll port and offset by the
+ // inverse of the scroll position.
+ nsRect overflow = aScrollPort - scrollPos;
+
+ // Expand it by our margins to get an overflow rect that would allow all
+ // edges of our transformed content to be scrolled into view.
+ overflow.Inflate(overhang);
+
+ // Merge it with the combined overflow
+ aScrolledFrameOverflowArea.UnionRect(aScrolledFrameOverflowArea,
+ overflow);
+ } else if (aCurrentFrame == aScrolledFrame) {
+ aScrolledFrameOverflowArea.UnionRect(
+ aScrolledFrameOverflowArea,
+ child->ScrollableOverflowRectRelativeToParent());
+ }
+ }
+ }
+}
+
+BaselineSharingGroup nsHTMLScrollFrame::GetDefaultBaselineSharingGroup() const {
+ return mScrolledFrame->GetDefaultBaselineSharingGroup();
+}
+
+nscoord nsHTMLScrollFrame::SynthesizeFallbackBaseline(
+ mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
+ // Marign-end even for central baselines.
+ if (aWM.IsLineInverted()) {
+ return -GetLogicalUsedMargin(aWM).BStart(aWM);
+ }
+ return aBaselineGroup == BaselineSharingGroup::First
+ ? BSize(aWM) + GetLogicalUsedMargin(aWM).BEnd(aWM)
+ : -GetLogicalUsedMargin(aWM).BEnd(aWM);
+}
+
+Maybe<nscoord> nsHTMLScrollFrame::GetNaturalBaselineBOffset(
+ WritingMode aWM, BaselineSharingGroup aBaselineGroup,
+ BaselineExportContext aExportContext) const {
+ // Block containers that are scrollable always have a last baseline
+ // that are synthesized from block-end margin edge.
+ // Note(dshin): This behaviour is really only relevant to `inline-block`
+ // alignment context. In the context of table/flex/grid alignment, first/last
+ // baselines are calculated through `GetFirstLineBaseline`, which does
+ // calculations of its own.
+ // https://drafts.csswg.org/css-align/#baseline-export
+ if (aExportContext == BaselineExportContext::LineLayout &&
+ aBaselineGroup == BaselineSharingGroup::Last &&
+ mScrolledFrame->IsBlockFrameOrSubclass()) {
+ return Some(SynthesizeFallbackBaseline(aWM, aBaselineGroup));
+ }
+
+ if (StyleDisplay()->IsContainLayout()) {
+ return Nothing{};
+ }
+
+ // OK, here's where we defer to our scrolled frame.
+ return mScrolledFrame
+ ->GetNaturalBaselineBOffset(aWM, aBaselineGroup, aExportContext)
+ .map([this, aWM](nscoord aBaseline) {
+ // We have to add our border BStart thickness to whatever it returns, to
+ // produce an offset in our frame-rect's coordinate system. (We don't
+ // have to add padding, because the scrolled frame handles our padding.)
+ LogicalMargin border = GetLogicalUsedBorder(aWM);
+ const auto bSize = GetLogicalSize(aWM).BSize(aWM);
+ // Clamp the baseline to the border rect. See bug 1791069.
+ return std::clamp(border.BStart(aWM) + aBaseline, 0, bSize);
+ });
+}
+
+void nsHTMLScrollFrame::AdjustForPerspective(nsRect& aScrollableOverflow) {
+ // If we have perspective that is being applied to our children, then
+ // the effective transform on the child depends on the relative position
+ // of the child to us and changes during scrolling.
+ if (!ChildrenHavePerspective()) {
+ return;
+ }
+ aScrollableOverflow.SetEmpty();
+ GetScrollableOverflowForPerspective(mScrolledFrame, mScrolledFrame,
+ ScrollPort(), nsPoint(),
+ aScrollableOverflow);
+}
+
+void nsHTMLScrollFrame::Reflow(nsPresContext* aPresContext,
+ ReflowOutput& aDesiredSize,
+ const ReflowInput& aReflowInput,
+ nsReflowStatus& aStatus) {
+ MarkInReflow();
+ DO_GLOBAL_REFLOW_COUNT("nsHTMLScrollFrame");
+ DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);
+ MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+
+ HandleScrollbarStyleSwitching();
+
+ ScrollReflowInput state(this, aReflowInput);
+
+ //------------ Handle Incremental Reflow -----------------
+ bool reflowHScrollbar = true;
+ bool reflowVScrollbar = true;
+ bool reflowScrollCorner = true;
+ if (!aReflowInput.ShouldReflowAllKids()) {
+ auto NeedsReflow = [](const nsIFrame* aFrame) {
+ return aFrame && aFrame->IsSubtreeDirty();
+ };
+
+ reflowHScrollbar = NeedsReflow(mHScrollbarBox);
+ reflowVScrollbar = NeedsReflow(mVScrollbarBox);
+ reflowScrollCorner =
+ NeedsReflow(mScrollCornerBox) || NeedsReflow(mResizerBox);
+ }
+
+ if (mIsRoot) {
+ reflowScrollCorner = false;
+ }
+
+ const nsRect oldScrollPort = ScrollPort();
+ nsRect oldScrolledAreaBounds =
+ mScrolledFrame->ScrollableOverflowRectRelativeToParent();
+ nsPoint oldScrollPosition = GetScrollPosition();
+
+ ReflowContents(state, aDesiredSize);
+
+ nsSize layoutSize =
+ mIsUsingMinimumScaleSize ? mMinimumScaleSize : state.mInsideBorderSize;
+ aDesiredSize.Width() = layoutSize.width + state.mComputedBorder.LeftRight();
+ aDesiredSize.Height() = layoutSize.height + state.mComputedBorder.TopBottom();
+
+ // Set the size of the frame now since computing the perspective-correct
+ // overflow (within PlaceScrollArea) can rely on it.
+ SetSize(aDesiredSize.GetWritingMode(),
+ aDesiredSize.Size(aDesiredSize.GetWritingMode()));
+
+ // Restore the old scroll position, for now, even if that's not valid anymore
+ // because we changed size. We'll fix it up in a post-reflow callback, because
+ // our current size may only be temporary (e.g. we're compute XUL desired
+ // sizes).
+ PlaceScrollArea(state, oldScrollPosition);
+ if (!mPostedReflowCallback) {
+ // Make sure we'll try scrolling to restored position
+ PresShell()->PostReflowCallback(this);
+ mPostedReflowCallback = true;
+ }
+
+ bool didOnlyHScrollbar = mOnlyNeedHScrollbarToScrollVVInsideLV;
+ bool didOnlyVScrollbar = mOnlyNeedVScrollbarToScrollVVInsideLV;
+ mOnlyNeedHScrollbarToScrollVVInsideLV =
+ state.mOnlyNeedHScrollbarToScrollVVInsideLV;
+ mOnlyNeedVScrollbarToScrollVVInsideLV =
+ state.mOnlyNeedVScrollbarToScrollVVInsideLV;
+
+ bool didHaveHScrollbar = mHasHorizontalScrollbar;
+ bool didHaveVScrollbar = mHasVerticalScrollbar;
+ mHasHorizontalScrollbar = state.mShowHScrollbar;
+ mHasVerticalScrollbar = state.mShowVScrollbar;
+ const nsRect& newScrollPort = ScrollPort();
+ nsRect newScrolledAreaBounds =
+ mScrolledFrame->ScrollableOverflowRectRelativeToParent();
+ if (mSkippedScrollbarLayout || reflowHScrollbar || reflowVScrollbar ||
+ reflowScrollCorner || HasAnyStateBits(NS_FRAME_IS_DIRTY) ||
+ didHaveHScrollbar != state.mShowHScrollbar ||
+ didHaveVScrollbar != state.mShowVScrollbar ||
+ didOnlyHScrollbar != mOnlyNeedHScrollbarToScrollVVInsideLV ||
+ didOnlyVScrollbar != mOnlyNeedVScrollbarToScrollVVInsideLV ||
+ !oldScrollPort.IsEqualEdges(newScrollPort) ||
+ !oldScrolledAreaBounds.IsEqualEdges(newScrolledAreaBounds)) {
+ if (!mSuppressScrollbarUpdate) {
+ mSkippedScrollbarLayout = false;
+ nsHTMLScrollFrame::SetScrollbarVisibility(mHScrollbarBox,
+ state.mShowHScrollbar);
+ nsHTMLScrollFrame::SetScrollbarVisibility(mVScrollbarBox,
+ state.mShowVScrollbar);
+ // place and reflow scrollbars
+ const nsRect insideBorderArea(
+ nsPoint(state.mComputedBorder.left, state.mComputedBorder.top),
+ layoutSize);
+ LayoutScrollbars(state, insideBorderArea, oldScrollPort);
+ } else {
+ mSkippedScrollbarLayout = true;
+ }
+ }
+ if (mIsRoot) {
+ if (RefPtr<MobileViewportManager> manager =
+ PresShell()->GetMobileViewportManager()) {
+ // Note that this runs during layout, and when we get here the root
+ // scrollframe has already been laid out. It may have added or removed
+ // scrollbars as a result of that layout, so we need to ensure the
+ // visual viewport is updated to account for that before we read the
+ // visual viewport size.
+ manager->UpdateVisualViewportSizeForPotentialScrollbarChange();
+ } else if (oldScrollPort.Size() != newScrollPort.Size()) {
+ // We want to make sure to send a visual viewport resize event if the
+ // scrollport changed sizes for root scroll frames. The
+ // MobileViewportManager will do that, but if we don't have one (ie we
+ // aren't a root content document for example) we have to send one
+ // ourselves.
+ if (auto* window = nsGlobalWindowInner::Cast(
+ aPresContext->Document()->GetInnerWindow())) {
+ window->VisualViewport()->PostResizeEvent();
+ }
+ }
+ }
+
+ // Note that we need to do this after the
+ // UpdateVisualViewportSizeForPotentialScrollbarChange call above because that
+ // is what updates the visual viewport size and we need it to be up to date.
+ if (mIsRoot && !state.OverlayScrollbars() &&
+ (didHaveHScrollbar != state.mShowHScrollbar ||
+ didHaveVScrollbar != state.mShowVScrollbar ||
+ didOnlyHScrollbar != mOnlyNeedHScrollbarToScrollVVInsideLV ||
+ didOnlyVScrollbar != mOnlyNeedVScrollbarToScrollVVInsideLV) &&
+ PresShell()->IsVisualViewportOffsetSet()) {
+ // Removing layout/classic scrollbars can make a previously valid vvoffset
+ // invalid. For example, if we are zoomed in on an overflow hidden document
+ // and then zoom back out, when apz reaches the initial resolution (ie 1.0)
+ // it won't know that we can remove the scrollbars, so the vvoffset can
+ // validly be upto the width/height of the scrollbars. After we reflow and
+ // remove the scrollbars the only valid vvoffset is (0,0). We could wait
+ // until we send the new frame metrics to apz and then have it reply with
+ // the new corrected vvoffset but having an inconsistent vvoffset causes
+ // problems so trigger the vvoffset to be re-set and re-clamped in
+ // ReflowFinished.
+ mReclampVVOffsetInReflowFinished = true;
+ }
+
+ aDesiredSize.SetOverflowAreasToDesiredBounds();
+
+ UpdateSticky();
+ FinishReflowWithAbsoluteFrames(aPresContext, aDesiredSize, aReflowInput,
+ aStatus);
+
+ if (!InInitialReflow() && !mHadNonInitialReflow) {
+ mHadNonInitialReflow = true;
+ }
+
+ if (mIsRoot && !oldScrolledAreaBounds.IsEqualEdges(newScrolledAreaBounds)) {
+ PostScrolledAreaEvent();
+ }
+
+ UpdatePrevScrolledRect();
+
+ aStatus.Reset(); // This type of frame can't be split.
+ PostOverflowEvent();
+}
+
+void nsHTMLScrollFrame::DidReflow(nsPresContext* aPresContext,
+ const ReflowInput* aReflowInput) {
+ nsContainerFrame::DidReflow(aPresContext, aReflowInput);
+ if (NeedsResnap()) {
+ PostPendingResnap();
+ } else {
+ PresShell()->PostPendingScrollAnchorAdjustment(Anchor());
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+#ifdef DEBUG_FRAME_DUMP
+nsresult nsHTMLScrollFrame::GetFrameName(nsAString& aResult) const {
+ return MakeFrameName(u"HTMLScroll"_ns, aResult);
+}
+#endif
+
+#ifdef ACCESSIBILITY
+a11y::AccType nsHTMLScrollFrame::AccessibleType() {
+ if (IsTableCaption()) {
+ return GetRect().IsEmpty() ? a11y::eNoType : a11y::eHTMLCaptionType;
+ }
+
+ // Create an accessible regardless of focusable state because the state can be
+ // changed during frame life cycle without any notifications to accessibility.
+ if (mContent->IsRootOfNativeAnonymousSubtree() ||
+ GetScrollStyles().IsHiddenInBothDirections()) {
+ return a11y::eNoType;
+ }
+
+ return a11y::eHyperTextType;
+}
+#endif
+
+NS_QUERYFRAME_HEAD(nsHTMLScrollFrame)
+ NS_QUERYFRAME_ENTRY(nsIAnonymousContentCreator)
+ NS_QUERYFRAME_ENTRY(nsIScrollableFrame)
+ NS_QUERYFRAME_ENTRY(nsIStatefulFrame)
+ NS_QUERYFRAME_ENTRY(nsIScrollbarMediator)
+ NS_QUERYFRAME_ENTRY(nsHTMLScrollFrame)
+NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
+
+nsMargin nsHTMLScrollFrame::GetDesiredScrollbarSizes() const {
+ nsPresContext* pc = PresContext();
+ if (pc->UseOverlayScrollbars()) {
+ return {};
+ }
+
+ const auto& style = *nsLayoutUtils::StyleForScrollbar(this);
+ const auto scrollbarWidth = style.StyleUIReset()->ScrollbarWidth();
+ if (scrollbarWidth == StyleScrollbarWidth::None) {
+ return {};
+ }
+
+ ScrollStyles styles = GetScrollStyles();
+ nsMargin result(0, 0, 0, 0);
+
+ auto size = pc->DevPixelsToAppUnits(
+ pc->Theme()->GetScrollbarSize(pc, scrollbarWidth, nsITheme::Overlay::No));
+ if (styles.mVertical != StyleOverflow::Hidden) {
+ if (IsScrollbarOnRight())
+ result.left = size;
+ else
+ result.right = size;
+ }
+
+ if (styles.mHorizontal != StyleOverflow::Hidden) {
+ // We don't currently support any scripts that would require a scrollbar
+ // at the top. (Are there any?)
+ result.bottom = size;
+ }
+
+ return result;
+}
+
+nscoord nsIScrollableFrame::GetNondisappearingScrollbarWidth(nsPresContext* aPc,
+ WritingMode aWM) {
+ // We use this to size the combobox dropdown button. For that, we need to have
+ // the proper big, non-overlay scrollbar size, regardless of whether we're
+ // using e.g. scrollbar-width: thin, or overlay scrollbars.
+ auto size = aPc->Theme()->GetScrollbarSize(aPc, StyleScrollbarWidth::Auto,
+ nsITheme::Overlay::No);
+ return aPc->DevPixelsToAppUnits(size);
+}
+
+void nsHTMLScrollFrame::HandleScrollbarStyleSwitching() {
+ // Check if we switched between scrollbar styles.
+ if (mScrollbarActivity && !UsesOverlayScrollbars()) {
+ mScrollbarActivity->Destroy();
+ mScrollbarActivity = nullptr;
+ } else if (!mScrollbarActivity && UsesOverlayScrollbars()) {
+ mScrollbarActivity = new ScrollbarActivity(do_QueryFrame(this));
+ }
+}
+
+#if defined(MOZ_WIDGET_ANDROID)
+static bool IsFocused(nsIContent* aContent) {
+ // Some content elements, like the GetContent() of a scroll frame
+ // for a text input field, are inside anonymous subtrees, but the focus
+ // manager always reports a non-anonymous element as the focused one, so
+ // walk up the tree until we reach a non-anonymous element.
+ while (aContent && aContent->IsInNativeAnonymousSubtree()) {
+ aContent = aContent->GetParent();
+ }
+
+ return aContent ? nsContentUtils::IsFocusedContent(aContent) : false;
+}
+#endif
+
+void nsHTMLScrollFrame::SetScrollableByAPZ(bool aScrollable) {
+ mScrollableByAPZ = aScrollable;
+}
+
+void nsHTMLScrollFrame::SetZoomableByAPZ(bool aZoomable) {
+ if (!nsLayoutUtils::UsesAsyncScrolling(this)) {
+ // If APZ is disabled on this window, then we're never actually going to
+ // do any zooming. So we don't need to do any of the setup for it. Note
+ // that this function gets called from ZoomConstraintsClient even if APZ
+ // is disabled to indicate the zoomability of content.
+ aZoomable = false;
+ }
+ if (mZoomableByAPZ != aZoomable) {
+ // We might be changing the result of DecideScrollableLayer() so schedule a
+ // paint to make sure we pick up the result of that change.
+ mZoomableByAPZ = aZoomable;
+ SchedulePaint();
+ }
+}
+
+void nsHTMLScrollFrame::SetHasOutOfFlowContentInsideFilter() {
+ mHasOutOfFlowContentInsideFilter = true;
+}
+
+bool nsHTMLScrollFrame::WantAsyncScroll() const {
+ ScrollStyles styles = GetScrollStyles();
+ nscoord oneDevPixel =
+ GetScrolledFrame()->PresContext()->AppUnitsPerDevPixel();
+ nsRect scrollRange = GetLayoutScrollRange();
+
+ // If the page has a visual viewport size that's different from
+ // the layout viewport size at the current zoom level, we need to be
+ // able to scroll the visual viewport inside the layout viewport
+ // even if the page is not zoomable.
+ if (!GetVisualScrollRange().IsEqualInterior(scrollRange)) {
+ return true;
+ }
+
+ bool isVScrollable = (scrollRange.height >= oneDevPixel) &&
+ (styles.mVertical != StyleOverflow::Hidden);
+ bool isHScrollable = (scrollRange.width >= oneDevPixel) &&
+ (styles.mHorizontal != StyleOverflow::Hidden);
+
+#if defined(MOZ_WIDGET_ANDROID)
+ // Mobile platforms need focus to scroll text inputs.
+ bool canScrollWithoutScrollbars =
+ !IsForTextControlWithNoScrollbars() || IsFocused(GetContent());
+#else
+ bool canScrollWithoutScrollbars = true;
+#endif
+
+ // The check for scroll bars was added in bug 825692 to prevent layerization
+ // of text inputs for performance reasons.
+ bool isVAsyncScrollable =
+ isVScrollable && (mVScrollbarBox || canScrollWithoutScrollbars);
+ bool isHAsyncScrollable =
+ isHScrollable && (mHScrollbarBox || canScrollWithoutScrollbars);
+ return isVAsyncScrollable || isHAsyncScrollable;
+}
+
+static nsRect GetOnePixelRangeAroundPoint(const nsPoint& aPoint,
+ bool aIsHorizontal) {
+ nsRect allowedRange(aPoint, nsSize());
+ nscoord halfPixel = nsPresContext::CSSPixelsToAppUnits(0.5f);
+ if (aIsHorizontal) {
+ allowedRange.x = aPoint.x - halfPixel;
+ allowedRange.width = halfPixel * 2 - 1;
+ } else {
+ allowedRange.y = aPoint.y - halfPixel;
+ allowedRange.height = halfPixel * 2 - 1;
+ }
+ return allowedRange;
+}
+
+void nsHTMLScrollFrame::ScrollByPage(nsScrollbarFrame* aScrollbar,
+ int32_t aDirection,
+ ScrollSnapFlags aSnapFlags) {
+ ScrollByUnit(aScrollbar, ScrollMode::Smooth, aDirection, ScrollUnit::PAGES,
+ aSnapFlags);
+}
+
+void nsHTMLScrollFrame::ScrollByWhole(nsScrollbarFrame* aScrollbar,
+ int32_t aDirection,
+ ScrollSnapFlags aSnapFlags) {
+ ScrollByUnit(aScrollbar, ScrollMode::Instant, aDirection, ScrollUnit::WHOLE,
+ aSnapFlags);
+}
+
+void nsHTMLScrollFrame::ScrollByLine(nsScrollbarFrame* aScrollbar,
+ int32_t aDirection,
+ ScrollSnapFlags aSnapFlags) {
+ bool isHorizontal = aScrollbar->IsHorizontal();
+ nsIntPoint delta;
+ if (isHorizontal) {
+ const double kScrollMultiplier =
+ StaticPrefs::toolkit_scrollbox_horizontalScrollDistance();
+ delta.x = aDirection * kScrollMultiplier;
+ if (GetLineScrollAmount().width * delta.x > GetPageScrollAmount().width) {
+ // The scroll frame is so small that the delta would be more
+ // than an entire page. Scroll by one page instead to maintain
+ // context.
+ ScrollByPage(aScrollbar, aDirection);
+ return;
+ }
+ } else {
+ const double kScrollMultiplier =
+ StaticPrefs::toolkit_scrollbox_verticalScrollDistance();
+ delta.y = aDirection * kScrollMultiplier;
+ if (GetLineScrollAmount().height * delta.y > GetPageScrollAmount().height) {
+ // The scroll frame is so small that the delta would be more
+ // than an entire page. Scroll by one page instead to maintain
+ // context.
+ ScrollByPage(aScrollbar, aDirection);
+ return;
+ }
+ }
+
+ nsIntPoint overflow;
+ ScrollBy(delta, ScrollUnit::LINES, ScrollMode::Smooth, &overflow,
+ ScrollOrigin::Other, nsIScrollableFrame::NOT_MOMENTUM, aSnapFlags);
+}
+
+void nsHTMLScrollFrame::RepeatButtonScroll(nsScrollbarFrame* aScrollbar) {
+ aScrollbar->MoveToNewPosition(nsScrollbarFrame::ImplementsScrollByUnit::Yes);
+}
+
+void nsHTMLScrollFrame::ThumbMoved(nsScrollbarFrame* aScrollbar,
+ nscoord aOldPos, nscoord aNewPos) {
+ MOZ_ASSERT(aScrollbar != nullptr);
+ bool isHorizontal = aScrollbar->IsHorizontal();
+ nsPoint current = GetScrollPosition();
+ nsPoint dest = current;
+ if (isHorizontal) {
+ dest.x = IsPhysicalLTR() ? aNewPos : aNewPos - GetLayoutScrollRange().width;
+ } else {
+ dest.y = aNewPos;
+ }
+ nsRect allowedRange = GetOnePixelRangeAroundPoint(dest, isHorizontal);
+
+ // Don't try to scroll if we're already at an acceptable place.
+ // Don't call Contains here since Contains returns false when the point is
+ // on the bottom or right edge of the rectangle.
+ if (allowedRange.ClampPoint(current) == current) {
+ return;
+ }
+
+ ScrollToWithOrigin(
+ dest, &allowedRange,
+ ScrollOperationParams{ScrollMode::Instant, ScrollOrigin::Other});
+}
+
+void nsHTMLScrollFrame::ScrollbarReleased(nsScrollbarFrame* aScrollbar) {
+ // Scrollbar scrolling does not result in fling gestures, clear any
+ // accumulated velocity
+ mVelocityQueue.Reset();
+
+ // Perform scroll snapping, if needed. Scrollbar movement uses the same
+ // smooth scrolling animation as keyboard scrolling.
+ ScrollSnap(mDestination, ScrollMode::Smooth);
+}
+
+void nsHTMLScrollFrame::ScrollByUnit(nsScrollbarFrame* aScrollbar,
+ ScrollMode aMode, int32_t aDirection,
+ ScrollUnit aUnit,
+ ScrollSnapFlags aSnapFlags) {
+ MOZ_ASSERT(aScrollbar != nullptr);
+ bool isHorizontal = aScrollbar->IsHorizontal();
+ nsIntPoint delta;
+ if (isHorizontal) {
+ delta.x = aDirection;
+ } else {
+ delta.y = aDirection;
+ }
+ nsIntPoint overflow;
+ ScrollBy(delta, aUnit, aMode, &overflow, ScrollOrigin::Other,
+ nsIScrollableFrame::NOT_MOMENTUM, aSnapFlags);
+}
+
+//-------------------- Helper ----------------------
+
+// AsyncSmoothMSDScroll has ref counting.
+class nsHTMLScrollFrame::AsyncSmoothMSDScroll final
+ : public nsARefreshObserver {
+ public:
+ AsyncSmoothMSDScroll(const nsPoint& aInitialPosition,
+ const nsPoint& aInitialDestination,
+ const nsSize& aInitialVelocity, const nsRect& aRange,
+ const mozilla::TimeStamp& aStartTime,
+ nsPresContext* aPresContext,
+ UniquePtr<ScrollSnapTargetIds> aSnapTargetIds,
+ ScrollTriggeredByScript aTriggeredByScript)
+ : mXAxisModel(aInitialPosition.x, aInitialDestination.x,
+ aInitialVelocity.width,
+ StaticPrefs::layout_css_scroll_behavior_spring_constant(),
+ StaticPrefs::layout_css_scroll_behavior_damping_ratio()),
+ mYAxisModel(aInitialPosition.y, aInitialDestination.y,
+ aInitialVelocity.height,
+ StaticPrefs::layout_css_scroll_behavior_spring_constant(),
+ StaticPrefs::layout_css_scroll_behavior_damping_ratio()),
+ mRange(aRange),
+ mStartPosition(aInitialPosition),
+ mLastRefreshTime(aStartTime),
+ mCallee(nullptr),
+ mOneDevicePixelInAppUnits(aPresContext->DevPixelsToAppUnits(1)),
+ mSnapTargetIds(std::move(aSnapTargetIds)),
+ mTriggeredByScript(aTriggeredByScript) {
+ Telemetry::SetHistogramRecordingEnabled(
+ Telemetry::FX_REFRESH_DRIVER_SYNC_SCROLL_FRAME_DELAY_MS, true);
+ }
+
+ NS_INLINE_DECL_REFCOUNTING(AsyncSmoothMSDScroll, override)
+
+ nsSize GetVelocity() {
+ // In nscoords per second
+ return nsSize(mXAxisModel.GetVelocity(), mYAxisModel.GetVelocity());
+ }
+
+ nsPoint GetPosition() {
+ // In nscoords
+ return nsPoint(NSToCoordRound(mXAxisModel.GetPosition()),
+ NSToCoordRound(mYAxisModel.GetPosition()));
+ }
+
+ void SetDestination(const nsPoint& aDestination,
+ ScrollTriggeredByScript aTriggeredByScript) {
+ mXAxisModel.SetDestination(static_cast<int32_t>(aDestination.x));
+ mYAxisModel.SetDestination(static_cast<int32_t>(aDestination.y));
+ mTriggeredByScript = aTriggeredByScript;
+ }
+
+ void SetRange(const nsRect& aRange) { mRange = aRange; }
+
+ nsRect GetRange() { return mRange; }
+
+ nsPoint GetStartPosition() { return mStartPosition; }
+
+ void Simulate(const TimeDuration& aDeltaTime) {
+ mXAxisModel.Simulate(aDeltaTime);
+ mYAxisModel.Simulate(aDeltaTime);
+
+ nsPoint desired = GetPosition();
+ nsPoint clamped = mRange.ClampPoint(desired);
+ if (desired.x != clamped.x) {
+ // The scroll has hit the "wall" at the left or right edge of the allowed
+ // scroll range.
+ // Absorb the impact to avoid bounceback effect.
+ mXAxisModel.SetVelocity(0.0);
+ mXAxisModel.SetPosition(clamped.x);
+ }
+
+ if (desired.y != clamped.y) {
+ // The scroll has hit the "wall" at the left or right edge of the allowed
+ // scroll range.
+ // Absorb the impact to avoid bounceback effect.
+ mYAxisModel.SetVelocity(0.0);
+ mYAxisModel.SetPosition(clamped.y);
+ }
+ }
+
+ bool IsFinished() {
+ return mXAxisModel.IsFinished(mOneDevicePixelInAppUnits) &&
+ mYAxisModel.IsFinished(mOneDevicePixelInAppUnits);
+ }
+
+ virtual void WillRefresh(mozilla::TimeStamp aTime) override {
+ mozilla::TimeDuration deltaTime = aTime - mLastRefreshTime;
+ mLastRefreshTime = aTime;
+
+ // The callback may release "this".
+ // We don't access members after returning, so no need for KungFuDeathGrip.
+ nsHTMLScrollFrame::AsyncSmoothMSDScrollCallback(mCallee, deltaTime);
+ }
+
+ /*
+ * Set a refresh observer for smooth scroll iterations (and start observing).
+ * Should be used at most once during the lifetime of this object.
+ */
+ void SetRefreshObserver(nsHTMLScrollFrame* aCallee) {
+ NS_ASSERTION(aCallee && !mCallee,
+ "AsyncSmoothMSDScroll::SetRefreshObserver - Invalid usage.");
+
+ RefreshDriver(aCallee)->AddRefreshObserver(this, FlushType::Style,
+ "Smooth scroll (MSD) animation");
+ mCallee = aCallee;
+ }
+
+ /**
+ * The mCallee holds a strong ref to us since the refresh driver doesn't.
+ * Our dtor and mCallee's Destroy() method both call RemoveObserver() -
+ * whichever comes first removes us from the refresh driver.
+ */
+ void RemoveObserver() {
+ if (mCallee) {
+ RefreshDriver(mCallee)->RemoveRefreshObserver(this, FlushType::Style);
+ mCallee = nullptr;
+ }
+ }
+
+ UniquePtr<ScrollSnapTargetIds> TakeSnapTargetIds() {
+ return std::move(mSnapTargetIds);
+ }
+
+ bool WasTriggeredByScript() const {
+ return mTriggeredByScript == ScrollTriggeredByScript::Yes;
+ }
+
+ private:
+ // Private destructor, to discourage deletion outside of Release():
+ ~AsyncSmoothMSDScroll() {
+ RemoveObserver();
+ Telemetry::SetHistogramRecordingEnabled(
+ Telemetry::FX_REFRESH_DRIVER_SYNC_SCROLL_FRAME_DELAY_MS, false);
+ }
+
+ nsRefreshDriver* RefreshDriver(nsHTMLScrollFrame* aCallee) {
+ return aCallee->PresContext()->RefreshDriver();
+ }
+
+ mozilla::layers::AxisPhysicsMSDModel mXAxisModel, mYAxisModel;
+ nsRect mRange;
+ nsPoint mStartPosition;
+ mozilla::TimeStamp mLastRefreshTime;
+ nsHTMLScrollFrame* mCallee;
+ nscoord mOneDevicePixelInAppUnits;
+ UniquePtr<ScrollSnapTargetIds> mSnapTargetIds;
+ ScrollTriggeredByScript mTriggeredByScript;
+};
+
+// AsyncScroll has ref counting.
+class nsHTMLScrollFrame::AsyncScroll final : public nsARefreshObserver {
+ public:
+ typedef mozilla::TimeStamp TimeStamp;
+ typedef mozilla::TimeDuration TimeDuration;
+
+ explicit AsyncScroll(UniquePtr<ScrollSnapTargetIds> aSnapTargetIds,
+ ScrollTriggeredByScript aTriggeredByScript)
+ : mOrigin(ScrollOrigin::NotSpecified),
+ mCallee(nullptr),
+ mSnapTargetIds(std::move(aSnapTargetIds)),
+ mTriggeredByScript(aTriggeredByScript) {
+ Telemetry::SetHistogramRecordingEnabled(
+ Telemetry::FX_REFRESH_DRIVER_SYNC_SCROLL_FRAME_DELAY_MS, true);
+ }
+
+ private:
+ // Private destructor, to discourage deletion outside of Release():
+ ~AsyncScroll() {
+ RemoveObserver();
+ Telemetry::SetHistogramRecordingEnabled(
+ Telemetry::FX_REFRESH_DRIVER_SYNC_SCROLL_FRAME_DELAY_MS, false);
+ }
+
+ public:
+ void InitSmoothScroll(TimeStamp aTime, nsPoint aInitialPosition,
+ nsPoint aDestination, ScrollOrigin aOrigin,
+ const nsRect& aRange, const nsSize& aCurrentVelocity);
+ void Init(nsPoint aInitialPosition, const nsRect& aRange) {
+ mAnimationPhysics = nullptr;
+ mRange = aRange;
+ mStartPosition = aInitialPosition;
+ }
+
+ bool IsSmoothScroll() { return mAnimationPhysics != nullptr; }
+
+ bool IsFinished(const TimeStamp& aTime) const {
+ MOZ_RELEASE_ASSERT(mAnimationPhysics);
+ return mAnimationPhysics->IsFinished(aTime);
+ }
+
+ nsPoint PositionAt(const TimeStamp& aTime) const {
+ MOZ_RELEASE_ASSERT(mAnimationPhysics);
+ return mAnimationPhysics->PositionAt(aTime);
+ }
+
+ nsSize VelocityAt(const TimeStamp& aTime) const {
+ MOZ_RELEASE_ASSERT(mAnimationPhysics);
+ return mAnimationPhysics->VelocityAt(aTime);
+ }
+
+ nsPoint GetStartPosition() const { return mStartPosition; }
+
+ // Most recent scroll origin.
+ ScrollOrigin mOrigin;
+
+ // Allowed destination positions around mDestination
+ nsRect mRange;
+
+ // Initial position where the async scroll was triggered.
+ nsPoint mStartPosition;
+
+ private:
+ void InitPreferences(TimeStamp aTime, nsAtom* aOrigin);
+
+ UniquePtr<ScrollAnimationPhysics> mAnimationPhysics;
+
+ // The next section is observer/callback management
+ // Bodies of WillRefresh and RefreshDriver contain nsHTMLScrollFrame specific
+ // code.
+ public:
+ NS_INLINE_DECL_REFCOUNTING(AsyncScroll, override)
+
+ /*
+ * Set a refresh observer for smooth scroll iterations (and start observing).
+ * Should be used at most once during the lifetime of this object.
+ */
+ void SetRefreshObserver(nsHTMLScrollFrame* aCallee) {
+ NS_ASSERTION(aCallee && !mCallee,
+ "AsyncScroll::SetRefreshObserver - Invalid usage.");
+
+ RefreshDriver(aCallee)->AddRefreshObserver(this, FlushType::Style,
+ "Smooth scroll animation");
+ mCallee = aCallee;
+ auto* presShell = mCallee->PresShell();
+ MOZ_ASSERT(presShell);
+ presShell->SuppressDisplayport(true);
+ }
+
+ virtual void WillRefresh(mozilla::TimeStamp aTime) override {
+ // The callback may release "this".
+ // We don't access members after returning, so no need for KungFuDeathGrip.
+ nsHTMLScrollFrame::AsyncScrollCallback(mCallee, aTime);
+ }
+
+ /**
+ * The mCallee holds a strong ref to us since the refresh driver doesn't.
+ * Our dtor and mCallee's Destroy() method both call RemoveObserver() -
+ * whichever comes first removes us from the refresh driver.
+ */
+ void RemoveObserver() {
+ if (mCallee) {
+ RefreshDriver(mCallee)->RemoveRefreshObserver(this, FlushType::Style);
+ auto* presShell = mCallee->PresShell();
+ MOZ_ASSERT(presShell);
+ presShell->SuppressDisplayport(false);
+ mCallee = nullptr;
+ }
+ }
+
+ UniquePtr<ScrollSnapTargetIds> TakeSnapTargetIds() {
+ return std::move(mSnapTargetIds);
+ }
+
+ bool WasTriggeredByScript() const {
+ return mTriggeredByScript == ScrollTriggeredByScript::Yes;
+ }
+
+ private:
+ nsHTMLScrollFrame* mCallee;
+ UniquePtr<ScrollSnapTargetIds> mSnapTargetIds;
+ ScrollTriggeredByScript mTriggeredByScript;
+
+ nsRefreshDriver* RefreshDriver(nsHTMLScrollFrame* aCallee) {
+ return aCallee->PresContext()->RefreshDriver();
+ }
+};
+
+void nsHTMLScrollFrame::AsyncScroll::InitSmoothScroll(
+ TimeStamp aTime, nsPoint aInitialPosition, nsPoint aDestination,
+ ScrollOrigin aOrigin, const nsRect& aRange,
+ const nsSize& aCurrentVelocity) {
+ switch (aOrigin) {
+ case ScrollOrigin::NotSpecified:
+ case ScrollOrigin::Restore:
+ case ScrollOrigin::Relative:
+ // We don't have special prefs for "restore", just treat it as "other".
+ // "restore" scrolls are (for now) always instant anyway so unless
+ // something changes we should never have aOrigin ==
+ // ScrollOrigin::Restore here.
+ aOrigin = ScrollOrigin::Other;
+ break;
+ case ScrollOrigin::Apz:
+ // Likewise we should never get APZ-triggered scrolls here, and if that
+ // changes something is likely broken somewhere.
+ MOZ_ASSERT(false);
+ break;
+ default:
+ break;
+ };
+
+ // Read preferences only on first iteration or for a different event origin.
+ if (!mAnimationPhysics || aOrigin != mOrigin) {
+ mOrigin = aOrigin;
+ if (StaticPrefs::general_smoothScroll_msdPhysics_enabled()) {
+ mAnimationPhysics =
+ MakeUnique<ScrollAnimationMSDPhysics>(aInitialPosition);
+ } else {
+ ScrollAnimationBezierPhysicsSettings settings =
+ layers::apz::ComputeBezierAnimationSettingsForOrigin(mOrigin);
+ mAnimationPhysics =
+ MakeUnique<ScrollAnimationBezierPhysics>(aInitialPosition, settings);
+ }
+ }
+
+ mStartPosition = aInitialPosition;
+ mRange = aRange;
+
+ mAnimationPhysics->Update(aTime, aDestination, aCurrentVelocity);
+}
+
+/*
+ * Callback function from AsyncSmoothMSDScroll, used in
+ * nsHTMLScrollFrame::ScrollTo
+ */
+void nsHTMLScrollFrame::AsyncSmoothMSDScrollCallback(
+ nsHTMLScrollFrame* aInstance, mozilla::TimeDuration aDeltaTime) {
+ NS_ASSERTION(aInstance != nullptr, "aInstance must not be null");
+ NS_ASSERTION(aInstance->mAsyncSmoothMSDScroll,
+ "Did not expect AsyncSmoothMSDScrollCallback without an active "
+ "MSD scroll.");
+
+ nsRect range = aInstance->mAsyncSmoothMSDScroll->GetRange();
+ aInstance->mAsyncSmoothMSDScroll->Simulate(aDeltaTime);
+
+ if (!aInstance->mAsyncSmoothMSDScroll->IsFinished()) {
+ nsPoint destination = aInstance->mAsyncSmoothMSDScroll->GetPosition();
+ // Allow this scroll operation to land on any pixel boundary within the
+ // allowed scroll range for this frame.
+ // If the MSD is under-dampened or the destination is changed rapidly,
+ // it is expected (and desired) that the scrolling may overshoot.
+ nsRect intermediateRange = nsRect(destination, nsSize()).UnionEdges(range);
+ aInstance->ScrollToImpl(destination, intermediateRange);
+ // 'aInstance' might be destroyed here
+ return;
+ }
+
+ aInstance->CompleteAsyncScroll(
+ aInstance->mAsyncSmoothMSDScroll->GetStartPosition(), range,
+ aInstance->mAsyncSmoothMSDScroll->TakeSnapTargetIds());
+}
+
+/*
+ * Callback function from AsyncScroll, used in nsHTMLScrollFrame::ScrollTo
+ */
+void nsHTMLScrollFrame::AsyncScrollCallback(nsHTMLScrollFrame* aInstance,
+ mozilla::TimeStamp aTime) {
+ MOZ_ASSERT(aInstance != nullptr, "aInstance must not be null");
+ MOZ_ASSERT(
+ aInstance->mAsyncScroll,
+ "Did not expect AsyncScrollCallback without an active async scroll.");
+
+ if (!aInstance || !aInstance->mAsyncScroll) {
+ return; // XXX wallpaper bug 1107353 for now.
+ }
+
+ nsRect range = aInstance->mAsyncScroll->mRange;
+ if (aInstance->mAsyncScroll->IsSmoothScroll()) {
+ if (!aInstance->mAsyncScroll->IsFinished(aTime)) {
+ nsPoint destination = aInstance->mAsyncScroll->PositionAt(aTime);
+ // Allow this scroll operation to land on any pixel boundary between the
+ // current position and the final allowed range. (We don't want
+ // intermediate steps to be more constrained than the final step!)
+ nsRect intermediateRange =
+ nsRect(aInstance->GetScrollPosition(), nsSize()).UnionEdges(range);
+ aInstance->ScrollToImpl(destination, intermediateRange);
+ // 'aInstance' might be destroyed here
+ return;
+ }
+ }
+
+ aInstance->CompleteAsyncScroll(aInstance->mAsyncScroll->GetStartPosition(),
+ range,
+ aInstance->mAsyncScroll->TakeSnapTargetIds());
+}
+
+void nsHTMLScrollFrame::SetTransformingByAPZ(bool aTransforming) {
+ if (mTransformingByAPZ && !aTransforming) {
+ PostScrollEndEvent();
+ }
+ mTransformingByAPZ = aTransforming;
+ if (!mozilla::css::TextOverflow::HasClippedTextOverflow(this) ||
+ mozilla::css::TextOverflow::HasBlockEllipsis(mScrolledFrame)) {
+ // If the block has some overflow marker stuff we should kick off a paint
+ // because we have special behaviour for it when APZ scrolling is active.
+ SchedulePaint();
+ }
+}
+
+void nsHTMLScrollFrame::CompleteAsyncScroll(
+ const nsPoint& aStartPosition, const nsRect& aRange,
+ UniquePtr<ScrollSnapTargetIds> aSnapTargetIds, ScrollOrigin aOrigin) {
+ SetLastSnapTargetIds(std::move(aSnapTargetIds));
+
+ bool scrollPositionChanged = mDestination != aStartPosition;
+ bool isNotHandledByApz =
+ nsLayoutUtils::CanScrollOriginClobberApz(aOrigin) ||
+ ScrollAnimationState().contains(AnimationState::MainThread);
+
+ // Apply desired destination range since this is the last step of scrolling.
+ RemoveObservers();
+ AutoWeakFrame weakFrame(this);
+ ScrollToImpl(mDestination, aRange, aOrigin);
+ if (!weakFrame.IsAlive()) {
+ return;
+ }
+ // We are done scrolling, set our destination to wherever we actually ended
+ // up scrolling to.
+ mDestination = GetScrollPosition();
+ // Post a `scrollend` event for scrolling not handled by APZ, including:
+ //
+ // - programmatic instant scrolls
+ // - the end of a smooth scroll animation running on the main thread
+ //
+ // For scrolling handled by APZ, the `scrollend` event is posted in
+ // SetTransformingByAPZ() when the APZC is transitioning from a transforming
+ // to a non-transforming state (e.g. a transition from PANNING to NOTHING).
+ // The scrollend event should not be fired for a scroll that does not
+ // result in a scroll position change.
+ if (isNotHandledByApz && scrollPositionChanged) {
+ PostScrollEndEvent();
+ }
+}
+
+bool nsHTMLScrollFrame::HasBgAttachmentLocal() const {
+ const nsStyleBackground* bg = StyleBackground();
+ return bg->HasLocalBackground();
+}
+
+void nsHTMLScrollFrame::ScrollToInternal(
+ nsPoint aScrollPosition, ScrollMode aMode, ScrollOrigin aOrigin,
+ const nsRect* aRange, ScrollSnapFlags aSnapFlags,
+ ScrollTriggeredByScript aTriggeredByScript) {
+ if (aOrigin == ScrollOrigin::NotSpecified) {
+ aOrigin = ScrollOrigin::Other;
+ }
+ ScrollToWithOrigin(
+ aScrollPosition, aRange,
+ ScrollOperationParams{aMode, aOrigin, aSnapFlags, aTriggeredByScript});
+}
+
+void nsHTMLScrollFrame::ScrollToCSSPixels(const CSSIntPoint& aScrollPosition,
+ ScrollMode aMode) {
+ CSSIntPoint currentCSSPixels = GetScrollPositionCSSPixels();
+ // Transmogrify this scroll to a relative one if there's any on-going
+ // animation in APZ triggered by __user__.
+ // Bug 1740164: We will apply it for cases there's no animation in APZ.
+
+ auto scrollAnimationState = ScrollAnimationState();
+ bool isScrollAnimating =
+ scrollAnimationState.contains(AnimationState::MainThread) ||
+ scrollAnimationState.contains(AnimationState::APZPending) ||
+ scrollAnimationState.contains(AnimationState::APZRequested);
+ if (mCurrentAPZScrollAnimationType ==
+ APZScrollAnimationType::TriggeredByUserInput &&
+ !isScrollAnimating) {
+ CSSIntPoint delta = aScrollPosition - currentCSSPixels;
+ // This transmogrification need to be an intended end position scroll
+ // operation.
+ ScrollByCSSPixelsInternal(delta, aMode,
+ ScrollSnapFlags::IntendedEndPosition);
+ return;
+ }
+
+ nscoord halfPixel = nsPresContext::CSSPixelsToAppUnits(0.5f);
+ nsPoint pt = CSSPoint::ToAppUnits(aScrollPosition);
+ nsRect range(pt.x - halfPixel, pt.y - halfPixel, 2 * halfPixel - 1,
+ 2 * halfPixel - 1);
+ // XXX I don't think the following blocks are needed anymore, now that
+ // ScrollToImpl simply tries to scroll an integer number of layer
+ // pixels from the current position
+ nsPoint current = GetScrollPosition();
+ if (currentCSSPixels.x == aScrollPosition.x) {
+ pt.x = current.x;
+ range.x = pt.x;
+ range.width = 0;
+ }
+ if (currentCSSPixels.y == aScrollPosition.y) {
+ pt.y = current.y;
+ range.y = pt.y;
+ range.height = 0;
+ }
+ ScrollToWithOrigin(
+ pt, &range,
+ ScrollOperationParams{
+ aMode, ScrollOrigin::Other,
+ // This ScrollToCSSPixels is used for Element.scrollTo,
+ // Element.scrollTop, Element.scrollLeft and for Window.scrollTo.
+ ScrollSnapFlags::IntendedEndPosition, ScrollTriggeredByScript::Yes});
+ // 'this' might be destroyed here
+}
+
+void nsHTMLScrollFrame::ScrollToCSSPixelsForApz(
+ const CSSPoint& aScrollPosition, ScrollSnapTargetIds&& aLastSnapTargetIds) {
+ nsPoint pt = CSSPoint::ToAppUnits(aScrollPosition);
+ nscoord halfRange = nsPresContext::CSSPixelsToAppUnits(1000);
+ nsRect range(pt.x - halfRange, pt.y - halfRange, 2 * halfRange - 1,
+ 2 * halfRange - 1);
+ ScrollToWithOrigin(
+ pt, &range,
+ ScrollOperationParams{ScrollMode::Instant, ScrollOrigin::Apz,
+ std::move(aLastSnapTargetIds)});
+ // 'this' might be destroyed here
+}
+
+CSSIntPoint nsHTMLScrollFrame::GetScrollPositionCSSPixels() {
+ return CSSIntPoint::FromAppUnitsRounded(GetScrollPosition());
+}
+
+/*
+ * this method wraps calls to ScrollToImpl(), either in one shot or
+ * incrementally, based on the setting of the smoothness scroll pref
+ */
+void nsHTMLScrollFrame::ScrollToWithOrigin(nsPoint aScrollPosition,
+ const nsRect* aRange,
+ ScrollOperationParams&& aParams) {
+ // None is never a valid scroll origin to be passed in.
+ MOZ_ASSERT(aParams.mOrigin != ScrollOrigin::None);
+
+ if (aParams.mOrigin != ScrollOrigin::Restore) {
+ // If we're doing a non-restore scroll, we don't want to later
+ // override it by restoring our saved scroll position.
+ SCROLLRESTORE_LOG("%p: Clearing mRestorePos (cur=%s, dst=%s)\n", this,
+ ToString(GetScrollPosition()).c_str(),
+ ToString(aScrollPosition).c_str());
+ mRestorePos.x = mRestorePos.y = -1;
+ }
+
+ Maybe<SnapTarget> snapTarget;
+ if (!aParams.IsScrollSnapDisabled()) {
+ snapTarget = GetSnapPointForDestination(ScrollUnit::DEVICE_PIXELS,
+ aParams.mSnapFlags, mDestination,
+ aScrollPosition);
+ if (snapTarget) {
+ aScrollPosition = snapTarget->mPosition;
+ }
+ }
+
+ nsRect scrollRange = GetLayoutScrollRange();
+ mDestination = scrollRange.ClampPoint(aScrollPosition);
+ if (mDestination != aScrollPosition &&
+ aParams.mOrigin == ScrollOrigin::Restore &&
+ GetPageLoadingState() != LoadingState::Loading) {
+ // If we're doing a restore but the scroll position is clamped, promote
+ // the origin from one that APZ can clobber to one that it can't clobber.
+ aParams.mOrigin = ScrollOrigin::Other;
+ }
+
+ nsRect range = aRange && snapTarget.isNothing()
+ ? *aRange
+ : nsRect(aScrollPosition, nsSize(0, 0));
+
+ UniquePtr<ScrollSnapTargetIds> snapTargetIds;
+ if (snapTarget) {
+ snapTargetIds =
+ MakeUnique<ScrollSnapTargetIds>(std::move(snapTarget->mTargetIds));
+ } else {
+ snapTargetIds =
+ MakeUnique<ScrollSnapTargetIds>(std::move(aParams.mTargetIds));
+ }
+ if (aParams.IsInstant()) {
+ // Asynchronous scrolling is not allowed, so we'll kill any existing
+ // async-scrolling process and do an instant scroll.
+ CompleteAsyncScroll(GetScrollPosition(), range, std::move(snapTargetIds),
+ aParams.mOrigin);
+ mApzSmoothScrollDestination = Nothing();
+ return;
+ }
+
+ if (!aParams.IsSmoothMsd()) {
+ // If we get a non-smooth-scroll, reset the cached APZ scroll destination,
+ // so that we know to process the next smooth-scroll destined for APZ.
+ mApzSmoothScrollDestination = Nothing();
+ }
+
+ nsPresContext* presContext = PresContext();
+ TimeStamp now =
+ presContext->RefreshDriver()->IsTestControllingRefreshesEnabled()
+ ? presContext->RefreshDriver()->MostRecentRefresh()
+ : TimeStamp::Now();
+
+ nsSize currentVelocity(0, 0);
+
+ if (aParams.IsSmoothMsd()) {
+ mIgnoreMomentumScroll = true;
+ if (!mAsyncSmoothMSDScroll) {
+ nsPoint sv = mVelocityQueue.GetVelocity();
+ currentVelocity.width = sv.x;
+ currentVelocity.height = sv.y;
+ if (mAsyncScroll) {
+ if (mAsyncScroll->IsSmoothScroll()) {
+ currentVelocity = mAsyncScroll->VelocityAt(now);
+ }
+ mAsyncScroll = nullptr;
+ }
+
+ if (nsLayoutUtils::AsyncPanZoomEnabled(this) && WantAsyncScroll() &&
+ CanApzScrollInTheseDirections(
+ DirectionsInDelta(mDestination - GetScrollPosition()))) {
+ ApzSmoothScrollTo(mDestination, aParams.mOrigin,
+ aParams.mTriggeredByScript, std::move(snapTargetIds));
+ return;
+ }
+
+ mAsyncSmoothMSDScroll = new AsyncSmoothMSDScroll(
+ GetScrollPosition(), mDestination, currentVelocity,
+ GetLayoutScrollRange(), now, presContext, std::move(snapTargetIds),
+ aParams.mTriggeredByScript);
+
+ mAsyncSmoothMSDScroll->SetRefreshObserver(this);
+ } else {
+ // A previous smooth MSD scroll is still in progress, so we just need to
+ // update its range and destination.
+ mAsyncSmoothMSDScroll->SetRange(GetLayoutScrollRange());
+ mAsyncSmoothMSDScroll->SetDestination(mDestination,
+ aParams.mTriggeredByScript);
+ }
+
+ return;
+ }
+
+ if (mAsyncSmoothMSDScroll) {
+ currentVelocity = mAsyncSmoothMSDScroll->GetVelocity();
+ mAsyncSmoothMSDScroll = nullptr;
+ }
+
+ if (!mAsyncScroll) {
+ mAsyncScroll =
+ new AsyncScroll(std::move(snapTargetIds), aParams.mTriggeredByScript);
+ mAsyncScroll->SetRefreshObserver(this);
+ }
+
+ const bool isSmoothScroll =
+ aParams.IsSmooth() && nsLayoutUtils::IsSmoothScrollingEnabled();
+ if (isSmoothScroll) {
+ mAsyncScroll->InitSmoothScroll(now, GetScrollPosition(), mDestination,
+ aParams.mOrigin, range, currentVelocity);
+ } else {
+ mAsyncScroll->Init(GetScrollPosition(), range);
+ }
+}
+
+// We can't use nsContainerFrame::PositionChildViews here because
+// we don't want to invalidate views that have moved.
+static void AdjustViews(nsIFrame* aFrame) {
+ nsView* view = aFrame->GetView();
+ if (view) {
+ nsPoint pt;
+ aFrame->GetParent()->GetClosestView(&pt);
+ pt += aFrame->GetPosition();
+ view->SetPosition(pt.x, pt.y);
+
+ return;
+ }
+
+ if (!aFrame->HasAnyStateBits(NS_FRAME_HAS_CHILD_WITH_VIEW)) {
+ return;
+ }
+
+ // Call AdjustViews recursively for all child frames except the popup list as
+ // the views for popups are not scrolled.
+ for (const auto& [list, listID] : aFrame->ChildLists()) {
+ if (listID == FrameChildListID::Popup) {
+ continue;
+ }
+ for (nsIFrame* child : list) {
+ AdjustViews(child);
+ }
+ }
+}
+
+void nsHTMLScrollFrame::MarkScrollbarsDirtyForReflow() const {
+ auto* presShell = PresShell();
+ if (mVScrollbarBox) {
+ presShell->FrameNeedsReflow(mVScrollbarBox,
+ IntrinsicDirty::FrameAncestorsAndDescendants,
+ NS_FRAME_IS_DIRTY);
+ }
+ if (mHScrollbarBox) {
+ presShell->FrameNeedsReflow(mHScrollbarBox,
+ IntrinsicDirty::FrameAncestorsAndDescendants,
+ NS_FRAME_IS_DIRTY);
+ }
+}
+
+void nsHTMLScrollFrame::InvalidateScrollbars() const {
+ if (mHScrollbarBox) {
+ mHScrollbarBox->InvalidateFrameSubtree();
+ }
+ if (mVScrollbarBox) {
+ mVScrollbarBox->InvalidateFrameSubtree();
+ }
+}
+
+bool nsHTMLScrollFrame::IsAlwaysActive() const {
+ if (nsDisplayItem::ForceActiveLayers()) {
+ return true;
+ }
+
+ // Unless this is the root scrollframe for a non-chrome document
+ // which is the direct child of a chrome document, we default to not
+ // being "active".
+ if (!(mIsRoot && PresContext()->IsRootContentDocumentCrossProcess())) {
+ return false;
+ }
+
+ // If we have scrolled before, then we should stay active.
+ if (mHasBeenScrolled) {
+ return true;
+ }
+
+ // If we're overflow:hidden, then start as inactive until
+ // we get scrolled manually.
+ ScrollStyles styles = GetScrollStyles();
+ return (styles.mHorizontal != StyleOverflow::Hidden &&
+ styles.mVertical != StyleOverflow::Hidden);
+}
+
+static void RemoveDisplayPortCallback(nsITimer* aTimer, void* aClosure) {
+ nsHTMLScrollFrame* sf = static_cast<nsHTMLScrollFrame*>(aClosure);
+
+ // This function only ever gets called from the expiry timer, so it must
+ // be non-null here. Set it to null here so that we don't keep resetting
+ // it unnecessarily in MarkRecentlyScrolled().
+ MOZ_ASSERT(sf->mDisplayPortExpiryTimer);
+ sf->mDisplayPortExpiryTimer = nullptr;
+
+ if (!sf->AllowDisplayPortExpiration() || sf->mIsParentToActiveScrollFrames) {
+ // If this is a scroll parent for some other scrollable frame, don't
+ // expire the displayport because it would break scroll handoff. Once the
+ // descendant scrollframes have their displayports expired, they will
+ // trigger the displayport expiration on this scrollframe as well, and
+ // mIsParentToActiveScrollFrames will presumably be false when that kicks
+ // in.
+ return;
+ }
+
+ // Remove the displayport from this scrollframe if it's been a while
+ // since it's scrolled, except if it needs to be always active. Note that
+ // there is one scrollframe that doesn't fall under this general rule, and
+ // that is the one that nsLayoutUtils::MaybeCreateDisplayPort decides to put
+ // a displayport on (i.e. the first scrollframe that WantAsyncScroll()s).
+ // If that scrollframe is this one, we remove the displayport anyway, and
+ // as part of the next paint MaybeCreateDisplayPort will put another
+ // displayport back on it. Although the displayport will "flicker" off and
+ // back on, the layer itself should never disappear, because this all
+ // happens between actual painting. If the displayport is reset to a
+ // different position that's ok; this scrollframe hasn't been scrolled
+ // recently and so the reset should be correct.
+
+ nsIContent* content = sf->GetContent();
+
+ if (nsHTMLScrollFrame::ShouldActivateAllScrollFrames()) {
+ // If we are activating all scroll frames then we only want to remove the
+ // regular display port and downgrade to a minimal display port.
+ MOZ_ASSERT(!content->GetProperty(nsGkAtoms::MinimalDisplayPort));
+ content->SetProperty(nsGkAtoms::MinimalDisplayPort,
+ reinterpret_cast<void*>(true));
+ } else {
+ content->RemoveProperty(nsGkAtoms::MinimalDisplayPort);
+ DisplayPortUtils::RemoveDisplayPort(content);
+ // Be conservative and unflag this this scrollframe as being scrollable by
+ // APZ. If it is still scrollable this will get flipped back soon enough.
+ sf->mScrollableByAPZ = false;
+ }
+
+ DisplayPortUtils::ExpireDisplayPortOnAsyncScrollableAncestor(sf);
+ sf->SchedulePaint();
+}
+
+void nsHTMLScrollFrame::MarkEverScrolled() {
+ // Mark this frame as having been scrolled. If this is the root
+ // scroll frame of a content document, then IsAlwaysActive()
+ // will return true from now on and MarkNotRecentlyScrolled() won't
+ // have any effect.
+ mHasBeenScrolled = true;
+}
+
+void nsHTMLScrollFrame::MarkNotRecentlyScrolled() {
+ if (!mHasBeenScrolledRecently) return;
+
+ mHasBeenScrolledRecently = false;
+ SchedulePaint();
+}
+
+void nsHTMLScrollFrame::MarkRecentlyScrolled() {
+ mHasBeenScrolledRecently = true;
+ if (IsAlwaysActive()) {
+ return;
+ }
+
+ if (mActivityExpirationState.IsTracked()) {
+ gScrollFrameActivityTracker->MarkUsed(this);
+ } else {
+ if (!gScrollFrameActivityTracker) {
+ gScrollFrameActivityTracker =
+ new ScrollFrameActivityTracker(GetMainThreadSerialEventTarget());
+ }
+ gScrollFrameActivityTracker->AddObject(this);
+ }
+
+ // If we just scrolled and there's a displayport expiry timer in place,
+ // reset the timer.
+ ResetDisplayPortExpiryTimer();
+}
+
+void nsHTMLScrollFrame::ResetDisplayPortExpiryTimer() {
+ if (mDisplayPortExpiryTimer) {
+ mDisplayPortExpiryTimer->InitWithNamedFuncCallback(
+ RemoveDisplayPortCallback, this,
+ StaticPrefs::apz_displayport_expiry_ms(), nsITimer::TYPE_ONE_SHOT,
+ "nsHTMLScrollFrame::ResetDisplayPortExpiryTimer");
+ }
+}
+
+bool nsHTMLScrollFrame::AllowDisplayPortExpiration() {
+ if (IsAlwaysActive()) {
+ return false;
+ }
+
+ if (mIsRoot && PresContext()->IsRoot()) {
+ return false;
+ }
+
+ // If this was the first scrollable frame found, this displayport should
+ // not expire.
+ if (IsFirstScrollableFrameSequenceNumber().isSome()) {
+ return false;
+ }
+
+ if (ShouldActivateAllScrollFrames() &&
+ GetContent()->GetProperty(nsGkAtoms::MinimalDisplayPort)) {
+ return false;
+ }
+ return true;
+}
+
+void nsHTMLScrollFrame::TriggerDisplayPortExpiration() {
+ if (!AllowDisplayPortExpiration()) {
+ return;
+ }
+
+ if (!StaticPrefs::apz_displayport_expiry_ms()) {
+ // a zero time disables the expiry
+ return;
+ }
+
+ if (!mDisplayPortExpiryTimer) {
+ mDisplayPortExpiryTimer = NS_NewTimer();
+ }
+ ResetDisplayPortExpiryTimer();
+}
+
+void nsHTMLScrollFrame::ScrollVisual() {
+ MarkEverScrolled();
+
+ AdjustViews(mScrolledFrame);
+ // We need to call this after fixing up the view positions
+ // to be consistent with the frame hierarchy.
+ MarkRecentlyScrolled();
+}
+
+/**
+ * Clamp desired scroll position aDesired and range [aDestLower, aDestUpper]
+ * to [aBoundLower, aBoundUpper] and then select the appunit value from among
+ * aBoundLower, aBoundUpper and those such that (aDesired - aCurrent) *
+ * aRes/aAppUnitsPerPixel is an integer (or as close as we can get
+ * modulo rounding to appunits) that is in [aDestLower, aDestUpper] and
+ * closest to aDesired. If no such value exists, return the nearest in
+ * [aDestLower, aDestUpper].
+ */
+static nscoord ClampAndAlignWithPixels(nscoord aDesired, nscoord aBoundLower,
+ nscoord aBoundUpper, nscoord aDestLower,
+ nscoord aDestUpper,
+ nscoord aAppUnitsPerPixel, double aRes,
+ nscoord aCurrent) {
+ // Intersect scroll range with allowed range, by clamping the ends
+ // of aRange to be within bounds
+ nscoord destLower = clamped(aDestLower, aBoundLower, aBoundUpper);
+ nscoord destUpper = clamped(aDestUpper, aBoundLower, aBoundUpper);
+
+ nscoord desired = clamped(aDesired, destLower, destUpper);
+
+ double currentLayerVal = (aRes * aCurrent) / aAppUnitsPerPixel;
+ double desiredLayerVal = (aRes * desired) / aAppUnitsPerPixel;
+ double delta = desiredLayerVal - currentLayerVal;
+ double nearestLayerVal = NS_round(delta) + currentLayerVal;
+
+ // Convert back from PaintedLayer space to appunits relative to the top-left
+ // of the scrolled frame.
+ nscoord aligned =
+ aRes == 0.0
+ ? 0.0
+ : NSToCoordRoundWithClamp(nearestLayerVal * aAppUnitsPerPixel / aRes);
+
+ // Use a bound if it is within the allowed range and closer to desired than
+ // the nearest pixel-aligned value.
+ if (aBoundUpper == destUpper &&
+ static_cast<decltype(Abs(desired))>(aBoundUpper - desired) <
+ Abs(desired - aligned)) {
+ return aBoundUpper;
+ }
+
+ if (aBoundLower == destLower &&
+ static_cast<decltype(Abs(desired))>(desired - aBoundLower) <
+ Abs(aligned - desired)) {
+ return aBoundLower;
+ }
+
+ // Accept the nearest pixel-aligned value if it is within the allowed range.
+ if (aligned >= destLower && aligned <= destUpper) {
+ return aligned;
+ }
+
+ // Check if opposite pixel boundary fits into allowed range.
+ double oppositeLayerVal =
+ nearestLayerVal + ((nearestLayerVal < desiredLayerVal) ? 1.0 : -1.0);
+ nscoord opposite = aRes == 0.0
+ ? 0.0
+ : NSToCoordRoundWithClamp(oppositeLayerVal *
+ aAppUnitsPerPixel / aRes);
+ if (opposite >= destLower && opposite <= destUpper) {
+ return opposite;
+ }
+
+ // No alignment available.
+ return desired;
+}
+
+/**
+ * Clamp desired scroll position aPt to aBounds and then snap
+ * it to the same layer pixel edges as aCurrent, keeping it within aRange
+ * during snapping. aCurrent is the current scroll position.
+ */
+static nsPoint ClampAndAlignWithLayerPixels(const nsPoint& aPt,
+ const nsRect& aBounds,
+ const nsRect& aRange,
+ const nsPoint& aCurrent,
+ nscoord aAppUnitsPerPixel,
+ const MatrixScales& aScale) {
+ return nsPoint(
+ ClampAndAlignWithPixels(aPt.x, aBounds.x, aBounds.XMost(), aRange.x,
+ aRange.XMost(), aAppUnitsPerPixel, aScale.xScale,
+ aCurrent.x),
+ ClampAndAlignWithPixels(aPt.y, aBounds.y, aBounds.YMost(), aRange.y,
+ aRange.YMost(), aAppUnitsPerPixel, aScale.yScale,
+ aCurrent.y));
+}
+
+/* static */
+void nsHTMLScrollFrame::ScrollActivityCallback(nsITimer* aTimer,
+ void* anInstance) {
+ nsHTMLScrollFrame* self = static_cast<nsHTMLScrollFrame*>(anInstance);
+
+ // Fire the synth mouse move.
+ self->mScrollActivityTimer->Cancel();
+ self->mScrollActivityTimer = nullptr;
+ self->PresShell()->SynthesizeMouseMove(true);
+}
+
+void nsHTMLScrollFrame::ScheduleSyntheticMouseMove() {
+ if (!mScrollActivityTimer) {
+ mScrollActivityTimer = NS_NewTimer(
+ PresContext()->Document()->EventTargetFor(TaskCategory::Other));
+ if (!mScrollActivityTimer) {
+ return;
+ }
+ }
+
+ mScrollActivityTimer->InitWithNamedFuncCallback(
+ ScrollActivityCallback, this, 100, nsITimer::TYPE_ONE_SHOT,
+ "nsHTMLScrollFrame::ScheduleSyntheticMouseMove");
+}
+
+void nsHTMLScrollFrame::NotifyApproximateFrameVisibilityUpdate(
+ bool aIgnoreDisplayPort) {
+ mLastUpdateFramesPos = GetScrollPosition();
+ if (aIgnoreDisplayPort) {
+ mHadDisplayPortAtLastFrameUpdate = false;
+ mDisplayPortAtLastFrameUpdate = nsRect();
+ } else {
+ mHadDisplayPortAtLastFrameUpdate = DisplayPortUtils::GetDisplayPort(
+ GetContent(), &mDisplayPortAtLastFrameUpdate);
+ }
+}
+
+bool nsHTMLScrollFrame::GetDisplayPortAtLastApproximateFrameVisibilityUpdate(
+ nsRect* aDisplayPort) {
+ if (mHadDisplayPortAtLastFrameUpdate) {
+ *aDisplayPort = mDisplayPortAtLastFrameUpdate;
+ }
+ return mHadDisplayPortAtLastFrameUpdate;
+}
+
+MatrixScales GetPaintedLayerScaleForFrame(nsIFrame* aFrame) {
+ MOZ_ASSERT(aFrame, "need a frame");
+
+ nsPresContext* presCtx = aFrame->PresContext()->GetRootPresContext();
+
+ if (!presCtx) {
+ presCtx = aFrame->PresContext();
+ MOZ_ASSERT(presCtx);
+ }
+
+ ParentLayerToScreenScale2D transformToAncestorScale =
+ ParentLayerToParentLayerScale(
+ presCtx->PresShell()->GetCumulativeResolution()) *
+ nsLayoutUtils::GetTransformToAncestorScaleCrossProcessForFrameMetrics(
+ aFrame);
+
+ return transformToAncestorScale.ToUnknownScale();
+}
+
+void nsHTMLScrollFrame::ScrollToImpl(
+ nsPoint aPt, const nsRect& aRange, ScrollOrigin aOrigin,
+ ScrollTriggeredByScript aTriggeredByScript) {
+ // None is never a valid scroll origin to be passed in.
+ MOZ_ASSERT(aOrigin != ScrollOrigin::None);
+
+ // Figure out the effective origin for this scroll request.
+ if (aOrigin == ScrollOrigin::NotSpecified) {
+ // If no origin was specified, we still want to set it to something that's
+ // non-unknown, so that we can use eUnknown to distinguish if the frame was
+ // scrolled at all. Default it to some generic placeholder.
+ aOrigin = ScrollOrigin::Other;
+ }
+
+ // If this scroll is |relative|, but we've already had a user scroll that
+ // was not relative, promote this origin to |other|. This ensures that we
+ // may only transmit a relative update to APZ if all scrolls since the last
+ // transaction or repaint request have been relative.
+ if (aOrigin == ScrollOrigin::Relative &&
+ (mLastScrollOrigin != ScrollOrigin::None &&
+ mLastScrollOrigin != ScrollOrigin::NotSpecified &&
+ mLastScrollOrigin != ScrollOrigin::Relative &&
+ mLastScrollOrigin != ScrollOrigin::Apz)) {
+ aOrigin = ScrollOrigin::Other;
+ }
+
+ // If the origin is a downgrade, and downgrades are allowed, process the
+ // downgrade even if we're going to early-exit because we're already at
+ // the correct scroll position. This ensures that if there wasn't a main-
+ // thread scroll update pending before a frame reconstruction (as indicated
+ // by mAllowScrollOriginDowngrade=true), then after the frame reconstruction
+ // the origin is downgraded to "restore" even if the layout scroll offset to
+ // be restored is (0,0) (which will take the early-exit below). This is
+ // important so that restoration of a *visual* scroll offset (which might be
+ // to something other than (0,0)) isn't clobbered.
+ bool isScrollOriginDowngrade =
+ nsLayoutUtils::CanScrollOriginClobberApz(mLastScrollOrigin) &&
+ !nsLayoutUtils::CanScrollOriginClobberApz(aOrigin);
+ bool allowScrollOriginChange =
+ mAllowScrollOriginDowngrade && isScrollOriginDowngrade;
+
+ if (allowScrollOriginChange) {
+ mLastScrollOrigin = aOrigin;
+ mAllowScrollOriginDowngrade = false;
+ }
+
+ nsPresContext* presContext = PresContext();
+ nscoord appUnitsPerDevPixel = presContext->AppUnitsPerDevPixel();
+ // 'scale' is our estimate of the scale factor that will be applied
+ // when rendering the scrolled content to its own PaintedLayer.
+ MatrixScales scale = GetPaintedLayerScaleForFrame(mScrolledFrame);
+ nsPoint curPos = GetScrollPosition();
+
+ // Try to align aPt with curPos so they have an integer number of layer
+ // pixels between them. This gives us the best chance of scrolling without
+ // having to invalidate due to changes in subpixel rendering.
+ // Note that when we actually draw into a PaintedLayer, the coordinates
+ // that get mapped onto the layer buffer pixels are from the display list,
+ // which are relative to the display root frame's top-left increasing down,
+ // whereas here our coordinates are scroll positions which increase upward
+ // and are relative to the scrollport top-left. This difference doesn't
+ // actually matter since all we are about is that there be an integer number
+ // of layer pixels between pt and curPos.
+ nsPoint pt = ClampAndAlignWithLayerPixels(aPt, GetLayoutScrollRange(), aRange,
+ curPos, appUnitsPerDevPixel, scale);
+ if (pt == curPos) {
+ // Even if we are bailing out due to no-op main-thread scroll position
+ // change, we might need to cancel an APZ smooth scroll that we already
+ // kicked off. It might be reasonable to eventually remove the
+ // mApzSmoothScrollDestination clause from this if statement, as that
+ // may simplify this a bit and should be fine from the APZ side.
+ if (mApzSmoothScrollDestination && aOrigin != ScrollOrigin::Clamp) {
+ if (aOrigin == ScrollOrigin::Relative) {
+ AppendScrollUpdate(
+ ScrollPositionUpdate::NewRelativeScroll(mApzScrollPos, pt));
+ mApzScrollPos = pt;
+ } else if (aOrigin != ScrollOrigin::Apz) {
+ ScrollOrigin origin =
+ (mAllowScrollOriginDowngrade || !isScrollOriginDowngrade)
+ ? aOrigin
+ : mLastScrollOrigin;
+ AppendScrollUpdate(ScrollPositionUpdate::NewScroll(origin, pt));
+ }
+ }
+ return;
+ }
+
+ // If we are scrolling the RCD-RSF, and a visual scroll update is pending,
+ // cancel it; otherwise, it will clobber this scroll.
+ if (IsRootScrollFrameOfDocument() &&
+ presContext->IsRootContentDocumentCrossProcess()) {
+ auto* ps = presContext->GetPresShell();
+ if (const auto& visualScrollUpdate = ps->GetPendingVisualScrollUpdate()) {
+ if (visualScrollUpdate->mVisualScrollOffset != aPt) {
+ // Only clobber if the scroll was originated by the main thread.
+ // Respect the priority of origins (an "eRestore" layout scroll should
+ // not clobber an "eMainThread" visual scroll.)
+ bool shouldClobber =
+ aOrigin == ScrollOrigin::Other ||
+ (aOrigin == ScrollOrigin::Restore &&
+ visualScrollUpdate->mUpdateType == FrameMetrics::eRestore);
+ if (shouldClobber) {
+ ps->AcknowledgePendingVisualScrollUpdate();
+ ps->ClearPendingVisualScrollUpdate();
+ }
+ }
+ }
+ }
+
+ bool needFrameVisibilityUpdate = mLastUpdateFramesPos == nsPoint(-1, -1);
+
+ nsPoint dist(std::abs(pt.x - mLastUpdateFramesPos.x),
+ std::abs(pt.y - mLastUpdateFramesPos.y));
+ nsSize visualViewportSize = GetVisualViewportSize();
+ nscoord horzAllowance = std::max(
+ visualViewportSize.width /
+ std::max(
+ StaticPrefs::
+ layout_framevisibility_amountscrollbeforeupdatehorizontal(),
+ 1),
+ AppUnitsPerCSSPixel());
+ nscoord vertAllowance = std::max(
+ visualViewportSize.height /
+ std::max(
+ StaticPrefs::
+ layout_framevisibility_amountscrollbeforeupdatevertical(),
+ 1),
+ AppUnitsPerCSSPixel());
+ if (dist.x >= horzAllowance || dist.y >= vertAllowance) {
+ needFrameVisibilityUpdate = true;
+ }
+
+ // notify the listeners.
+ for (uint32_t i = 0; i < mListeners.Length(); i++) {
+ mListeners[i]->ScrollPositionWillChange(pt.x, pt.y);
+ }
+
+ nsRect oldDisplayPort;
+ nsIContent* content = GetContent();
+ DisplayPortUtils::GetDisplayPort(content, &oldDisplayPort);
+ oldDisplayPort.MoveBy(-mScrolledFrame->GetPosition());
+
+ // Update frame position for scrolling
+ mScrolledFrame->SetPosition(mScrollPort.TopLeft() - pt);
+
+ // If |mLastScrollOrigin| is already set to something that can clobber APZ's
+ // scroll offset, then we don't want to change it to something that can't.
+ // If we allowed this, then we could end up in a state where APZ ignores
+ // legitimate scroll offset updates because the origin has been masked by
+ // a later change within the same refresh driver tick.
+ allowScrollOriginChange =
+ (mAllowScrollOriginDowngrade || !isScrollOriginDowngrade);
+
+ if (allowScrollOriginChange) {
+ mLastScrollOrigin = aOrigin;
+ mAllowScrollOriginDowngrade = false;
+ }
+
+ if (aOrigin == ScrollOrigin::Relative) {
+ MOZ_ASSERT(!isScrollOriginDowngrade);
+ MOZ_ASSERT(mLastScrollOrigin == ScrollOrigin::Relative);
+ AppendScrollUpdate(
+ ScrollPositionUpdate::NewRelativeScroll(mApzScrollPos, pt));
+ mApzScrollPos = pt;
+ } else if (aOrigin != ScrollOrigin::Apz) {
+ AppendScrollUpdate(ScrollPositionUpdate::NewScroll(mLastScrollOrigin, pt));
+ }
+
+ if (mLastScrollOrigin == ScrollOrigin::Apz) {
+ mApzScrollPos = GetScrollPosition();
+ }
+
+ ScrollVisual();
+ mAnchor.UserScrolled();
+
+ // Only report user-triggered scrolling interactions
+ bool jsOnStack = nsContentUtils::GetCurrentJSContext() != nullptr;
+ bool scrollingToAnchor = ScrollingInteractionContext::IsScrollingToAnchor();
+ if (!jsOnStack && !scrollingToAnchor) {
+ nsPoint distanceScrolled(std::abs(pt.x - curPos.x),
+ std::abs(pt.y - curPos.y));
+ ScrollingMetrics::OnScrollingInteraction(
+ CSSPoint::FromAppUnits(distanceScrolled).Length());
+ }
+
+ bool schedulePaint = true;
+ if (nsLayoutUtils::AsyncPanZoomEnabled(this) &&
+ !nsLayoutUtils::ShouldDisableApzForElement(content) &&
+ !content->GetProperty(nsGkAtoms::MinimalDisplayPort) &&
+ StaticPrefs::apz_paint_skipping_enabled()) {
+ // If APZ is enabled with paint-skipping, there are certain conditions in
+ // which we can skip paints:
+ // 1) If APZ triggered this scroll, and the tile-aligned displayport is
+ // unchanged.
+ // 2) If non-APZ triggered this scroll, but we can handle it by just asking
+ // APZ to update the scroll position. Again we make this conditional on
+ // the tile-aligned displayport being unchanged.
+ // We do the displayport check first since it's common to all scenarios,
+ // and then if the displayport is unchanged, we check if APZ triggered,
+ // or can handle, this scroll. If so, we set schedulePaint to false and
+ // skip the paint.
+ // Because of bug 1264297, we also don't do paint-skipping for elements with
+ // perspective, because the displayport may not have captured everything
+ // that needs to be painted. So even if the final tile-aligned displayport
+ // is the same, we force a repaint for these elements. Bug 1254260 tracks
+ // fixing this properly.
+ nsRect displayPort;
+ bool usingDisplayPort =
+ DisplayPortUtils::GetDisplayPort(content, &displayPort);
+ displayPort.MoveBy(-mScrolledFrame->GetPosition());
+
+ PAINT_SKIP_LOG(
+ "New scrollpos %s usingDP %d dpEqual %d scrollableByApz "
+ "%d perspective %d bglocal %d filter %d\n",
+ ToString(CSSPoint::FromAppUnits(GetScrollPosition())).c_str(),
+ usingDisplayPort, displayPort.IsEqualEdges(oldDisplayPort),
+ mScrollableByAPZ, HasPerspective(), HasBgAttachmentLocal(),
+ mHasOutOfFlowContentInsideFilter);
+ if (usingDisplayPort && displayPort.IsEqualEdges(oldDisplayPort) &&
+ !HasPerspective() && !HasBgAttachmentLocal() &&
+ !mHasOutOfFlowContentInsideFilter) {
+ bool haveScrollLinkedEffects =
+ content->GetComposedDoc()->HasScrollLinkedEffect();
+ bool apzDisabled = haveScrollLinkedEffects &&
+ StaticPrefs::apz_disable_for_scroll_linked_effects();
+ if (!apzDisabled) {
+ if (LastScrollOrigin() == ScrollOrigin::Apz) {
+ schedulePaint = false;
+ PAINT_SKIP_LOG("Skipping due to APZ scroll\n");
+ } else if (mScrollableByAPZ) {
+ nsIWidget* widget = presContext->GetNearestWidget();
+ WindowRenderer* renderer =
+ widget ? widget->GetWindowRenderer() : nullptr;
+ if (renderer) {
+ mozilla::layers::ScrollableLayerGuid::ViewID id;
+ bool success = nsLayoutUtils::FindIDFor(content, &id);
+ MOZ_ASSERT(success); // we have a displayport, we better have an ID
+
+ // Schedule an empty transaction to carry over the scroll offset
+ // update, instead of a full transaction. This empty transaction
+ // might still get squashed into a full transaction if something
+ // happens to trigger one.
+ MOZ_ASSERT(!mScrollUpdates.IsEmpty());
+ success = renderer->AddPendingScrollUpdateForNextTransaction(
+ id, mScrollUpdates.LastElement());
+ if (success) {
+ schedulePaint = false;
+ SchedulePaint(nsIFrame::PAINT_COMPOSITE_ONLY);
+ PAINT_SKIP_LOG(
+ "Skipping due to APZ-forwarded main-thread scroll\n");
+ } else {
+ PAINT_SKIP_LOG(
+ "Failed to set pending scroll update on layer manager\n");
+ }
+ }
+ }
+ }
+ }
+ }
+
+ // If the new scroll offset is going to clobber APZ's scroll offset, for
+ // the RCD-RSF this will have the effect of updating the visual viewport
+ // offset in a way that keeps the relative offset between the layout and
+ // visual viewports constant. This will cause APZ to send us a new visual
+ // viewport offset, but instead of waiting for that, just set the value
+ // we expect APZ will set ourselves, to minimize the chances of
+ // inconsistencies from querying a stale value.
+ if (mIsRoot && nsLayoutUtils::CanScrollOriginClobberApz(aOrigin)) {
+ AutoWeakFrame weakFrame(this);
+ AutoScrollbarRepaintSuppression repaintSuppression(this, weakFrame,
+ !schedulePaint);
+
+ nsPoint visualViewportOffset = curPos;
+ if (presContext->PresShell()->IsVisualViewportOffsetSet()) {
+ visualViewportOffset =
+ presContext->PresShell()->GetVisualViewportOffset();
+ }
+ nsPoint relativeOffset = visualViewportOffset - curPos;
+
+ presContext->PresShell()->SetVisualViewportOffset(pt + relativeOffset,
+ curPos);
+ if (!weakFrame.IsAlive()) {
+ return;
+ }
+ }
+
+ if (schedulePaint) {
+ SchedulePaint();
+
+ if (needFrameVisibilityUpdate) {
+ presContext->PresShell()->ScheduleApproximateFrameVisibilityUpdateNow();
+ }
+ }
+
+ if (ChildrenHavePerspective()) {
+ // The overflow areas of descendants may depend on the scroll position,
+ // so ensure they get updated.
+
+ // First we recompute the overflow areas of the transformed children
+ // that use the perspective. FinishAndStoreOverflow only calls this
+ // if the size changes, so we need to do it manually.
+ RecomputePerspectiveChildrenOverflow(this);
+
+ // Update the overflow for the scrolled frame to take any changes from the
+ // children into account.
+ mScrolledFrame->UpdateOverflow();
+
+ // Update the overflow for the outer so that we recompute scrollbars.
+ UpdateOverflow();
+ }
+
+ ScheduleSyntheticMouseMove();
+
+ nsAutoScriptBlocker scriptBlocker;
+ PresShell::AutoAssertNoFlush noFlush(*PresShell());
+
+ { // scope the AutoScrollbarRepaintSuppression
+ AutoWeakFrame weakFrame(this);
+ AutoScrollbarRepaintSuppression repaintSuppression(this, weakFrame,
+ !schedulePaint);
+ UpdateScrollbarPosition();
+ if (!weakFrame.IsAlive()) {
+ return;
+ }
+ }
+
+ presContext->RecordInteractionTime(
+ nsPresContext::InteractionType::ScrollInteraction, TimeStamp::Now());
+
+ PostScrollEvent();
+ // If this is a viewport scroll, this could affect the relative offset
+ // between layout and visual viewport, so we might have to fire a visual
+ // viewport scroll event as well.
+ if (mIsRoot) {
+ if (auto* window = nsGlobalWindowInner::Cast(
+ PresContext()->Document()->GetInnerWindow())) {
+ window->VisualViewport()->PostScrollEvent(
+ presContext->PresShell()->GetVisualViewportOffset(), curPos);
+ }
+ }
+
+ // Schedule the scroll-timelines linked to its scrollable frame.
+ // if `pt == curPos`, we early return, so the position must be changed at
+ // this moment. Therefore, we can schedule scroll animations directly.
+ ScheduleScrollAnimations();
+
+ // notify the listeners.
+ for (uint32_t i = 0; i < mListeners.Length(); i++) {
+ mListeners[i]->ScrollPositionDidChange(pt.x, pt.y);
+ }
+
+ if (nsCOMPtr<nsIDocShell> docShell = presContext->GetDocShell()) {
+ docShell->NotifyScrollObservers();
+ }
+}
+
+// Finds the max z-index of the items in aList that meet the following
+// conditions
+// 1) have z-index auto or z-index >= 0, and
+// 2) aFrame is a proper ancestor of the item's frame.
+// Returns Nothing() if there is no such item.
+static Maybe<int32_t> MaxZIndexInListOfItemsContainedInFrame(
+ nsDisplayList* aList, nsIFrame* aFrame) {
+ Maybe<int32_t> maxZIndex = Nothing();
+ for (nsDisplayItem* item : *aList) {
+ int32_t zIndex = item->ZIndex();
+ if (zIndex < 0 ||
+ !nsLayoutUtils::IsProperAncestorFrame(aFrame, item->Frame())) {
+ continue;
+ }
+ if (!maxZIndex) {
+ maxZIndex = Some(zIndex);
+ } else {
+ maxZIndex = Some(std::max(maxZIndex.value(), zIndex));
+ }
+ }
+ return maxZIndex;
+}
+
+template <class T>
+static void AppendInternalItemToTop(const nsDisplayListSet& aLists, T* aItem,
+ const Maybe<int32_t>& aZIndex) {
+ if (aZIndex) {
+ aItem->SetOverrideZIndex(aZIndex.value());
+ aLists.PositionedDescendants()->AppendToTop(aItem);
+ } else {
+ aLists.Content()->AppendToTop(aItem);
+ }
+}
+
+static const uint32_t APPEND_OWN_LAYER = 0x1;
+static const uint32_t APPEND_POSITIONED = 0x2;
+static const uint32_t APPEND_SCROLLBAR_CONTAINER = 0x4;
+static const uint32_t APPEND_OVERLAY = 0x8;
+static const uint32_t APPEND_TOP = 0x10;
+
+static void AppendToTop(nsDisplayListBuilder* aBuilder,
+ const nsDisplayListSet& aLists, nsDisplayList* aSource,
+ nsIFrame* aSourceFrame, nsIFrame* aScrollFrame,
+ uint32_t aFlags) {
+ if (aSource->IsEmpty()) {
+ return;
+ }
+
+ nsDisplayWrapList* newItem;
+ const ActiveScrolledRoot* asr = aBuilder->CurrentActiveScrolledRoot();
+ if (aFlags & APPEND_OWN_LAYER) {
+ ScrollbarData scrollbarData;
+ if (aFlags & APPEND_SCROLLBAR_CONTAINER) {
+ scrollbarData = ScrollbarData::CreateForScrollbarContainer(
+ aBuilder->GetCurrentScrollbarDirection(),
+ aBuilder->GetCurrentScrollbarTarget());
+ // Direction should be set
+ MOZ_ASSERT(scrollbarData.mDirection.isSome());
+ }
+
+ newItem = MakeDisplayItemWithIndex<nsDisplayOwnLayer>(
+ aBuilder, aSourceFrame,
+ /* aIndex = */ nsDisplayOwnLayer::OwnLayerForScrollbar, aSource, asr,
+ nsDisplayOwnLayerFlags::None, scrollbarData, true, false);
+ } else {
+ // Build the wrap list with an index of 1, since the scrollbar frame itself
+ // might have already built an nsDisplayWrapList.
+ newItem = MakeDisplayItemWithIndex<nsDisplayWrapper>(
+ aBuilder, aSourceFrame, 1, aSource, asr, false);
+ }
+ if (!newItem) {
+ return;
+ }
+
+ if (aFlags & APPEND_POSITIONED) {
+ // We want overlay scrollbars to always be on top of the scrolled content,
+ // but we don't want them to unnecessarily cover overlapping elements from
+ // outside our scroll frame.
+ Maybe<int32_t> zIndex = Nothing();
+ if (aFlags & APPEND_TOP) {
+ zIndex = Some(INT32_MAX);
+ } else if (aFlags & APPEND_OVERLAY) {
+ zIndex = MaxZIndexInListOfItemsContainedInFrame(
+ aLists.PositionedDescendants(), aScrollFrame);
+ } else if (aSourceFrame->StylePosition()->mZIndex.IsInteger()) {
+ zIndex = Some(aSourceFrame->StylePosition()->mZIndex.integer._0);
+ }
+ AppendInternalItemToTop(aLists, newItem, zIndex);
+ } else {
+ aLists.BorderBackground()->AppendToTop(newItem);
+ }
+}
+
+struct HoveredStateComparator {
+ static bool Hovered(const nsIFrame* aFrame) {
+ return aFrame->GetContent()->IsElement() &&
+ aFrame->GetContent()->AsElement()->HasAttr(kNameSpaceID_None,
+ nsGkAtoms::hover);
+ }
+
+ bool Equals(nsIFrame* A, nsIFrame* B) const {
+ return Hovered(A) == Hovered(B);
+ }
+
+ bool LessThan(nsIFrame* A, nsIFrame* B) const {
+ return !Hovered(A) && Hovered(B);
+ }
+};
+
+void nsHTMLScrollFrame::AppendScrollPartsTo(nsDisplayListBuilder* aBuilder,
+ const nsDisplayListSet& aLists,
+ bool aCreateLayer,
+ bool aPositioned) {
+ const bool overlayScrollbars = UsesOverlayScrollbars();
+
+ AutoTArray<nsIFrame*, 3> scrollParts;
+ for (nsIFrame* kid : PrincipalChildList()) {
+ if (kid == mScrolledFrame ||
+ (kid->IsAbsPosContainingBlock() || overlayScrollbars) != aPositioned) {
+ continue;
+ }
+
+ scrollParts.AppendElement(kid);
+ }
+ if (scrollParts.IsEmpty()) {
+ return;
+ }
+
+ // We can't check will-change budget during display list building phase.
+ // This means that we will build scroll bar layers for out of budget
+ // will-change: scroll position.
+ const mozilla::layers::ScrollableLayerGuid::ViewID scrollTargetId =
+ IsScrollingActive()
+ ? nsLayoutUtils::FindOrCreateIDFor(mScrolledFrame->GetContent())
+ : mozilla::layers::ScrollableLayerGuid::NULL_SCROLL_ID;
+
+ scrollParts.Sort(HoveredStateComparator());
+
+ DisplayListClipState::AutoSaveRestore clipState(aBuilder);
+ // Don't let scrollparts extent outside our frame's border-box, if these are
+ // viewport scrollbars. They would create layerization problems. This wouldn't
+ // normally be an issue but themes can add overflow areas to scrollbar parts.
+ if (mIsRoot) {
+ nsRect scrollPartsClip(aBuilder->ToReferenceFrame(this),
+ TrueOuterSize(aBuilder));
+ clipState.ClipContentDescendants(scrollPartsClip);
+ }
+
+ for (uint32_t i = 0; i < scrollParts.Length(); ++i) {
+ MOZ_ASSERT(scrollParts[i]);
+ Maybe<ScrollDirection> scrollDirection;
+ uint32_t appendToTopFlags = 0;
+ if (scrollParts[i] == mVScrollbarBox) {
+ scrollDirection.emplace(ScrollDirection::eVertical);
+ appendToTopFlags |= APPEND_SCROLLBAR_CONTAINER;
+ }
+ if (scrollParts[i] == mHScrollbarBox) {
+ MOZ_ASSERT(!scrollDirection.isSome());
+ scrollDirection.emplace(ScrollDirection::eHorizontal);
+ appendToTopFlags |= APPEND_SCROLLBAR_CONTAINER;
+ }
+
+ // The display port doesn't necessarily include the scrollbars, so just
+ // include all of the scrollbars if we are in a RCD-RSF. We only do
+ // this for the root scrollframe of the root content document, which is
+ // zoomable, and where the scrollbar sizes are bounded by the widget.
+ const nsRect visible =
+ mIsRoot && PresContext()->IsRootContentDocumentCrossProcess()
+ ? scrollParts[i]->InkOverflowRectRelativeToParent()
+ : aBuilder->GetVisibleRect();
+ if (visible.IsEmpty()) {
+ continue;
+ }
+ const nsRect dirty =
+ mIsRoot && PresContext()->IsRootContentDocumentCrossProcess()
+ ? scrollParts[i]->InkOverflowRectRelativeToParent()
+ : aBuilder->GetDirtyRect();
+
+ // Always create layers for overlay scrollbars so that we don't create a
+ // giant layer covering the whole scrollport if both scrollbars are visible.
+ const bool isOverlayScrollbar =
+ scrollDirection.isSome() && overlayScrollbars;
+ const bool createLayer =
+ aCreateLayer || isOverlayScrollbar ||
+ StaticPrefs::layout_scrollbars_always_layerize_track();
+
+ nsDisplayListCollection partList(aBuilder);
+ {
+ nsDisplayListBuilder::AutoBuildingDisplayList buildingForChild(
+ aBuilder, this, visible, dirty);
+
+ nsDisplayListBuilder::AutoCurrentScrollbarInfoSetter infoSetter(
+ aBuilder, scrollTargetId, scrollDirection, createLayer);
+ BuildDisplayListForChild(
+ aBuilder, scrollParts[i], partList,
+ nsIFrame::DisplayChildFlag::ForceStackingContext);
+ }
+
+ // DisplayChildFlag::ForceStackingContext put everything into
+ // partList.PositionedDescendants().
+ if (partList.PositionedDescendants()->IsEmpty()) {
+ continue;
+ }
+
+ if (createLayer) {
+ appendToTopFlags |= APPEND_OWN_LAYER;
+ }
+ if (aPositioned) {
+ appendToTopFlags |= APPEND_POSITIONED;
+ }
+
+ if (isOverlayScrollbar || scrollParts[i] == mResizerBox) {
+ if (isOverlayScrollbar && mIsRoot) {
+ appendToTopFlags |= APPEND_TOP;
+ } else {
+ appendToTopFlags |= APPEND_OVERLAY;
+ aBuilder->SetDisablePartialUpdates(true);
+ }
+ }
+
+ {
+ nsDisplayListBuilder::AutoBuildingDisplayList buildingForChild(
+ aBuilder, scrollParts[i], visible + GetOffsetTo(scrollParts[i]),
+ dirty + GetOffsetTo(scrollParts[i]));
+ if (scrollParts[i]->IsTransformed()) {
+ nsPoint toOuterReferenceFrame;
+ const nsIFrame* outerReferenceFrame = aBuilder->FindReferenceFrameFor(
+ scrollParts[i]->GetParent(), &toOuterReferenceFrame);
+ toOuterReferenceFrame += scrollParts[i]->GetPosition();
+
+ buildingForChild.SetReferenceFrameAndCurrentOffset(
+ outerReferenceFrame, toOuterReferenceFrame);
+ }
+ nsDisplayListBuilder::AutoCurrentScrollbarInfoSetter infoSetter(
+ aBuilder, scrollTargetId, scrollDirection, createLayer);
+
+ ::AppendToTop(aBuilder, aLists, partList.PositionedDescendants(),
+ scrollParts[i], this, appendToTopFlags);
+ }
+ }
+}
+
+nsRect nsHTMLScrollFrame::ExpandRectToNearlyVisible(const nsRect& aRect) const {
+ // We don't want to expand a rect in a direction that we can't scroll, so we
+ // check the scroll range.
+ nsRect scrollRange = GetLayoutScrollRange();
+ nsPoint scrollPos = GetScrollPosition();
+ nsMargin expand(0, 0, 0, 0);
+
+ nscoord vertShift =
+ StaticPrefs::layout_framevisibility_numscrollportheights() * aRect.height;
+ if (scrollRange.y < scrollPos.y) {
+ expand.top = vertShift;
+ }
+ if (scrollPos.y < scrollRange.YMost()) {
+ expand.bottom = vertShift;
+ }
+
+ nscoord horzShift =
+ StaticPrefs::layout_framevisibility_numscrollportwidths() * aRect.width;
+ if (scrollRange.x < scrollPos.x) {
+ expand.left = horzShift;
+ }
+ if (scrollPos.x < scrollRange.XMost()) {
+ expand.right = horzShift;
+ }
+
+ nsRect rect = aRect;
+ rect.Inflate(expand);
+ return rect;
+}
+
+static bool ShouldBeClippedByFrame(nsIFrame* aClipFrame,
+ nsIFrame* aClippedFrame) {
+ return nsLayoutUtils::IsProperAncestorFrame(aClipFrame, aClippedFrame);
+}
+
+static void ClipItemsExceptCaret(
+ nsDisplayList* aList, nsDisplayListBuilder* aBuilder, nsIFrame* aClipFrame,
+ const DisplayItemClipChain* aExtraClip,
+ nsTHashMap<nsPtrHashKey<const DisplayItemClipChain>,
+ const DisplayItemClipChain*>& aCache) {
+ for (nsDisplayItem* i : *aList) {
+ if (!ShouldBeClippedByFrame(aClipFrame, i->Frame())) {
+ continue;
+ }
+
+ const DisplayItemType type = i->GetType();
+ if (type != DisplayItemType::TYPE_CARET &&
+ type != DisplayItemType::TYPE_CONTAINER) {
+ const DisplayItemClipChain* clip = i->GetClipChain();
+ const DisplayItemClipChain* intersection = nullptr;
+ if (aCache.Get(clip, &intersection)) {
+ i->SetClipChain(intersection, true);
+ } else {
+ i->IntersectClip(aBuilder, aExtraClip, true);
+ aCache.InsertOrUpdate(clip, i->GetClipChain());
+ }
+ }
+ nsDisplayList* children = i->GetSameCoordinateSystemChildren();
+ if (children) {
+ ClipItemsExceptCaret(children, aBuilder, aClipFrame, aExtraClip, aCache);
+ }
+ }
+}
+
+static void ClipListsExceptCaret(nsDisplayListCollection* aLists,
+ nsDisplayListBuilder* aBuilder,
+ nsIFrame* aClipFrame,
+ const DisplayItemClipChain* aExtraClip) {
+ nsTHashMap<nsPtrHashKey<const DisplayItemClipChain>,
+ const DisplayItemClipChain*>
+ cache;
+ ClipItemsExceptCaret(aLists->BorderBackground(), aBuilder, aClipFrame,
+ aExtraClip, cache);
+ ClipItemsExceptCaret(aLists->BlockBorderBackgrounds(), aBuilder, aClipFrame,
+ aExtraClip, cache);
+ ClipItemsExceptCaret(aLists->Floats(), aBuilder, aClipFrame, aExtraClip,
+ cache);
+ ClipItemsExceptCaret(aLists->PositionedDescendants(), aBuilder, aClipFrame,
+ aExtraClip, cache);
+ ClipItemsExceptCaret(aLists->Outlines(), aBuilder, aClipFrame, aExtraClip,
+ cache);
+ ClipItemsExceptCaret(aLists->Content(), aBuilder, aClipFrame, aExtraClip,
+ cache);
+}
+
+// This is similar to a "save-restore" RAII class for
+// DisplayListBuilder::ContainsBlendMode(), with a slight enhancement.
+// If this class is put on the stack and then unwound, the DL builder's
+// ContainsBlendMode flag will be effectively the same as if this class wasn't
+// put on the stack. However, if the CaptureContainsBlendMode method is called,
+// there will be a difference - the blend mode in the descendant display lists
+// will be "captured" and extracted.
+// The main goal here is to allow conditionally capturing the flag that
+// indicates whether or not a blend mode was encountered in the descendant part
+// of the display list.
+class MOZ_RAII AutoContainsBlendModeCapturer {
+ nsDisplayListBuilder& mBuilder;
+ bool mSavedContainsBlendMode;
+
+ public:
+ explicit AutoContainsBlendModeCapturer(nsDisplayListBuilder& aBuilder)
+ : mBuilder(aBuilder),
+ mSavedContainsBlendMode(aBuilder.ContainsBlendMode()) {
+ mBuilder.SetContainsBlendMode(false);
+ }
+
+ bool CaptureContainsBlendMode() {
+ // "Capture" the flag by extracting and clearing the ContainsBlendMode flag
+ // on the builder.
+ bool capturedBlendMode = mBuilder.ContainsBlendMode();
+ mBuilder.SetContainsBlendMode(false);
+ return capturedBlendMode;
+ }
+
+ ~AutoContainsBlendModeCapturer() {
+ // If CaptureContainsBlendMode() was called, the descendant blend mode was
+ // "captured" and so uncapturedContainsBlendMode will be false. If
+ // CaptureContainsBlendMode() wasn't called, then no capture occurred, and
+ // uncapturedContainsBlendMode may be true if there was a descendant blend
+ // mode. In that case, we set the flag on the DL builder so that we restore
+ // state to what it would have been without this RAII class on the stack.
+ bool uncapturedContainsBlendMode = mBuilder.ContainsBlendMode();
+ mBuilder.SetContainsBlendMode(mSavedContainsBlendMode ||
+ uncapturedContainsBlendMode);
+ }
+};
+
+void nsHTMLScrollFrame::MaybeCreateTopLayerAndWrapRootItems(
+ nsDisplayListBuilder* aBuilder, nsDisplayListCollection& aSet,
+ bool aCreateAsyncZoom,
+ AutoContainsBlendModeCapturer* aAsyncZoomBlendCapture,
+ const nsRect& aAsyncZoomClipRect, nscoord* aRadii) {
+ if (!mIsRoot) {
+ return;
+ }
+
+ // Create any required items for the 'top layer' and check if they'll be
+ // opaque over the entire area of the viewport. If they are, then we can
+ // skip building display items for the rest of the page.
+ if (ViewportFrame* viewport = do_QueryFrame(GetParent())) {
+ bool topLayerIsOpaque = false;
+ if (nsDisplayWrapList* topLayerWrapList =
+ viewport->BuildDisplayListForTopLayer(aBuilder,
+ &topLayerIsOpaque)) {
+ // If the top layer content is opaque, and we're the root content document
+ // in the process, we can drop the display items behind it. We only
+ // support doing this for the root content document in the process, since
+ // the top layer content might have fixed position items that have a
+ // scrolltarget referencing the APZ data for the document. APZ builds this
+ // data implicitly for the root content document in the process, but
+ // subdocuments etc need their display items to generate it, so we can't
+ // cull those.
+ if (topLayerIsOpaque && PresContext()->IsRootContentDocumentInProcess()) {
+ aSet.DeleteAll(aBuilder);
+ }
+ aSet.PositionedDescendants()->AppendToTop(topLayerWrapList);
+ }
+ }
+
+ nsDisplayList rootResultList(aBuilder);
+
+ bool serializedList = false;
+ auto SerializeList = [&] {
+ if (!serializedList) {
+ serializedList = true;
+ aSet.SerializeWithCorrectZOrder(&rootResultList, GetContent());
+ }
+ };
+
+ if (nsIFrame* rootStyleFrame = GetFrameForStyle()) {
+ bool usingBackdropFilter =
+ rootStyleFrame->StyleEffects()->HasBackdropFilters() &&
+ rootStyleFrame->IsVisibleForPainting();
+
+ if (rootStyleFrame->StyleEffects()->HasFilters() &&
+ !aBuilder->IsForGenerateGlyphMask()) {
+ SerializeList();
+ rootResultList.AppendNewToTop<nsDisplayFilters>(
+ aBuilder, this, &rootResultList, rootStyleFrame, usingBackdropFilter);
+ }
+
+ if (usingBackdropFilter) {
+ SerializeList();
+ DisplayListClipState::AutoSaveRestore clipState(aBuilder);
+ nsRect backdropRect =
+ GetRectRelativeToSelf() + aBuilder->ToReferenceFrame(this);
+ rootResultList.AppendNewToTop<nsDisplayBackdropFilters>(
+ aBuilder, this, &rootResultList, backdropRect, rootStyleFrame);
+ }
+ }
+
+ if (aCreateAsyncZoom) {
+ MOZ_ASSERT(mIsRoot);
+
+ // Wrap all our scrolled contents in an nsDisplayAsyncZoom. This will be
+ // the layer that gets scaled for APZ zooming. It does not have the
+ // scrolled ASR, but it does have the composition bounds clip applied to
+ // it. The children have the layout viewport clip applied to them (above).
+ // Effectively we are double clipping to the viewport, at potentially
+ // different async scales.
+ SerializeList();
+
+ if (aAsyncZoomBlendCapture->CaptureContainsBlendMode()) {
+ // The async zoom contents contain a mix-blend mode, so let's wrap all
+ // those contents into a blend container, and then wrap the blend
+ // container in the async zoom container. Otherwise the blend container
+ // ends up outside the zoom container which results in blend failure for
+ // WebRender.
+ nsDisplayItem* blendContainer =
+ nsDisplayBlendContainer::CreateForMixBlendMode(
+ aBuilder, this, &rootResultList,
+ aBuilder->CurrentActiveScrolledRoot());
+ rootResultList.AppendToTop(blendContainer);
+
+ // Blend containers can be created or omitted during partial updates
+ // depending on the dirty rect. So we basically can't do partial updates
+ // if there's a blend container involved. There is equivalent code to this
+ // in the BuildDisplayListForStackingContext function as well, with a more
+ // detailed comment explaining things better.
+ if (aBuilder->IsRetainingDisplayList()) {
+ if (aBuilder->IsPartialUpdate()) {
+ aBuilder->SetPartialBuildFailed(true);
+ } else {
+ aBuilder->SetDisablePartialUpdates(true);
+ }
+ }
+ }
+
+ mozilla::layers::FrameMetrics::ViewID viewID =
+ nsLayoutUtils::FindOrCreateIDFor(mScrolledFrame->GetContent());
+
+ DisplayListClipState::AutoSaveRestore clipState(aBuilder);
+ clipState.ClipContentDescendants(aAsyncZoomClipRect, aRadii);
+
+ rootResultList.AppendNewToTop<nsDisplayAsyncZoom>(
+ aBuilder, this, &rootResultList, aBuilder->CurrentActiveScrolledRoot(),
+ viewID);
+ }
+
+ if (serializedList) {
+ aSet.Content()->AppendToTop(&rootResultList);
+ }
+}
+
+void nsHTMLScrollFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
+ const nsDisplayListSet& aLists) {
+ SetAndNullOnExit<const nsIFrame> tmpBuilder(
+ mReferenceFrameDuringPainting, aBuilder->GetCurrentReferenceFrame());
+ if (aBuilder->IsForFrameVisibility()) {
+ NotifyApproximateFrameVisibilityUpdate(false);
+ }
+
+ DisplayBorderBackgroundOutline(aBuilder, aLists);
+
+ const bool isRootContent =
+ mIsRoot && PresContext()->IsRootContentDocumentCrossProcess();
+
+ nsRect effectiveScrollPort = mScrollPort;
+ if (isRootContent && PresContext()->HasDynamicToolbar()) {
+ // Expand the scroll port to the size including the area covered by dynamic
+ // toolbar in the case where the dynamic toolbar is being used since
+ // position:fixed elements attached to this root scroller might be taller
+ // than its scroll port (e.g 100vh). Even if the dynamic toolbar covers the
+ // taller area, it doesn't mean the area is clipped by the toolbar because
+ // the dynamic toolbar is laid out outside of our topmost window and it
+ // transitions without changing our topmost window size.
+ effectiveScrollPort.SizeTo(nsLayoutUtils::ExpandHeightForDynamicToolbar(
+ PresContext(), effectiveScrollPort.Size()));
+ }
+
+ // It's safe to get this value before the DecideScrollableLayer call below
+ // because that call cannot create a displayport for root scroll frames,
+ // and hence it cannot create an ignore scroll frame.
+ const bool ignoringThisScrollFrame = aBuilder->GetIgnoreScrollFrame() == this;
+
+ // Overflow clipping can never clip frames outside our subtree, so there
+ // is no need to worry about whether we are a moving frame that might clip
+ // non-moving frames.
+ // Not all our descendants will be clipped by overflow clipping, but all
+ // the ones that aren't clipped will be out of flow frames that have already
+ // had dirty rects saved for them by their parent frames calling
+ // MarkOutOfFlowChildrenForDisplayList, so it's safe to restrict our
+ // dirty rect here.
+ nsRect visibleRect = aBuilder->GetVisibleRect();
+ nsRect dirtyRect = aBuilder->GetDirtyRect();
+ if (!ignoringThisScrollFrame) {
+ visibleRect = visibleRect.Intersect(effectiveScrollPort);
+ dirtyRect = dirtyRect.Intersect(effectiveScrollPort);
+ }
+
+ bool dirtyRectHasBeenOverriden = false;
+ Unused << DecideScrollableLayer(aBuilder, &visibleRect, &dirtyRect,
+ /* aSetBase = */ !mIsRoot,
+ &dirtyRectHasBeenOverriden);
+
+ if (aBuilder->IsForFrameVisibility()) {
+ // We expand the dirty rect to catch frames just outside of the scroll port.
+ // We use the dirty rect instead of the whole scroll port to prevent
+ // too much expansion in the presence of very large (bigger than the
+ // viewport) scroll ports.
+ dirtyRect = ExpandRectToNearlyVisible(dirtyRect);
+ visibleRect = dirtyRect;
+ }
+
+ // We put non-overlay scrollbars in their own layers when this is the root
+ // scroll frame and we are a toplevel content document. In this situation,
+ // the scrollbar(s) would normally be assigned their own layer anyway, since
+ // they're not scrolled with the rest of the document. But when both
+ // scrollbars are visible, the layer's visible rectangle would be the size
+ // of the viewport, so most layer implementations would create a layer buffer
+ // that's much larger than necessary. Creating independent layers for each
+ // scrollbar works around the problem.
+ const bool createLayersForScrollbars = isRootContent;
+
+ nsDisplayListCollection set(aBuilder);
+
+ if (ignoringThisScrollFrame) {
+ // If we are a root scroll frame that has a display port we want to add
+ // scrollbars, they will be children of the scrollable layer, but they get
+ // adjusted by the APZC automatically.
+ bool addScrollBars =
+ mIsRoot && mWillBuildScrollableLayer && aBuilder->IsPaintingToWindow();
+
+ if (addScrollBars) {
+ // Add classic scrollbars.
+ AppendScrollPartsTo(aBuilder, set, createLayersForScrollbars, false);
+ }
+
+ {
+ nsDisplayListBuilder::AutoBuildingDisplayList building(
+ aBuilder, this, visibleRect, dirtyRect);
+
+ // Don't clip the scrolled child, and don't paint scrollbars/scrollcorner.
+ // The scrolled frame shouldn't have its own background/border, so we
+ // can just pass aLists directly.
+ BuildDisplayListForChild(aBuilder, mScrolledFrame, set);
+ }
+
+ MaybeCreateTopLayerAndWrapRootItems(aBuilder, set,
+ /* aCreateAsyncZoom = */ false, nullptr,
+ nsRect(), nullptr);
+
+ if (addScrollBars) {
+ // Add overlay scrollbars.
+ AppendScrollPartsTo(aBuilder, set, createLayersForScrollbars, true);
+ }
+
+ set.MoveTo(aLists);
+ return;
+ }
+
+ // Whether we might want to build a scrollable layer for this scroll frame
+ // at some point in the future. This controls whether we add the information
+ // to the layer tree (a scroll info layer if necessary, and add the right
+ // area to the dispatch to content layer event regions) necessary to activate
+ // a scroll frame so it creates a scrollable layer.
+ const bool couldBuildLayer = [&] {
+ if (!aBuilder->IsPaintingToWindow()) {
+ return false;
+ }
+ if (mWillBuildScrollableLayer) {
+ return true;
+ }
+ return StyleVisibility()->IsVisible() &&
+ nsLayoutUtils::AsyncPanZoomEnabled(this) && WantAsyncScroll();
+ }();
+
+ // Now display the scrollbars and scrollcorner. These parts are drawn
+ // in the border-background layer, on top of our own background and
+ // borders and underneath borders and backgrounds of later elements
+ // in the tree.
+ // Note that this does not apply for overlay scrollbars; those are drawn
+ // in the positioned-elements layer on top of everything else by the call
+ // to AppendScrollPartsTo(..., true) further down.
+ AppendScrollPartsTo(aBuilder, aLists, createLayersForScrollbars, false);
+
+ const nsStyleDisplay* disp = StyleDisplay();
+ if (aBuilder->IsForPainting() &&
+ disp->mWillChange.bits & StyleWillChangeBits::SCROLL) {
+ aBuilder->AddToWillChangeBudget(this, GetVisualViewportSize());
+ }
+
+ mScrollParentID = aBuilder->GetCurrentScrollParentId();
+
+ Maybe<nsRect> contentBoxClip;
+ Maybe<const DisplayItemClipChain*> extraContentBoxClipForNonCaretContent;
+ if (MOZ_UNLIKELY(
+ disp->mOverflowClipBoxBlock == StyleOverflowClipBox::ContentBox ||
+ disp->mOverflowClipBoxInline == StyleOverflowClipBox::ContentBox)) {
+ WritingMode wm = mScrolledFrame->GetWritingMode();
+ bool cbH = (wm.IsVertical() ? disp->mOverflowClipBoxBlock
+ : disp->mOverflowClipBoxInline) ==
+ StyleOverflowClipBox::ContentBox;
+ bool cbV = (wm.IsVertical() ? disp->mOverflowClipBoxInline
+ : disp->mOverflowClipBoxBlock) ==
+ StyleOverflowClipBox::ContentBox;
+ // We only clip if there is *scrollable* overflow, to avoid clipping
+ // *ink* overflow unnecessarily.
+ nsRect clipRect = effectiveScrollPort + aBuilder->ToReferenceFrame(this);
+ nsMargin padding = GetUsedPadding();
+ if (!cbH) {
+ padding.left = padding.right = nscoord(0);
+ }
+ if (!cbV) {
+ padding.top = padding.bottom = nscoord(0);
+ }
+ clipRect.Deflate(padding);
+
+ nsRect so = mScrolledFrame->ScrollableOverflowRect();
+ if ((cbH && (clipRect.width != so.width || so.x < 0)) ||
+ (cbV && (clipRect.height != so.height || so.y < 0))) {
+ // The non-inflated clip needs to be set on all non-caret items.
+ // We prepare an extra DisplayItemClipChain here that will be intersected
+ // with those items after they've been created.
+ const ActiveScrolledRoot* asr = aBuilder->CurrentActiveScrolledRoot();
+
+ DisplayItemClip newClip;
+ newClip.SetTo(clipRect);
+
+ const DisplayItemClipChain* extraClip =
+ aBuilder->AllocateDisplayItemClipChain(newClip, asr, nullptr);
+
+ extraContentBoxClipForNonCaretContent = Some(extraClip);
+
+ nsIFrame* caretFrame = aBuilder->GetCaretFrame();
+ // Avoid clipping it in a zero-height line box (heuristic only).
+ if (caretFrame && caretFrame->GetRect().height != 0) {
+ nsRect caretRect = aBuilder->GetCaretRect();
+ // Allow the caret to stick out of the content box clip by half the
+ // caret height on the top, and its full width on the right.
+ nsRect inflatedClip = clipRect;
+ inflatedClip.Inflate(
+ nsMargin(caretRect.height / 2, caretRect.width, 0, 0));
+ contentBoxClip = Some(inflatedClip);
+ }
+ }
+ }
+
+ AutoContainsBlendModeCapturer blendCapture(*aBuilder);
+
+ const bool willBuildAsyncZoomContainer =
+ mWillBuildScrollableLayer && aBuilder->ShouldBuildAsyncZoomContainer() &&
+ isRootContent;
+
+ nsRect scrollPortClip =
+ effectiveScrollPort + aBuilder->ToReferenceFrame(this);
+ nsRect clipRect = scrollPortClip;
+ // Our override of GetBorderRadii ensures we never have a radius at
+ // the corners where we have a scrollbar.
+ nscoord radii[8];
+ const bool haveRadii = GetPaddingBoxBorderRadii(radii);
+ if (mIsRoot) {
+ clipRect.SizeTo(nsLayoutUtils::CalculateCompositionSizeForFrame(
+ this, true /* aSubtractScrollbars */,
+ nullptr /* aOverrideScrollPortSize */,
+ // With the dynamic toolbar, this CalculateCompositionSizeForFrame call
+ // basically expands the region being covered up by the dynamic toolbar,
+ // but if the root scroll container is not scrollable, e.g. the root
+ // element has `overflow: hidden` or `position: fixed`, the function
+ // doesn't expand the region since expanding the region in such cases
+ // will prevent the content from restoring zooming to 1.0 zoom level
+ // such as bug 1652190. That said, this `clipRect` which will be used
+ // for the async zoom container needs to be expanded because zoomed-in
+ // contents can be scrollable __visually__ so that the region under the
+ // dynamic toolbar area will be revealed.
+ nsLayoutUtils::IncludeDynamicToolbar::Force));
+
+ // The composition size is essentially in visual coordinates.
+ // If we are hit-testing in layout coordinates, transform the clip rect
+ // to layout coordinates to match.
+ if (aBuilder->IsRelativeToLayoutViewport() && isRootContent) {
+ clipRect = ViewportUtils::VisualToLayout(clipRect, PresShell());
+ }
+ }
+
+ {
+ DisplayListClipState::AutoSaveRestore clipState(aBuilder);
+
+ // If we're building an async zoom container, clip the contents inside
+ // to the layout viewport (scrollPortClip). The composition bounds clip
+ // (clipRect) will be applied to the zoom container itself in
+ // MaybeCreateTopLayerAndWrapRootItems.
+ nsRect clipRectForContents =
+ willBuildAsyncZoomContainer ? scrollPortClip : clipRect;
+ if (mIsRoot) {
+ clipState.ClipContentDescendants(clipRectForContents,
+ haveRadii ? radii : nullptr);
+ } else {
+ clipState.ClipContainingBlockDescendants(clipRectForContents,
+ haveRadii ? radii : nullptr);
+ }
+
+ Maybe<DisplayListClipState::AutoSaveRestore> contentBoxClipState;
+ if (contentBoxClip) {
+ contentBoxClipState.emplace(aBuilder);
+ if (mIsRoot) {
+ contentBoxClipState->ClipContentDescendants(*contentBoxClip);
+ } else {
+ contentBoxClipState->ClipContainingBlockDescendants(*contentBoxClip);
+ }
+ }
+
+ nsDisplayListBuilder::AutoCurrentActiveScrolledRootSetter asrSetter(
+ aBuilder);
+
+ if (mWillBuildScrollableLayer && aBuilder->IsPaintingToWindow()) {
+ // If this scroll frame has a first scrollable frame sequence number,
+ // ensure that it matches the current paint sequence number. If it does
+ // not, reset it so that we can expire the displayport. The stored
+ // sequence number will not match that of the current paint if the dom
+ // was mutated in some way that alters the order of scroll frames.
+ if (IsFirstScrollableFrameSequenceNumber().isSome() &&
+ *IsFirstScrollableFrameSequenceNumber() !=
+ nsDisplayListBuilder::GetPaintSequenceNumber()) {
+ SetIsFirstScrollableFrameSequenceNumber(Nothing());
+ }
+ asrSetter.EnterScrollFrame(this);
+ }
+
+ if (couldBuildLayer && mScrolledFrame->GetContent()) {
+ asrSetter.SetCurrentScrollParentId(
+ nsLayoutUtils::FindOrCreateIDFor(mScrolledFrame->GetContent()));
+ }
+
+ if (mWillBuildScrollableLayer && aBuilder->BuildCompositorHitTestInfo()) {
+ // Create a hit test info item for the scrolled content that's not
+ // clipped to the displayport. This ensures that within the bounds
+ // of the scroll frame, the scrolled content is always hit, even
+ // if we are checkerboarding.
+ CompositorHitTestInfo info =
+ mScrolledFrame->GetCompositorHitTestInfo(aBuilder);
+
+ if (info != CompositorHitTestInvisibleToHit) {
+ auto* hitInfo =
+ MakeDisplayItemWithIndex<nsDisplayCompositorHitTestInfo>(
+ aBuilder, mScrolledFrame, 1);
+ if (hitInfo) {
+ aBuilder->SetCompositorHitTestInfo(info);
+ set.BorderBackground()->AppendToTop(hitInfo);
+ }
+ }
+ }
+
+ {
+ // Clip our contents to the unsnapped scrolled rect. This makes sure
+ // that we don't have display items over the subpixel seam at the edge
+ // of the scrolled area.
+ DisplayListClipState::AutoSaveRestore scrolledRectClipState(aBuilder);
+ nsRect scrolledRectClip =
+ GetUnsnappedScrolledRectInternal(
+ mScrolledFrame->ScrollableOverflowRect(), mScrollPort.Size()) +
+ mScrolledFrame->GetPosition();
+ bool clippedToDisplayPort = false;
+ if (mWillBuildScrollableLayer && aBuilder->IsPaintingToWindow()) {
+ // Clip the contents to the display port.
+ // The dirty rect already acts kind of like a clip, in that
+ // FrameLayerBuilder intersects item bounds and opaque regions with
+ // it, but it doesn't have the consistent snapping behavior of a
+ // true clip.
+ // For a case where this makes a difference, imagine the following
+ // scenario: The display port has an edge that falls on a fractional
+ // layer pixel, and there's an opaque display item that covers the
+ // whole display port up until that fractional edge, and there is a
+ // transparent display item that overlaps the edge. We want to prevent
+ // this transparent item from enlarging the scrolled layer's visible
+ // region beyond its opaque region. The dirty rect doesn't do that -
+ // it gets rounded out, whereas a true clip gets rounded to nearest
+ // pixels.
+ // If there is no display port, we don't need this because the clip
+ // from the scroll port is still applied.
+ scrolledRectClip = scrolledRectClip.Intersect(visibleRect);
+ clippedToDisplayPort = scrolledRectClip.IsEqualEdges(visibleRect);
+ }
+ scrolledRectClipState.ClipContainingBlockDescendants(
+ scrolledRectClip + aBuilder->ToReferenceFrame(this));
+ if (clippedToDisplayPort) {
+ // We have to do this after the ClipContainingBlockDescendants call
+ // above, otherwise that call will clobber the flag set by this call
+ // to SetClippedToDisplayPort.
+ scrolledRectClipState.SetClippedToDisplayPort();
+ }
+
+ nsRect visibleRectForChildren = visibleRect;
+ nsRect dirtyRectForChildren = dirtyRect;
+
+ // If we are entering the RCD-RSF, we are crossing the async zoom
+ // container boundary, and need to convert from visual to layout
+ // coordinates.
+ if (willBuildAsyncZoomContainer && aBuilder->IsForEventDelivery()) {
+ MOZ_ASSERT(ViewportUtils::IsZoomedContentRoot(mScrolledFrame));
+ visibleRectForChildren =
+ ViewportUtils::VisualToLayout(visibleRectForChildren, PresShell());
+ dirtyRectForChildren =
+ ViewportUtils::VisualToLayout(dirtyRectForChildren, PresShell());
+ }
+
+ nsDisplayListBuilder::AutoBuildingDisplayList building(
+ aBuilder, this, visibleRectForChildren, dirtyRectForChildren);
+
+ BuildDisplayListForChild(aBuilder, mScrolledFrame, set);
+
+ if (dirtyRectHasBeenOverriden &&
+ StaticPrefs::layout_display_list_show_rebuild_area()) {
+ nsDisplaySolidColor* color = MakeDisplayItem<nsDisplaySolidColor>(
+ aBuilder, this,
+ dirtyRect + aBuilder->GetCurrentFrameOffsetToReferenceFrame(),
+ NS_RGBA(0, 0, 255, 64), false);
+ if (color) {
+ color->SetOverrideZIndex(INT32_MAX);
+ set.PositionedDescendants()->AppendToTop(color);
+ }
+ }
+ }
+
+ if (extraContentBoxClipForNonCaretContent) {
+ // The items were built while the inflated content box clip was in
+ // effect, so that the caret wasn't clipped unnecessarily. We apply
+ // the non-inflated clip to the non-caret items now, by intersecting
+ // it with their existing clip.
+ ClipListsExceptCaret(&set, aBuilder, mScrolledFrame,
+ *extraContentBoxClipForNonCaretContent);
+ }
+
+ if (aBuilder->IsPaintingToWindow()) {
+ mIsParentToActiveScrollFrames =
+ ShouldActivateAllScrollFrames()
+ ? asrSetter.GetContainsNonMinimalDisplayPort()
+ : asrSetter.ShouldForceLayerForScrollParent();
+ }
+
+ if (asrSetter.ShouldForceLayerForScrollParent()) {
+ // Note that forcing layerization of scroll parents follows the scroll
+ // handoff chain which is subject to the out-of-flow-frames caveat noted
+ // above (where the asrSetter variable is created).
+ MOZ_ASSERT(couldBuildLayer && mScrolledFrame->GetContent() &&
+ aBuilder->IsPaintingToWindow());
+ if (!mWillBuildScrollableLayer) {
+ // Set a displayport so next paint we don't have to force layerization
+ // after the fact. It's ok to pass DoNotRepaint here, since we've
+ // already painted the change and we're just optimizing it to be
+ // detected earlier. We also won't confuse RetainedDisplayLists
+ // with the silent change, since we explicitly request partial updates
+ // to be disabled on the next paint.
+ DisplayPortUtils::SetDisplayPortMargins(
+ GetContent(), PresShell(), DisplayPortMargins::Empty(GetContent()),
+ DisplayPortUtils::ClearMinimalDisplayPortProperty::Yes, 0,
+ DisplayPortUtils::RepaintMode::DoNotRepaint);
+ // Call DecideScrollableLayer to recompute mWillBuildScrollableLayer
+ // and recompute the current animated geometry root if needed. It's
+ // too late to change the dirty rect so pass a copy.
+ nsRect copyOfDirtyRect = dirtyRect;
+ nsRect copyOfVisibleRect = visibleRect;
+ Unused << DecideScrollableLayer(aBuilder, &copyOfVisibleRect,
+ &copyOfDirtyRect,
+ /* aSetBase = */ false, nullptr);
+ if (mWillBuildScrollableLayer) {
+ asrSetter.InsertScrollFrame(this);
+ aBuilder->SetDisablePartialUpdates(true);
+ }
+ }
+ }
+ }
+
+ if (mWillBuildScrollableLayer && aBuilder->IsPaintingToWindow()) {
+ aBuilder->ForceLayerForScrollParent();
+ }
+
+ MaybeCreateTopLayerAndWrapRootItems(
+ aBuilder, set, willBuildAsyncZoomContainer, &blendCapture, clipRect,
+ haveRadii ? radii : nullptr);
+
+ // We want to call SetContainsNonMinimalDisplayPort if
+ // mWillBuildScrollableLayer is true for any reason other than having a
+ // minimal display port.
+ if (aBuilder->IsPaintingToWindow()) {
+ if (DisplayPortUtils::HasNonMinimalDisplayPort(GetContent()) ||
+ mZoomableByAPZ || nsContentUtils::HasScrollgrab(GetContent())) {
+ aBuilder->SetContainsNonMinimalDisplayPort();
+ }
+ }
+
+ if (couldBuildLayer) {
+ CompositorHitTestInfo info(CompositorHitTestFlags::eVisibleToHitTest,
+ CompositorHitTestFlags::eInactiveScrollframe);
+ // If the scroll frame has non-default overscroll-behavior, instruct
+ // APZ to require a target confirmation before processing events that
+ // hit this scroll frame (that is, to drop the events if a
+ // confirmation does not arrive within the timeout period). Otherwise,
+ // APZ's fallback behaviour of scrolling the enclosing scroll frame
+ // would violate the specified overscroll-behavior.
+ auto overscroll = GetOverscrollBehaviorInfo();
+ if (overscroll.mBehaviorX != OverscrollBehavior::Auto ||
+ overscroll.mBehaviorY != OverscrollBehavior::Auto) {
+ info += CompositorHitTestFlags::eRequiresTargetConfirmation;
+ }
+
+ nsRect area = effectiveScrollPort + aBuilder->ToReferenceFrame(this);
+
+ // Make sure that APZ will dispatch events back to content so we can
+ // create a displayport for this frame. We'll add the item later on.
+ if (!mWillBuildScrollableLayer && aBuilder->BuildCompositorHitTestInfo()) {
+ // Make sure the z-index of the inactive item is at least zero.
+ // Otherwise, it will end up behind non-positioned items in the scrolled
+ // content.
+ int32_t zIndex = MaxZIndexInListOfItemsContainedInFrame(
+ set.PositionedDescendants(), this)
+ .valueOr(0);
+ if (aBuilder->IsPartialUpdate()) {
+ for (nsDisplayItem* item : mScrolledFrame->DisplayItems()) {
+ if (item->GetType() ==
+ DisplayItemType::TYPE_COMPOSITOR_HITTEST_INFO) {
+ auto* hitTestItem =
+ static_cast<nsDisplayCompositorHitTestInfo*>(item);
+ if (hitTestItem->GetHitTestInfo().Info().contains(
+ CompositorHitTestFlags::eInactiveScrollframe)) {
+ zIndex = std::max(zIndex, hitTestItem->ZIndex());
+ item->SetCantBeReused();
+ }
+ }
+ }
+ }
+ nsDisplayCompositorHitTestInfo* hitInfo =
+ MakeDisplayItemWithIndex<nsDisplayCompositorHitTestInfo>(
+ aBuilder, mScrolledFrame, 1, area, info);
+ if (hitInfo) {
+ AppendInternalItemToTop(set, hitInfo, Some(zIndex));
+ aBuilder->SetCompositorHitTestInfo(info);
+ }
+ }
+
+ if (aBuilder->ShouldBuildScrollInfoItemsForHoisting()) {
+ aBuilder->AppendNewScrollInfoItemForHoisting(
+ MakeDisplayItem<nsDisplayScrollInfoLayer>(aBuilder, mScrolledFrame,
+ this, info, area));
+ }
+ }
+
+ // Now display overlay scrollbars and the resizer, if we have one.
+ AppendScrollPartsTo(aBuilder, set, createLayersForScrollbars, true);
+
+ set.MoveTo(aLists);
+}
+
+nsRect nsHTMLScrollFrame::RestrictToRootDisplayPort(
+ const nsRect& aDisplayportBase) {
+ // This function clips aDisplayportBase so that it is no larger than the
+ // root frame's displayport (or the root composition bounds, if we can't
+ // obtain the root frame's displayport). This is useful for ensuring that
+ // the displayport of a tall scrollframe doesn't gobble up all the memory.
+
+ nsPresContext* pc = PresContext();
+ const nsPresContext* rootPresContext =
+ pc->GetInProcessRootContentDocumentPresContext();
+ if (!rootPresContext) {
+ rootPresContext = pc->GetRootPresContext();
+ }
+ if (!rootPresContext) {
+ return aDisplayportBase;
+ }
+ const mozilla::PresShell* const rootPresShell = rootPresContext->PresShell();
+ nsIFrame* rootFrame = rootPresShell->GetRootScrollFrame();
+ if (!rootFrame) {
+ rootFrame = rootPresShell->GetRootFrame();
+ }
+ if (!rootFrame) {
+ return aDisplayportBase;
+ }
+
+ // Make sure we aren't trying to restrict to our own displayport, which is a
+ // circular dependency.
+ MOZ_ASSERT(!mIsRoot || rootPresContext != pc);
+
+ nsRect rootDisplayPort;
+ bool hasDisplayPort =
+ rootFrame->GetContent() && DisplayPortUtils::GetDisplayPort(
+ rootFrame->GetContent(), &rootDisplayPort);
+ if (hasDisplayPort) {
+ // The display port of the root frame already factors in it's callback
+ // transform, so subtract it out here, the GetCumulativeApzCallbackTransform
+ // call below will add it back.
+ MOZ_LOG(sDisplayportLog, LogLevel::Verbose,
+ ("RestrictToRootDisplayPort: Existing root displayport is %s\n",
+ ToString(rootDisplayPort).c_str()));
+ if (nsIContent* content = rootFrame->GetContent()) {
+ if (void* property =
+ content->GetProperty(nsGkAtoms::apzCallbackTransform)) {
+ rootDisplayPort -=
+ CSSPoint::ToAppUnits(*static_cast<CSSPoint*>(property));
+ }
+ }
+ } else {
+ // If we don't have a display port on the root frame let's fall back to
+ // the root composition bounds instead.
+ nsRect rootCompBounds =
+ nsRect(nsPoint(0, 0),
+ nsLayoutUtils::CalculateCompositionSizeForFrame(rootFrame));
+
+ // If rootFrame is the RCD-RSF then
+ // CalculateCompositionSizeForFrame did not take the document's
+ // resolution into account, so we must.
+ if (rootPresContext->IsRootContentDocumentCrossProcess() &&
+ rootFrame == rootPresShell->GetRootScrollFrame()) {
+ MOZ_LOG(
+ sDisplayportLog, LogLevel::Verbose,
+ ("RestrictToRootDisplayPort: Removing resolution %f from root "
+ "composition bounds %s\n",
+ rootPresShell->GetResolution(), ToString(rootCompBounds).c_str()));
+ rootCompBounds =
+ rootCompBounds.RemoveResolution(rootPresShell->GetResolution());
+ }
+
+ rootDisplayPort = rootCompBounds;
+ }
+ MOZ_LOG(sDisplayportLog, LogLevel::Verbose,
+ ("RestrictToRootDisplayPort: Intermediate root displayport %s\n",
+ ToString(rootDisplayPort).c_str()));
+
+ // We want to convert the root display port from the
+ // coordinate space of |rootFrame| to the coordinate space of
+ // |this|. We do that with the TransformRect call below.
+ // However, since we care about the root display port
+ // relative to what the user is actually seeing, we also need to
+ // incorporate the APZ callback transforms into this. Most of the
+ // time those transforms are negligible, but in some cases (e.g.
+ // when a zoom is applied on an overflow:hidden document) it is
+ // not (see bug 1280013).
+ // XXX: Eventually we may want to create a modified version of
+ // TransformRect that includes the APZ callback transforms
+ // directly.
+ nsLayoutUtils::TransformRect(rootFrame, this, rootDisplayPort);
+ MOZ_LOG(sDisplayportLog, LogLevel::Verbose,
+ ("RestrictToRootDisplayPort: Transformed root displayport %s\n",
+ ToString(rootDisplayPort).c_str()));
+ rootDisplayPort += CSSPoint::ToAppUnits(
+ nsLayoutUtils::GetCumulativeApzCallbackTransform(this));
+ MOZ_LOG(sDisplayportLog, LogLevel::Verbose,
+ ("RestrictToRootDisplayPort: Final root displayport %s\n",
+ ToString(rootDisplayPort).c_str()));
+
+ // We want to limit aDisplayportBase to be no larger than
+ // rootDisplayPort on either axis, but we don't want to just
+ // blindly intersect the two, because rootDisplayPort might be
+ // offset from where aDisplayportBase is (see bug 1327095 comment
+ // 8). Instead, we translate rootDisplayPort so as to maximize the
+ // overlap with aDisplayportBase, and *then* do the intersection.
+ if (rootDisplayPort.x > aDisplayportBase.x &&
+ rootDisplayPort.XMost() > aDisplayportBase.XMost()) {
+ // rootDisplayPort is at a greater x-position for both left and
+ // right, so translate it such that the XMost() values are the
+ // same. This will line up the right edge of the two rects, and
+ // might mean that rootDisplayPort.x is smaller than
+ // aDisplayportBase.x. We can avoid that by taking the min of the
+ // x delta and XMost() delta, but it doesn't really matter
+ // because the intersection between the two rects below will end
+ // up the same.
+ rootDisplayPort.x -= (rootDisplayPort.XMost() - aDisplayportBase.XMost());
+ } else if (rootDisplayPort.x < aDisplayportBase.x &&
+ rootDisplayPort.XMost() < aDisplayportBase.XMost()) {
+ // Analaogous code for when the rootDisplayPort is at a smaller
+ // x-position.
+ rootDisplayPort.x = aDisplayportBase.x;
+ }
+ // Do the same for y-axis
+ if (rootDisplayPort.y > aDisplayportBase.y &&
+ rootDisplayPort.YMost() > aDisplayportBase.YMost()) {
+ rootDisplayPort.y -= (rootDisplayPort.YMost() - aDisplayportBase.YMost());
+ } else if (rootDisplayPort.y < aDisplayportBase.y &&
+ rootDisplayPort.YMost() < aDisplayportBase.YMost()) {
+ rootDisplayPort.y = aDisplayportBase.y;
+ }
+ MOZ_LOG(
+ sDisplayportLog, LogLevel::Verbose,
+ ("RestrictToRootDisplayPort: Root displayport translated to %s to "
+ "better enclose %s\n",
+ ToString(rootDisplayPort).c_str(), ToString(aDisplayportBase).c_str()));
+
+ // Now we can do the intersection
+ return aDisplayportBase.Intersect(rootDisplayPort);
+}
+
+/* static */ bool nsHTMLScrollFrame::ShouldActivateAllScrollFrames() {
+ return (StaticPrefs::apz_wr_activate_all_scroll_frames() ||
+ (StaticPrefs::apz_wr_activate_all_scroll_frames_when_fission() &&
+ FissionAutostart()));
+}
+
+bool nsHTMLScrollFrame::DecideScrollableLayer(
+ nsDisplayListBuilder* aBuilder, nsRect* aVisibleRect, nsRect* aDirtyRect,
+ bool aSetBase, bool* aDirtyRectHasBeenOverriden) {
+ nsIContent* content = GetContent();
+ // For hit testing purposes with fission we want to create a
+ // minimal display port for every scroll frame that could be active. (We only
+ // do this when aSetBase is true because we only want to do this the first
+ // time this function is called for the same scroll frame.)
+ if (ShouldActivateAllScrollFrames() &&
+ !DisplayPortUtils::HasDisplayPort(content) &&
+ nsLayoutUtils::AsyncPanZoomEnabled(this) && WantAsyncScroll() &&
+ aBuilder->IsPaintingToWindow() && aSetBase) {
+ // SetDisplayPortMargins calls TriggerDisplayPortExpiration which starts a
+ // display port expiry timer for display ports that do expire. However
+ // minimal display ports do not expire, so the display port has to be
+ // marked before the SetDisplayPortMargins call so the expiry timer
+ // doesn't get started.
+ content->SetProperty(nsGkAtoms::MinimalDisplayPort,
+ reinterpret_cast<void*>(true));
+
+ DisplayPortUtils::SetDisplayPortMargins(
+ content, PresShell(), DisplayPortMargins::Empty(content),
+ DisplayPortUtils::ClearMinimalDisplayPortProperty::No, 0,
+ DisplayPortUtils::RepaintMode::DoNotRepaint);
+ }
+
+ bool usingDisplayPort = DisplayPortUtils::HasDisplayPort(content);
+ if (aBuilder->IsPaintingToWindow()) {
+ if (aSetBase) {
+ nsRect displayportBase = *aVisibleRect;
+ nsPresContext* pc = PresContext();
+
+ bool isContentRootDoc = pc->IsRootContentDocumentCrossProcess();
+ bool isChromeRootDoc =
+ !pc->Document()->IsContentDocument() && !pc->GetParentPresContext();
+
+ if (mIsRoot && (isContentRootDoc || isChromeRootDoc)) {
+ displayportBase =
+ nsRect(nsPoint(0, 0),
+ nsLayoutUtils::CalculateCompositionSizeForFrame(this));
+ } else {
+ // Make the displayport base equal to the visible rect restricted to
+ // the scrollport and the root composition bounds, relative to the
+ // scrollport.
+ displayportBase = aVisibleRect->Intersect(mScrollPort);
+
+ mozilla::layers::ScrollableLayerGuid::ViewID viewID =
+ mozilla::layers::ScrollableLayerGuid::NULL_SCROLL_ID;
+ if (MOZ_LOG_TEST(sDisplayportLog, LogLevel::Verbose)) {
+ nsLayoutUtils::FindIDFor(GetContent(), &viewID);
+ MOZ_LOG(
+ sDisplayportLog, LogLevel::Verbose,
+ ("Scroll id %" PRIu64 " has visible rect %s, scroll port %s\n",
+ viewID, ToString(*aVisibleRect).c_str(),
+ ToString(mScrollPort).c_str()));
+ }
+
+ // Only restrict to the root displayport bounds if necessary,
+ // as the required coordinate transformation is expensive.
+ // And don't call RestrictToRootDisplayPort if we would be trying to
+ // restrict to our own display port, which doesn't make sense (ie if we
+ // are a root scroll frame in a process root prescontext).
+ if (usingDisplayPort && (!mIsRoot || pc->GetParentPresContext())) {
+ displayportBase = RestrictToRootDisplayPort(displayportBase);
+ MOZ_LOG(sDisplayportLog, LogLevel::Verbose,
+ ("Scroll id %" PRIu64 " has restricted base %s\n", viewID,
+ ToString(displayportBase).c_str()));
+ }
+ displayportBase -= mScrollPort.TopLeft();
+ }
+
+ DisplayPortUtils::SetDisplayPortBase(GetContent(), displayportBase);
+ }
+
+ // If we don't have aSetBase == true then should have already
+ // been called with aSetBase == true which should have set a
+ // displayport base.
+ MOZ_ASSERT(content->GetProperty(nsGkAtoms::DisplayPortBase));
+ nsRect displayPort;
+ usingDisplayPort = DisplayPortUtils::GetDisplayPort(
+ content, &displayPort,
+ DisplayPortOptions().With(DisplayportRelativeTo::ScrollFrame));
+
+ auto OverrideDirtyRect = [&](const nsRect& aRect) {
+ *aDirtyRect = aRect;
+ if (aDirtyRectHasBeenOverriden) {
+ *aDirtyRectHasBeenOverriden = true;
+ }
+ };
+
+ if (usingDisplayPort) {
+ // Override the dirty rectangle if the displayport has been set.
+ *aVisibleRect = displayPort;
+ if (aBuilder->IsReusingStackingContextItems() ||
+ !aBuilder->IsPartialUpdate() || aBuilder->InInvalidSubtree() ||
+ IsFrameModified()) {
+ OverrideDirtyRect(displayPort);
+ } else if (HasOverrideDirtyRegion()) {
+ nsRect* rect = GetProperty(
+ nsDisplayListBuilder::DisplayListBuildingDisplayPortRect());
+ if (rect) {
+ OverrideDirtyRect(*rect);
+ }
+ }
+ } else if (mIsRoot) {
+ // The displayPort getter takes care of adjusting for resolution. So if
+ // we have resolution but no displayPort then we need to adjust for
+ // resolution here.
+ auto* presShell = PresShell();
+ *aVisibleRect =
+ aVisibleRect->RemoveResolution(presShell->GetResolution());
+ *aDirtyRect = aDirtyRect->RemoveResolution(presShell->GetResolution());
+ }
+ }
+
+ // Since making new layers is expensive, only create a scrollable layer
+ // for some scroll frames.
+ // When a displayport is being used, force building of a layer so that
+ // the compositor can find the scrollable layer for async scrolling.
+ // If the element is marked 'scrollgrab', also force building of a layer
+ // so that APZ can implement scroll grabbing.
+ mWillBuildScrollableLayer = usingDisplayPort ||
+ nsContentUtils::HasScrollgrab(content) ||
+ mZoomableByAPZ;
+ return mWillBuildScrollableLayer;
+}
+
+void nsHTMLScrollFrame::NotifyApzTransaction() {
+ mAllowScrollOriginDowngrade = true;
+ mApzScrollPos = GetScrollPosition();
+ mApzAnimationRequested = IsLastScrollUpdateAnimating();
+ mApzAnimationTriggeredByScriptRequested =
+ IsLastScrollUpdateTriggeredByScriptAnimating();
+ mScrollUpdates.Clear();
+ if (mIsRoot) {
+ PresShell()->SetResolutionUpdated(false);
+ }
+}
+
+Maybe<ScrollMetadata> nsHTMLScrollFrame::ComputeScrollMetadata(
+ WebRenderLayerManager* aLayerManager, const nsIFrame* aItemFrame,
+ const nsPoint& aOffsetToReferenceFrame) const {
+ if (!mWillBuildScrollableLayer) {
+ return Nothing();
+ }
+
+ bool isRootContent =
+ mIsRoot && PresContext()->IsRootContentDocumentCrossProcess();
+
+ MOZ_ASSERT(mScrolledFrame->GetContent());
+
+ return Some(nsLayoutUtils::ComputeScrollMetadata(
+ mScrolledFrame, this, GetContent(), aItemFrame, aOffsetToReferenceFrame,
+ aLayerManager, mScrollParentID, mScrollPort.Size(), isRootContent));
+}
+
+bool nsHTMLScrollFrame::IsRectNearlyVisible(const nsRect& aRect) const {
+ // Use the right rect depending on if a display port is set.
+ nsRect displayPort;
+ bool usingDisplayport = DisplayPortUtils::GetDisplayPort(
+ GetContent(), &displayPort,
+ DisplayPortOptions().With(DisplayportRelativeTo::ScrollFrame));
+
+ if (mIsRoot && !usingDisplayport &&
+ PresContext()->IsRootContentDocumentInProcess() &&
+ !PresContext()->IsRootContentDocumentCrossProcess()) {
+ // In the case of the root scroller of OOP iframes, there are cases where
+ // any display port value isn't set, e.g. the iframe element is out of view
+ // in the parent document. In such cases we'd consider the iframe is not
+ // visible.
+ return false;
+ }
+
+ return aRect.Intersects(
+ ExpandRectToNearlyVisible(usingDisplayport ? displayPort : mScrollPort));
+}
+
+OverscrollBehaviorInfo nsHTMLScrollFrame::GetOverscrollBehaviorInfo() const {
+ nsIFrame* frame = GetFrameForStyle();
+ if (!frame) {
+ return {};
+ }
+
+ auto& disp = *frame->StyleDisplay();
+ return OverscrollBehaviorInfo::FromStyleConstants(disp.mOverscrollBehaviorX,
+ disp.mOverscrollBehaviorY);
+}
+
+ScrollStyles nsHTMLScrollFrame::GetScrollStyles() const {
+ nsPresContext* presContext = PresContext();
+ if (!presContext->IsDynamic() &&
+ !(mIsRoot && presContext->HasPaginatedScrolling())) {
+ return ScrollStyles(StyleOverflow::Hidden, StyleOverflow::Hidden);
+ }
+
+ if (!mIsRoot) {
+ return ScrollStyles(*StyleDisplay(),
+ ScrollStyles::MapOverflowToValidScrollStyle);
+ }
+
+ ScrollStyles result = presContext->GetViewportScrollStylesOverride();
+ if (nsDocShell* ds = presContext->GetDocShell()) {
+ switch (ds->ScrollbarPreference()) {
+ case ScrollbarPreference::Auto:
+ break;
+ case ScrollbarPreference::Never:
+ result.mHorizontal = result.mVertical = StyleOverflow::Hidden;
+ break;
+ }
+ }
+ return result;
+}
+
+nsRect nsHTMLScrollFrame::GetLayoutScrollRange() const {
+ return GetScrollRange(mScrollPort.width, mScrollPort.height);
+}
+
+nsRect nsHTMLScrollFrame::GetScrollRange(nscoord aWidth,
+ nscoord aHeight) const {
+ nsRect range = GetScrolledRect();
+ range.width = std::max(range.width - aWidth, 0);
+ range.height = std::max(range.height - aHeight, 0);
+ return range;
+}
+
+nsRect nsHTMLScrollFrame::GetVisualScrollRange() const {
+ nsSize visualViewportSize = GetVisualViewportSize();
+ return GetScrollRange(visualViewportSize.width, visualViewportSize.height);
+}
+
+nsSize nsHTMLScrollFrame::GetVisualViewportSize() const {
+ auto* presShell = PresShell();
+ if (mIsRoot && presShell->IsVisualViewportSizeSet()) {
+ return presShell->GetVisualViewportSize();
+ }
+ return mScrollPort.Size();
+}
+
+nsPoint nsHTMLScrollFrame::GetVisualViewportOffset() const {
+ if (mIsRoot) {
+ auto* presShell = PresShell();
+ if (auto pendingUpdate = presShell->GetPendingVisualScrollUpdate()) {
+ // The pending visual scroll update on the PresShell contains a raw,
+ // unclamped offset (basically, whatever was passed to ScrollToVisual()).
+ // It will be clamped on the APZ side, but if we use it as the
+ // main-thread's visual viewport offset we need to clamp it ourselves.
+ // Use GetScrollRangeForUserInputEvents() to do the clamping because this
+ // the scroll range that APZ will use.
+ return GetScrollRangeForUserInputEvents().ClampPoint(
+ pendingUpdate->mVisualScrollOffset);
+ }
+ return presShell->GetVisualViewportOffset();
+ }
+ return GetScrollPosition();
+}
+
+bool nsHTMLScrollFrame::SetVisualViewportOffset(const nsPoint& aOffset,
+ bool aRepaint) {
+ MOZ_ASSERT(mIsRoot);
+ AutoWeakFrame weakFrame(this);
+ AutoScrollbarRepaintSuppression repaintSuppression(this, weakFrame,
+ !aRepaint);
+
+ bool retVal =
+ PresShell()->SetVisualViewportOffset(aOffset, GetScrollPosition());
+ if (!weakFrame.IsAlive()) {
+ return false;
+ }
+ return retVal;
+}
+
+nsRect nsHTMLScrollFrame::GetVisualOptimalViewingRect() const {
+ auto* presShell = PresShell();
+ nsRect rect = mScrollPort;
+ if (mIsRoot && presShell->IsVisualViewportSizeSet() &&
+ presShell->IsVisualViewportOffsetSet()) {
+ rect = nsRect(mScrollPort.TopLeft() - GetScrollPosition() +
+ presShell->GetVisualViewportOffset(),
+ presShell->GetVisualViewportSize());
+ }
+ // NOTE: We intentionally resolve scroll-padding percentages against the
+ // scrollport even when the visual viewport is set, see
+ // https://github.com/w3c/csswg-drafts/issues/4393.
+ rect.Deflate(GetScrollPadding());
+ return rect;
+}
+
+static void AdjustDestinationForWholeDelta(const nsIntPoint& aDelta,
+ const nsRect& aScrollRange,
+ nsPoint& aPoint) {
+ if (aDelta.x < 0) {
+ aPoint.x = aScrollRange.X();
+ } else if (aDelta.x > 0) {
+ aPoint.x = aScrollRange.XMost();
+ }
+ if (aDelta.y < 0) {
+ aPoint.y = aScrollRange.Y();
+ } else if (aDelta.y > 0) {
+ aPoint.y = aScrollRange.YMost();
+ }
+}
+
+/**
+ * Calculate lower/upper scrollBy range in given direction.
+ * @param aDelta specifies scrollBy direction, if 0 then range will be 0 size
+ * @param aPos desired destination in AppUnits
+ * @param aNeg/PosTolerance defines relative range distance
+ * below and above of aPos point
+ * @param aMultiplier used for conversion of tolerance into appUnis
+ */
+static void CalcRangeForScrollBy(int32_t aDelta, nscoord aPos,
+ float aNegTolerance, float aPosTolerance,
+ nscoord aMultiplier, nscoord* aLower,
+ nscoord* aUpper) {
+ if (!aDelta) {
+ *aLower = *aUpper = aPos;
+ return;
+ }
+ *aLower = aPos - NSToCoordRound(aMultiplier *
+ (aDelta > 0 ? aNegTolerance : aPosTolerance));
+ *aUpper = aPos + NSToCoordRound(aMultiplier *
+ (aDelta > 0 ? aPosTolerance : aNegTolerance));
+}
+
+void nsHTMLScrollFrame::ScrollBy(nsIntPoint aDelta, ScrollUnit aUnit,
+ ScrollMode aMode, nsIntPoint* aOverflow,
+ ScrollOrigin aOrigin,
+ nsIScrollableFrame::ScrollMomentum aMomentum,
+ ScrollSnapFlags aSnapFlags) {
+ // When a smooth scroll is being processed on a frame, mouse wheel and
+ // trackpad momentum scroll event updates must notcancel the SMOOTH or
+ // SMOOTH_MSD scroll animations, enabling Javascript that depends on them to
+ // be responsive without forcing the user to wait for the fling animations to
+ // completely stop.
+ switch (aMomentum) {
+ case nsIScrollableFrame::NOT_MOMENTUM:
+ mIgnoreMomentumScroll = false;
+ break;
+ case nsIScrollableFrame::SYNTHESIZED_MOMENTUM_EVENT:
+ if (mIgnoreMomentumScroll) {
+ return;
+ }
+ break;
+ }
+
+ if (mAsyncSmoothMSDScroll != nullptr) {
+ // When CSSOM-View scroll-behavior smooth scrolling is interrupted,
+ // the scroll is not completed to avoid non-smooth snapping to the
+ // prior smooth scroll's destination.
+ mDestination = GetScrollPosition();
+ }
+
+ nsSize deltaMultiplier;
+ float negativeTolerance;
+ float positiveTolerance;
+ if (aOrigin == ScrollOrigin::NotSpecified) {
+ aOrigin = ScrollOrigin::Other;
+ }
+ bool isGenericOrigin = (aOrigin == ScrollOrigin::Other);
+
+ bool askApzToDoTheScroll = false;
+ if ((aSnapFlags == ScrollSnapFlags::Disabled || !NeedsScrollSnap()) &&
+ gfxPlatform::UseDesktopZoomingScrollbars() &&
+ nsLayoutUtils::AsyncPanZoomEnabled(this) &&
+ !nsLayoutUtils::ShouldDisableApzForElement(GetContent()) &&
+ (WantAsyncScroll() || mZoomableByAPZ) &&
+ CanApzScrollInTheseDirections(DirectionsInDelta(aDelta))) {
+ askApzToDoTheScroll = true;
+ }
+
+ switch (aUnit) {
+ case ScrollUnit::DEVICE_PIXELS: {
+ nscoord appUnitsPerDevPixel = PresContext()->AppUnitsPerDevPixel();
+ deltaMultiplier = nsSize(appUnitsPerDevPixel, appUnitsPerDevPixel);
+ if (isGenericOrigin) {
+ aOrigin = ScrollOrigin::Pixels;
+ }
+ negativeTolerance = positiveTolerance = 0.5f;
+ break;
+ }
+ case ScrollUnit::LINES: {
+ deltaMultiplier = GetLineScrollAmount();
+ if (isGenericOrigin) {
+ aOrigin = ScrollOrigin::Lines;
+ }
+ negativeTolerance = positiveTolerance = 0.1f;
+ break;
+ }
+ case ScrollUnit::PAGES: {
+ deltaMultiplier = GetPageScrollAmount();
+ if (isGenericOrigin) {
+ aOrigin = ScrollOrigin::Pages;
+ }
+ negativeTolerance = 0.05f;
+ positiveTolerance = 0;
+ break;
+ }
+ case ScrollUnit::WHOLE: {
+ if (askApzToDoTheScroll) {
+ MOZ_ASSERT(aDelta.x >= -1 && aDelta.x <= 1 && aDelta.y >= -1 &&
+ aDelta.y <= 1);
+ deltaMultiplier = GetScrollRangeForUserInputEvents().Size();
+ break;
+ } else {
+ nsPoint pos = GetScrollPosition();
+ AdjustDestinationForWholeDelta(aDelta, GetLayoutScrollRange(), pos);
+ ScrollToWithOrigin(
+ pos, nullptr /* range */,
+ ScrollOperationParams{aMode, ScrollOrigin::Other, aSnapFlags,
+ ScrollTriggeredByScript::No});
+ // 'this' might be destroyed here
+ if (aOverflow) {
+ *aOverflow = nsIntPoint(0, 0);
+ }
+ return;
+ }
+ }
+ default:
+ NS_ERROR("Invalid scroll mode");
+ return;
+ }
+
+ if (askApzToDoTheScroll) {
+ nsPoint delta(
+ NSCoordSaturatingNonnegativeMultiply(aDelta.x, deltaMultiplier.width),
+ NSCoordSaturatingNonnegativeMultiply(aDelta.y, deltaMultiplier.height));
+
+ AppendScrollUpdate(
+ ScrollPositionUpdate::NewPureRelativeScroll(aOrigin, aMode, delta));
+
+ nsIContent* content = GetContent();
+ if (!DisplayPortUtils::HasNonMinimalNonZeroDisplayPort(content)) {
+ if (MOZ_LOG_TEST(sDisplayportLog, LogLevel::Debug)) {
+ mozilla::layers::ScrollableLayerGuid::ViewID viewID =
+ mozilla::layers::ScrollableLayerGuid::NULL_SCROLL_ID;
+ nsLayoutUtils::FindIDFor(content, &viewID);
+ MOZ_LOG(
+ sDisplayportLog, LogLevel::Debug,
+ ("ScrollBy setting displayport on scrollId=%" PRIu64 "\n", viewID));
+ }
+
+ DisplayPortUtils::CalculateAndSetDisplayPortMargins(
+ GetScrollTargetFrame(), DisplayPortUtils::RepaintMode::Repaint);
+ nsIFrame* frame = do_QueryFrame(GetScrollTargetFrame());
+ DisplayPortUtils::SetZeroMarginDisplayPortOnAsyncScrollableAncestors(
+ frame);
+ }
+
+ SchedulePaint();
+ return;
+ }
+
+ nsPoint newPos(NSCoordSaturatingAdd(mDestination.x,
+ NSCoordSaturatingNonnegativeMultiply(
+ aDelta.x, deltaMultiplier.width)),
+ NSCoordSaturatingAdd(mDestination.y,
+ NSCoordSaturatingNonnegativeMultiply(
+ aDelta.y, deltaMultiplier.height)));
+
+ Maybe<SnapTarget> snapTarget;
+ if (aSnapFlags != ScrollSnapFlags::Disabled) {
+ if (NeedsScrollSnap()) {
+ nscoord appUnitsPerDevPixel = PresContext()->AppUnitsPerDevPixel();
+ deltaMultiplier = nsSize(appUnitsPerDevPixel, appUnitsPerDevPixel);
+ negativeTolerance = 0.1f;
+ positiveTolerance = 0;
+ ScrollUnit snapUnit = aUnit;
+ if (aOrigin == ScrollOrigin::MouseWheel) {
+ // When using a clicky scroll wheel, snap point selection works the same
+ // as keyboard up/down/left/right navigation, but with varying amounts
+ // of scroll delta.
+ snapUnit = ScrollUnit::LINES;
+ }
+ snapTarget = GetSnapPointForDestination(snapUnit, aSnapFlags,
+ mDestination, newPos);
+ if (snapTarget) {
+ newPos = snapTarget->mPosition;
+ }
+ }
+ }
+
+ // Calculate desired range values.
+ nscoord rangeLowerX, rangeUpperX, rangeLowerY, rangeUpperY;
+ CalcRangeForScrollBy(aDelta.x, newPos.x, negativeTolerance, positiveTolerance,
+ deltaMultiplier.width, &rangeLowerX, &rangeUpperX);
+ CalcRangeForScrollBy(aDelta.y, newPos.y, negativeTolerance, positiveTolerance,
+ deltaMultiplier.height, &rangeLowerY, &rangeUpperY);
+ nsRect range(rangeLowerX, rangeLowerY, rangeUpperX - rangeLowerX,
+ rangeUpperY - rangeLowerY);
+ AutoWeakFrame weakFrame(this);
+ ScrollToWithOrigin(
+ newPos, &range,
+ snapTarget ? ScrollOperationParams{aMode, aOrigin,
+ std::move(snapTarget->mTargetIds)}
+ : ScrollOperationParams{aMode, aOrigin});
+ if (!weakFrame.IsAlive()) {
+ return;
+ }
+
+ if (aOverflow) {
+ nsPoint clampAmount = newPos - mDestination;
+ float appUnitsPerDevPixel = PresContext()->AppUnitsPerDevPixel();
+ *aOverflow =
+ nsIntPoint(NSAppUnitsToIntPixels(clampAmount.x, appUnitsPerDevPixel),
+ NSAppUnitsToIntPixels(clampAmount.y, appUnitsPerDevPixel));
+ }
+
+ if (aUnit == ScrollUnit::DEVICE_PIXELS &&
+ !nsLayoutUtils::AsyncPanZoomEnabled(this)) {
+ // When APZ is disabled, we must track the velocity
+ // on the main thread; otherwise, the APZC will manage this.
+ mVelocityQueue.Sample(GetScrollPosition());
+ }
+}
+
+void nsHTMLScrollFrame::ScrollByCSSPixelsInternal(const CSSIntPoint& aDelta,
+ ScrollMode aMode,
+ ScrollSnapFlags aSnapFlags) {
+ nsPoint current = GetScrollPosition();
+ // `current` value above might be a value which was aligned to in
+ // layer-pixels, so starting from such points will make the difference between
+ // the given position in script (e.g. scrollTo) and the aligned position
+ // larger, in the worst case the difference can be observed in CSS pixels.
+ // To avoid it, we use the current position in CSS pixels as the start
+ // position. Hopefully it exactly matches the position where it was given by
+ // the previous scrolling operation, but there may be some edge cases where
+ // the current position in CSS pixels differs from the given position, the
+ // cases should be fixed in bug 1556685.
+ CSSIntPoint currentCSSPixels = GetScrollPositionCSSPixels();
+ nsPoint pt = CSSPoint::ToAppUnits(currentCSSPixels + aDelta);
+
+ nscoord halfPixel = nsPresContext::CSSPixelsToAppUnits(0.5f);
+ nsRect range(pt.x - halfPixel, pt.y - halfPixel, 2 * halfPixel - 1,
+ 2 * halfPixel - 1);
+ // XXX I don't think the following blocks are needed anymore, now that
+ // ScrollToImpl simply tries to scroll an integer number of layer
+ // pixels from the current position
+ if (aDelta.x == 0.0f) {
+ pt.x = current.x;
+ range.x = pt.x;
+ range.width = 0;
+ }
+ if (aDelta.y == 0.0f) {
+ pt.y = current.y;
+ range.y = pt.y;
+ range.height = 0;
+ }
+ ScrollToWithOrigin(
+ pt, &range,
+ ScrollOperationParams{aMode, ScrollOrigin::Relative, aSnapFlags,
+ ScrollTriggeredByScript::Yes});
+ // 'this' might be destroyed here
+}
+
+void nsHTMLScrollFrame::ScrollSnap(ScrollMode aMode) {
+ float flingSensitivity =
+ StaticPrefs::layout_css_scroll_snap_prediction_sensitivity();
+ int maxVelocity =
+ StaticPrefs::layout_css_scroll_snap_prediction_max_velocity();
+ maxVelocity = nsPresContext::CSSPixelsToAppUnits(maxVelocity);
+ int maxOffset = maxVelocity * flingSensitivity;
+ nsPoint velocity = mVelocityQueue.GetVelocity();
+ // Multiply each component individually to avoid integer multiply
+ nsPoint predictedOffset =
+ nsPoint(velocity.x * flingSensitivity, velocity.y * flingSensitivity);
+ predictedOffset.Clamp(maxOffset);
+ nsPoint pos = GetScrollPosition();
+ nsPoint destinationPos = pos + predictedOffset;
+ ScrollSnap(destinationPos, aMode);
+}
+
+void nsHTMLScrollFrame::ScrollSnap(const nsPoint& aDestination,
+ ScrollMode aMode) {
+ nsRect scrollRange = GetLayoutScrollRange();
+ nsPoint pos = GetScrollPosition();
+ nsPoint snapDestination = scrollRange.ClampPoint(aDestination);
+ ScrollSnapFlags snapFlags = ScrollSnapFlags::IntendedEndPosition;
+ if (mVelocityQueue.GetVelocity() != nsPoint()) {
+ snapFlags |= ScrollSnapFlags::IntendedDirection;
+ }
+
+ // Bug 1776624 : Consider using mDestination as |aStartPos| argument for this
+ // GetSnapPointForDestination call, this function call is the only one call
+ // site using `GetScrollPosition()` as |aStartPos|.
+ if (auto snapTarget = GetSnapPointForDestination(
+ ScrollUnit::DEVICE_PIXELS, snapFlags, pos, snapDestination)) {
+ snapDestination = snapTarget->mPosition;
+ ScrollToWithOrigin(
+ snapDestination, nullptr /* range */,
+ ScrollOperationParams{aMode, ScrollOrigin::Other,
+ std::move(snapTarget->mTargetIds)});
+ }
+}
+
+nsSize nsHTMLScrollFrame::GetLineScrollAmount() const {
+ RefPtr<nsFontMetrics> fm =
+ nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
+ NS_ASSERTION(fm, "FontMetrics is null, assuming fontHeight == 1 appunit");
+ int32_t appUnitsPerDevPixel = PresContext()->AppUnitsPerDevPixel();
+ nscoord minScrollAmountInAppUnits =
+ std::max(1, StaticPrefs::mousewheel_min_line_scroll_amount()) *
+ appUnitsPerDevPixel;
+ nscoord horizontalAmount = fm ? fm->AveCharWidth() : 0;
+ nscoord verticalAmount = fm ? fm->MaxHeight() : 0;
+ return nsSize(std::max(horizontalAmount, minScrollAmountInAppUnits),
+ std::max(verticalAmount, minScrollAmountInAppUnits));
+}
+
+/**
+ * Compute the scrollport size excluding any fixed-pos and sticky-pos (that are
+ * stuck) headers and footers. A header or footer is an box that spans that
+ * entire width of the viewport and touches the top (or bottom, respectively) of
+ * the viewport. We also want to consider fixed/sticky elements that stack or
+ * overlap to effectively create a larger header or footer. Headers and footers
+ * that cover more than a third of the the viewport are ignored since they
+ * probably aren't true headers and footers and we don't want to restrict
+ * scrolling too much in such cases. This is a bit conservative --- some
+ * pages use elements as headers or footers that don't span the entire width
+ * of the viewport --- but it should be a good start.
+ *
+ * If aViewportFrame is non-null then the scroll frame is the root scroll
+ * frame and we should consider fixed-pos items.
+ */
+struct TopAndBottom {
+ TopAndBottom(nscoord aTop, nscoord aBottom) : top(aTop), bottom(aBottom) {}
+
+ nscoord top, bottom;
+};
+struct TopComparator {
+ bool Equals(const TopAndBottom& A, const TopAndBottom& B) const {
+ return A.top == B.top;
+ }
+ bool LessThan(const TopAndBottom& A, const TopAndBottom& B) const {
+ return A.top < B.top;
+ }
+};
+struct ReverseBottomComparator {
+ bool Equals(const TopAndBottom& A, const TopAndBottom& B) const {
+ return A.bottom == B.bottom;
+ }
+ bool LessThan(const TopAndBottom& A, const TopAndBottom& B) const {
+ return A.bottom > B.bottom;
+ }
+};
+
+static void AddToListIfHeaderFooter(nsIFrame* aFrame,
+ nsIFrame* aScrollPortFrame,
+ const nsRect& aScrollPort,
+ nsTArray<TopAndBottom>& aList) {
+ nsRect r = aFrame->GetRectRelativeToSelf();
+ r = nsLayoutUtils::TransformFrameRectToAncestor(aFrame, r, aScrollPortFrame);
+ r = r.Intersect(aScrollPort);
+ if ((r.width >= aScrollPort.width / 2 ||
+ r.width >= NSIntPixelsToAppUnits(800, AppUnitsPerCSSPixel())) &&
+ r.height <= aScrollPort.height / 3) {
+ aList.AppendElement(TopAndBottom(r.y, r.YMost()));
+ }
+}
+
+static nsSize GetScrollPortSizeExcludingHeadersAndFooters(
+ nsIFrame* aScrollFrame, nsIFrame* aViewportFrame,
+ const nsRect& aScrollPort) {
+ AutoTArray<TopAndBottom, 10> list;
+ if (aViewportFrame) {
+ for (nsIFrame* f : aViewportFrame->GetChildList(FrameChildListID::Fixed)) {
+ AddToListIfHeaderFooter(f, aViewportFrame, aScrollPort, list);
+ }
+ }
+
+ // Add sticky frames that are currently in "fixed" positions
+ StickyScrollContainer* ssc =
+ StickyScrollContainer::GetStickyScrollContainerForScrollFrame(
+ aScrollFrame);
+ if (ssc) {
+ const nsTArray<nsIFrame*>& stickyFrames = ssc->GetFrames();
+ for (nsIFrame* f : stickyFrames) {
+ // If it's acting like fixed position.
+ if (ssc->IsStuckInYDirection(f)) {
+ AddToListIfHeaderFooter(f, aScrollFrame, aScrollPort, list);
+ }
+ }
+ }
+
+ list.Sort(TopComparator());
+ nscoord headerBottom = 0;
+ for (uint32_t i = 0; i < list.Length(); ++i) {
+ if (list[i].top <= headerBottom) {
+ headerBottom = std::max(headerBottom, list[i].bottom);
+ }
+ }
+
+ list.Sort(ReverseBottomComparator());
+ nscoord footerTop = aScrollPort.height;
+ for (uint32_t i = 0; i < list.Length(); ++i) {
+ if (list[i].bottom >= footerTop) {
+ footerTop = std::min(footerTop, list[i].top);
+ }
+ }
+
+ headerBottom = std::min(aScrollPort.height / 3, headerBottom);
+ footerTop = std::max(aScrollPort.height - aScrollPort.height / 3, footerTop);
+
+ return nsSize(aScrollPort.width, footerTop - headerBottom);
+}
+
+nsSize nsHTMLScrollFrame::GetPageScrollAmount() const {
+ nsSize effectiveScrollPortSize;
+
+ if (GetVisualViewportSize() != mScrollPort.Size()) {
+ // We want to use the visual viewport size if one is set.
+ // The headers/footers adjustment is too complicated to do if there is a
+ // visual viewport that differs from the layout viewport, this is probably
+ // okay.
+ effectiveScrollPortSize = GetVisualViewportSize();
+ } else {
+ // Reduce effective scrollport height by the height of any
+ // fixed-pos/sticky-pos headers or footers
+ effectiveScrollPortSize = GetScrollPortSizeExcludingHeadersAndFooters(
+ const_cast<nsHTMLScrollFrame*>(this),
+ mIsRoot ? PresShell()->GetRootFrame() : nullptr, mScrollPort);
+ }
+
+ nsSize lineScrollAmount = GetLineScrollAmount();
+
+ // The page increment is the size of the page, minus the smaller of
+ // 10% of the size or 2 lines.
+ return nsSize(effectiveScrollPortSize.width -
+ std::min(effectiveScrollPortSize.width / 10,
+ 2 * lineScrollAmount.width),
+ effectiveScrollPortSize.height -
+ std::min(effectiveScrollPortSize.height / 10,
+ 2 * lineScrollAmount.height));
+}
+
+/**
+ * this code is resposible for restoring the scroll position back to some
+ * saved position. if the user has not moved the scroll position manually
+ * we keep scrolling down until we get to our original position. keep in
+ * mind that content could incrementally be coming in. we only want to stop
+ * when we reach our new position.
+ */
+void nsHTMLScrollFrame::ScrollToRestoredPosition() {
+ if (mRestorePos.y == -1 || mLastPos.x == -1 || mLastPos.y == -1) {
+ return;
+ }
+ // make sure our scroll position did not change for where we last put
+ // it. if it does then the user must have moved it, and we no longer
+ // need to restore.
+ //
+ // In the RTL case, we check whether the scroll position changed using the
+ // logical scroll position, but we scroll to the physical scroll position in
+ // all cases
+
+ // The layout offset we want to restore is the same as the visual offset
+ // (for now, may change in bug 1499210), but clamped to the layout scroll
+ // range (which can be a subset of the visual scroll range).
+ // Note that we can't do the clamping when initializing mRestorePos in
+ // RestoreState(), since the scrollable rect (which the clamping depends
+ // on) can change over the course of the restoration process.
+ nsPoint layoutRestorePos = GetLayoutScrollRange().ClampPoint(mRestorePos);
+ nsPoint visualRestorePos = GetVisualScrollRange().ClampPoint(mRestorePos);
+
+ // Continue restoring until both the layout and visual scroll positions
+ // reach the destination. (Note that the two can only be different for
+ // the root content document's root scroll frame, and when zoomed in).
+ // This is necessary to avoid situations where the two offsets get stuck
+ // at different values and nothing reconciles them (see bug 1519621 comment
+ // 8).
+ nsPoint logicalLayoutScrollPos = GetLogicalScrollPosition();
+
+ SCROLLRESTORE_LOG(
+ "%p: ScrollToRestoredPosition (mRestorePos=%s, mLastPos=%s, "
+ "layoutRestorePos=%s, visualRestorePos=%s, "
+ "logicalLayoutScrollPos=%s, "
+ "GetLogicalVisualViewportOffset()=%s)\n",
+ this, ToString(mRestorePos).c_str(), ToString(mLastPos).c_str(),
+ ToString(layoutRestorePos).c_str(), ToString(visualRestorePos).c_str(),
+ ToString(logicalLayoutScrollPos).c_str(),
+ ToString(GetLogicalVisualViewportOffset()).c_str());
+
+ // if we didn't move, we still need to restore
+ if (GetLogicalVisualViewportOffset() == mLastPos ||
+ logicalLayoutScrollPos == mLastPos) {
+ // if our desired position is different to the scroll position, scroll.
+ // remember that we could be incrementally loading so we may enter
+ // and scroll many times.
+ if (mRestorePos != mLastPos /* GetLogicalVisualViewportOffset() */ ||
+ layoutRestorePos != logicalLayoutScrollPos) {
+ LoadingState state = GetPageLoadingState();
+ if (state == LoadingState::Stopped && !IsSubtreeDirty()) {
+ return;
+ }
+ nsPoint visualScrollToPos = visualRestorePos;
+ nsPoint layoutScrollToPos = layoutRestorePos;
+ if (!IsPhysicalLTR()) {
+ // convert from logical to physical scroll position
+ visualScrollToPos.x -=
+ (GetVisualViewportSize().width - mScrolledFrame->GetRect().width);
+ layoutScrollToPos.x -=
+ (GetVisualViewportSize().width - mScrolledFrame->GetRect().width);
+ }
+ AutoWeakFrame weakFrame(this);
+ // It's very important to pass ScrollOrigin::Restore here, so
+ // ScrollToWithOrigin won't clear out mRestorePos.
+ ScrollToWithOrigin(
+ layoutScrollToPos, nullptr,
+ ScrollOperationParams{ScrollMode::Instant, ScrollOrigin::Restore});
+ if (!weakFrame.IsAlive()) {
+ return;
+ }
+ if (mIsRoot) {
+ PresShell()->ScrollToVisual(visualScrollToPos, FrameMetrics::eRestore,
+ ScrollMode::Instant);
+ }
+ if (state == LoadingState::Loading || IsSubtreeDirty()) {
+ // If we're trying to do a history scroll restore, then we want to
+ // keep trying this until we succeed, because the page can be loading
+ // incrementally. So re-get the scroll position for the next iteration,
+ // it might not be exactly equal to mRestorePos due to rounding and
+ // clamping.
+ mLastPos = GetLogicalVisualViewportOffset();
+ return;
+ }
+ }
+ // If we get here, either we reached the desired position (mLastPos ==
+ // mRestorePos) or we're not trying to do a history scroll restore, so
+ // we can stop after the scroll attempt above.
+ mRestorePos.y = -1;
+ mLastPos.x = -1;
+ mLastPos.y = -1;
+ } else {
+ // user moved the position, so we won't need to restore
+ mLastPos.x = -1;
+ mLastPos.y = -1;
+ }
+}
+
+auto nsHTMLScrollFrame::GetPageLoadingState() -> LoadingState {
+ bool loadCompleted = false, stopped = false;
+ nsCOMPtr<nsIDocShell> ds = GetContent()->GetComposedDoc()->GetDocShell();
+ if (ds) {
+ nsCOMPtr<nsIContentViewer> cv;
+ ds->GetContentViewer(getter_AddRefs(cv));
+ if (cv) {
+ loadCompleted = cv->GetLoadCompleted();
+ stopped = cv->GetIsStopped();
+ }
+ }
+ return loadCompleted
+ ? (stopped ? LoadingState::Stopped : LoadingState::Loaded)
+ : LoadingState::Loading;
+}
+
+nsHTMLScrollFrame::OverflowState nsHTMLScrollFrame::GetOverflowState() const {
+ nsSize scrollportSize = mScrollPort.Size();
+ nsSize childSize = GetScrolledRect().Size();
+
+ OverflowState result = OverflowState::None;
+
+ if (childSize.height > scrollportSize.height) {
+ result |= OverflowState::Vertical;
+ }
+
+ if (childSize.width > scrollportSize.width) {
+ result |= OverflowState::Horizontal;
+ }
+
+ return result;
+}
+
+nsresult nsHTMLScrollFrame::FireScrollPortEvent() {
+ mAsyncScrollPortEvent.Forget();
+
+ // TODO(emilio): why do we need the whole WillPaintObserver infrastructure and
+ // can't use AddScriptRunner & co? I guess it made sense when we used
+ // WillPaintObserver for scroll events too, or when this used to flush.
+ //
+ // Should we remove this?
+
+ OverflowState overflowState = GetOverflowState();
+
+ bool newVerticalOverflow = !!(overflowState & OverflowState::Vertical);
+ bool vertChanged = mVerticalOverflow != newVerticalOverflow;
+
+ bool newHorizontalOverflow = !!(overflowState & OverflowState::Horizontal);
+ bool horizChanged = mHorizontalOverflow != newHorizontalOverflow;
+
+ if (!vertChanged && !horizChanged) {
+ return NS_OK;
+ }
+
+ // If both either overflowed or underflowed then we dispatch only one
+ // DOM event.
+ bool both = vertChanged && horizChanged &&
+ newVerticalOverflow == newHorizontalOverflow;
+ InternalScrollPortEvent::OrientType orient;
+ if (both) {
+ orient = InternalScrollPortEvent::eBoth;
+ mHorizontalOverflow = newHorizontalOverflow;
+ mVerticalOverflow = newVerticalOverflow;
+ } else if (vertChanged) {
+ orient = InternalScrollPortEvent::eVertical;
+ mVerticalOverflow = newVerticalOverflow;
+ if (horizChanged) {
+ // We need to dispatch a separate horizontal DOM event. Do that the next
+ // time around since dispatching the vertical DOM event might destroy
+ // the frame.
+ PostOverflowEvent();
+ }
+ } else {
+ orient = InternalScrollPortEvent::eHorizontal;
+ mHorizontalOverflow = newHorizontalOverflow;
+ }
+
+ InternalScrollPortEvent event(
+ true,
+ (orient == InternalScrollPortEvent::eHorizontal ? mHorizontalOverflow
+ : mVerticalOverflow)
+ ? eScrollPortOverflow
+ : eScrollPortUnderflow,
+ nullptr);
+ event.mOrient = orient;
+
+ RefPtr<nsIContent> content = GetContent();
+ RefPtr<nsPresContext> presContext = PresContext();
+ return EventDispatcher::Dispatch(content, presContext, &event);
+}
+
+void nsHTMLScrollFrame::PostScrollEndEvent() {
+ if (mScrollEndEvent) {
+ return;
+ }
+
+ // The ScrollEndEvent constructor registers itself with the refresh driver.
+ mScrollEndEvent = new ScrollEndEvent(this);
+}
+
+void nsHTMLScrollFrame::FireScrollEndEvent() {
+ MOZ_ASSERT(GetContent());
+ MOZ_ASSERT(mScrollEndEvent);
+
+ RefPtr<nsPresContext> presContext = PresContext();
+ mScrollEndEvent->Revoke();
+ mScrollEndEvent = nullptr;
+
+ nsEventStatus status = nsEventStatus_eIgnore;
+ WidgetGUIEvent event(true, eScrollend, nullptr);
+ event.mFlags.mBubbles = mIsRoot;
+ event.mFlags.mCancelable = false;
+ // If apz.scrollend-event.content.enabled is not set, the event should
+ // only be dispatched to the browser chrome.
+ event.mFlags.mOnlyChromeDispatch =
+ !StaticPrefs::apz_scrollend_event_content_enabled();
+ RefPtr<nsINode> target =
+ mIsRoot ? static_cast<nsINode*>(presContext->Document()) : GetContent();
+ EventDispatcher::Dispatch(target, presContext, &event, nullptr, &status);
+}
+
+void nsHTMLScrollFrame::ReloadChildFrames() {
+ mScrolledFrame = nullptr;
+ mHScrollbarBox = nullptr;
+ mVScrollbarBox = nullptr;
+ mScrollCornerBox = nullptr;
+ mResizerBox = nullptr;
+
+ for (nsIFrame* frame : PrincipalChildList()) {
+ nsIContent* content = frame->GetContent();
+ if (content == GetContent()) {
+ NS_ASSERTION(!mScrolledFrame, "Already found the scrolled frame");
+ mScrolledFrame = frame;
+ } else {
+ nsAutoString value;
+ if (content->IsElement()) {
+ content->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::orient,
+ value);
+ }
+ if (!value.IsEmpty()) {
+ // probably a scrollbar then
+ if (value.LowerCaseEqualsLiteral("horizontal")) {
+ NS_ASSERTION(!mHScrollbarBox,
+ "Found multiple horizontal scrollbars?");
+ mHScrollbarBox = do_QueryFrame(frame);
+ MOZ_ASSERT(mHScrollbarBox, "Not a scrollbar?");
+ } else {
+ NS_ASSERTION(!mVScrollbarBox, "Found multiple vertical scrollbars?");
+ mVScrollbarBox = do_QueryFrame(frame);
+ MOZ_ASSERT(mVScrollbarBox, "Not a scrollbar?");
+ }
+ } else if (content->IsXULElement(nsGkAtoms::resizer)) {
+ NS_ASSERTION(!mResizerBox, "Found multiple resizers");
+ mResizerBox = frame;
+ } else if (content->IsXULElement(nsGkAtoms::scrollcorner)) {
+ // probably a scrollcorner
+ NS_ASSERTION(!mScrollCornerBox, "Found multiple scrollcorners");
+ mScrollCornerBox = frame;
+ }
+ }
+ }
+}
+
+already_AddRefed<Element> nsHTMLScrollFrame::MakeScrollbar(
+ NodeInfo* aNodeInfo, bool aVertical, AnonymousContentKey& aKey) {
+ MOZ_ASSERT(aNodeInfo);
+ MOZ_ASSERT(
+ aNodeInfo->Equals(nsGkAtoms::scrollbar, nullptr, kNameSpaceID_XUL));
+
+ static constexpr nsLiteralString kOrientValues[2] = {
+ u"horizontal"_ns,
+ u"vertical"_ns,
+ };
+
+ aKey = AnonymousContentKey::Type_Scrollbar;
+ if (aVertical) {
+ aKey |= AnonymousContentKey::Flag_Vertical;
+ }
+
+ RefPtr<Element> e;
+ NS_TrustedNewXULElement(getter_AddRefs(e), do_AddRef(aNodeInfo));
+
+#ifdef DEBUG
+ // Scrollbars can get restyled by theme changes. Whether such a restyle
+ // will actually reconstruct them correctly if it involves a frame
+ // reconstruct... I don't know. :(
+ e->SetProperty(nsGkAtoms::restylableAnonymousNode,
+ reinterpret_cast<void*>(true));
+#endif // DEBUG
+
+ e->SetAttr(kNameSpaceID_None, nsGkAtoms::orient, kOrientValues[aVertical],
+ false);
+
+ if (mIsRoot) {
+ e->SetProperty(nsGkAtoms::docLevelNativeAnonymousContent,
+ reinterpret_cast<void*>(true));
+ e->SetAttr(kNameSpaceID_None, nsGkAtoms::root_, u"true"_ns, false);
+
+ // Don't bother making style caching take [root="true"] styles into account.
+ aKey = AnonymousContentKey::None;
+ }
+
+ return e.forget();
+}
+
+bool nsHTMLScrollFrame::IsForTextControlWithNoScrollbars() const {
+ // FIXME(emilio): we should probably make the scroller inside <input> an
+ // internal pseudo-element, and then this would be simpler.
+ //
+ // Also, this could just use scrollbar-width these days.
+ auto* content = GetContent();
+ if (!content) {
+ return false;
+ }
+ auto* input = content->GetClosestNativeAnonymousSubtreeRootParentOrHost();
+ return input && input->IsHTMLElement(nsGkAtoms::input);
+}
+
+auto nsHTMLScrollFrame::GetCurrentAnonymousContent() const
+ -> EnumSet<AnonymousContentType> {
+ EnumSet<AnonymousContentType> result;
+ if (mHScrollbarContent) {
+ result += AnonymousContentType::HorizontalScrollbar;
+ }
+ if (mVScrollbarContent) {
+ result += AnonymousContentType::VerticalScrollbar;
+ }
+ if (mResizerContent) {
+ result += AnonymousContentType::Resizer;
+ }
+ return result;
+}
+
+auto nsHTMLScrollFrame::GetNeededAnonymousContent() const
+ -> EnumSet<AnonymousContentType> {
+ nsPresContext* pc = PresContext();
+
+ // Don't create scrollbars if we're an SVG document being used as an image,
+ // or if we're printing/print previewing.
+ // (In the printing case, we allow scrollbars if this is the child of the
+ // viewport & paginated scrolling is enabled, because then we must be the
+ // scroll frame for the print preview window, & that does need scrollbars.)
+ if (pc->Document()->IsBeingUsedAsImage() ||
+ (!pc->IsDynamic() && !(mIsRoot && pc->HasPaginatedScrolling()))) {
+ return {};
+ }
+
+ if (IsForTextControlWithNoScrollbars()) {
+ return {};
+ }
+
+ EnumSet<AnonymousContentType> result;
+ // If we're the scrollframe for the root, then we want to construct our
+ // scrollbar frames no matter what. That way later dynamic changes to
+ // propagated overflow styles will show or hide scrollbars on the viewport
+ // without requiring frame reconstruction of the viewport (good!).
+ //
+ // TODO(emilio): Figure out if we can remove this special-case now that we
+ // have more targeted optimizations.
+ if (mIsRoot) {
+ result += AnonymousContentType::HorizontalScrollbar;
+ result += AnonymousContentType::VerticalScrollbar;
+ // If scrollbar-width is none, don't generate scrollbars.
+ } else if (StyleUIReset()->ScrollbarWidth() != StyleScrollbarWidth::None) {
+ ScrollStyles styles = GetScrollStyles();
+ if (styles.mHorizontal != StyleOverflow::Hidden) {
+ result += AnonymousContentType::HorizontalScrollbar;
+ }
+ if (styles.mVertical != StyleOverflow::Hidden) {
+ result += AnonymousContentType::VerticalScrollbar;
+ }
+
+ // If we have scrollbar-gutter, construct the scrollbar frames to query its
+ // size to reserve the gutter space at the inline start or end edges.
+ if (StyleDisplay()->mScrollbarGutter & StyleScrollbarGutter::STABLE) {
+ result += GetWritingMode().IsVertical()
+ ? AnonymousContentType::HorizontalScrollbar
+ : AnonymousContentType::VerticalScrollbar;
+ }
+ }
+
+ // Check if the frame is resizable. Note:
+ // "The effect of the resize property on generated content is undefined.
+ // Implementations should not apply the resize property to generated
+ // content." [1]
+ // For info on what is generated content, see [2].
+ // [1]: https://drafts.csswg.org/css-ui/#resize
+ // [2]: https://www.w3.org/TR/CSS2/generate.html#content
+ auto resizeStyle = StyleDisplay()->mResize;
+ if (resizeStyle != StyleResize::None &&
+ !HasAnyStateBits(NS_FRAME_GENERATED_CONTENT)) {
+ result += AnonymousContentType::Resizer;
+ }
+
+ return result;
+}
+
+nsresult nsHTMLScrollFrame::CreateAnonymousContent(
+ nsTArray<nsIAnonymousContentCreator::ContentInfo>& aElements) {
+ typedef nsIAnonymousContentCreator::ContentInfo ContentInfo;
+
+ nsPresContext* presContext = PresContext();
+ nsNodeInfoManager* nodeInfoManager =
+ presContext->Document()->NodeInfoManager();
+
+ auto neededAnonContent = GetNeededAnonymousContent();
+ if (neededAnonContent.isEmpty()) {
+ return NS_OK;
+ }
+
+ {
+ RefPtr<NodeInfo> nodeInfo = nodeInfoManager->GetNodeInfo(
+ nsGkAtoms::scrollbar, nullptr, kNameSpaceID_XUL, nsINode::ELEMENT_NODE);
+ NS_ENSURE_TRUE(nodeInfo, NS_ERROR_OUT_OF_MEMORY);
+
+ if (neededAnonContent.contains(AnonymousContentType::HorizontalScrollbar)) {
+ AnonymousContentKey key;
+ mHScrollbarContent = MakeScrollbar(nodeInfo, /* aVertical */ false, key);
+ aElements.AppendElement(ContentInfo(mHScrollbarContent, key));
+ }
+
+ if (neededAnonContent.contains(AnonymousContentType::VerticalScrollbar)) {
+ AnonymousContentKey key;
+ mVScrollbarContent = MakeScrollbar(nodeInfo, /* aVertical */ true, key);
+ aElements.AppendElement(ContentInfo(mVScrollbarContent, key));
+ }
+ }
+
+ if (neededAnonContent.contains(AnonymousContentType::Resizer)) {
+ MOZ_ASSERT(!mIsRoot, "Root scroll frame shouldn't be resizable");
+
+ RefPtr<NodeInfo> nodeInfo;
+ nodeInfo = nodeInfoManager->GetNodeInfo(
+ nsGkAtoms::resizer, nullptr, kNameSpaceID_XUL, nsINode::ELEMENT_NODE);
+ NS_ENSURE_TRUE(nodeInfo, NS_ERROR_OUT_OF_MEMORY);
+
+ NS_TrustedNewXULElement(getter_AddRefs(mResizerContent), nodeInfo.forget());
+
+ nsAutoString dir;
+ switch (StyleDisplay()->mResize) {
+ case StyleResize::Horizontal:
+ if (IsScrollbarOnRight()) {
+ dir.AssignLiteral("right");
+ } else {
+ dir.AssignLiteral("left");
+ }
+ break;
+ case StyleResize::Vertical:
+ dir.AssignLiteral("bottom");
+ if (!IsScrollbarOnRight()) {
+ mResizerContent->SetAttr(kNameSpaceID_None, nsGkAtoms::flip, u""_ns,
+ false);
+ }
+ break;
+ case StyleResize::Both:
+ if (IsScrollbarOnRight()) {
+ dir.AssignLiteral("bottomright");
+ } else {
+ dir.AssignLiteral("bottomleft");
+ }
+ break;
+ default:
+ NS_WARNING("only resizable types should have resizers");
+ }
+ mResizerContent->SetAttr(kNameSpaceID_None, nsGkAtoms::dir, dir, false);
+ aElements.AppendElement(mResizerContent);
+ }
+
+ if (neededAnonContent.contains(AnonymousContentType::HorizontalScrollbar) &&
+ neededAnonContent.contains(AnonymousContentType::VerticalScrollbar)) {
+ AnonymousContentKey key = AnonymousContentKey::Type_ScrollCorner;
+
+ RefPtr<NodeInfo> nodeInfo =
+ nodeInfoManager->GetNodeInfo(nsGkAtoms::scrollcorner, nullptr,
+ kNameSpaceID_XUL, nsINode::ELEMENT_NODE);
+ NS_TrustedNewXULElement(getter_AddRefs(mScrollCornerContent),
+ nodeInfo.forget());
+ if (mIsRoot) {
+ mScrollCornerContent->SetProperty(
+ nsGkAtoms::docLevelNativeAnonymousContent,
+ reinterpret_cast<void*>(true));
+ mScrollCornerContent->SetAttr(kNameSpaceID_None, nsGkAtoms::root_,
+ u"true"_ns, false);
+
+ // Don't bother making style caching take [root="true"] styles into
+ // account.
+ key = AnonymousContentKey::None;
+ }
+ aElements.AppendElement(ContentInfo(mScrollCornerContent, key));
+ }
+
+ // Don't cache styles if we are a child of a <select> element, since we have
+ // some UA style sheet rules that depend on the <select>'s attributes.
+ if (GetContent()->IsHTMLElement(nsGkAtoms::select)) {
+ for (auto& info : aElements) {
+ info.mKey = AnonymousContentKey::None;
+ }
+ }
+
+ return NS_OK;
+}
+
+void nsHTMLScrollFrame::AppendAnonymousContentTo(
+ nsTArray<nsIContent*>& aElements, uint32_t aFilter) {
+ if (mHScrollbarContent) {
+ aElements.AppendElement(mHScrollbarContent);
+ }
+
+ if (mVScrollbarContent) {
+ aElements.AppendElement(mVScrollbarContent);
+ }
+
+ if (mScrollCornerContent) {
+ aElements.AppendElement(mScrollCornerContent);
+ }
+
+ if (mResizerContent) {
+ aElements.AppendElement(mResizerContent);
+ }
+}
+
+void nsHTMLScrollFrame::DidSetComputedStyle(ComputedStyle* aOldComputedStyle) {
+ nsContainerFrame::DidSetComputedStyle(aOldComputedStyle);
+ if (aOldComputedStyle && !mIsRoot &&
+ StyleDisplay()->mScrollSnapType !=
+ aOldComputedStyle->StyleDisplay()->mScrollSnapType) {
+ PostPendingResnap();
+ }
+}
+
+void nsHTMLScrollFrame::RemoveObservers() {
+ if (mAsyncScroll) {
+ mAsyncScroll->RemoveObserver();
+ mAsyncScroll = nullptr;
+ }
+ if (mAsyncSmoothMSDScroll) {
+ mAsyncSmoothMSDScroll->RemoveObserver();
+ mAsyncSmoothMSDScroll = nullptr;
+ }
+}
+
+/**
+ * Called when we want to update the scrollbar position, either because
+ * scrolling happened or the user moved the scrollbar position and we need to
+ * undo that (e.g., when the user clicks to scroll and we're using smooth
+ * scrolling, so we need to put the thumb back to its initial position for the
+ * start of the smooth sequence).
+ */
+void nsHTMLScrollFrame::UpdateScrollbarPosition() {
+ AutoWeakFrame weakFrame(this);
+ mFrameIsUpdatingScrollbar = true;
+
+ nsPoint pt = GetScrollPosition();
+ nsRect scrollRange = GetVisualScrollRange();
+
+ if (gfxPlatform::UseDesktopZoomingScrollbars()) {
+ pt = GetVisualViewportOffset();
+ scrollRange = GetScrollRangeForUserInputEvents();
+ }
+
+ if (mVScrollbarBox) {
+ SetCoordAttribute(mVScrollbarBox->GetContent()->AsElement(),
+ nsGkAtoms::curpos, pt.y - scrollRange.y);
+ if (!weakFrame.IsAlive()) {
+ return;
+ }
+ }
+ if (mHScrollbarBox) {
+ SetCoordAttribute(mHScrollbarBox->GetContent()->AsElement(),
+ nsGkAtoms::curpos, pt.x - scrollRange.x);
+ if (!weakFrame.IsAlive()) {
+ return;
+ }
+ }
+
+ mFrameIsUpdatingScrollbar = false;
+}
+
+void nsHTMLScrollFrame::CurPosAttributeChangedInternal(nsIContent* aContent,
+ bool aDoScroll) {
+ NS_ASSERTION(aContent, "aContent must not be null");
+ NS_ASSERTION((mHScrollbarBox && mHScrollbarBox->GetContent() == aContent) ||
+ (mVScrollbarBox && mVScrollbarBox->GetContent() == aContent),
+ "unexpected child");
+ MOZ_ASSERT(aContent->IsElement());
+
+ // Attribute changes on the scrollbars happen in one of three ways:
+ // 1) The scrollbar changed the attribute in response to some user event
+ // 2) We changed the attribute in response to a ScrollPositionDidChange
+ // callback from the scrolling view
+ // 3) We changed the attribute to adjust the scrollbars for the start
+ // of a smooth scroll operation
+ //
+ // In cases 2 and 3 we do not need to scroll because we're just
+ // updating our scrollbar.
+ if (mFrameIsUpdatingScrollbar) {
+ return;
+ }
+
+ nsRect scrollRange = GetVisualScrollRange();
+
+ nsPoint current = GetScrollPosition() - scrollRange.TopLeft();
+
+ if (gfxPlatform::UseDesktopZoomingScrollbars()) {
+ scrollRange = GetScrollRangeForUserInputEvents();
+ current = GetVisualViewportOffset() - scrollRange.TopLeft();
+ }
+
+ nsPoint dest;
+ nsRect allowedRange;
+ dest.x = GetCoordAttribute(mHScrollbarBox, nsGkAtoms::curpos, current.x,
+ &allowedRange.x, &allowedRange.width);
+ dest.y = GetCoordAttribute(mVScrollbarBox, nsGkAtoms::curpos, current.y,
+ &allowedRange.y, &allowedRange.height);
+ current += scrollRange.TopLeft();
+ dest += scrollRange.TopLeft();
+ allowedRange += scrollRange.TopLeft();
+
+ // Don't try to scroll if we're already at an acceptable place.
+ // Don't call Contains here since Contains returns false when the point is
+ // on the bottom or right edge of the rectangle.
+ if (allowedRange.ClampPoint(current) == current) {
+ return;
+ }
+
+ if (mScrollbarActivity &&
+ (mHasHorizontalScrollbar || mHasVerticalScrollbar)) {
+ RefPtr<ScrollbarActivity> scrollbarActivity(mScrollbarActivity);
+ scrollbarActivity->ActivityOccurred();
+ }
+
+ const bool isSmooth = aContent->AsElement()->HasAttr(nsGkAtoms::smooth);
+ if (isSmooth) {
+ // Make sure an attribute-setting callback occurs even if the view
+ // didn't actually move yet. We need to make sure other listeners
+ // see that the scroll position is not (yet) what they thought it
+ // was.
+ AutoWeakFrame weakFrame(this);
+ UpdateScrollbarPosition();
+ if (!weakFrame.IsAlive()) {
+ return;
+ }
+ }
+
+ if (aDoScroll) {
+ ScrollToWithOrigin(dest, &allowedRange,
+ ScrollOperationParams{
+ isSmooth ? ScrollMode::Smooth : ScrollMode::Instant,
+ ScrollOrigin::Scrollbars});
+ }
+ // 'this' might be destroyed here
+}
+
+/* ============= Scroll events ========== */
+
+nsHTMLScrollFrame::ScrollEvent::ScrollEvent(nsHTMLScrollFrame* aHelper,
+ bool aDelayed)
+ : Runnable("nsHTMLScrollFrame::ScrollEvent"), mHelper(aHelper) {
+ mHelper->PresContext()->RefreshDriver()->PostScrollEvent(this, aDelayed);
+}
+
+// TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230, bug 1535398)
+MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHODIMP
+nsHTMLScrollFrame::ScrollEvent::Run() {
+ if (mHelper) {
+ mHelper->FireScrollEvent();
+ }
+ return NS_OK;
+}
+
+nsHTMLScrollFrame::ScrollEndEvent::ScrollEndEvent(nsHTMLScrollFrame* aHelper)
+ : Runnable("nsHTMLScrollFrame::ScrollEndEvent"), mHelper(aHelper) {
+ mHelper->PresContext()->RefreshDriver()->PostScrollEvent(this);
+}
+
+MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHODIMP
+nsHTMLScrollFrame::ScrollEndEvent::Run() {
+ if (mHelper) {
+ mHelper->FireScrollEndEvent();
+ }
+ return NS_OK;
+}
+
+void nsHTMLScrollFrame::FireScrollEvent() {
+ RefPtr<nsIContent> content = GetContent();
+ RefPtr<nsPresContext> presContext = PresContext();
+ AUTO_PROFILER_TRACING_MARKER_DOCSHELL("Paint", "FireScrollEvent", GRAPHICS,
+ presContext->GetDocShell());
+
+ MOZ_ASSERT(mScrollEvent);
+ mScrollEvent->Revoke();
+ mScrollEvent = nullptr;
+
+ // If event handling is suppressed, keep posting the scroll event to the
+ // refresh driver until it is unsuppressed. The event is marked as delayed so
+ // that the refresh driver does not continue ticking.
+ if (content->GetComposedDoc() &&
+ content->GetComposedDoc()->EventHandlingSuppressed()) {
+ content->GetComposedDoc()->SetHasDelayedRefreshEvent();
+ PostScrollEvent(/* aDelayed = */ true);
+ return;
+ }
+
+ bool oldProcessing = mProcessingScrollEvent;
+ AutoWeakFrame weakFrame(this);
+ auto RestoreProcessingScrollEvent = mozilla::MakeScopeExit([&] {
+ if (weakFrame.IsAlive()) { // Otherwise `this` will be dead too.
+ mProcessingScrollEvent = oldProcessing;
+ }
+ });
+
+ mProcessingScrollEvent = true;
+
+ WidgetGUIEvent event(true, eScroll, nullptr);
+ nsEventStatus status = nsEventStatus_eIgnore;
+ // Fire viewport scroll events at the document (where they
+ // will bubble to the window)
+ mozilla::layers::ScrollLinkedEffectDetector detector(
+ content->GetComposedDoc(),
+ presContext->RefreshDriver()->MostRecentRefresh());
+ if (mIsRoot) {
+ if (RefPtr<Document> doc = content->GetUncomposedDoc()) {
+ // TODO: Bug 1506441
+ EventDispatcher::Dispatch(MOZ_KnownLive(ToSupports(doc)), presContext,
+ &event, nullptr, &status);
+ }
+ } else {
+ // scroll events fired at elements don't bubble (although scroll events
+ // fired at documents do, to the window)
+ event.mFlags.mBubbles = false;
+ EventDispatcher::Dispatch(content, presContext, &event, nullptr, &status);
+ }
+}
+
+void nsHTMLScrollFrame::PostScrollEvent(bool aDelayed) {
+ if (mScrollEvent) {
+ return;
+ }
+
+ // The ScrollEvent constructor registers itself with the refresh driver.
+ mScrollEvent = new ScrollEvent(this, aDelayed);
+}
+
+// TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230, bug 1535398)
+MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHODIMP
+nsHTMLScrollFrame::AsyncScrollPortEvent::Run() {
+ return mHelper ? mHelper->FireScrollPortEvent() : NS_OK;
+}
+
+void nsHTMLScrollFrame::PostOverflowEvent() {
+ if (mAsyncScrollPortEvent.IsPending()) {
+ return;
+ }
+
+ OverflowState overflowState = GetOverflowState();
+
+ bool newVerticalOverflow = !!(overflowState & OverflowState::Vertical);
+ bool vertChanged = mVerticalOverflow != newVerticalOverflow;
+
+ bool newHorizontalOverflow = !!(overflowState & OverflowState::Horizontal);
+ bool horizChanged = mHorizontalOverflow != newHorizontalOverflow;
+
+ if (!vertChanged && !horizChanged) {
+ return;
+ }
+
+ nsRootPresContext* rpc = PresContext()->GetRootPresContext();
+ if (!rpc) {
+ return;
+ }
+
+ mAsyncScrollPortEvent = new AsyncScrollPortEvent(this);
+ rpc->AddWillPaintObserver(mAsyncScrollPortEvent.get());
+}
+
+nsIFrame* nsHTMLScrollFrame::GetFrameForStyle() const {
+ nsIFrame* styleFrame = nullptr;
+ if (mIsRoot) {
+ if (const Element* rootElement =
+ PresContext()->Document()->GetRootElement()) {
+ styleFrame = rootElement->GetPrimaryFrame();
+ }
+ } else {
+ styleFrame = const_cast<nsHTMLScrollFrame*>(this);
+ }
+
+ return styleFrame;
+}
+
+bool nsHTMLScrollFrame::NeedsScrollSnap() const {
+ nsIFrame* scrollSnapFrame = GetFrameForStyle();
+ if (!scrollSnapFrame) {
+ return false;
+ }
+ return scrollSnapFrame->StyleDisplay()->mScrollSnapType.strictness !=
+ StyleScrollSnapStrictness::None;
+}
+
+nsSize nsHTMLScrollFrame::GetSnapportSize() const {
+ nsRect snapport = GetScrollPortRect();
+ nsMargin scrollPadding = GetScrollPadding();
+ snapport.Deflate(scrollPadding);
+ return snapport.Size();
+}
+
+bool nsHTMLScrollFrame::IsScrollbarOnRight() const {
+ nsPresContext* presContext = PresContext();
+
+ // The position of the scrollbar in top-level windows depends on the pref
+ // layout.scrollbar.side. For non-top-level elements, it depends only on the
+ // directionaliy of the element (equivalent to a value of "1" for the pref).
+ if (!mIsRoot) {
+ return IsPhysicalLTR();
+ }
+ switch (presContext->GetCachedIntPref(kPresContext_ScrollbarSide)) {
+ default:
+ case 0: // UI directionality
+ return presContext->GetCachedIntPref(kPresContext_BidiDirection) ==
+ IBMBIDI_TEXTDIRECTION_LTR;
+ case 1: // Document / content directionality
+ return IsPhysicalLTR();
+ case 2: // Always right
+ return true;
+ case 3: // Always left
+ return false;
+ }
+}
+
+bool nsHTMLScrollFrame::IsScrollingActive() const {
+ const nsStyleDisplay* disp = StyleDisplay();
+ if (disp->mWillChange.bits & StyleWillChangeBits::SCROLL) {
+ return true;
+ }
+
+ nsIContent* content = GetContent();
+ return mHasBeenScrolledRecently || IsAlwaysActive() ||
+ DisplayPortUtils::HasDisplayPort(content) ||
+ nsContentUtils::HasScrollgrab(content);
+}
+
+void nsHTMLScrollFrame::FinishReflowForScrollbar(Element* aElement,
+ nscoord aMinXY, nscoord aMaxXY,
+ nscoord aCurPosXY,
+ nscoord aPageIncrement,
+ nscoord aIncrement) {
+ // Scrollbars assume zero is the minimum position, so translate for them.
+ SetCoordAttribute(aElement, nsGkAtoms::curpos, aCurPosXY - aMinXY);
+ SetScrollbarEnabled(aElement, aMaxXY - aMinXY);
+ SetCoordAttribute(aElement, nsGkAtoms::maxpos, aMaxXY - aMinXY);
+ SetCoordAttribute(aElement, nsGkAtoms::pageincrement, aPageIncrement);
+ SetCoordAttribute(aElement, nsGkAtoms::increment, aIncrement);
+}
+
+class MOZ_RAII AutoMinimumScaleSizeChangeDetector final {
+ public:
+ explicit AutoMinimumScaleSizeChangeDetector(
+ nsHTMLScrollFrame* ansHTMLScrollFrame)
+ : mHelper(ansHTMLScrollFrame) {
+ MOZ_ASSERT(mHelper);
+ MOZ_ASSERT(mHelper->mIsRoot);
+
+ mPreviousMinimumScaleSize = ansHTMLScrollFrame->mMinimumScaleSize;
+ mPreviousIsUsingMinimumScaleSize =
+ ansHTMLScrollFrame->mIsUsingMinimumScaleSize;
+ }
+ ~AutoMinimumScaleSizeChangeDetector() {
+ if (mPreviousMinimumScaleSize != mHelper->mMinimumScaleSize ||
+ mPreviousIsUsingMinimumScaleSize != mHelper->mIsUsingMinimumScaleSize) {
+ mHelper->mMinimumScaleSizeChanged = true;
+ }
+ }
+
+ private:
+ nsHTMLScrollFrame* mHelper;
+
+ nsSize mPreviousMinimumScaleSize;
+ bool mPreviousIsUsingMinimumScaleSize;
+};
+
+nsSize nsHTMLScrollFrame::TrueOuterSize(nsDisplayListBuilder* aBuilder) const {
+ if (!PresShell()->UsesMobileViewportSizing()) {
+ return GetSize();
+ }
+
+ RefPtr<MobileViewportManager> manager =
+ PresShell()->GetMobileViewportManager();
+ MOZ_ASSERT(manager);
+
+ LayoutDeviceIntSize displaySize = manager->DisplaySize();
+
+ MOZ_ASSERT(aBuilder);
+ // In case of WebRender, we expand the outer size to include the dynamic
+ // toolbar area here.
+ // In case of non WebRender, we expand the size dynamically in
+ // MoveScrollbarForLayerMargin in AsyncCompositionManager.cpp.
+ WebRenderLayerManager* layerManager = aBuilder->GetWidgetLayerManager();
+ if (layerManager) {
+ displaySize.height += ViewAs<LayoutDevicePixel>(
+ PresContext()->GetDynamicToolbarMaxHeight(),
+ PixelCastJustification::LayoutDeviceIsScreenForBounds);
+ }
+
+ return LayoutDeviceSize::ToAppUnits(displaySize,
+ PresContext()->AppUnitsPerDevPixel());
+}
+
+void nsHTMLScrollFrame::UpdateMinimumScaleSize(
+ const nsRect& aScrollableOverflow, const nsSize& aICBSize) {
+ MOZ_ASSERT(mIsRoot);
+
+ AutoMinimumScaleSizeChangeDetector minimumScaleSizeChangeDetector(this);
+
+ mIsUsingMinimumScaleSize = false;
+
+ if (!PresShell()->UsesMobileViewportSizing()) {
+ return;
+ }
+
+ nsPresContext* pc = PresContext();
+ MOZ_ASSERT(pc->IsRootContentDocumentCrossProcess(),
+ "The pres context should be for the root content document");
+
+ RefPtr<MobileViewportManager> manager =
+ PresShell()->GetMobileViewportManager();
+ MOZ_ASSERT(manager);
+
+ ScreenIntSize displaySize = ViewAs<ScreenPixel>(
+ manager->DisplaySize(),
+ PixelCastJustification::LayoutDeviceIsScreenForBounds);
+ if (displaySize.width == 0 || displaySize.height == 0) {
+ return;
+ }
+ if (aScrollableOverflow.IsEmpty()) {
+ // Bail if the scrollable overflow rect is empty, as we're going to be
+ // dividing by it.
+ return;
+ }
+
+ Document* doc = pc->Document();
+ MOZ_ASSERT(doc, "The document should be valid");
+ if (doc->GetFullscreenElement()) {
+ // Don't use the minimum scale size in the case of fullscreen state.
+ // FIXME: 1508177: We will no longer need this.
+ return;
+ }
+
+ nsViewportInfo viewportInfo = doc->GetViewportInfo(displaySize);
+ if (!viewportInfo.IsZoomAllowed()) {
+ // Don't apply the minimum scale size if user-scalable=no is specified.
+ return;
+ }
+
+ // The intrinsic minimum scale is the scale that fits the entire content
+ // width into the visual viewport.
+ CSSToScreenScale intrinsicMinScale(
+ displaySize.width / CSSRect::FromAppUnits(aScrollableOverflow).XMost());
+
+ // The scale used to compute the minimum-scale size is the larger of the
+ // intrinsic minimum and the min-scale from the meta viewport tag.
+ CSSToScreenScale minScale =
+ std::max(intrinsicMinScale, viewportInfo.GetMinZoom());
+
+ // The minimum-scale size is the size of the visual viewport when zoomed
+ // to be the minimum scale.
+ mMinimumScaleSize = CSSSize::ToAppUnits(ScreenSize(displaySize) / minScale);
+
+ // Ensure the minimum-scale size is never smaller than the ICB size.
+ // That could happen if a page has a meta viewport tag with large explicitly
+ // specified viewport dimensions (making the ICB large) and also a large
+ // minimum scale (making the min-scale size small).
+ mMinimumScaleSize = Max(aICBSize, mMinimumScaleSize);
+
+ mIsUsingMinimumScaleSize = true;
+}
+
+bool nsHTMLScrollFrame::ReflowFinished() {
+ mPostedReflowCallback = false;
+
+ TryScheduleScrollAnimations();
+
+ if (mIsRoot) {
+ if (mMinimumScaleSizeChanged && PresShell()->UsesMobileViewportSizing() &&
+ !PresShell()->IsResolutionUpdatedByApz()) {
+ RefPtr<MobileViewportManager> manager =
+ PresShell()->GetMobileViewportManager();
+ MOZ_ASSERT(manager);
+
+ manager->ShrinkToDisplaySizeIfNeeded();
+ mMinimumScaleSizeChanged = false;
+ }
+
+ if (!UsesOverlayScrollbars()) {
+ // Layout scrollbars may have added or removed during reflow, so let's
+ // update the visual viewport accordingly. Note that this may be a no-op
+ // because we might have recomputed the visual viewport size during the
+ // reflow itself, just before laying out the fixed-pos items. But there
+ // might be cases where that code doesn't run, so this is a sort of
+ // backstop to ensure we do that recomputation.
+ if (RefPtr<MobileViewportManager> manager =
+ PresShell()->GetMobileViewportManager()) {
+ manager->UpdateVisualViewportSizeForPotentialScrollbarChange();
+ }
+ }
+
+#if defined(MOZ_WIDGET_ANDROID)
+ const bool hasVerticalOverflow =
+ GetOverflowState() & OverflowState::Vertical &&
+ GetScrollStyles().mVertical != StyleOverflow::Hidden;
+ if (!mFirstReflow && mHasVerticalOverflowForDynamicToolbar &&
+ !hasVerticalOverflow) {
+ PresShell()->MaybeNotifyShowDynamicToolbar();
+ }
+ mHasVerticalOverflowForDynamicToolbar = hasVerticalOverflow;
+#endif // defined(MOZ_WIDGET_ANDROID)
+ }
+
+ bool doScroll = true;
+ if (IsSubtreeDirty()) {
+ // We will get another call after the next reflow and scrolling
+ // later is less janky.
+ doScroll = false;
+ }
+
+ if (mFirstReflow) {
+ nsPoint currentScrollPos = GetScrollPosition();
+ if (!mScrollUpdates.IsEmpty() &&
+ mScrollUpdates.LastElement().GetOrigin() == ScrollOrigin::None &&
+ currentScrollPos != nsPoint()) {
+ // With frame reconstructions, the reconstructed frame may have a nonzero
+ // scroll position by the end of the reflow, but without going through
+ // RestoreState. In particular this can happen with RTL XUL scrollframes,
+ // see https://bugzilla.mozilla.org/show_bug.cgi?id=1664638#c14.
+ // Upon construction, the nsHTMLScrollFrame constructor will have inserted
+ // a ScrollPositionUpdate into mScrollUpdates with origin None and a zero
+ // scroll position, but here we update that to hold the correct scroll
+ // position. Otherwise APZ may end up resetting the scroll position to
+ // zero incorrectly. If we ever hit this codepath, it must be on a reflow
+ // immediately following the scrollframe construction, so there should be
+ // exactly one ScrollPositionUpdate in mScrollUpdates.
+ MOZ_ASSERT(mScrollUpdates.Length() == 1);
+ MOZ_ASSERT(mScrollUpdates.LastElement().GetGeneration() ==
+ mScrollGeneration);
+ MOZ_ASSERT(mScrollUpdates.LastElement().GetDestination() == CSSPoint());
+ SCROLLRESTORE_LOG("%p: updating initial SPU to pos %s\n", this,
+ ToString(currentScrollPos).c_str());
+ mScrollUpdates.Clear();
+ AppendScrollUpdate(
+ ScrollPositionUpdate::NewScrollframe(currentScrollPos));
+ }
+
+ mFirstReflow = false;
+ }
+
+ nsAutoScriptBlocker scriptBlocker;
+
+ if (mReclampVVOffsetInReflowFinished) {
+ MOZ_ASSERT(mIsRoot && PresShell()->IsVisualViewportOffsetSet());
+ mReclampVVOffsetInReflowFinished = false;
+ AutoWeakFrame weakFrame(this);
+ PresShell()->SetVisualViewportOffset(PresShell()->GetVisualViewportOffset(),
+ GetScrollPosition());
+ NS_ENSURE_TRUE(weakFrame.IsAlive(), false);
+ }
+
+ if (doScroll) {
+ ScrollToRestoredPosition();
+
+ // Clamp current scroll position to new bounds. Normally this won't
+ // do anything.
+ nsPoint currentScrollPos = GetScrollPosition();
+ ScrollToImpl(currentScrollPos, nsRect(currentScrollPos, nsSize(0, 0)),
+ ScrollOrigin::Clamp);
+ if (ScrollAnimationState().isEmpty()) {
+ // We need to have mDestination track the current scroll position,
+ // in case it falls outside the new reflow area. mDestination is used
+ // by ScrollBy as its starting position.
+ mDestination = GetScrollPosition();
+ }
+ }
+
+ if (!mUpdateScrollbarAttributes) {
+ return false;
+ }
+ mUpdateScrollbarAttributes = false;
+
+ // Update scrollbar attributes.
+ if (mMayHaveDirtyFixedChildren) {
+ mMayHaveDirtyFixedChildren = false;
+ nsIFrame* parentFrame = GetParent();
+ for (nsIFrame* fixedChild =
+ parentFrame->GetChildList(FrameChildListID::Fixed).FirstChild();
+ fixedChild; fixedChild = fixedChild->GetNextSibling()) {
+ // force a reflow of the fixed child
+ PresShell()->FrameNeedsReflow(fixedChild, IntrinsicDirty::None,
+ NS_FRAME_HAS_DIRTY_CHILDREN);
+ }
+ }
+
+ // Suppress handling of the curpos attribute changes we make here.
+ NS_ASSERTION(!mFrameIsUpdatingScrollbar, "We shouldn't be reentering here");
+ mFrameIsUpdatingScrollbar = true;
+
+ // FIXME(emilio): Why this instead of mHScrollbarContent / mVScrollbarContent?
+ RefPtr<Element> vScroll =
+ mVScrollbarBox ? mVScrollbarBox->GetContent()->AsElement() : nullptr;
+ RefPtr<Element> hScroll =
+ mHScrollbarBox ? mHScrollbarBox->GetContent()->AsElement() : nullptr;
+
+ // Note, in some cases this may get deleted while finishing reflow
+ // for scrollbars. XXXmats is this still true now that we have a script
+ // blocker in this scope? (if not, remove the weak frame checks below).
+ if (vScroll || hScroll) {
+ nsSize visualViewportSize = GetVisualViewportSize();
+ nsRect scrollRange = GetVisualScrollRange();
+ nsPoint scrollPos = GetScrollPosition();
+ nsSize lineScrollAmount = GetLineScrollAmount();
+
+ if (gfxPlatform::UseDesktopZoomingScrollbars()) {
+ scrollRange = GetScrollRangeForUserInputEvents();
+ scrollPos = GetVisualViewportOffset();
+ }
+
+ // If modifying the logic here, be sure to modify the corresponding
+ // compositor-side calculation in ScrollThumbUtils::ApplyTransformForAxis().
+ AutoWeakFrame weakFrame(this);
+ if (vScroll) {
+ const double kScrollMultiplier =
+ StaticPrefs::toolkit_scrollbox_verticalScrollDistance();
+ nscoord increment = lineScrollAmount.height * kScrollMultiplier;
+ // We normally use (visualViewportSize.height - increment) for height of
+ // page scrolling. However, it is too small when increment is very large.
+ // (If increment is larger than visualViewportSize.height, direction of
+ // scrolling will be opposite). To avoid it, we use
+ // (float(visualViewportSize.height) * 0.8) as lower bound value of height
+ // of page scrolling. (bug 383267)
+ // XXX shouldn't we use GetPageScrollAmount here?
+ nscoord pageincrement = nscoord(visualViewportSize.height - increment);
+ nscoord pageincrementMin =
+ nscoord(float(visualViewportSize.height) * 0.8);
+ FinishReflowForScrollbar(
+ vScroll, scrollRange.y, scrollRange.YMost(), scrollPos.y,
+ std::max(pageincrement, pageincrementMin), increment);
+ }
+ if (hScroll) {
+ const double kScrollMultiplier =
+ StaticPrefs::toolkit_scrollbox_horizontalScrollDistance();
+ nscoord increment = lineScrollAmount.width * kScrollMultiplier;
+ FinishReflowForScrollbar(
+ hScroll, scrollRange.x, scrollRange.XMost(), scrollPos.x,
+ nscoord(float(visualViewportSize.width) * 0.8), increment);
+ }
+ NS_ENSURE_TRUE(weakFrame.IsAlive(), false);
+ }
+
+ mFrameIsUpdatingScrollbar = false;
+ // We used to rely on the curpos attribute changes above to scroll the
+ // view. However, for scrolling to the left of the viewport, we
+ // rescale the curpos attribute, which means that operations like
+ // resizing the window while it is scrolled all the way to the left
+ // hold the curpos attribute constant at 0 while still requiring
+ // scrolling. So we suppress the effect of the changes above with
+ // mFrameIsUpdatingScrollbar and call CurPosAttributeChanged here.
+ // (It actually even works some of the time without this, thanks to
+ // nsSliderFrame::AttributeChanged's handling of maxpos, but not when
+ // we hide the scrollbar on a large size change, such as
+ // maximization.)
+ if (!mHScrollbarBox && !mVScrollbarBox) {
+ return false;
+ }
+ CurPosAttributeChangedInternal(
+ mVScrollbarBox ? mVScrollbarBox->GetContent()->AsElement()
+ : mHScrollbarBox->GetContent()->AsElement(),
+ doScroll);
+ return doScroll;
+}
+
+void nsHTMLScrollFrame::ReflowCallbackCanceled() {
+ mPostedReflowCallback = false;
+}
+
+bool nsHTMLScrollFrame::ComputeCustomOverflow(OverflowAreas& aOverflowAreas) {
+ ScrollStyles ss = GetScrollStyles();
+
+ // Reflow when the change in overflow leads to one of our scrollbars
+ // changing or might require repositioning the scrolled content due to
+ // reduced extents.
+ nsRect scrolledRect = GetScrolledRect();
+ ScrollDirections overflowChange =
+ GetOverflowChange(scrolledRect, mPrevScrolledRect);
+ mPrevScrolledRect = scrolledRect;
+
+ bool needReflow = false;
+ nsPoint scrollPosition = GetScrollPosition();
+ if (overflowChange.contains(ScrollDirection::eHorizontal)) {
+ if (ss.mHorizontal != StyleOverflow::Hidden || scrollPosition.x) {
+ needReflow = true;
+ }
+ }
+ if (overflowChange.contains(ScrollDirection::eVertical)) {
+ if (ss.mVertical != StyleOverflow::Hidden || scrollPosition.y) {
+ needReflow = true;
+ }
+ }
+
+ if (needReflow) {
+ // If there are scrollbars, or we're not at the beginning of the pane,
+ // the scroll position may change. In this case, mark the frame as
+ // needing reflow. Don't use NS_FRAME_IS_DIRTY as dirty as that means
+ // we have to reflow the frame and all its descendants, and we don't
+ // have to do that here. Only this frame needs to be reflowed.
+ PresShell()->FrameNeedsReflow(this, IntrinsicDirty::None,
+ NS_FRAME_HAS_DIRTY_CHILDREN);
+ // Ensure that next time nsHTMLScrollFrame::Reflow runs, we don't skip
+ // updating the scrollbars. (Because the overflow area of the scrolled
+ // frame has probably just been updated, Reflow won't see it change.)
+ mSkippedScrollbarLayout = true;
+ return false; // reflowing will update overflow
+ }
+ PostOverflowEvent();
+ return nsContainerFrame::ComputeCustomOverflow(aOverflowAreas);
+}
+
+void nsHTMLScrollFrame::UpdateSticky() {
+ StickyScrollContainer* ssc =
+ StickyScrollContainer::GetStickyScrollContainerForScrollFrame(this);
+ if (ssc) {
+ ssc->UpdatePositions(GetScrollPosition(), this);
+ }
+}
+
+void nsHTMLScrollFrame::UpdatePrevScrolledRect() {
+ // The layout scroll range is determinated by the scrolled rect and the scroll
+ // port, so if the scrolled rect is updated, we may have to schedule the
+ // associated scroll-driven animations' restyles.
+ nsRect currScrolledRect = GetScrolledRect();
+ if (!currScrolledRect.IsEqualEdges(mPrevScrolledRect)) {
+ mMayScheduleScrollAnimations = true;
+ }
+ mPrevScrolledRect = currScrolledRect;
+}
+
+void nsHTMLScrollFrame::AdjustScrollbarRectForResizer(
+ nsIFrame* aFrame, nsPresContext* aPresContext, nsRect& aRect,
+ bool aHasResizer, ScrollDirection aDirection) {
+ if ((aDirection == ScrollDirection::eVertical ? aRect.width : aRect.height) ==
+ 0) {
+ return;
+ }
+
+ // if a content resizer is present, use its size. Otherwise, check if the
+ // widget has a resizer.
+ nsRect resizerRect;
+ if (aHasResizer) {
+ resizerRect = mResizerBox->GetRect();
+ } else {
+ nsPoint offset;
+ nsIWidget* widget = aFrame->GetNearestWidget(offset);
+ LayoutDeviceIntRect widgetRect;
+ if (!widget || !widget->ShowsResizeIndicator(&widgetRect)) {
+ return;
+ }
+
+ resizerRect =
+ nsRect(aPresContext->DevPixelsToAppUnits(widgetRect.x) - offset.x,
+ aPresContext->DevPixelsToAppUnits(widgetRect.y) - offset.y,
+ aPresContext->DevPixelsToAppUnits(widgetRect.width),
+ aPresContext->DevPixelsToAppUnits(widgetRect.height));
+ }
+
+ if (resizerRect.Contains(aRect.BottomRight() - nsPoint(1, 1))) {
+ switch (aDirection) {
+ case ScrollDirection::eVertical:
+ aRect.height = std::max(0, resizerRect.y - aRect.y);
+ break;
+ case ScrollDirection::eHorizontal:
+ aRect.width = std::max(0, resizerRect.x - aRect.x);
+ break;
+ }
+ } else if (resizerRect.Contains(aRect.BottomLeft() + nsPoint(1, -1))) {
+ switch (aDirection) {
+ case ScrollDirection::eVertical:
+ aRect.height = std::max(0, resizerRect.y - aRect.y);
+ break;
+ case ScrollDirection::eHorizontal: {
+ nscoord xmost = aRect.XMost();
+ aRect.x = std::max(aRect.x, resizerRect.XMost());
+ aRect.width = xmost - aRect.x;
+ break;
+ }
+ }
+ }
+}
+
+static void AdjustOverlappingScrollbars(nsRect& aVRect, nsRect& aHRect) {
+ if (aVRect.IsEmpty() || aHRect.IsEmpty()) return;
+
+ const nsRect oldVRect = aVRect;
+ const nsRect oldHRect = aHRect;
+ if (oldVRect.Contains(oldHRect.BottomRight() - nsPoint(1, 1))) {
+ aHRect.width = std::max(0, oldVRect.x - oldHRect.x);
+ } else if (oldVRect.Contains(oldHRect.BottomLeft() - nsPoint(0, 1))) {
+ nscoord overlap = std::min(oldHRect.width, oldVRect.XMost() - oldHRect.x);
+ aHRect.x += overlap;
+ aHRect.width -= overlap;
+ }
+ if (oldHRect.Contains(oldVRect.BottomRight() - nsPoint(1, 1))) {
+ aVRect.height = std::max(0, oldHRect.y - oldVRect.y);
+ }
+}
+
+void nsHTMLScrollFrame::LayoutScrollbarPartAtRect(
+ const ScrollReflowInput& aState, ReflowInput& aKidReflowInput,
+ const nsRect& aRect) {
+ nsPresContext* pc = PresContext();
+ nsIFrame* kid = aKidReflowInput.mFrame;
+ const auto wm = kid->GetWritingMode();
+ ReflowOutput desiredSize(wm);
+ MOZ_ASSERT(!wm.IsVertical(),
+ "Scrollbar parts should have writing-mode: initial");
+ MOZ_ASSERT(!wm.IsInlineReversed(),
+ "Scrollbar parts should have writing-mode: initial");
+ // XXX Maybe get a meaningful container size or something. Shouldn't matter
+ // given our asserts above.
+ const nsSize containerSize;
+ aKidReflowInput.SetComputedISize(aRect.Width());
+ aKidReflowInput.SetComputedBSize(aRect.Height());
+
+ const LogicalPoint pos(wm, aRect.TopLeft(), containerSize);
+ const auto flags = ReflowChildFlags::Default;
+ nsReflowStatus status;
+ ReflowOutput kidDesiredSize(wm);
+ ReflowChild(kid, pc, kidDesiredSize, aKidReflowInput, wm, pos, containerSize,
+ flags, status);
+ FinishReflowChild(kid, pc, kidDesiredSize, &aKidReflowInput, wm, pos,
+ containerSize, flags);
+}
+
+void nsHTMLScrollFrame::LayoutScrollbars(ScrollReflowInput& aState,
+ const nsRect& aInsideBorderArea,
+ const nsRect& aOldScrollPort) {
+ NS_ASSERTION(!mSuppressScrollbarUpdate, "This should have been suppressed");
+
+ const bool scrollbarOnLeft = !IsScrollbarOnRight();
+ const bool overlayScrollbars = UsesOverlayScrollbars();
+ const bool overlayScrollBarsOnRoot = overlayScrollbars && mIsRoot;
+ const bool showVScrollbar = mVScrollbarBox && mHasVerticalScrollbar;
+ const bool showHScrollbar = mHScrollbarBox && mHasHorizontalScrollbar;
+
+ nsSize compositionSize = mScrollPort.Size();
+ if (overlayScrollBarsOnRoot) {
+ compositionSize = nsLayoutUtils::CalculateCompositionSizeForFrame(
+ this, false, &compositionSize);
+ }
+
+ nsPresContext* presContext = mScrolledFrame->PresContext();
+ nsRect vRect;
+ if (showVScrollbar) {
+ vRect.height =
+ overlayScrollBarsOnRoot ? compositionSize.height : mScrollPort.height;
+ vRect.y = mScrollPort.y;
+ if (scrollbarOnLeft) {
+ vRect.width = mScrollPort.x - aInsideBorderArea.x;
+ vRect.x = aInsideBorderArea.x;
+ } else {
+ vRect.width = aInsideBorderArea.XMost() - mScrollPort.XMost();
+ vRect.x = mScrollPort.x + compositionSize.width;
+ }
+ if (overlayScrollbars || mOnlyNeedVScrollbarToScrollVVInsideLV) {
+ const nscoord width = aState.VScrollbarPrefWidth();
+ // There is no space reserved for the layout scrollbar, it is currently
+ // not visible because it is positioned just outside the scrollport. But
+ // we know that it needs to be made visible so we shift it back in.
+ vRect.width += width;
+ if (!scrollbarOnLeft) {
+ vRect.x -= width;
+ }
+ }
+ }
+
+ nsRect hRect;
+ if (showHScrollbar) {
+ hRect.width =
+ overlayScrollBarsOnRoot ? compositionSize.width : mScrollPort.width;
+ hRect.x = mScrollPort.x;
+ hRect.height = aInsideBorderArea.YMost() - mScrollPort.YMost();
+ hRect.y = mScrollPort.y + compositionSize.height;
+
+ if (overlayScrollbars || mOnlyNeedHScrollbarToScrollVVInsideLV) {
+ const nscoord height = aState.HScrollbarPrefHeight();
+ hRect.height += height;
+ // There is no space reserved for the layout scrollbar, it is currently
+ // not visible because it is positioned just outside the scrollport. But
+ // we know that it needs to be made visible so we shift it back in.
+ hRect.y -= height;
+ }
+ }
+
+ const bool hasVisualOnlyScrollbarsOnBothDirections =
+ !overlayScrollbars && showHScrollbar &&
+ mOnlyNeedHScrollbarToScrollVVInsideLV && showVScrollbar &&
+ mOnlyNeedVScrollbarToScrollVVInsideLV;
+ nsPresContext* pc = PresContext();
+
+ // place the scrollcorner
+ if (mScrollCornerBox) {
+ nsRect r(0, 0, 0, 0);
+ if (scrollbarOnLeft) {
+ // scrollbar (if any) on left
+ r.width = showVScrollbar ? mScrollPort.x - aInsideBorderArea.x : 0;
+ r.x = aInsideBorderArea.x;
+ } else {
+ // scrollbar (if any) on right
+ r.width =
+ showVScrollbar ? aInsideBorderArea.XMost() - mScrollPort.XMost() : 0;
+ r.x = aInsideBorderArea.XMost() - r.width;
+ }
+ NS_ASSERTION(r.width >= 0, "Scroll area should be inside client rect");
+
+ if (showHScrollbar) {
+ // scrollbar (if any) on bottom
+ // Note we don't support the horizontal scrollbar at the top side.
+ r.height = aInsideBorderArea.YMost() - mScrollPort.YMost();
+ NS_ASSERTION(r.height >= 0, "Scroll area should be inside client rect");
+ }
+ r.y = aInsideBorderArea.YMost() - r.height;
+
+ // If we have layout scrollbars and both scrollbars are present and both are
+ // only needed to scroll the VV inside the LV then we need a scrollcorner
+ // but the above calculation will result in an empty rect, so adjust it.
+ if (r.IsEmpty() && hasVisualOnlyScrollbarsOnBothDirections) {
+ r.width = vRect.width;
+ r.height = hRect.height;
+ r.x = scrollbarOnLeft ? mScrollPort.x : mScrollPort.XMost() - r.width;
+ r.y = mScrollPort.YMost() - r.height;
+ }
+
+ ReflowInput scrollCornerRI(
+ pc, aState.mReflowInput, mScrollCornerBox,
+ LogicalSize(mScrollCornerBox->GetWritingMode(), r.Size()));
+ LayoutScrollbarPartAtRect(aState, scrollCornerRI, r);
+ }
+
+ if (mResizerBox) {
+ // If a resizer is present, get its size.
+ //
+ // TODO(emilio): Should this really account for scrollbar-width?
+ auto scrollbarWidth = nsLayoutUtils::StyleForScrollbar(this)
+ ->StyleUIReset()
+ ->ScrollbarWidth();
+ auto scrollbarSize = pc->Theme()->GetScrollbarSize(pc, scrollbarWidth,
+ nsITheme::Overlay::No);
+ ReflowInput resizerRI(pc, aState.mReflowInput, mResizerBox,
+ LogicalSize(mResizerBox->GetWritingMode()));
+ nsSize resizerMinSize = {resizerRI.ComputedMinWidth(),
+ resizerRI.ComputedMinHeight()};
+
+ nsRect r;
+ nscoord vScrollbarWidth = pc->DevPixelsToAppUnits(scrollbarSize);
+ r.width =
+ std::max(std::max(r.width, vScrollbarWidth), resizerMinSize.width);
+ r.x = scrollbarOnLeft ? aInsideBorderArea.x
+ : aInsideBorderArea.XMost() - r.width;
+
+ nscoord hScrollbarHeight = pc->DevPixelsToAppUnits(scrollbarSize);
+ r.height =
+ std::max(std::max(r.height, hScrollbarHeight), resizerMinSize.height);
+ r.y = aInsideBorderArea.YMost() - r.height;
+
+ LayoutScrollbarPartAtRect(aState, resizerRI, r);
+ }
+
+ // Note that AdjustScrollbarRectForResizer has to be called after the
+ // resizer has been laid out immediately above this because it gets the rect
+ // of the resizer frame.
+ if (mVScrollbarBox) {
+ AdjustScrollbarRectForResizer(this, presContext, vRect, mResizerBox,
+ ScrollDirection::eVertical);
+ }
+ if (mHScrollbarBox) {
+ AdjustScrollbarRectForResizer(this, presContext, hRect, mResizerBox,
+ ScrollDirection::eHorizontal);
+ }
+
+ // Layout scrollbars can overlap at this point if they are both present and
+ // both only needed to scroll the VV inside the LV.
+ if (!LookAndFeel::GetInt(LookAndFeel::IntID::AllowOverlayScrollbarsOverlap) ||
+ hasVisualOnlyScrollbarsOnBothDirections) {
+ AdjustOverlappingScrollbars(vRect, hRect);
+ }
+ if (mVScrollbarBox) {
+ ReflowInput vScrollbarRI(
+ pc, aState.mReflowInput, mVScrollbarBox,
+ LogicalSize(mVScrollbarBox->GetWritingMode(), vRect.Size()));
+ LayoutScrollbarPartAtRect(aState, vScrollbarRI, vRect);
+ }
+ if (mHScrollbarBox) {
+ ReflowInput hScrollbarRI(
+ pc, aState.mReflowInput, mHScrollbarBox,
+ LogicalSize(mHScrollbarBox->GetWritingMode(), hRect.Size()));
+ LayoutScrollbarPartAtRect(aState, hScrollbarRI, hRect);
+ }
+
+ // may need to update fixed position children of the viewport,
+ // if the client area changed size because of an incremental
+ // reflow of a descendant. (If the outer frame is dirty, the fixed
+ // children will be re-laid out anyway)
+ if (aOldScrollPort.Size() != mScrollPort.Size() &&
+ !HasAnyStateBits(NS_FRAME_IS_DIRTY) && mIsRoot) {
+ mMayHaveDirtyFixedChildren = true;
+ }
+
+ // post reflow callback to modify scrollbar attributes
+ mUpdateScrollbarAttributes = true;
+ if (!mPostedReflowCallback) {
+ PresShell()->PostReflowCallback(this);
+ mPostedReflowCallback = true;
+ }
+}
+
+#if DEBUG
+static bool ShellIsAlive(nsWeakPtr& aWeakPtr) {
+ RefPtr<PresShell> presShell = do_QueryReferent(aWeakPtr);
+ return !!presShell;
+}
+#endif
+
+void nsHTMLScrollFrame::SetScrollbarEnabled(Element* aElement,
+ nscoord aMaxPos) {
+ DebugOnly<nsWeakPtr> weakShell(do_GetWeakReference(PresShell()));
+ if (aMaxPos) {
+ aElement->UnsetAttr(kNameSpaceID_None, nsGkAtoms::disabled, true);
+ } else {
+ aElement->SetAttr(kNameSpaceID_None, nsGkAtoms::disabled, u"true"_ns, true);
+ }
+ MOZ_ASSERT(ShellIsAlive(weakShell), "pres shell was destroyed by scrolling");
+}
+
+void nsHTMLScrollFrame::SetCoordAttribute(Element* aElement, nsAtom* aAtom,
+ nscoord aSize) {
+ DebugOnly<nsWeakPtr> weakShell(do_GetWeakReference(PresShell()));
+ // convert to pixels
+ int32_t pixelSize = nsPresContext::AppUnitsToIntCSSPixels(aSize);
+
+ // only set the attribute if it changed.
+
+ nsAutoString newValue;
+ newValue.AppendInt(pixelSize);
+
+ if (aElement->AttrValueIs(kNameSpaceID_None, aAtom, newValue, eCaseMatters)) {
+ return;
+ }
+
+ AutoWeakFrame weakFrame(this);
+ RefPtr<Element> kungFuDeathGrip = aElement;
+ aElement->SetAttr(kNameSpaceID_None, aAtom, newValue, true);
+ MOZ_ASSERT(ShellIsAlive(weakShell), "pres shell was destroyed by scrolling");
+ if (!weakFrame.IsAlive()) {
+ return;
+ }
+
+ if (mScrollbarActivity &&
+ (mHasHorizontalScrollbar || mHasVerticalScrollbar)) {
+ RefPtr<ScrollbarActivity> scrollbarActivity(mScrollbarActivity);
+ scrollbarActivity->ActivityOccurred();
+ }
+}
+
+static void ReduceRadii(nscoord aXBorder, nscoord aYBorder, nscoord& aXRadius,
+ nscoord& aYRadius) {
+ // In order to ensure that the inside edge of the border has no
+ // curvature, we need at least one of its radii to be zero.
+ if (aXRadius <= aXBorder || aYRadius <= aYBorder) return;
+
+ // For any corner where we reduce the radii, preserve the corner's shape.
+ double ratio =
+ std::max(double(aXBorder) / aXRadius, double(aYBorder) / aYRadius);
+ aXRadius *= ratio;
+ aYRadius *= ratio;
+}
+
+/**
+ * Implement an override for nsIFrame::GetBorderRadii to ensure that
+ * the clipping region for the border radius does not clip the scrollbars.
+ *
+ * In other words, we require that the border radius be reduced until the
+ * inner border radius at the inner edge of the border is 0 wherever we
+ * have scrollbars.
+ */
+bool nsHTMLScrollFrame::GetBorderRadii(const nsSize& aFrameSize,
+ const nsSize& aBorderArea,
+ Sides aSkipSides,
+ nscoord aRadii[8]) const {
+ if (!nsContainerFrame::GetBorderRadii(aFrameSize, aBorderArea, aSkipSides,
+ aRadii)) {
+ return false;
+ }
+
+ // Since we can use GetActualScrollbarSizes (rather than
+ // GetDesiredScrollbarSizes) since this doesn't affect reflow, we
+ // probably should.
+ nsMargin sb = GetActualScrollbarSizes();
+ nsMargin border = GetUsedBorder();
+
+ if (sb.left > 0 || sb.top > 0) {
+ ReduceRadii(border.left, border.top, aRadii[eCornerTopLeftX],
+ aRadii[eCornerTopLeftY]);
+ }
+
+ if (sb.top > 0 || sb.right > 0) {
+ ReduceRadii(border.right, border.top, aRadii[eCornerTopRightX],
+ aRadii[eCornerTopRightY]);
+ }
+
+ if (sb.right > 0 || sb.bottom > 0) {
+ ReduceRadii(border.right, border.bottom, aRadii[eCornerBottomRightX],
+ aRadii[eCornerBottomRightY]);
+ }
+
+ if (sb.bottom > 0 || sb.left > 0) {
+ ReduceRadii(border.left, border.bottom, aRadii[eCornerBottomLeftX],
+ aRadii[eCornerBottomLeftY]);
+ }
+
+ return true;
+}
+
+static nscoord SnapCoord(nscoord aCoord, double aRes,
+ nscoord aAppUnitsPerPixel) {
+ double snappedToLayerPixels = NS_round((aRes * aCoord) / aAppUnitsPerPixel);
+ return NSToCoordRoundWithClamp(snappedToLayerPixels * aAppUnitsPerPixel /
+ aRes);
+}
+
+nsRect nsHTMLScrollFrame::GetScrolledRect() const {
+ nsRect result = GetUnsnappedScrolledRectInternal(
+ mScrolledFrame->ScrollableOverflowRect(), mScrollPort.Size());
+
+#if 0
+ // This happens often enough.
+ if (result.width < mScrollPort.width || result.height < mScrollPort.height) {
+ NS_WARNING("Scrolled rect smaller than scrollport?");
+ }
+#endif
+
+ // Expand / contract the result by up to half a layer pixel so that scrolling
+ // to the right / bottom edge does not change the layer pixel alignment of
+ // the scrolled contents.
+
+ if (result.x == 0 && result.y == 0 && result.width == mScrollPort.width &&
+ result.height == mScrollPort.height) {
+ // The edges that we would snap are already aligned with the scroll port,
+ // so we can skip all the work below.
+ return result;
+ }
+
+ // For that, we first convert the scroll port and the scrolled rect to rects
+ // relative to the reference frame, since that's the space where painting does
+ // snapping.
+ nsSize visualViewportSize = GetVisualViewportSize();
+ const nsIFrame* referenceFrame =
+ mReferenceFrameDuringPainting ? mReferenceFrameDuringPainting
+ : nsLayoutUtils::GetReferenceFrame(
+ const_cast<nsHTMLScrollFrame*>(this));
+ nsPoint toReferenceFrame = GetOffsetToCrossDoc(referenceFrame);
+ nsRect scrollPort(mScrollPort.TopLeft() + toReferenceFrame,
+ visualViewportSize);
+ nsRect scrolledRect = result + scrollPort.TopLeft();
+
+ if (scrollPort.Overflows() || scrolledRect.Overflows()) {
+ return result;
+ }
+
+ // Now, snap the bottom right corner of both of these rects.
+ // We snap to layer pixels, so we need to respect the layer's scale.
+ nscoord appUnitsPerDevPixel =
+ mScrolledFrame->PresContext()->AppUnitsPerDevPixel();
+ MatrixScales scale = GetPaintedLayerScaleForFrame(mScrolledFrame);
+ if (scale.xScale == 0 || scale.yScale == 0) {
+ scale = MatrixScales();
+ }
+
+ // Compute bounds for the scroll position, and computed the snapped scrolled
+ // rect from the scroll position bounds.
+ nscoord snappedScrolledAreaBottom =
+ SnapCoord(scrolledRect.YMost(), scale.yScale, appUnitsPerDevPixel);
+ nscoord snappedScrollPortBottom =
+ SnapCoord(scrollPort.YMost(), scale.yScale, appUnitsPerDevPixel);
+ nscoord maximumScrollOffsetY =
+ snappedScrolledAreaBottom - snappedScrollPortBottom;
+ result.SetBottomEdge(scrollPort.height + maximumScrollOffsetY);
+
+ if (GetScrolledFrameDir() == StyleDirection::Ltr) {
+ nscoord snappedScrolledAreaRight =
+ SnapCoord(scrolledRect.XMost(), scale.xScale, appUnitsPerDevPixel);
+ nscoord snappedScrollPortRight =
+ SnapCoord(scrollPort.XMost(), scale.xScale, appUnitsPerDevPixel);
+ nscoord maximumScrollOffsetX =
+ snappedScrolledAreaRight - snappedScrollPortRight;
+ result.SetRightEdge(scrollPort.width + maximumScrollOffsetX);
+ } else {
+ // In RTL, the scrolled area's right edge is at scrollPort.XMost(),
+ // and the scrolled area's x position is zero or negative. We want
+ // the right edge to stay flush with the scroll port, so we snap the
+ // left edge.
+ nscoord snappedScrolledAreaLeft =
+ SnapCoord(scrolledRect.x, scale.xScale, appUnitsPerDevPixel);
+ nscoord snappedScrollPortLeft =
+ SnapCoord(scrollPort.x, scale.xScale, appUnitsPerDevPixel);
+ nscoord minimumScrollOffsetX =
+ snappedScrolledAreaLeft - snappedScrollPortLeft;
+ result.SetLeftEdge(minimumScrollOffsetX);
+ }
+
+ return result;
+}
+
+StyleDirection nsHTMLScrollFrame::GetScrolledFrameDir() const {
+ // If the scrolled frame has unicode-bidi: plaintext, the paragraph
+ // direction set by the text content overrides the direction of the frame
+ if (mScrolledFrame->StyleTextReset()->mUnicodeBidi ==
+ StyleUnicodeBidi::Plaintext) {
+ if (nsIFrame* child = mScrolledFrame->PrincipalChildList().FirstChild()) {
+ return nsBidiPresUtils::ParagraphDirection(child) ==
+ mozilla::intl::BidiDirection::LTR
+ ? StyleDirection::Ltr
+ : StyleDirection::Rtl;
+ }
+ }
+ return IsBidiLTR() ? StyleDirection::Ltr : StyleDirection::Rtl;
+}
+
+nsRect nsHTMLScrollFrame::GetUnsnappedScrolledRectInternal(
+ const nsRect& aScrolledOverflowArea, const nsSize& aScrollPortSize) const {
+ return nsLayoutUtils::GetScrolledRect(mScrolledFrame, aScrolledOverflowArea,
+ aScrollPortSize, GetScrolledFrameDir());
+}
+
+nsMargin nsHTMLScrollFrame::GetActualScrollbarSizes(
+ nsIScrollableFrame::ScrollbarSizesOptions
+ aOptions /* = nsIScrollableFrame::ScrollbarSizesOptions::NONE */)
+ const {
+ nsRect r = GetPaddingRectRelativeToSelf();
+
+ nsMargin m(mScrollPort.y - r.y, r.XMost() - mScrollPort.XMost(),
+ r.YMost() - mScrollPort.YMost(), mScrollPort.x - r.x);
+
+ if (aOptions == nsIScrollableFrame::ScrollbarSizesOptions::
+ INCLUDE_VISUAL_VIEWPORT_SCROLLBARS &&
+ !UsesOverlayScrollbars()) {
+ // If we are using layout scrollbars and they only exist to scroll the
+ // visual viewport then they do not take up any layout space (so the
+ // scrollport is the same as the padding rect) but they do cover everything
+ // below them so some callers may want to include this special type of
+ // scrollbars in the returned value.
+ if (mHScrollbarBox && mHasHorizontalScrollbar &&
+ mOnlyNeedHScrollbarToScrollVVInsideLV) {
+ m.bottom += mHScrollbarBox->GetRect().height;
+ }
+ if (mVScrollbarBox && mHasVerticalScrollbar &&
+ mOnlyNeedVScrollbarToScrollVVInsideLV) {
+ if (IsScrollbarOnRight()) {
+ m.right += mVScrollbarBox->GetRect().width;
+ } else {
+ m.left += mVScrollbarBox->GetRect().width;
+ }
+ }
+ }
+
+ return m;
+}
+
+void nsHTMLScrollFrame::SetScrollbarVisibility(nsIFrame* aScrollbar,
+ bool aVisible) {
+ nsScrollbarFrame* scrollbar = do_QueryFrame(aScrollbar);
+ if (scrollbar) {
+ // See if we have a mediator.
+ nsIScrollbarMediator* mediator = scrollbar->GetScrollbarMediator();
+ if (mediator) {
+ // Inform the mediator of the visibility change.
+ mediator->VisibilityChanged(aVisible);
+ }
+ }
+}
+
+nscoord nsHTMLScrollFrame::GetCoordAttribute(nsIFrame* aBox, nsAtom* aAtom,
+ nscoord aDefaultValue,
+ nscoord* aRangeStart,
+ nscoord* aRangeLength) {
+ if (aBox) {
+ nsIContent* content = aBox->GetContent();
+
+ nsAutoString value;
+ if (content->IsElement()) {
+ content->AsElement()->GetAttr(kNameSpaceID_None, aAtom, value);
+ }
+ if (!value.IsEmpty()) {
+ nsresult error;
+ // convert it to appunits
+ nscoord result =
+ nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
+ nscoord halfPixel = nsPresContext::CSSPixelsToAppUnits(0.5f);
+ // Any nscoord value that would round to the attribute value when
+ // converted to CSS pixels is allowed.
+ *aRangeStart = result - halfPixel;
+ *aRangeLength = halfPixel * 2 - 1;
+ return result;
+ }
+ }
+
+ // Only this exact default value is allowed.
+ *aRangeStart = aDefaultValue;
+ *aRangeLength = 0;
+ return aDefaultValue;
+}
+
+bool nsHTMLScrollFrame::IsLastScrollUpdateAnimating() const {
+ if (!mScrollUpdates.IsEmpty()) {
+ switch (mScrollUpdates.LastElement().GetMode()) {
+ case ScrollMode::Smooth:
+ case ScrollMode::SmoothMsd:
+ return true;
+ case ScrollMode::Instant:
+ case ScrollMode::Normal:
+ break;
+ }
+ }
+ return false;
+}
+
+bool nsHTMLScrollFrame::IsLastScrollUpdateTriggeredByScriptAnimating() const {
+ if (!mScrollUpdates.IsEmpty()) {
+ const ScrollPositionUpdate& lastUpdate = mScrollUpdates.LastElement();
+ if (lastUpdate.WasTriggeredByScript() &&
+ (mScrollUpdates.LastElement().GetMode() == ScrollMode::Smooth ||
+ mScrollUpdates.LastElement().GetMode() == ScrollMode::SmoothMsd)) {
+ return true;
+ }
+ }
+ return false;
+}
+
+using AnimationState = nsIScrollableFrame::AnimationState;
+EnumSet<AnimationState> nsHTMLScrollFrame::ScrollAnimationState() const {
+ EnumSet<AnimationState> retval;
+ if (IsApzAnimationInProgress()) {
+ retval += AnimationState::APZInProgress;
+ if (mCurrentAPZScrollAnimationType ==
+ APZScrollAnimationType::TriggeredByScript) {
+ retval += AnimationState::TriggeredByScript;
+ }
+ }
+
+ if (mApzAnimationRequested) {
+ retval += AnimationState::APZRequested;
+ if (mApzAnimationTriggeredByScriptRequested) {
+ retval += AnimationState::TriggeredByScript;
+ }
+ }
+
+ if (IsLastScrollUpdateAnimating()) {
+ retval += AnimationState::APZPending;
+ if (IsLastScrollUpdateTriggeredByScriptAnimating()) {
+ retval += AnimationState::TriggeredByScript;
+ }
+ }
+ if (mAsyncScroll) {
+ retval += AnimationState::MainThread;
+ if (mAsyncScroll->WasTriggeredByScript()) {
+ retval += AnimationState::TriggeredByScript;
+ }
+ }
+
+ if (mAsyncSmoothMSDScroll) {
+ retval += AnimationState::MainThread;
+ if (mAsyncSmoothMSDScroll->WasTriggeredByScript()) {
+ retval += AnimationState::TriggeredByScript;
+ }
+ }
+ return retval;
+}
+
+void nsHTMLScrollFrame::ResetScrollInfoIfNeeded(
+ const MainThreadScrollGeneration& aGeneration,
+ const APZScrollGeneration& aGenerationOnApz,
+ APZScrollAnimationType aAPZScrollAnimationType,
+ InScrollingGesture aInScrollingGesture) {
+ if (aGeneration == mScrollGeneration) {
+ mLastScrollOrigin = ScrollOrigin::None;
+ mApzAnimationRequested = false;
+ mApzAnimationTriggeredByScriptRequested = false;
+ }
+
+ mScrollGenerationOnApz = aGenerationOnApz;
+ // We can reset this regardless of scroll generation, as this is only set
+ // here, as a response to APZ requesting a repaint.
+ mCurrentAPZScrollAnimationType = aAPZScrollAnimationType;
+
+ mInScrollingGesture = aInScrollingGesture;
+}
+
+UniquePtr<PresState> nsHTMLScrollFrame::SaveState() {
+ nsIScrollbarMediator* mediator = do_QueryFrame(GetScrolledFrame());
+ if (mediator) {
+ // child handles its own scroll state, so don't bother saving state here
+ return nullptr;
+ }
+
+ // Don't store a scroll state if we never have been scrolled or restored
+ // a previous scroll state, and we're not in the middle of a smooth scroll.
+ auto scrollAnimationState = ScrollAnimationState();
+ bool isScrollAnimating =
+ scrollAnimationState.contains(AnimationState::MainThread) ||
+ scrollAnimationState.contains(AnimationState::APZPending) ||
+ scrollAnimationState.contains(AnimationState::APZRequested);
+ if (!mHasBeenScrolled && !mDidHistoryRestore && !isScrollAnimating) {
+ return nullptr;
+ }
+
+ UniquePtr<PresState> state = NewPresState();
+ bool allowScrollOriginDowngrade =
+ !nsLayoutUtils::CanScrollOriginClobberApz(mLastScrollOrigin) ||
+ mAllowScrollOriginDowngrade;
+ // Save mRestorePos instead of our actual current scroll position, if it's
+ // valid and we haven't moved since the last update of mLastPos (same check
+ // that ScrollToRestoredPosition uses). This ensures if a reframe occurs
+ // while we're in the process of loading content to scroll to a restored
+ // position, we'll keep trying after the reframe. Similarly, if we're in the
+ // middle of a smooth scroll, store the destination so that when we restore
+ // we'll jump straight to the end of the scroll animation, rather than
+ // effectively dropping it. Note that the mRestorePos will override the
+ // smooth scroll destination if both are present.
+ nsPoint pt = GetLogicalVisualViewportOffset();
+ if (isScrollAnimating) {
+ pt = mDestination;
+ allowScrollOriginDowngrade = false;
+ }
+ SCROLLRESTORE_LOG("%p: SaveState, pt=%s, mLastPos=%s, mRestorePos=%s\n", this,
+ ToString(pt).c_str(), ToString(mLastPos).c_str(),
+ ToString(mRestorePos).c_str());
+ if (mRestorePos.y != -1 && pt == mLastPos) {
+ pt = mRestorePos;
+ }
+ state->scrollState() = pt;
+ state->allowScrollOriginDowngrade() = allowScrollOriginDowngrade;
+ if (mIsRoot) {
+ // Only save resolution properties for root scroll frames
+ state->resolution() = PresShell()->GetResolution();
+ }
+ return state;
+}
+
+NS_IMETHODIMP nsHTMLScrollFrame::RestoreState(PresState* aState) {
+ mRestorePos = aState->scrollState();
+ MOZ_ASSERT(mLastScrollOrigin == ScrollOrigin::None);
+ mAllowScrollOriginDowngrade = aState->allowScrollOriginDowngrade();
+ // When restoring state, we promote mLastScrollOrigin to a stronger value
+ // from the default of eNone, to restore the behaviour that existed when
+ // the state was saved. If mLastScrollOrigin was a weaker value previously,
+ // then mAllowScrollOriginDowngrade will be true, and so the combination of
+ // mAllowScrollOriginDowngrade and the stronger mLastScrollOrigin will allow
+ // the same types of scrolls as before. It might be possible to also just
+ // save and restore the mAllowScrollOriginDowngrade and mLastScrollOrigin
+ // values directly without this sort of fiddling. Something to try in the
+ // future or if we tinker with this code more.
+ mLastScrollOrigin = ScrollOrigin::Other;
+ mDidHistoryRestore = true;
+ mLastPos = mScrolledFrame ? GetLogicalVisualViewportOffset() : nsPoint(0, 0);
+ SCROLLRESTORE_LOG("%p: RestoreState, set mRestorePos=%s mLastPos=%s\n", this,
+ ToString(mRestorePos).c_str(), ToString(mLastPos).c_str());
+
+ // Resolution properties should only exist on root scroll frames.
+ MOZ_ASSERT(mIsRoot || aState->resolution() == 1.0);
+
+ if (mIsRoot) {
+ PresShell()->SetResolutionAndScaleTo(
+ aState->resolution(), ResolutionChangeOrigin::MainThreadRestore);
+ }
+ return NS_OK;
+}
+
+void nsHTMLScrollFrame::PostScrolledAreaEvent() {
+ if (mScrolledAreaEvent.IsPending()) {
+ return;
+ }
+ mScrolledAreaEvent = new ScrolledAreaEvent(this);
+ nsContentUtils::AddScriptRunner(mScrolledAreaEvent.get());
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ScrolledArea change event dispatch
+
+// TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230, bug 1535398)
+MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHODIMP
+nsHTMLScrollFrame::ScrolledAreaEvent::Run() {
+ if (mHelper) {
+ mHelper->FireScrolledAreaEvent();
+ }
+ return NS_OK;
+}
+
+void nsHTMLScrollFrame::FireScrolledAreaEvent() {
+ mScrolledAreaEvent.Forget();
+
+ InternalScrollAreaEvent event(true, eScrolledAreaChanged, nullptr);
+ RefPtr<nsPresContext> presContext = PresContext();
+ nsIContent* content = GetContent();
+
+ event.mArea = mScrolledFrame->ScrollableOverflowRectRelativeToParent();
+ if (RefPtr<Document> doc = content->GetUncomposedDoc()) {
+ // TODO: Bug 1506441
+ EventDispatcher::Dispatch(MOZ_KnownLive(ToSupports(doc)), presContext,
+ &event, nullptr);
+ }
+}
+
+ScrollDirections nsIScrollableFrame::GetAvailableScrollingDirections() const {
+ nscoord oneDevPixel =
+ GetScrolledFrame()->PresContext()->AppUnitsPerDevPixel();
+ ScrollDirections directions;
+ nsRect scrollRange = GetScrollRange();
+ if (scrollRange.width >= oneDevPixel) {
+ directions += ScrollDirection::eHorizontal;
+ }
+ if (scrollRange.height >= oneDevPixel) {
+ directions += ScrollDirection::eVertical;
+ }
+ return directions;
+}
+
+nsRect nsHTMLScrollFrame::GetScrollRangeForUserInputEvents() const {
+ // This function computes a scroll range based on a scrolled rect and scroll
+ // port defined as follows:
+ // scrollable rect = overflow:hidden ? layout viewport : scrollable rect
+ // scroll port = have visual viewport ? visual viewport : layout viewport
+ // The results in the same notion of scroll range that APZ uses (the combined
+ // effect of FrameMetrics::CalculateScrollRange() and
+ // nsLayoutUtils::CalculateScrollableRectForFrame).
+
+ ScrollStyles ss = GetScrollStyles();
+
+ nsPoint scrollPos = GetScrollPosition();
+
+ nsRect scrolledRect = GetScrolledRect();
+ if (StyleOverflow::Hidden == ss.mHorizontal) {
+ scrolledRect.width = mScrollPort.width;
+ scrolledRect.x = scrollPos.x;
+ }
+ if (StyleOverflow::Hidden == ss.mVertical) {
+ scrolledRect.height = mScrollPort.height;
+ scrolledRect.y = scrollPos.y;
+ }
+
+ nsSize scrollPort = GetVisualViewportSize();
+
+ nsRect scrollRange = scrolledRect;
+ scrollRange.width = std::max(scrolledRect.width - scrollPort.width, 0);
+ scrollRange.height = std::max(scrolledRect.height - scrollPort.height, 0);
+
+ return scrollRange;
+}
+
+ScrollDirections
+nsHTMLScrollFrame::GetAvailableScrollingDirectionsForUserInputEvents() const {
+ nsRect scrollRange = GetScrollRangeForUserInputEvents();
+
+ // We check if there is at least one half of a screen pixel of scroll range to
+ // roughly match what apz does when it checks if the change in scroll position
+ // in screen pixels round to zero or not.
+ // (https://searchfox.org/mozilla-central/rev/2f09184ec781a2667feec87499d4b81b32b6c48e/gfx/layers/apz/src/AsyncPanZoomController.cpp#3210)
+ // This isn't quite half a screen pixel, it doesn't take into account CSS
+ // transforms, but should be good enough.
+ float halfScreenPixel =
+ GetScrolledFrame()->PresContext()->AppUnitsPerDevPixel() /
+ (PresShell()->GetCumulativeResolution() * 2.f);
+ ScrollDirections directions;
+ if (scrollRange.width >= halfScreenPixel) {
+ directions += ScrollDirection::eHorizontal;
+ }
+ if (scrollRange.height >= halfScreenPixel) {
+ directions += ScrollDirection::eVertical;
+ }
+ return directions;
+}
+
+/**
+ * Append scroll positions for valid snap positions into |aSnapInfo| if
+ * applicable.
+ */
+static void AppendScrollPositionsForSnap(
+ const nsIFrame* aFrame, const nsIFrame* aScrolledFrame,
+ const nsRect& aScrolledRect, const nsMargin& aScrollPadding,
+ const nsRect& aScrollRange, WritingMode aWritingModeOnScroller,
+ ScrollSnapInfo& aSnapInfo, nsHTMLScrollFrame::SnapTargetSet* aSnapTargets) {
+ ScrollSnapTargetId targetId = ScrollSnapUtils::GetTargetIdFor(aFrame);
+
+ nsRect snapArea =
+ ScrollSnapUtils::GetSnapAreaFor(aFrame, aScrolledFrame, aScrolledRect);
+ // Use the writing-mode on the target element if the snap area is larger than
+ // the snapport.
+ // https://drafts.csswg.org/css-scroll-snap/#snap-scope
+ WritingMode writingMode = ScrollSnapUtils::NeedsToRespectTargetWritingMode(
+ snapArea.Size(), aSnapInfo.mSnapportSize)
+ ? aFrame->GetWritingMode()
+ : aWritingModeOnScroller;
+
+ // These snap range shouldn't be involved with scroll-margin since we just
+ // need the visible range of the target element.
+ if (snapArea.width > aSnapInfo.mSnapportSize.width) {
+ aSnapInfo.mXRangeWiderThanSnapport.AppendElement(
+ ScrollSnapInfo::ScrollSnapRange(snapArea.X(), snapArea.XMost(),
+ targetId));
+ }
+ if (snapArea.height > aSnapInfo.mSnapportSize.height) {
+ aSnapInfo.mYRangeWiderThanSnapport.AppendElement(
+ ScrollSnapInfo::ScrollSnapRange(snapArea.Y(), snapArea.YMost(),
+ targetId));
+ }
+
+ // Shift target rect position by the scroll padding to get the padded
+ // position thus we don't need to take account scroll-padding values in
+ // ScrollSnapUtils::GetSnapPointForDestination() when it gets called from
+ // the compositor thread.
+ snapArea.y -= aScrollPadding.top;
+ snapArea.x -= aScrollPadding.left;
+
+ LogicalRect logicalTargetRect(writingMode, snapArea, aSnapInfo.mSnapportSize);
+ LogicalSize logicalSnapportRect(writingMode, aSnapInfo.mSnapportSize);
+ LogicalRect logicalScrollRange(aWritingModeOnScroller, aScrollRange,
+ // The origin of this logical coordinate system
+ // what we need here is (0, 0), so we use an
+ // empty size.
+ nsSize());
+
+ Maybe<nscoord> blockDirectionPosition;
+ const nsStyleDisplay* styleDisplay = aFrame->StyleDisplay();
+ nscoord containerBSize = logicalSnapportRect.BSize(writingMode);
+ switch (styleDisplay->mScrollSnapAlign.block) {
+ case StyleScrollSnapAlignKeyword::None:
+ break;
+ case StyleScrollSnapAlignKeyword::Start:
+ blockDirectionPosition.emplace(
+ writingMode.IsVerticalRL() ? -logicalTargetRect.BStart(writingMode)
+ : logicalTargetRect.BStart(writingMode));
+ break;
+ case StyleScrollSnapAlignKeyword::End: {
+ nscoord candidate = std::clamp(
+ // What we need here is the scroll position instead of the snap
+ // position itself, so we need, for example, the top edge of the
+ // scroll port on horizontal-tb when the frame is positioned at
+ // the bottom edge of the scroll port. For this reason we subtract
+ // containerBSize from BEnd of the target and clamp it inside the
+ // scrollable range.
+ logicalTargetRect.BEnd(writingMode) - containerBSize,
+ logicalScrollRange.BStart(writingMode),
+ logicalScrollRange.BEnd(writingMode));
+ blockDirectionPosition.emplace(writingMode.IsVerticalRL() ? -candidate
+ : candidate);
+ break;
+ }
+ case StyleScrollSnapAlignKeyword::Center: {
+ nscoord targetCenter = (logicalTargetRect.BStart(writingMode) +
+ logicalTargetRect.BEnd(writingMode)) /
+ 2;
+ nscoord halfSnapportSize = containerBSize / 2;
+ // Get the center of the target to align with the center of the snapport
+ // depending on direction.
+ nscoord candidate = std::clamp(targetCenter - halfSnapportSize,
+ logicalScrollRange.BStart(writingMode),
+ logicalScrollRange.BEnd(writingMode));
+ blockDirectionPosition.emplace(writingMode.IsVerticalRL() ? -candidate
+ : candidate);
+ break;
+ }
+ }
+
+ Maybe<nscoord> inlineDirectionPosition;
+ nscoord containerISize = logicalSnapportRect.ISize(writingMode);
+ switch (styleDisplay->mScrollSnapAlign.inline_) {
+ case StyleScrollSnapAlignKeyword::None:
+ break;
+ case StyleScrollSnapAlignKeyword::Start:
+ inlineDirectionPosition.emplace(
+ writingMode.IsInlineReversed()
+ ? -logicalTargetRect.IStart(writingMode)
+ : logicalTargetRect.IStart(writingMode));
+ break;
+ case StyleScrollSnapAlignKeyword::End: {
+ nscoord candidate = std::clamp(
+ // Same as above BEnd case, we subtract containerISize.
+ //
+ // Note that the logical scroll range is mapped to [0, x] range even
+ // if it's in RTL contents. So for example, if the physical range is
+ // [-200, 0], it's mapped to [0, 200], i.e. IStart() is 0, IEnd() is
+ // 200. So we can just use std::clamp with the same arguments in both
+ // RTL/LTR cases.
+ logicalTargetRect.IEnd(writingMode) - containerISize,
+ logicalScrollRange.IStart(writingMode),
+ logicalScrollRange.IEnd(writingMode));
+ inlineDirectionPosition.emplace(
+ writingMode.IsInlineReversed() ? -candidate : candidate);
+ break;
+ }
+ case StyleScrollSnapAlignKeyword::Center: {
+ nscoord targetCenter = (logicalTargetRect.IStart(writingMode) +
+ logicalTargetRect.IEnd(writingMode)) /
+ 2;
+ nscoord halfSnapportSize = containerISize / 2;
+ // Get the center of the target to align with the center of the snapport
+ // depending on direction.
+ nscoord candidate = std::clamp(targetCenter - halfSnapportSize,
+ logicalScrollRange.IStart(writingMode),
+ logicalScrollRange.IEnd(writingMode));
+ inlineDirectionPosition.emplace(
+ writingMode.IsInlineReversed() ? -candidate : candidate);
+ break;
+ }
+ }
+
+ if (blockDirectionPosition || inlineDirectionPosition) {
+ aSnapInfo.mSnapTargets.AppendElement(
+ writingMode.IsVertical()
+ ? ScrollSnapInfo::SnapTarget(
+ std::move(blockDirectionPosition),
+ std::move(inlineDirectionPosition), std::move(snapArea),
+ styleDisplay->mScrollSnapStop, targetId)
+ : ScrollSnapInfo::SnapTarget(
+ std::move(inlineDirectionPosition),
+ std::move(blockDirectionPosition), std::move(snapArea),
+ styleDisplay->mScrollSnapStop, targetId));
+ if (aSnapTargets) {
+ aSnapTargets->EnsureInserted(aFrame->GetContent());
+ }
+ }
+}
+
+/**
+ * Collect the scroll positions corresponding to snap positions of frames in the
+ * subtree rooted at |aFrame|, relative to |aScrolledFrame|, into |aSnapInfo|.
+ */
+static void CollectScrollPositionsForSnap(
+ nsIFrame* aFrame, nsIFrame* aScrolledFrame, const nsRect& aScrolledRect,
+ const nsMargin& aScrollPadding, const nsRect& aScrollRange,
+ WritingMode aWritingModeOnScroller, ScrollSnapInfo& aSnapInfo,
+ nsHTMLScrollFrame::SnapTargetSet* aSnapTargets) {
+ // Snap positions only affect the nearest ancestor scroll container on the
+ // element's containing block chain.
+ nsIScrollableFrame* sf = do_QueryFrame(aFrame);
+ if (sf) {
+ return;
+ }
+
+ for (const auto& childList : aFrame->ChildLists()) {
+ for (nsIFrame* f : childList.mList) {
+ const nsStyleDisplay* styleDisplay = f->StyleDisplay();
+ if (styleDisplay->mScrollSnapAlign.inline_ !=
+ StyleScrollSnapAlignKeyword::None ||
+ styleDisplay->mScrollSnapAlign.block !=
+ StyleScrollSnapAlignKeyword::None) {
+ AppendScrollPositionsForSnap(
+ f, aScrolledFrame, aScrolledRect, aScrollPadding, aScrollRange,
+ aWritingModeOnScroller, aSnapInfo, aSnapTargets);
+ }
+ CollectScrollPositionsForSnap(
+ f, aScrolledFrame, aScrolledRect, aScrollPadding, aScrollRange,
+ aWritingModeOnScroller, aSnapInfo, aSnapTargets);
+ }
+ }
+}
+
+static nscoord ResolveScrollPaddingStyleValue(
+ const StyleRect<mozilla::NonNegativeLengthPercentageOrAuto>&
+ aScrollPaddingStyle,
+ Side aSide, const nsSize& aScrollPortSize) {
+ if (aScrollPaddingStyle.Get(aSide).IsAuto()) {
+ // https://drafts.csswg.org/css-scroll-snap-1/#valdef-scroll-padding-auto
+ return 0;
+ }
+
+ nscoord percentageBasis;
+ switch (aSide) {
+ case eSideTop:
+ case eSideBottom:
+ percentageBasis = aScrollPortSize.height;
+ break;
+ case eSideLeft:
+ case eSideRight:
+ percentageBasis = aScrollPortSize.width;
+ break;
+ }
+
+ return aScrollPaddingStyle.Get(aSide).AsLengthPercentage().Resolve(
+ percentageBasis);
+}
+
+static nsMargin ResolveScrollPaddingStyle(
+ const StyleRect<mozilla::NonNegativeLengthPercentageOrAuto>&
+ aScrollPaddingStyle,
+ const nsSize& aScrollPortSize) {
+ return nsMargin(ResolveScrollPaddingStyleValue(aScrollPaddingStyle, eSideTop,
+ aScrollPortSize),
+ ResolveScrollPaddingStyleValue(aScrollPaddingStyle,
+ eSideRight, aScrollPortSize),
+ ResolveScrollPaddingStyleValue(aScrollPaddingStyle,
+ eSideBottom, aScrollPortSize),
+ ResolveScrollPaddingStyleValue(aScrollPaddingStyle, eSideLeft,
+ aScrollPortSize));
+}
+
+nsMargin nsHTMLScrollFrame::GetScrollPadding() const {
+ nsIFrame* styleFrame = GetFrameForStyle();
+ if (!styleFrame) {
+ return nsMargin();
+ }
+
+ // The spec says percentage values are relative to the scroll port size.
+ // https://drafts.csswg.org/css-scroll-snap-1/#scroll-padding
+ return ResolveScrollPaddingStyle(styleFrame->StylePadding()->mScrollPadding,
+ GetScrollPortRect().Size());
+}
+
+layers::ScrollSnapInfo nsHTMLScrollFrame::ComputeScrollSnapInfo() {
+ ScrollSnapInfo result;
+
+ nsIFrame* scrollSnapFrame = GetFrameForStyle();
+ if (!scrollSnapFrame) {
+ return result;
+ }
+
+ const nsStyleDisplay* disp = scrollSnapFrame->StyleDisplay();
+ if (disp->mScrollSnapType.strictness == StyleScrollSnapStrictness::None) {
+ // We won't be snapping, short-circuit the computation.
+ return result;
+ }
+
+ WritingMode writingMode = GetWritingMode();
+ result.InitializeScrollSnapStrictness(writingMode, disp);
+
+ result.mSnapportSize = GetSnapportSize();
+ CollectScrollPositionsForSnap(
+ mScrolledFrame, mScrolledFrame, GetScrolledRect(), GetScrollPadding(),
+ GetLayoutScrollRange(), writingMode, result, &mSnapTargets);
+ return result;
+}
+
+layers::ScrollSnapInfo nsHTMLScrollFrame::GetScrollSnapInfo() {
+ // TODO(botond): Should we cache it?
+ return ComputeScrollSnapInfo();
+}
+
+Maybe<SnapTarget> nsHTMLScrollFrame::GetSnapPointForDestination(
+ ScrollUnit aUnit, ScrollSnapFlags aFlags, const nsPoint& aStartPos,
+ const nsPoint& aDestination) {
+ // We can release the strong references for the previous snap target
+ // elements here since calling this ComputeScrollSnapInfo means we are going
+ // to evaluate new snap points, thus there's no chance to generating
+ // nsIContent instances in between this function call and the function call
+ // for the (re-)evaluation.
+ mSnapTargets.Clear();
+ return ScrollSnapUtils::GetSnapPointForDestination(
+ ComputeScrollSnapInfo(), aUnit, aFlags, GetLayoutScrollRange(), aStartPos,
+ aDestination);
+}
+
+Maybe<SnapTarget> nsHTMLScrollFrame::GetSnapPointForResnap() {
+ // Same as in GetSnapPointForDestination, We can release the strong references
+ // for the previous snap targets here.
+ mSnapTargets.Clear();
+ nsIContent* focusedContent =
+ GetContent()->GetComposedDoc()->GetUnretargetedFocusedContent();
+ return ScrollSnapUtils::GetSnapPointForResnap(
+ ComputeScrollSnapInfo(), GetLayoutScrollRange(), GetScrollPosition(),
+ mLastSnapTargetIds, focusedContent);
+}
+
+bool nsHTMLScrollFrame::NeedsResnap() {
+ nsIContent* focusedContent =
+ GetContent()->GetComposedDoc()->GetUnretargetedFocusedContent();
+ return ScrollSnapUtils::GetSnapPointForResnap(
+ ComputeScrollSnapInfo(), GetLayoutScrollRange(),
+ GetScrollPosition(), mLastSnapTargetIds, focusedContent)
+ .isSome();
+}
+
+void nsHTMLScrollFrame::SetLastSnapTargetIds(
+ UniquePtr<ScrollSnapTargetIds> aIds) {
+ if (!aIds) {
+ mLastSnapTargetIds = nullptr;
+ return;
+ }
+
+ // This SetLastSnapTargetIds gets called asynchronously so that there's a race
+ // condition something like;
+ // 1) an async scroll operation triggered snapping to a point on an element
+ // 2) during the async scroll operation, the element got removed from this
+ // scroll container
+ // 3) re-snapping triggered
+ // 4) this SetLastSnapTargetIds got called
+ // In such case |aIds| are stale, we shouldn't use it.
+ for (const auto* idList : {&aIds->mIdsOnX, &aIds->mIdsOnY}) {
+ for (const auto id : *idList) {
+ if (!mSnapTargets.Contains(reinterpret_cast<nsIContent*>(id))) {
+ mLastSnapTargetIds = nullptr;
+ return;
+ }
+ }
+ }
+
+ mLastSnapTargetIds = std::move(aIds);
+}
+
+bool nsHTMLScrollFrame::IsLastSnappedTarget(const nsIFrame* aFrame) const {
+ ScrollSnapTargetId id = ScrollSnapUtils::GetTargetIdFor(aFrame);
+ MOZ_ASSERT(id != ScrollSnapTargetId::None,
+ "This function is supposed to be called for contents");
+
+ if (!mLastSnapTargetIds) {
+ return false;
+ }
+
+ return mLastSnapTargetIds->mIdsOnX.Contains(id) ||
+ mLastSnapTargetIds->mIdsOnY.Contains(id);
+}
+
+void nsHTMLScrollFrame::TryResnap() {
+ // If there's any async scroll is running or we are processing pan/touch
+ // gestures or scroll thumb dragging, don't clobber the scroll.
+ if (!ScrollAnimationState().isEmpty() ||
+ mInScrollingGesture == InScrollingGesture::Yes) {
+ return;
+ }
+
+ if (auto snapTarget = GetSnapPointForResnap()) {
+ // We are going to re-snap so that we need to clobber scroll anchoring.
+ mAnchor.UserScrolled();
+
+ // Snap to the nearest snap position if exists.
+ ScrollToWithOrigin(
+ snapTarget->mPosition, nullptr /* range */,
+ ScrollOperationParams{
+ IsSmoothScroll(ScrollBehavior::Auto) ? ScrollMode::SmoothMsd
+ : ScrollMode::Instant,
+ ScrollOrigin::Other, std::move(snapTarget->mTargetIds)});
+ }
+}
+
+void nsHTMLScrollFrame::PostPendingResnapIfNeeded(const nsIFrame* aFrame) {
+ if (!IsLastSnappedTarget(aFrame)) {
+ return;
+ }
+
+ PostPendingResnap();
+}
+
+void nsHTMLScrollFrame::PostPendingResnap() {
+ PresShell()->PostPendingScrollResnap(this);
+}
+
+nsIScrollableFrame::PhysicalScrollSnapAlign
+nsHTMLScrollFrame::GetScrollSnapAlignFor(const nsIFrame* aFrame) const {
+ StyleScrollSnapAlignKeyword alignForY = StyleScrollSnapAlignKeyword::None;
+ StyleScrollSnapAlignKeyword alignForX = StyleScrollSnapAlignKeyword::None;
+
+ nsIFrame* styleFrame = GetFrameForStyle();
+ if (!styleFrame) {
+ return {alignForX, alignForY};
+ }
+
+ if (styleFrame->StyleDisplay()->mScrollSnapType.strictness ==
+ StyleScrollSnapStrictness::None) {
+ return {alignForX, alignForY};
+ }
+
+ const nsStyleDisplay* styleDisplay = aFrame->StyleDisplay();
+ if (styleDisplay->mScrollSnapAlign.inline_ ==
+ StyleScrollSnapAlignKeyword::None &&
+ styleDisplay->mScrollSnapAlign.block ==
+ StyleScrollSnapAlignKeyword::None) {
+ return {alignForX, alignForY};
+ }
+
+ nsSize snapAreaSize =
+ ScrollSnapUtils::GetSnapAreaFor(aFrame, mScrolledFrame, GetScrolledRect())
+ .Size();
+ const WritingMode writingMode =
+ ScrollSnapUtils::NeedsToRespectTargetWritingMode(snapAreaSize,
+ GetSnapportSize())
+ ? aFrame->GetWritingMode()
+ : styleFrame->GetWritingMode();
+
+ switch (styleFrame->StyleDisplay()->mScrollSnapType.axis) {
+ case StyleScrollSnapAxis::X:
+ alignForX = writingMode.IsVertical()
+ ? styleDisplay->mScrollSnapAlign.block
+ : styleDisplay->mScrollSnapAlign.inline_;
+ break;
+ case StyleScrollSnapAxis::Y:
+ alignForY = writingMode.IsVertical()
+ ? styleDisplay->mScrollSnapAlign.inline_
+ : styleDisplay->mScrollSnapAlign.block;
+ break;
+ case StyleScrollSnapAxis::Block:
+ if (writingMode.IsVertical()) {
+ alignForX = styleDisplay->mScrollSnapAlign.block;
+ } else {
+ alignForY = styleDisplay->mScrollSnapAlign.block;
+ }
+ break;
+ case StyleScrollSnapAxis::Inline:
+ if (writingMode.IsVertical()) {
+ alignForY = styleDisplay->mScrollSnapAlign.inline_;
+ } else {
+ alignForX = styleDisplay->mScrollSnapAlign.inline_;
+ }
+ break;
+ case StyleScrollSnapAxis::Both:
+ if (writingMode.IsVertical()) {
+ alignForX = styleDisplay->mScrollSnapAlign.block;
+ alignForY = styleDisplay->mScrollSnapAlign.inline_;
+ } else {
+ alignForX = styleDisplay->mScrollSnapAlign.inline_;
+ alignForY = styleDisplay->mScrollSnapAlign.block;
+ }
+ break;
+ }
+
+ return {alignForX, alignForY};
+}
+
+bool nsHTMLScrollFrame::UsesOverlayScrollbars() const {
+ return PresContext()->UseOverlayScrollbars();
+}
+
+bool nsHTMLScrollFrame::DragScroll(WidgetEvent* aEvent) {
+ // Dragging is allowed while within a 20 pixel border. Note that device pixels
+ // are used so that the same margin is used even when zoomed in or out.
+ nscoord margin = 20 * PresContext()->AppUnitsPerDevPixel();
+
+ // Don't drag scroll for small scrollareas.
+ if (mScrollPort.width < margin * 2 || mScrollPort.height < margin * 2) {
+ return false;
+ }
+
+ // If willScroll is computed as false, then the frame is already scrolled as
+ // far as it can go in both directions. Return false so that an ancestor
+ // scrollframe can scroll instead.
+ bool willScroll = false;
+ nsPoint pnt =
+ nsLayoutUtils::GetEventCoordinatesRelativeTo(aEvent, RelativeTo{this});
+ nsPoint scrollPoint = GetScrollPosition();
+ nsRect rangeRect = GetLayoutScrollRange();
+
+ // Only drag scroll when a scrollbar is present.
+ nsPoint offset;
+ if (mHasHorizontalScrollbar) {
+ if (pnt.x >= mScrollPort.x && pnt.x <= mScrollPort.x + margin) {
+ offset.x = -margin;
+ if (scrollPoint.x > 0) {
+ willScroll = true;
+ }
+ } else if (pnt.x >= mScrollPort.XMost() - margin &&
+ pnt.x <= mScrollPort.XMost()) {
+ offset.x = margin;
+ if (scrollPoint.x < rangeRect.width) {
+ willScroll = true;
+ }
+ }
+ }
+
+ if (mHasVerticalScrollbar) {
+ if (pnt.y >= mScrollPort.y && pnt.y <= mScrollPort.y + margin) {
+ offset.y = -margin;
+ if (scrollPoint.y > 0) {
+ willScroll = true;
+ }
+ } else if (pnt.y >= mScrollPort.YMost() - margin &&
+ pnt.y <= mScrollPort.YMost()) {
+ offset.y = margin;
+ if (scrollPoint.y < rangeRect.height) {
+ willScroll = true;
+ }
+ }
+ }
+
+ if (offset.x || offset.y) {
+ ScrollToWithOrigin(
+ GetScrollPosition() + offset, nullptr /* range */,
+ ScrollOperationParams{ScrollMode::Normal, ScrollOrigin::Other});
+ }
+
+ return willScroll;
+}
+
+static nsSliderFrame* GetSliderFrame(nsIFrame* aScrollbarFrame) {
+ if (!aScrollbarFrame) {
+ return nullptr;
+ }
+
+ for (const auto& childList : aScrollbarFrame->ChildLists()) {
+ for (nsIFrame* frame : childList.mList) {
+ if (nsSliderFrame* sliderFrame = do_QueryFrame(frame)) {
+ return sliderFrame;
+ }
+ }
+ }
+ return nullptr;
+}
+
+static void AsyncScrollbarDragInitiated(uint64_t aDragBlockId,
+ nsIFrame* aScrollbar) {
+ if (nsSliderFrame* sliderFrame = GetSliderFrame(aScrollbar)) {
+ sliderFrame->AsyncScrollbarDragInitiated(aDragBlockId);
+ }
+}
+
+void nsHTMLScrollFrame::AsyncScrollbarDragInitiated(
+ uint64_t aDragBlockId, ScrollDirection aDirection) {
+ switch (aDirection) {
+ case ScrollDirection::eVertical:
+ ::AsyncScrollbarDragInitiated(aDragBlockId, mVScrollbarBox);
+ break;
+ case ScrollDirection::eHorizontal:
+ ::AsyncScrollbarDragInitiated(aDragBlockId, mHScrollbarBox);
+ break;
+ }
+}
+
+static void AsyncScrollbarDragRejected(nsIFrame* aScrollbar) {
+ if (nsSliderFrame* sliderFrame = GetSliderFrame(aScrollbar)) {
+ sliderFrame->AsyncScrollbarDragRejected();
+ }
+}
+
+void nsHTMLScrollFrame::AsyncScrollbarDragRejected() {
+ // We don't get told which scrollbar requested the async drag,
+ // so we notify both.
+ ::AsyncScrollbarDragRejected(mHScrollbarBox);
+ ::AsyncScrollbarDragRejected(mVScrollbarBox);
+}
+
+void nsHTMLScrollFrame::ApzSmoothScrollTo(
+ const nsPoint& aDestination, ScrollOrigin aOrigin,
+ ScrollTriggeredByScript aTriggeredByScript,
+ UniquePtr<ScrollSnapTargetIds> aSnapTargetIds) {
+ if (mApzSmoothScrollDestination == Some(aDestination)) {
+ // If we already sent APZ a smooth-scroll request to this
+ // destination (i.e. it was the last request
+ // we sent), then don't send another one because it is redundant.
+ // This is to avoid a scenario where pages do repeated scrollBy
+ // calls, incrementing the generation counter, and blocking APZ from
+ // syncing the scroll offset back to the main thread.
+ // Note that if we get two smooth-scroll requests to the same
+ // destination with some other scroll in between,
+ // mApzSmoothScrollDestination will get reset to Nothing() and so
+ // we shouldn't have the problem where this check discards a
+ // legitimate smooth-scroll.
+ return;
+ }
+
+ // The animation will be handled in the compositor, pass the
+ // information needed to start the animation and skip the main-thread
+ // animation for this scroll.
+ MOZ_ASSERT(aOrigin != ScrollOrigin::None);
+ mApzSmoothScrollDestination = Some(aDestination);
+ AppendScrollUpdate(ScrollPositionUpdate::NewSmoothScroll(
+ aOrigin, aDestination, aTriggeredByScript, std::move(aSnapTargetIds)));
+
+ nsIContent* content = GetContent();
+ if (!DisplayPortUtils::HasNonMinimalNonZeroDisplayPort(content)) {
+ // If this frame doesn't have a displayport then there won't be an
+ // APZC instance for it and so there won't be anything to process
+ // this smooth scroll request. We should set a displayport on this
+ // frame to force an APZC which can handle the request.
+ if (MOZ_LOG_TEST(sDisplayportLog, LogLevel::Debug)) {
+ mozilla::layers::ScrollableLayerGuid::ViewID viewID =
+ mozilla::layers::ScrollableLayerGuid::NULL_SCROLL_ID;
+ nsLayoutUtils::FindIDFor(content, &viewID);
+ MOZ_LOG(
+ sDisplayportLog, LogLevel::Debug,
+ ("ApzSmoothScrollTo setting displayport on scrollId=%" PRIu64 "\n",
+ viewID));
+ }
+
+ DisplayPortUtils::CalculateAndSetDisplayPortMargins(
+ GetScrollTargetFrame(), DisplayPortUtils::RepaintMode::Repaint);
+ nsIFrame* frame = do_QueryFrame(GetScrollTargetFrame());
+ DisplayPortUtils::SetZeroMarginDisplayPortOnAsyncScrollableAncestors(frame);
+ }
+
+ // Schedule a paint to ensure that the frame metrics get updated on
+ // the compositor thread.
+ SchedulePaint();
+}
+
+bool nsHTMLScrollFrame::CanApzScrollInTheseDirections(
+ ScrollDirections aDirections) {
+ ScrollStyles styles = GetScrollStyles();
+ if (aDirections.contains(ScrollDirection::eHorizontal) &&
+ styles.mHorizontal == StyleOverflow::Hidden)
+ return false;
+ if (aDirections.contains(ScrollDirection::eVertical) &&
+ styles.mVertical == StyleOverflow::Hidden)
+ return false;
+ return true;
+}
+
+bool nsHTMLScrollFrame::SmoothScrollVisual(
+ const nsPoint& aVisualViewportOffset,
+ FrameMetrics::ScrollOffsetUpdateType aUpdateType) {
+ bool canDoApzSmoothScroll =
+ nsLayoutUtils::AsyncPanZoomEnabled(this) && WantAsyncScroll();
+ if (!canDoApzSmoothScroll) {
+ return false;
+ }
+
+ // Clamp the destination to the visual scroll range.
+ // There is a potential issue here, where |mDestination| is usually
+ // clamped to the layout scroll range, and so e.g. a subsequent
+ // window.scrollBy() may have an undesired effect. However, as this function
+ // is only called internally, this should not be a problem in practice.
+ // If it turns out to be, the fix would be:
+ // - add a new "destination" field that doesn't have to be clamped to
+ // the layout scroll range
+ // - clamp mDestination to the layout scroll range here
+ // - make sure ComputeScrollMetadata() picks up the former as the
+ // smooth scroll destination to send to APZ.
+ mDestination = GetVisualScrollRange().ClampPoint(aVisualViewportOffset);
+
+ UniquePtr<ScrollSnapTargetIds> snapTargetIds;
+ // Perform the scroll.
+ ApzSmoothScrollTo(mDestination,
+ aUpdateType == FrameMetrics::eRestore
+ ? ScrollOrigin::Restore
+ : ScrollOrigin::Other,
+ ScrollTriggeredByScript::No, std::move(snapTargetIds));
+ return true;
+}
+
+bool nsHTMLScrollFrame::IsSmoothScroll(dom::ScrollBehavior aBehavior) const {
+ // The user smooth scrolling preference should be honored for any requested
+ // smooth scrolls. A requested smooth scroll when smooth scrolling is
+ // disabled should be equivalent to an instant scroll.
+ if (aBehavior == dom::ScrollBehavior::Instant ||
+ !nsLayoutUtils::IsSmoothScrollingEnabled()) {
+ return false;
+ }
+
+ if (aBehavior == dom::ScrollBehavior::Smooth) {
+ return true;
+ }
+
+ nsIFrame* styleFrame = GetFrameForStyle();
+ if (!styleFrame) {
+ return false;
+ }
+ return (aBehavior == dom::ScrollBehavior::Auto &&
+ styleFrame->StyleDisplay()->mScrollBehavior ==
+ StyleScrollBehavior::Smooth);
+}
+
+nsTArray<ScrollPositionUpdate> nsHTMLScrollFrame::GetScrollUpdates() const {
+ return mScrollUpdates.Clone();
+}
+
+void nsHTMLScrollFrame::AppendScrollUpdate(
+ const ScrollPositionUpdate& aUpdate) {
+ mScrollGeneration = aUpdate.GetGeneration();
+ mScrollUpdates.AppendElement(aUpdate);
+}
+
+void nsHTMLScrollFrame::ScheduleScrollAnimations() {
+ nsIContent* content = GetContent();
+ MOZ_ASSERT(content && content->IsElement(),
+ "The nsIScrollableFrame should have the element.");
+
+ const Element* elementOrPseudo = content->AsElement();
+ PseudoStyleType pseudo = elementOrPseudo->GetPseudoElementType();
+ if (pseudo != PseudoStyleType::NotPseudo &&
+ !AnimationUtils::IsSupportedPseudoForAnimations(pseudo)) {
+ // This is not an animatable pseudo element, and so we don't generate
+ // scroll-timeline for it.
+ return;
+ }
+
+ const auto [element, type] =
+ AnimationUtils::GetElementPseudoPair(elementOrPseudo);
+ const auto* scheduler = ProgressTimelineScheduler::Get(element, type);
+ if (!scheduler) {
+ // We don't have scroll timelines associated with this frame.
+ return;
+ }
+
+ scheduler->ScheduleAnimations();
+}