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-rw-r--r--layout/generic/nsPageContentFrame.cpp452
1 files changed, 452 insertions, 0 deletions
diff --git a/layout/generic/nsPageContentFrame.cpp b/layout/generic/nsPageContentFrame.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/. */
+#include "nsPageContentFrame.h"
+
+#include "mozilla/PresShell.h"
+#include "mozilla/PresShellInlines.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/dom/Document.h"
+
+#include "nsContentUtils.h"
+#include "nsPageFrame.h"
+#include "nsCSSFrameConstructor.h"
+#include "nsPresContext.h"
+#include "nsGkAtoms.h"
+#include "nsLayoutUtils.h"
+#include "nsPageSequenceFrame.h"
+
+using namespace mozilla;
+
+nsPageContentFrame* NS_NewPageContentFrame(
+ PresShell* aPresShell, ComputedStyle* aStyle,
+ already_AddRefed<const nsAtom> aPageName) {
+ return new (aPresShell) nsPageContentFrame(
+ aStyle, aPresShell->GetPresContext(), std::move(aPageName));
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsPageContentFrame)
+
+void nsPageContentFrame::Reflow(nsPresContext* aPresContext,
+ ReflowOutput& aReflowOutput,
+ const ReflowInput& aReflowInput,
+ nsReflowStatus& aStatus) {
+ MarkInReflow();
+ DO_GLOBAL_REFLOW_COUNT("nsPageContentFrame");
+ DISPLAY_REFLOW(aPresContext, this, aReflowInput, aReflowOutput, aStatus);
+ MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+ MOZ_ASSERT(mPD, "Need a pointer to nsSharedPageData before reflow starts");
+
+ if (GetPrevInFlow() && HasAnyStateBits(NS_FRAME_FIRST_REFLOW)) {
+ nsresult rv =
+ aPresContext->PresShell()->FrameConstructor()->ReplicateFixedFrames(
+ this);
+ if (NS_FAILED(rv)) {
+ return;
+ }
+ }
+
+ // Set our size up front, since some parts of reflow depend on it
+ // being already set. Note that the computed height may be
+ // unconstrained; that's ok. Consumers should watch out for that.
+ const nsSize maxSize(aReflowInput.ComputedWidth(),
+ aReflowInput.ComputedHeight());
+ SetSize(maxSize);
+
+ // Writing mode for the page content frame.
+ const WritingMode pcfWM = aReflowInput.GetWritingMode();
+ aReflowOutput.ISize(pcfWM) = aReflowInput.ComputedISize();
+ if (aReflowInput.ComputedBSize() != NS_UNCONSTRAINEDSIZE) {
+ aReflowOutput.BSize(pcfWM) = aReflowInput.ComputedBSize();
+ }
+ aReflowOutput.SetOverflowAreasToDesiredBounds();
+
+ // A PageContentFrame must always have one child: the canvas frame.
+ // Resize our frame allowing it only to be as big as we are
+ // XXX Pay attention to the page's border and padding...
+ if (mFrames.NotEmpty()) {
+ nsIFrame* const frame = mFrames.FirstChild();
+ const WritingMode frameWM = frame->GetWritingMode();
+ const LogicalSize logicalSize(frameWM, maxSize);
+ ReflowInput kidReflowInput(aPresContext, aReflowInput, frame, logicalSize);
+ kidReflowInput.SetComputedBSize(logicalSize.BSize(frameWM));
+ ReflowOutput kidReflowOutput(kidReflowInput);
+ ReflowChild(frame, aPresContext, kidReflowOutput, kidReflowInput, 0, 0,
+ ReflowChildFlags::Default, aStatus);
+
+ // The document element's background should cover the entire canvas, so
+ // take into account the combined area and any space taken up by
+ // absolutely positioned elements
+ nsMargin padding(0, 0, 0, 0);
+
+ // XXXbz this screws up percentage padding (sets padding to zero
+ // in the percentage padding case)
+ frame->StylePadding()->GetPadding(padding);
+
+ // This is for shrink-to-fit, and therefore we want to use the
+ // scrollable overflow, since the purpose of shrink to fit is to
+ // make the content that ought to be reachable (represented by the
+ // scrollable overflow) fit in the page.
+ if (frame->HasOverflowAreas()) {
+ // The background covers the content area and padding area, so check
+ // for children sticking outside the child frame's padding edge
+ nscoord xmost = kidReflowOutput.ScrollableOverflow().XMost();
+ if (xmost > kidReflowOutput.Width()) {
+ const nscoord widthToFit =
+ xmost + padding.right +
+ kidReflowInput.mStyleBorder->GetComputedBorderWidth(eSideRight);
+ const float ratio = float(maxSize.width) / float(widthToFit);
+ NS_ASSERTION(ratio >= 0.0 && ratio < 1.0,
+ "invalid shrink-to-fit ratio");
+ mPD->mShrinkToFitRatio = std::min(mPD->mShrinkToFitRatio, ratio);
+ }
+ // In the case of pdf.js documents, we also want to consider the height,
+ // so that we don't clip the page in either axis if the aspect ratio of
+ // the PDF doesn't match the destination.
+ if (nsContentUtils::IsPDFJS(PresContext()->Document()->GetPrincipal())) {
+ nscoord ymost = kidReflowOutput.ScrollableOverflow().YMost();
+ if (ymost > kidReflowOutput.Height()) {
+ const nscoord heightToFit =
+ ymost + padding.bottom +
+ kidReflowInput.mStyleBorder->GetComputedBorderWidth(eSideBottom);
+ const float ratio = float(maxSize.height) / float(heightToFit);
+ MOZ_ASSERT(ratio >= 0.0 && ratio < 1.0);
+ mPD->mShrinkToFitRatio = std::min(mPD->mShrinkToFitRatio, ratio);
+ }
+
+ // pdf.js pages should never overflow given the scaling above.
+ // nsPrintJob::SetupToPrintContent ignores some ratios close to 1.0
+ // though and doesn't reflow us again in that case, so we need to clear
+ // the overflow area here in case that happens. (bug 1689789)
+ frame->ClearOverflowRects();
+ kidReflowOutput.mOverflowAreas = aReflowOutput.mOverflowAreas;
+ }
+ }
+
+ // Place and size the child
+ FinishReflowChild(frame, aPresContext, kidReflowOutput, &kidReflowInput, 0,
+ 0, ReflowChildFlags::Default);
+
+ NS_ASSERTION(aPresContext->IsDynamic() || !aStatus.IsFullyComplete() ||
+ !frame->GetNextInFlow(),
+ "bad child flow list");
+
+ aReflowOutput.mOverflowAreas.UnionWith(kidReflowOutput.mOverflowAreas);
+ }
+
+ FinishAndStoreOverflow(&aReflowOutput);
+
+ // Reflow our fixed frames
+ nsReflowStatus fixedStatus;
+ ReflowAbsoluteFrames(aPresContext, aReflowOutput, aReflowInput, fixedStatus);
+ NS_ASSERTION(fixedStatus.IsComplete(),
+ "fixed frames can be truncated, but not incomplete");
+
+ if (StaticPrefs::layout_display_list_improve_fragmentation() &&
+ mFrames.NotEmpty()) {
+ auto* const previous =
+ static_cast<nsPageContentFrame*>(GetPrevContinuation());
+ const nscoord previousPageOverflow =
+ previous ? previous->mRemainingOverflow : 0;
+ const nsSize containerSize(aReflowInput.AvailableWidth(),
+ aReflowInput.AvailableHeight());
+ const nscoord pageBSize = GetLogicalRect(containerSize).BSize(pcfWM);
+ const nscoord overflowBSize =
+ LogicalRect(pcfWM, ScrollableOverflowRect(), GetSize()).BEnd(pcfWM);
+ const nscoord currentPageOverflow = overflowBSize - pageBSize;
+ nscoord remainingOverflow =
+ std::max(currentPageOverflow, previousPageOverflow - pageBSize);
+
+ if (aStatus.IsFullyComplete() && remainingOverflow > 0) {
+ // If we have ScrollableOverflow off the end of our page, then we report
+ // ourselves as overflow-incomplete in order to produce an additional
+ // content-less page, which we expect to draw our overflow on our behalf.
+ aStatus.SetOverflowIncomplete();
+ }
+
+ mRemainingOverflow = std::max(remainingOverflow, 0);
+ }
+}
+
+using PageAndOffset = std::pair<nsPageContentFrame*, nscoord>;
+
+// Returns the previous continuation PageContentFrames that have overflow areas,
+// and their offsets to the top of the given PageContentFrame |aPage|. Since the
+// iteration is done backwards, the returned pages are arranged in descending
+// order of page number.
+static nsTArray<PageAndOffset> GetPreviousPagesWithOverflow(
+ nsPageContentFrame* aPage) {
+ nsTArray<PageAndOffset> pages(8);
+
+ auto GetPreviousPageContentFrame = [](nsPageContentFrame* aPageCF) {
+ nsIFrame* prevCont = aPageCF->GetPrevContinuation();
+ MOZ_ASSERT(!prevCont || prevCont->IsPageContentFrame(),
+ "Expected nsPageContentFrame or nullptr");
+
+ return static_cast<nsPageContentFrame*>(prevCont);
+ };
+
+ nsPageContentFrame* pageCF = aPage;
+ // The collective height of all prev-continuations we've traversed so far:
+ nscoord offsetToCurrentPageBStart = 0;
+ const auto wm = pageCF->GetWritingMode();
+ while ((pageCF = GetPreviousPageContentFrame(pageCF))) {
+ offsetToCurrentPageBStart += pageCF->BSize(wm);
+
+ if (pageCF->HasOverflowAreas()) {
+ pages.EmplaceBack(pageCF, offsetToCurrentPageBStart);
+ }
+ }
+
+ return pages;
+}
+
+static void BuildPreviousPageOverflow(nsDisplayListBuilder* aBuilder,
+ nsPageFrame* aPageFrame,
+ nsPageContentFrame* aCurrentPageCF,
+ const nsDisplayListSet& aLists) {
+ const auto previousPagesAndOffsets =
+ GetPreviousPagesWithOverflow(aCurrentPageCF);
+
+ const auto wm = aCurrentPageCF->GetWritingMode();
+ for (const PageAndOffset& pair : Reversed(previousPagesAndOffsets)) {
+ auto* prevPageCF = pair.first;
+ const nscoord offsetToCurrentPageBStart = pair.second;
+ // Only scrollable overflow create new pages, not ink overflow.
+ const LogicalRect scrollableOverflow(
+ wm, prevPageCF->ScrollableOverflowRectRelativeToSelf(),
+ prevPageCF->GetSize());
+ const auto remainingOverflow =
+ scrollableOverflow.BEnd(wm) - offsetToCurrentPageBStart;
+ if (remainingOverflow <= 0) {
+ continue;
+ }
+
+ // This rect represents the piece of prevPageCF's overflow that ends up on
+ // the current pageContentFrame (in prevPageCF's coordinate system).
+ // Note that we use InkOverflow here since this is for painting.
+ LogicalRect overflowRect(wm, prevPageCF->InkOverflowRectRelativeToSelf(),
+ prevPageCF->GetSize());
+ overflowRect.BStart(wm) = offsetToCurrentPageBStart;
+ overflowRect.BSize(wm) = std::min(remainingOverflow, prevPageCF->BSize(wm));
+
+ {
+ // Convert the overflowRect to the coordinate system of aPageFrame, and
+ // set it as the visible rect for display list building.
+ const nsRect visibleRect =
+ overflowRect.GetPhysicalRect(wm, prevPageCF->GetSize()) +
+ prevPageCF->GetOffsetTo(aPageFrame);
+ nsDisplayListBuilder::AutoBuildingDisplayList buildingForChild(
+ aBuilder, aPageFrame, visibleRect, visibleRect);
+
+ // This part is tricky. Because display items are positioned based on the
+ // frame tree, building a display list for the previous page yields
+ // display items that are outside of the current page bounds.
+ // To fix that, an additional reference frame offset is added, which
+ // shifts the display items down (block axis) as if the current and
+ // previous page were one long page in the same coordinate system.
+ const nsSize containerSize = aPageFrame->GetSize();
+ LogicalPoint pageOffset(wm, aCurrentPageCF->GetOffsetTo(prevPageCF),
+ containerSize);
+ pageOffset.B(wm) -= offsetToCurrentPageBStart;
+ buildingForChild.SetAdditionalOffset(
+ pageOffset.GetPhysicalPoint(wm, containerSize));
+
+ aPageFrame->BuildDisplayListForChild(aBuilder, prevPageCF, aLists);
+ }
+ }
+}
+
+/**
+ * Remove all leaf display items that are not for descendants of
+ * aBuilder->GetReferenceFrame() from aList.
+ * @param aPage the page we're constructing the display list for
+ * @param aList the list that is modified in-place
+ */
+static void PruneDisplayListForExtraPage(nsDisplayListBuilder* aBuilder,
+ nsPageFrame* aPage,
+ nsDisplayList* aList) {
+ for (nsDisplayItem* i : aList->TakeItems()) {
+ if (!i) break;
+ nsDisplayList* subList = i->GetSameCoordinateSystemChildren();
+ if (subList) {
+ PruneDisplayListForExtraPage(aBuilder, aPage, subList);
+ i->UpdateBounds(aBuilder);
+ } else {
+ nsIFrame* f = i->Frame();
+ if (!nsLayoutUtils::IsProperAncestorFrameCrossDocInProcess(aPage, f)) {
+ // We're throwing this away so call its destructor now. The memory
+ // is owned by aBuilder which destroys all items at once.
+ i->Destroy(aBuilder);
+ continue;
+ }
+ }
+ aList->AppendToTop(i);
+ }
+}
+
+static void BuildDisplayListForExtraPage(nsDisplayListBuilder* aBuilder,
+ nsPageFrame* aPage,
+ nsIFrame* aExtraPage,
+ nsDisplayList* aList) {
+ // The only content in aExtraPage we care about is out-of-flow content from
+ // aPage, whose placeholders have occurred in aExtraPage. If
+ // NS_FRAME_FORCE_DISPLAY_LIST_DESCEND_INTO is not set, then aExtraPage has
+ // no such content.
+ if (!aExtraPage->HasAnyStateBits(NS_FRAME_FORCE_DISPLAY_LIST_DESCEND_INTO)) {
+ return;
+ }
+ nsDisplayList list(aBuilder);
+ aExtraPage->BuildDisplayListForStackingContext(aBuilder, &list);
+ PruneDisplayListForExtraPage(aBuilder, aPage, &list);
+ aList->AppendToTop(&list);
+}
+
+static gfx::Matrix4x4 ComputePageContentTransform(const nsIFrame* aFrame,
+ float aAppUnitsPerPixel) {
+ float scale = aFrame->PresContext()->GetPageScale();
+ return gfx::Matrix4x4::Scaling(scale, scale, 1);
+}
+
+nsIFrame::ComputeTransformFunction nsPageContentFrame::GetTransformGetter()
+ const {
+ return ComputePageContentTransform;
+}
+
+void nsPageContentFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
+ const nsDisplayListSet& aLists) {
+ MOZ_ASSERT(GetParent());
+ MOZ_ASSERT(GetParent()->IsPageFrame());
+ auto* pageFrame = static_cast<nsPageFrame*>(GetParent());
+ auto pageNum = pageFrame->GetPageNum();
+ NS_ASSERTION(pageNum <= 255, "Too many pages to handle OOFs");
+
+ if (aBuilder->GetBuildingExtraPagesForPageNum()) {
+ return mozilla::ViewportFrame::BuildDisplayList(aBuilder, aLists);
+ }
+
+ nsDisplayListCollection set(aBuilder);
+
+ nsDisplayList content(aBuilder);
+ {
+ const nsRect clipRect(aBuilder->ToReferenceFrame(this), GetSize());
+ DisplayListClipState::AutoSaveRestore clipState(aBuilder);
+
+ // Overwrite current clip, since we're going to wrap in a transform and the
+ // current clip is no longer meaningful.
+ clipState.Clear();
+ clipState.ClipContentDescendants(clipRect);
+
+ if (StaticPrefs::layout_display_list_improve_fragmentation() &&
+ pageNum <= 255) {
+ nsDisplayListBuilder::AutoPageNumberSetter p(aBuilder, pageNum);
+ BuildPreviousPageOverflow(aBuilder, pageFrame, this, set);
+ }
+ mozilla::ViewportFrame::BuildDisplayList(aBuilder, set);
+
+ set.SerializeWithCorrectZOrder(&content, GetContent());
+
+ // We may need to paint out-of-flow frames whose placeholders are on other
+ // pages. Add those pages to our display list. Note that out-of-flow frames
+ // can't be placed after their placeholders so
+ // we don't have to process earlier pages. The display lists for
+ // these extra pages are pruned so that only display items for the
+ // page we currently care about (which we would have reached by
+ // following placeholders to their out-of-flows) end up on the list.
+ //
+ // Stacking context frames that wrap content on their normal page,
+ // as well as OOF content for this page will have their container
+ // items duplicated. We tell the builder to include our page number
+ // in the unique key for any extra page items so that they can be
+ // differentiated from the ones created on the normal page.
+ if (pageNum <= 255) {
+ const nsRect overflowRect = ScrollableOverflowRectRelativeToSelf();
+ nsDisplayListBuilder::AutoPageNumberSetter p(aBuilder, pageNum);
+
+ // The static_cast here is technically unnecessary, but it helps
+ // devirtualize the GetNextContinuation() function call if pcf has a
+ // concrete type (with an inherited `final` GetNextContinuation() impl).
+ auto* pageCF = this;
+ while ((pageCF = static_cast<nsPageContentFrame*>(
+ pageCF->GetNextContinuation()))) {
+ nsRect childVisible = overflowRect + GetOffsetTo(pageCF);
+
+ nsDisplayListBuilder::AutoBuildingDisplayList buildingForChild(
+ aBuilder, pageCF, childVisible, childVisible);
+ BuildDisplayListForExtraPage(aBuilder, pageFrame, pageCF, &content);
+ }
+ }
+
+ // Add the canvas background color to the bottom of the list. This
+ // happens after we've built the list so that AddCanvasBackgroundColorItem
+ // can monkey with the contents if necessary.
+ const nsRect backgroundRect(aBuilder->ToReferenceFrame(this), GetSize());
+ PresShell()->AddCanvasBackgroundColorItem(
+ aBuilder, &content, this, backgroundRect, NS_RGBA(0, 0, 0, 0));
+ }
+
+ content.AppendNewToTop<nsDisplayTransform>(
+ aBuilder, this, &content, content.GetBuildingRect(),
+ nsDisplayTransform::WithTransformGetter);
+
+ aLists.Content()->AppendToTop(&content);
+}
+
+void nsPageContentFrame::AppendDirectlyOwnedAnonBoxes(
+ nsTArray<OwnedAnonBox>& aResult) {
+ MOZ_ASSERT(mFrames.FirstChild(),
+ "pageContentFrame must have a canvasFrame child");
+ aResult.AppendElement(mFrames.FirstChild());
+}
+
+void nsPageContentFrame::EnsurePageName() {
+ MOZ_ASSERT(HasAnyStateBits(NS_FRAME_FIRST_REFLOW),
+ "Should only have been called on first reflow");
+ if (mPageName) {
+ return;
+ }
+ MOZ_ASSERT(!GetPrevInFlow(),
+ "Only the first page should initially have a null page name.");
+ // This was the first page, we need to find our own page name and then set
+ // our computed style based on that.
+ mPageName = ComputePageValue();
+
+ MOZ_ASSERT(mPageName, "Page name should never be null");
+ // We don't need to resolve any further styling if the page name is empty.
+ if (mPageName == nsGkAtoms::_empty) {
+ return;
+ }
+ RefPtr<ComputedStyle> pageContentPseudoStyle =
+ PresShell()->StyleSet()->ResolvePageContentStyle(mPageName);
+ SetComputedStyleWithoutNotification(pageContentPseudoStyle);
+}
+
+nsIFrame* nsPageContentFrame::FirstContinuation() const {
+ const nsContainerFrame* const parent = GetParent();
+ MOZ_ASSERT(parent && parent->IsPageFrame(),
+ "Parent of nsPageContentFrame should be nsPageFrame");
+ // static cast so the compiler has a chance to devirtualize the call.
+ const auto* const pageFrameParent = static_cast<const nsPageFrame*>(parent);
+ nsPageContentFrame* const pageContentFrame =
+ static_cast<const nsPageFrame*>(pageFrameParent->FirstContinuation())
+ ->PageContentFrame();
+ MOZ_ASSERT(pageContentFrame && !pageContentFrame->GetPrevContinuation(),
+ "First descendent of nsPageSequenceFrame should not have a "
+ "previous continuation");
+ return pageContentFrame;
+}
+
+#ifdef DEBUG_FRAME_DUMP
+nsresult nsPageContentFrame::GetFrameName(nsAString& aResult) const {
+ return MakeFrameName(u"PageContent"_ns, aResult);
+}
+void nsPageContentFrame::ExtraContainerFrameInfo(nsACString& aTo) const {
+ if (mPageName) {
+ aTo += " [page=";
+ aTo += nsAtomCString(mPageName);
+ aTo += "]";
+ }
+}
+#endif