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Diffstat (limited to 'layout/generic/nsIScrollableFrame.h')
| -rw-r--r-- | layout/generic/nsIScrollableFrame.h | 621 |
1 files changed, 621 insertions, 0 deletions
diff --git a/layout/generic/nsIScrollableFrame.h b/layout/generic/nsIScrollableFrame.h new file mode 100644 index 0000000000..4ecbc3e5bb --- /dev/null +++ b/layout/generic/nsIScrollableFrame.h @@ -0,0 +1,621 @@ +/* -*- 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/. */ + +/* + * interface that provides scroll APIs implemented by scrollable frames + */ + +#ifndef nsIScrollFrame_h___ +#define nsIScrollFrame_h___ + +#include "nsCoord.h" +#include "mozilla/dom/WindowBinding.h" // for mozilla::dom::ScrollBehavior +#include "mozilla/Maybe.h" +#include "mozilla/ScrollOrigin.h" +#include "mozilla/ScrollPositionUpdate.h" +#include "mozilla/ScrollStyles.h" +#include "mozilla/ScrollTypes.h" +#include "mozilla/gfx/Point.h" +#include "nsIScrollbarMediator.h" +#include "Units.h" +#include "FrameMetrics.h" + +#define NS_DEFAULT_VERTICAL_SCROLL_DISTANCE 3 +#define NS_DEFAULT_HORIZONTAL_SCROLL_DISTANCE 5 + +class gfxContext; +class nsBoxLayoutState; +class nsIScrollPositionListener; +class nsIFrame; +class nsPresContext; +class nsIContent; +class nsDisplayListBuilder; + +namespace mozilla { +struct ContainerLayerParameters; +class DisplayItemClip; +namespace layers { +struct ScrollMetadata; +class Layer; +class LayerManager; +} // namespace layers +namespace layout { +class ScrollAnchorContainer; +} // namespace layout +} // namespace mozilla + +/** + * Interface for frames that are scrollable. This interface exposes + * APIs for examining scroll state, observing changes to scroll state, + * and triggering scrolling. + */ +class nsIScrollableFrame : public nsIScrollbarMediator { + public: + typedef mozilla::CSSIntPoint CSSIntPoint; + typedef mozilla::ContainerLayerParameters ContainerLayerParameters; + typedef mozilla::layers::ScrollSnapInfo ScrollSnapInfo; + typedef mozilla::layout::ScrollAnchorContainer ScrollAnchorContainer; + typedef mozilla::ScrollMode ScrollMode; + typedef mozilla::ScrollOrigin ScrollOrigin; + + NS_DECL_QUERYFRAME_TARGET(nsIScrollableFrame) + + /** + * Get the frame for the content that we are scrolling within + * this scrollable frame. + */ + virtual nsIFrame* GetScrolledFrame() const = 0; + + /** + * Get the overflow styles (StyleOverflow::Scroll, StyleOverflow::Hidden, or + * StyleOverflow::Auto) governing the horizontal and vertical scrollbars for + * this frame. + * + * This is special because they can be propagated from the <body> element, + * unlike other styles. + */ + virtual mozilla::ScrollStyles GetScrollStyles() const = 0; + + /** + * Returns whether this scroll frame is for a text control element with no + * scrollbars (for <input>, basically). + */ + virtual bool IsForTextControlWithNoScrollbars() const = 0; + + /** + * Get the overscroll-behavior styles. + */ + virtual mozilla::layers::OverscrollBehaviorInfo GetOverscrollBehaviorInfo() + const = 0; + + /** + * Return the scrollbars which are visible. It's OK to call this during reflow + * of the scrolled contents, in which case it will reflect the current + * assumptions about scrollbar visibility. + */ + virtual mozilla::layers::ScrollDirections GetScrollbarVisibility() const = 0; + /** + * Returns the directions in which scrolling is allowed (if the scroll range + * is at least one device pixel in that direction). + */ + mozilla::layers::ScrollDirections GetAvailableScrollingDirections() const; + /** + * Returns the directions in which scrolling is allowed when taking into + * account the visual viewport size and overflow hidden. (An (apz) zoomed in + * overflow hidden scrollframe is actually user scrollable.) + */ + virtual mozilla::layers::ScrollDirections + GetAvailableScrollingDirectionsForUserInputEvents() const = 0; + /** + * Return the actual sizes of all possible scrollbars. Returns 0 for scrollbar + * positions that don't have a scrollbar or where the scrollbar is not + * visible. Do not call this while this frame's descendants are being + * reflowed, it won't be accurate. + * INCLUDE_VISUAL_VIEWPORT_SCROLLBARS means we include the size of layout + * scrollbars that are only visible to scroll the visual viewport inside the + * layout viewport (ie the layout viewport cannot be scrolled) even though + * there is no layout space set aside for these scrollbars. + */ + enum class ScrollbarSizesOptions { NONE, INCLUDE_VISUAL_VIEWPORT_SCROLLBARS }; + virtual nsMargin GetActualScrollbarSizes( + ScrollbarSizesOptions aOptions = ScrollbarSizesOptions::NONE) const = 0; + /** + * Return the sizes of all scrollbars assuming that any scrollbars that could + * be visible due to overflowing content, are. This can be called during + * reflow of the scrolled contents. + */ + virtual nsMargin GetDesiredScrollbarSizes(nsBoxLayoutState* aState) = 0; + /** + * Return the sizes of all scrollbars assuming that any scrollbars that could + * be visible due to overflowing content, are. This can be called during + * reflow of the scrolled contents. + */ + virtual nsMargin GetDesiredScrollbarSizes(nsPresContext* aPresContext, + gfxContext* aRC) = 0; + /** + * Return the width for non-disappearing scrollbars. + */ + virtual nscoord GetNondisappearingScrollbarWidth( + nsPresContext* aPresContext, gfxContext* aRC, + mozilla::WritingMode aWM) = 0; + /** + * Get the layout size of this frame. + * Note that this is a value which is not expanded by the minimum scale size. + * For scroll frames other than the root content document's scroll frame, this + * value will be the same as GetScrollPortRect().Size(). + * + * This value is used for Element.clientWidth and clientHeight. + */ + virtual nsSize GetLayoutSize() const = 0; + /** + * GetScrolledRect is designed to encapsulate deciding which + * directions of overflow should be reachable by scrolling and which + * should not. Callers should NOT depend on it having any particular + * behavior (although nsXULScrollFrame currently does). + * + * This should only be called when the scrolled frame has been + * reflowed with the scroll port size given in mScrollPort. + * + * Currently it allows scrolling down and to the right for + * nsHTMLScrollFrames with LTR directionality and for all + * nsXULScrollFrames, and allows scrolling down and to the left for + * nsHTMLScrollFrames with RTL directionality. + */ + virtual nsRect GetScrolledRect() const = 0; + /** + * Get the area of the scrollport relative to the origin of this frame's + * border-box. + * This is the area of this frame minus border and scrollbars. + */ + virtual nsRect GetScrollPortRect() const = 0; + /** + * Get the offset of the scrollport origin relative to the scrolled + * frame origin. Typically the position will be non-negative. + * This will always be a multiple of device pixels. + */ + virtual nsPoint GetScrollPosition() const = 0; + /** + * As GetScrollPosition(), but uses the top-right as origin for RTL frames. + */ + virtual nsPoint GetLogicalScrollPosition() const = 0; + + /** + * Get the area that must contain the scroll position. Typically + * (but not always, e.g. for RTL content) x and y will be 0, and + * width or height will be nonzero if the content can be scrolled in + * that direction. Since scroll positions must be a multiple of + * device pixels, the range extrema will also be a multiple of + * device pixels. + */ + virtual nsRect GetScrollRange() const = 0; + /** + * Get the size of the view port to use when clamping the scroll + * position. + */ + virtual nsSize GetVisualViewportSize() const = 0; + /** + * Returns the offset of the visual viewport relative to + * the origin of the scrolled content. Note that only the RCD-RSF + * has a distinct visual viewport; for other scroll frames, the + * visual viewport always coincides with the layout viewport, and + * consequently the offset this function returns is equal to + * GetScrollPosition(). + */ + virtual nsPoint GetVisualViewportOffset() const = 0; + /** + * Set the visual viewport offset associated with a root scroll frame. This is + * only valid when called on a root scroll frame and will assert otherwise. + * aRepaint indicates if we need to ask for a main thread paint if this + * changes scrollbar positions or not. For example, if the compositor has + * already put the scrollbars at this position then they don't need to move so + * we can skip the repaint. Returns true if the offset changed and the scroll + * frame is still alive after this call. + */ + virtual bool SetVisualViewportOffset(const nsPoint& aOffset, + bool aRepaint) = 0; + /** + * Get the area that must contain the visual viewport offset. + */ + virtual nsRect GetVisualScrollRange() const = 0; + /** + * Like GetVisualScrollRange but also takes into account overflow: hidden. + */ + virtual nsRect GetScrollRangeForUserInputEvents() const = 0; + /** + * Return how much we would try to scroll by in each direction if + * asked to scroll by one "line" vertically and horizontally. + */ + virtual nsSize GetLineScrollAmount() const = 0; + /** + * Return how much we would try to scroll by in each direction if + * asked to scroll by one "page" vertically and horizontally. + */ + virtual nsSize GetPageScrollAmount() const = 0; + + /** + * Return scroll-padding value of this frame. + */ + virtual nsMargin GetScrollPadding() const = 0; + /** + * Some platforms (OSX) may generate additional scrolling events even + * after the user has stopped scrolling, simulating a momentum scrolling + * effect resulting from fling gestures. + * SYNTHESIZED_MOMENTUM_EVENT indicates that the scrolling is being requested + * by such a synthesized event and may be ignored if another scroll has + * been started since the last actual user input. + */ + enum ScrollMomentum { NOT_MOMENTUM, SYNTHESIZED_MOMENTUM_EVENT }; + /** + * @note This method might destroy the frame, pres shell and other objects. + * Clamps aScrollPosition to GetScrollRange and sets the scroll position + * to that value. + * @param aRange If non-null, specifies area which contains aScrollPosition + * and can be used for choosing a performance-optimized scroll position. + * Any point within this area can be chosen. + * The choosen point will be as close as possible to aScrollPosition. + */ + virtual void ScrollTo(nsPoint aScrollPosition, ScrollMode aMode, + const nsRect* aRange = nullptr, + nsIScrollbarMediator::ScrollSnapMode aSnap = + nsIScrollbarMediator::DISABLE_SNAP) = 0; + /** + * @note This method might destroy the frame, pres shell and other objects. + * Scrolls to a particular position in integer CSS pixels. + * Keeps the exact current horizontal or vertical position if the current + * position, rounded to CSS pixels, matches aScrollPosition. If + * aScrollPosition.x/y is different from the current CSS pixel position, + * makes sure we only move in the direction given by the difference. + * + * When aMode is SMOOTH, INSTANT, or NORMAL, GetScrollPositionCSSPixels (the + * scroll position after rounding to CSS pixels) will be exactly + * aScrollPosition at the end of the scroll animation. + * + * When aMode is SMOOTH_MSD, intermediate animation frames may be outside the + * range and / or moving in any direction; GetScrollPositionCSSPixels will be + * exactly aScrollPosition at the end of the scroll animation unless the + * SMOOTH_MSD animation is interrupted. + * + * FIXME: Drop |aSnap| argument once after we finished the migration to the + * Scroll Snap Module v1. We should alway use ENABLE_SNAP. + */ + virtual void ScrollToCSSPixels( + const CSSIntPoint& aScrollPosition, + ScrollMode aMode = ScrollMode::Instant, + nsIScrollbarMediator::ScrollSnapMode aSnap = + nsIScrollbarMediator::DEFAULT, + ScrollOrigin aOrigin = ScrollOrigin::NotSpecified) = 0; + /** + * @note This method might destroy the frame, pres shell and other objects. + * Scrolls to a particular position in float CSS pixels. + * This does not guarantee that GetScrollPositionCSSPixels equals + * aScrollPosition afterward. It tries to scroll as close to + * aScrollPosition as possible while scrolling by an integer + * number of layer pixels (so the operation is fast and looks clean). + */ + virtual void ScrollToCSSPixelsApproximate( + const mozilla::CSSPoint& aScrollPosition, + ScrollOrigin aOrigin = ScrollOrigin::NotSpecified) = 0; + + /** + * Returns the scroll position in integer CSS pixels, rounded to the nearest + * pixel. + */ + virtual CSSIntPoint GetScrollPositionCSSPixels() = 0; + /** + * @note This method might destroy the frame, pres shell and other objects. + * Modifies the current scroll position by aDelta units given by aUnit, + * clamping it to GetScrollRange. If WHOLE is specified as the unit, + * content is scrolled all the way in the direction(s) given by aDelta. + * @param aOverflow if non-null, returns the amount that scrolling + * was clamped by in each direction (how far we moved the scroll position + * to bring it back into the legal range). This is never negative. The + * values are in device pixels. + */ + virtual void ScrollBy(nsIntPoint aDelta, mozilla::ScrollUnit aUnit, + ScrollMode aMode, nsIntPoint* aOverflow = nullptr, + ScrollOrigin aOrigin = ScrollOrigin::NotSpecified, + ScrollMomentum aMomentum = NOT_MOMENTUM, + nsIScrollbarMediator::ScrollSnapMode aSnap = + nsIScrollbarMediator::DISABLE_SNAP) = 0; + + /** + * FIXME: Drop |aSnap| argument once after we finished the migration to the + * Scroll Snap Module v1. We should alway use ENABLE_SNAP. + */ + virtual void ScrollByCSSPixels( + const CSSIntPoint& aDelta, ScrollMode aMode = ScrollMode::Instant, + ScrollOrigin aOrigin = ScrollOrigin::NotSpecified, + nsIScrollbarMediator::ScrollSnapMode aSnap = + nsIScrollbarMediator::DEFAULT) = 0; + + /** + * Perform scroll snapping, possibly resulting in a smooth scroll to + * maintain the scroll snap position constraints. Velocity sampled from + * main thread scrolling is used to determine best matching snap point + * when called after a fling gesture on a trackpad or mouse wheel. + */ + virtual void ScrollSnap() = 0; + + /** + * @note This method might destroy the frame, pres shell and other objects. + * This tells the scroll frame to try scrolling to the scroll + * position that was restored from the history. This must be called + * at least once after state has been restored. It is called by the + * scrolled frame itself during reflow, but sometimes state can be + * restored after reflows are done... + * XXX should we take an aMode parameter here? Currently it's instant. + */ + virtual void ScrollToRestoredPosition() = 0; + + /** + * Add a scroll position listener. This listener must be removed + * before it is destroyed. + */ + virtual void AddScrollPositionListener( + nsIScrollPositionListener* aListener) = 0; + /** + * Remove a scroll position listener. + */ + virtual void RemoveScrollPositionListener( + nsIScrollPositionListener* aListener) = 0; + + /** + * Internal method used by scrollbars to notify their scrolling + * container of changes. + */ + virtual void CurPosAttributeChanged(nsIContent* aChild) = 0; + + /** + * Allows the docshell to request that the scroll frame post an event + * after being restored from history. + */ + NS_IMETHOD PostScrolledAreaEventForCurrentArea() = 0; + + /** + * Returns true if this scrollframe is being "actively scrolled". + * This basically means that we should allocate resources in the + * expectation that scrolling is going to happen. + */ + virtual bool IsScrollingActive(nsDisplayListBuilder* aBuilder) = 0; + + /** + * Returns true if this scroll frame might be scrolled + * asynchronously by the compositor. + */ + virtual bool IsMaybeAsynchronouslyScrolled() = 0; + + /** + * Same as the above except doesn't take into account will-change budget, + * which means that it can be called during display list building. + */ + virtual bool IsMaybeScrollingActive() const = 0; + /** + * Call this when the layer(s) induced by active scrolling are being + * completely redrawn. + */ + virtual void ResetScrollPositionForLayerPixelAlignment() = 0; + /** + * Was the current presentation state for this frame restored from history? + */ + virtual bool DidHistoryRestore() const = 0; + /** + * Clear the flag so that DidHistoryRestore() returns false until the next + * RestoreState call. + * @see nsIStatefulFrame::RestoreState + */ + virtual void ClearDidHistoryRestore() = 0; + /** + * Mark the frame as having been scrolled at least once, so that it remains + * active and we can also start storing its scroll position when saving state. + */ + virtual void MarkEverScrolled() = 0; + /** + * Determine if the passed in rect is nearly visible according to the frame + * visibility heuristics for how close it is to the visible scrollport. + */ + virtual bool IsRectNearlyVisible(const nsRect& aRect) = 0; + /** + * Expand the given rect taking into account which directions we can scroll + * and how far we want to expand for frame visibility purposes. + */ + virtual nsRect ExpandRectToNearlyVisible(const nsRect& aRect) const = 0; + /** + * Returns the origin that triggered the last instant scroll. Will equal + * ScrollOrigin::Apz when the compositor's replica frame metrics includes the + * latest instant scroll. + */ + virtual ScrollOrigin LastScrollOrigin() = 0; + + /** + * Returns whether there's an async scroll going on. + * + * The argument allows a subtle distinction that's needed for APZ. When + * `IncludeApzAnimation::No` is given, ongoing APZ animations that have + * already been synced to the main thread are not included, which is needed so + * that APZ can keep syncing the scroll offset properly. + */ + enum class IncludeApzAnimation : bool { No, Yes }; + virtual bool IsScrollAnimating( + IncludeApzAnimation = IncludeApzAnimation::Yes) = 0; + + /** + * Returns the current generation counter for the scrollframe. This counter + * increments every time the scroll position is set. + */ + virtual mozilla::ScrollGeneration CurrentScrollGeneration() const = 0; + /** + * LastScrollDestination returns the destination of the most recently + * requested smooth scroll animation. + */ + virtual nsPoint LastScrollDestination() = 0; + /** + * Returns the list of scroll position updates since the last call to + * NotifyApzTransaction(). + */ + virtual nsTArray<mozilla::ScrollPositionUpdate> GetScrollUpdates() const = 0; + /** + * Returns true if the scroll frame has any scroll position updates since + * the last call to NotifyApzTransaction(). + */ + virtual bool HasScrollUpdates() const = 0; + /** + * Clears the "origin of last scroll" property stored in this frame, if + * the generation counter passed in matches the current scroll generation + * counter, and clears the "origin of last smooth scroll" property if the + * generation counter matches. It also resets whether there's an ongoing apz + * animation. + */ + virtual void ResetScrollInfoIfNeeded( + const mozilla::ScrollGeneration& aGeneration, + bool aApzAnimationInProgress) = 0; + /** + * Determine whether it is desirable to be able to asynchronously scroll this + * scroll frame. + */ + virtual bool WantAsyncScroll() const = 0; + /** + * Returns the ScrollMetadata contributed by this frame, if there is one. + */ + virtual mozilla::Maybe<mozilla::layers::ScrollMetadata> ComputeScrollMetadata( + mozilla::layers::LayerManager* aLayerManager, + const nsIFrame* aContainerReferenceFrame, + const mozilla::Maybe<ContainerLayerParameters>& aParameters, + const mozilla::DisplayItemClip* aClip) const = 0; + /** + * Ensure's aLayer is clipped to the display port. + */ + virtual void ClipLayerToDisplayPort( + mozilla::layers::Layer* aLayer, const mozilla::DisplayItemClip* aClip, + const ContainerLayerParameters& aParameters) const = 0; + + /** + * Mark the scrollbar frames for reflow. + */ + virtual void MarkScrollbarsDirtyForReflow() const = 0; + + virtual void UpdateScrollbarPosition() = 0; + + virtual void SetTransformingByAPZ(bool aTransforming) = 0; + virtual bool IsTransformingByAPZ() const = 0; + + /** + * Notify this scroll frame that it can be scrolled by APZ. In particular, + * this is called *after* the APZ code has created an APZC for this scroll + * frame and verified that it is not a scrollinfo layer. Therefore, setting an + * async transform on it is actually user visible. + */ + virtual void SetScrollableByAPZ(bool aScrollable) = 0; + + /** + * Notify this scroll frame that it can be zoomed by APZ. + */ + virtual void SetZoomableByAPZ(bool aZoomable) = 0; + + /** + * Mark this scroll frame as having out-of-flow content inside a CSS filter. + * Such content will move incorrectly during async-scrolling; to mitigate + * this, paint skipping is disabled for such scroll frames. + */ + virtual void SetHasOutOfFlowContentInsideFilter() = 0; + + /** + * Determine if we should build a scrollable layer for this scroll frame and + * return the result. It will also record this result on the scroll frame. + * Pass the visible rect in aVisibleRect. On return it will be set to the + * displayport if there is one. + * Pass the dirty rect in aDirtyRect. On return it will be set to the + * dirty rect inside the displayport (ie the dirty rect that should be used). + * This function will set the display port base rect if aSetBase is true. + * aSetBase is only allowed to be false if there has been a call with it + * set to true before on the same paint. + */ + virtual bool DecideScrollableLayer(nsDisplayListBuilder* aBuilder, + nsRect* aVisibleRect, nsRect* aDirtyRect, + bool aSetBase) = 0; + + /** + * Notify the scrollframe that the current scroll offset and origin have been + * sent over in a layers transaction. + * + * This sets a flag on the scrollframe that indicates subsequent changes + * to the scroll position by "weaker" origins are permitted to overwrite the + * the scroll origin. Scroll origins that + * nsLayoutUtils::CanScrollOriginClobberApz returns false for are considered + * "weaker" than scroll origins for which that function returns true. + * + * This function must be called for a scrollframe after all calls to + * ComputeScrollMetadata in a layers transaction have been completed. + * + */ + virtual void NotifyApzTransaction() = 0; + + /** + * Notification that this scroll frame is getting its frame visibility + * updated. aIgnoreDisplayPort indicates that the display port was ignored + * (because there was no suitable base rect) + */ + virtual void NotifyApproximateFrameVisibilityUpdate( + bool aIgnoreDisplayPort) = 0; + + /** + * Returns true if this scroll frame had a display port at the last frame + * visibility update and fills in aDisplayPort with that displayport. Returns + * false otherwise, and doesn't touch aDisplayPort. + */ + virtual bool GetDisplayPortAtLastApproximateFrameVisibilityUpdate( + nsRect* aDisplayPort) = 0; + + /** + * This is called when a descendant scrollframe's has its displayport expired. + * This function will check to see if this scrollframe may safely expire its + * own displayport and schedule a timer to do that if it is safe. + */ + virtual void TriggerDisplayPortExpiration() = 0; + + /** + * Returns information required to determine where to snap to after a scroll. + */ + virtual ScrollSnapInfo GetScrollSnapInfo() const = 0; + + /** + * Given the drag event aEvent, determine whether the mouse is near the edge + * of the scrollable area, and scroll the view in the direction of that edge + * if so. If scrolling occurred, true is returned. When false is returned, the + * caller should look for an ancestor to scroll. + */ + virtual bool DragScroll(mozilla::WidgetEvent* aEvent) = 0; + + virtual void AsyncScrollbarDragInitiated( + uint64_t aDragBlockId, mozilla::layers::ScrollDirection aDirection) = 0; + virtual void AsyncScrollbarDragRejected() = 0; + + /** + * Returns whether this scroll frame is the root scroll frame of the document + * that it is in. Note that some documents don't have root scroll frames at + * all (ie XUL documents) even though they may contain other scroll frames. + */ + virtual bool IsRootScrollFrameOfDocument() const = 0; + + /** + * Returns the scroll anchor associated with this scrollable frame. This is + * never null. + */ + virtual const ScrollAnchorContainer* Anchor() const = 0; + virtual ScrollAnchorContainer* Anchor() = 0; + + virtual bool SmoothScrollVisual( + const nsPoint& aVisualViewportOffset, + mozilla::layers::FrameMetrics::ScrollOffsetUpdateType aUpdateType) = 0; + + /** + * Returns true if this scroll frame should perform smooth scroll with the + * given |aBehavior|. + */ + virtual bool IsSmoothScroll(mozilla::dom::ScrollBehavior aBehavior = + mozilla::dom::ScrollBehavior::Auto) const = 0; +}; + +#endif |