/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=2 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/. */ /** * compute sticky positioning, both during reflow and when the scrolling * container scrolls */ #ifndef StickyScrollContainer_h #define StickyScrollContainer_h #include "nsPoint.h" #include "nsTArray.h" #include "nsIScrollPositionListener.h" struct nsRect; class nsIFrame; class nsIScrollableFrame; namespace mozilla { class StickyScrollContainer final : public nsIScrollPositionListener { public: /** * Find (and create if necessary) the StickyScrollContainer associated with * the scroll container of the given frame, if a scroll container exists. */ static StickyScrollContainer* GetStickyScrollContainerForFrame(nsIFrame* aFrame); /** * Find the StickyScrollContainer associated with the given scroll frame, * if it exists. */ static StickyScrollContainer* GetStickyScrollContainerForScrollFrame(nsIFrame* aScrollFrame); /** * aFrame may have moved into or out of a scroll frame's frame subtree. */ static void NotifyReparentedFrameAcrossScrollFrameBoundary(nsIFrame* aFrame, nsIFrame* aOldParent); void AddFrame(nsIFrame* aFrame) { mFrames.AppendElement(aFrame); } void RemoveFrame(nsIFrame* aFrame) { mFrames.RemoveElement(aFrame); } nsIScrollableFrame* ScrollFrame() const { return mScrollFrame; } // Compute the offsets for a sticky position element static void ComputeStickyOffsets(nsIFrame* aFrame); /** * Compute the position of a sticky positioned frame, based on information * stored in its properties along with our scroll frame and scroll position. */ nsPoint ComputePosition(nsIFrame* aFrame) const; /** * Compute where a frame should not scroll with the page, represented by the * difference of two rectangles. */ void GetScrollRanges(nsIFrame* aFrame, nsRect* aOuter, nsRect* aInner) const; /** * Compute and set the position of a frame and its following continuations. */ void PositionContinuations(nsIFrame* aFrame); /** * Compute and set the position of all sticky frames, given the current * scroll position of the scroll frame. If not in reflow, aSubtreeRoot should * be null; otherwise, overflow-area updates will be limited to not affect * aSubtreeRoot or its ancestors. */ void UpdatePositions(nsPoint aScrollPosition, nsIFrame* aSubtreeRoot); // nsIScrollPositionListener virtual void ScrollPositionWillChange(nscoord aX, nscoord aY) override; virtual void ScrollPositionDidChange(nscoord aX, nscoord aY) override; ~StickyScrollContainer(); private: explicit StickyScrollContainer(nsIScrollableFrame* aScrollFrame); /** * Compute two rectangles that determine sticky positioning: |aStick|, based * on the scroll container, and |aContain|, based on the containing block. * Sticky positioning keeps the frame position (its upper-left corner) always * within |aContain| and secondarily within |aStick|. */ void ComputeStickyLimits(nsIFrame* aFrame, nsRect* aStick, nsRect* aContain) const; nsIScrollableFrame* const mScrollFrame; nsTArray<nsIFrame*> mFrames; nsPoint mScrollPosition; }; } // namespace mozilla #endif /* StickyScrollContainer_h */