1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/layout/generic/StickyScrollContainer.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,111 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim: set ts=2 sts=2 et sw=2 tw=80: */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +/**
1.11 + * compute sticky positioning, both during reflow and when the scrolling
1.12 + * container scrolls
1.13 + */
1.14 +
1.15 +#ifndef StickyScrollContainer_h
1.16 +#define StickyScrollContainer_h
1.17 +
1.18 +#include "nsPoint.h"
1.19 +#include "nsTArray.h"
1.20 +#include "nsIScrollPositionListener.h"
1.21 +
1.22 +class nsRect;
1.23 +class nsIFrame;
1.24 +class nsIScrollableFrame;
1.25 +
1.26 +namespace mozilla {
1.27 +
1.28 +class StickyScrollContainer MOZ_FINAL : public nsIScrollPositionListener
1.29 +{
1.30 +public:
1.31 + /**
1.32 + * Find (and create if necessary) the StickyScrollContainer associated with
1.33 + * the scroll container of the given frame, if a scroll container exists.
1.34 + */
1.35 + static StickyScrollContainer* GetStickyScrollContainerForFrame(nsIFrame* aFrame);
1.36 +
1.37 + /**
1.38 + * Find the StickyScrollContainer associated with the given scroll frame,
1.39 + * if it exists.
1.40 + */
1.41 + static StickyScrollContainer* GetStickyScrollContainerForScrollFrame(nsIFrame* aScrollFrame);
1.42 +
1.43 + /**
1.44 + * aFrame may have moved into or out of a scroll frame's frame subtree.
1.45 + */
1.46 + static void NotifyReparentedFrameAcrossScrollFrameBoundary(nsIFrame* aFrame,
1.47 + nsIFrame* aOldParent);
1.48 +
1.49 + void AddFrame(nsIFrame* aFrame) {
1.50 + mFrames.AppendElement(aFrame);
1.51 + }
1.52 + void RemoveFrame(nsIFrame* aFrame) {
1.53 + mFrames.RemoveElement(aFrame);
1.54 + }
1.55 +
1.56 + nsIScrollableFrame* ScrollFrame() const {
1.57 + return mScrollFrame;
1.58 + }
1.59 +
1.60 + // Compute the offsets for a sticky position element
1.61 + static void ComputeStickyOffsets(nsIFrame* aFrame);
1.62 +
1.63 + /**
1.64 + * Compute the position of a sticky positioned frame, based on information
1.65 + * stored in its properties along with our scroll frame and scroll position.
1.66 + */
1.67 + nsPoint ComputePosition(nsIFrame* aFrame) const;
1.68 +
1.69 + /**
1.70 + * Compute where a frame should not scroll with the page, represented by the
1.71 + * difference of two rectangles.
1.72 + */
1.73 + void GetScrollRanges(nsIFrame* aFrame, nsRect* aOuter, nsRect* aInner) const;
1.74 +
1.75 + /**
1.76 + * Compute and set the position of a frame and its following continuations.
1.77 + */
1.78 + void PositionContinuations(nsIFrame* aFrame);
1.79 +
1.80 + /**
1.81 + * Compute and set the position of all sticky frames, given the current
1.82 + * scroll position of the scroll frame. If not in reflow, aSubtreeRoot should
1.83 + * be null; otherwise, overflow-area updates will be limited to not affect
1.84 + * aSubtreeRoot or its ancestors.
1.85 + */
1.86 + void UpdatePositions(nsPoint aScrollPosition, nsIFrame* aSubtreeRoot);
1.87 +
1.88 + // nsIScrollPositionListener
1.89 + virtual void ScrollPositionWillChange(nscoord aX, nscoord aY) MOZ_OVERRIDE;
1.90 + virtual void ScrollPositionDidChange(nscoord aX, nscoord aY) MOZ_OVERRIDE;
1.91 +
1.92 +private:
1.93 + StickyScrollContainer(nsIScrollableFrame* aScrollFrame);
1.94 + ~StickyScrollContainer();
1.95 +
1.96 + /**
1.97 + * Compute two rectangles that determine sticky positioning: |aStick|, based
1.98 + * on the scroll container, and |aContain|, based on the containing block.
1.99 + * Sticky positioning keeps the frame position (its upper-left corner) always
1.100 + * within |aContain| and secondarily within |aStick|.
1.101 + */
1.102 + void ComputeStickyLimits(nsIFrame* aFrame, nsRect* aStick,
1.103 + nsRect* aContain) const;
1.104 +
1.105 + friend void DestroyStickyScrollContainer(void* aPropertyValue);
1.106 +
1.107 + nsIScrollableFrame* const mScrollFrame;
1.108 + nsTArray<nsIFrame*> mFrames;
1.109 + nsPoint mScrollPosition;
1.110 +};
1.111 +
1.112 +} // namespace mozilla
1.113 +
1.114 +#endif /* StickyScrollContainer_h */
