The Tor Browser: layout/generic/StickyScrollContainer.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* vim: set ts=2 sts=2 et sw=2 tw=80: */

     3 /* This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 /**

     8  * compute sticky positioning, both during reflow and when the scrolling

     9  * container scrolls

    10  */

    12 #ifndef StickyScrollContainer_h

    13 #define StickyScrollContainer_h

    15 #include "nsPoint.h"

    16 #include "nsTArray.h"

    17 #include "nsIScrollPositionListener.h"

    19 class nsRect;

    20 class nsIFrame;

    21 class nsIScrollableFrame;

    23 namespace mozilla {

    25 class StickyScrollContainer MOZ_FINAL : public nsIScrollPositionListener

    26 {

    27 public:

    28   /**

    29    * Find (and create if necessary) the StickyScrollContainer associated with

    30    * the scroll container of the given frame, if a scroll container exists.

    31    */

    32   static StickyScrollContainer* GetStickyScrollContainerForFrame(nsIFrame* aFrame);

    34   /**

    35    * Find the StickyScrollContainer associated with the given scroll frame,

    36    * if it exists.

    37    */

    38   static StickyScrollContainer* GetStickyScrollContainerForScrollFrame(nsIFrame* aScrollFrame);

    40   /**

    41    * aFrame may have moved into or out of a scroll frame's frame subtree.

    42    */

    43   static void NotifyReparentedFrameAcrossScrollFrameBoundary(nsIFrame* aFrame,

    44                                                              nsIFrame* aOldParent);

    46   void AddFrame(nsIFrame* aFrame) {

    47     mFrames.AppendElement(aFrame);

    48   }

    49   void RemoveFrame(nsIFrame* aFrame) {

    50     mFrames.RemoveElement(aFrame);

    51   }

    53   nsIScrollableFrame* ScrollFrame() const {

    54     return mScrollFrame;

    55   }

    57   // Compute the offsets for a sticky position element

    58   static void ComputeStickyOffsets(nsIFrame* aFrame);

    60   /**

    61    * Compute the position of a sticky positioned frame, based on information

    62    * stored in its properties along with our scroll frame and scroll position.

    63    */

    64   nsPoint ComputePosition(nsIFrame* aFrame) const;

    66   /**

    67    * Compute where a frame should not scroll with the page, represented by the

    68    * difference of two rectangles.

    69    */

    70   void GetScrollRanges(nsIFrame* aFrame, nsRect* aOuter, nsRect* aInner) const;

    72   /**

    73    * Compute and set the position of a frame and its following continuations.

    74    */

    75   void PositionContinuations(nsIFrame* aFrame);

    77   /**

    78    * Compute and set the position of all sticky frames, given the current

    79    * scroll position of the scroll frame. If not in reflow, aSubtreeRoot should

    80    * be null; otherwise, overflow-area updates will be limited to not affect

    81    * aSubtreeRoot or its ancestors.

    82    */

    83   void UpdatePositions(nsPoint aScrollPosition, nsIFrame* aSubtreeRoot);

    85   // nsIScrollPositionListener

    86   virtual void ScrollPositionWillChange(nscoord aX, nscoord aY) MOZ_OVERRIDE;

    87   virtual void ScrollPositionDidChange(nscoord aX, nscoord aY) MOZ_OVERRIDE;

    89 private:

    90   StickyScrollContainer(nsIScrollableFrame* aScrollFrame);

    91   ~StickyScrollContainer();

    93   /**

    94    * Compute two rectangles that determine sticky positioning: |aStick|, based

    95    * on the scroll container, and |aContain|, based on the containing block.

    96    * Sticky positioning keeps the frame position (its upper-left corner) always

    97    * within |aContain| and secondarily within |aStick|.

    98    */

    99   void ComputeStickyLimits(nsIFrame* aFrame, nsRect* aStick,

   100                            nsRect* aContain) const;

   102   friend void DestroyStickyScrollContainer(void* aPropertyValue);

   104   nsIScrollableFrame* const mScrollFrame;

   105   nsTArray<nsIFrame*> mFrames;

   106   nsPoint mScrollPosition;

   107 };

   109 } // namespace mozilla

   111 #endif /* StickyScrollContainer_h */

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