michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=2 sts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /**
michael@0:  * compute sticky positioning, both during reflow and when the scrolling
michael@0:  * container scrolls
michael@0:  */
michael@0: 
michael@0: #ifndef StickyScrollContainer_h
michael@0: #define StickyScrollContainer_h
michael@0: 
michael@0: #include "nsPoint.h"
michael@0: #include "nsTArray.h"
michael@0: #include "nsIScrollPositionListener.h"
michael@0: 
michael@0: class nsRect;
michael@0: class nsIFrame;
michael@0: class nsIScrollableFrame;
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: class StickyScrollContainer MOZ_FINAL : public nsIScrollPositionListener
michael@0: {
michael@0: public:
michael@0:   /**
michael@0:    * Find (and create if necessary) the StickyScrollContainer associated with
michael@0:    * the scroll container of the given frame, if a scroll container exists.
michael@0:    */
michael@0:   static StickyScrollContainer* GetStickyScrollContainerForFrame(nsIFrame* aFrame);
michael@0: 
michael@0:   /**
michael@0:    * Find the StickyScrollContainer associated with the given scroll frame,
michael@0:    * if it exists.
michael@0:    */
michael@0:   static StickyScrollContainer* GetStickyScrollContainerForScrollFrame(nsIFrame* aScrollFrame);
michael@0: 
michael@0:   /**
michael@0:    * aFrame may have moved into or out of a scroll frame's frame subtree.
michael@0:    */
michael@0:   static void NotifyReparentedFrameAcrossScrollFrameBoundary(nsIFrame* aFrame,
michael@0:                                                              nsIFrame* aOldParent);
michael@0: 
michael@0:   void AddFrame(nsIFrame* aFrame) {
michael@0:     mFrames.AppendElement(aFrame);
michael@0:   }
michael@0:   void RemoveFrame(nsIFrame* aFrame) {
michael@0:     mFrames.RemoveElement(aFrame);
michael@0:   }
michael@0: 
michael@0:   nsIScrollableFrame* ScrollFrame() const {
michael@0:     return mScrollFrame;
michael@0:   }
michael@0: 
michael@0:   // Compute the offsets for a sticky position element
michael@0:   static void ComputeStickyOffsets(nsIFrame* aFrame);
michael@0: 
michael@0:   /**
michael@0:    * Compute the position of a sticky positioned frame, based on information
michael@0:    * stored in its properties along with our scroll frame and scroll position.
michael@0:    */
michael@0:   nsPoint ComputePosition(nsIFrame* aFrame) const;
michael@0: 
michael@0:   /**
michael@0:    * Compute where a frame should not scroll with the page, represented by the
michael@0:    * difference of two rectangles.
michael@0:    */
michael@0:   void GetScrollRanges(nsIFrame* aFrame, nsRect* aOuter, nsRect* aInner) const;
michael@0: 
michael@0:   /**
michael@0:    * Compute and set the position of a frame and its following continuations.
michael@0:    */
michael@0:   void PositionContinuations(nsIFrame* aFrame);
michael@0: 
michael@0:   /**
michael@0:    * Compute and set the position of all sticky frames, given the current
michael@0:    * scroll position of the scroll frame. If not in reflow, aSubtreeRoot should
michael@0:    * be null; otherwise, overflow-area updates will be limited to not affect
michael@0:    * aSubtreeRoot or its ancestors.
michael@0:    */
michael@0:   void UpdatePositions(nsPoint aScrollPosition, nsIFrame* aSubtreeRoot);
michael@0: 
michael@0:   // nsIScrollPositionListener
michael@0:   virtual void ScrollPositionWillChange(nscoord aX, nscoord aY) MOZ_OVERRIDE;
michael@0:   virtual void ScrollPositionDidChange(nscoord aX, nscoord aY) MOZ_OVERRIDE;
michael@0: 
michael@0: private:
michael@0:   StickyScrollContainer(nsIScrollableFrame* aScrollFrame);
michael@0:   ~StickyScrollContainer();
michael@0: 
michael@0:   /**
michael@0:    * Compute two rectangles that determine sticky positioning: |aStick|, based
michael@0:    * on the scroll container, and |aContain|, based on the containing block.
michael@0:    * Sticky positioning keeps the frame position (its upper-left corner) always
michael@0:    * within |aContain| and secondarily within |aStick|.
michael@0:    */
michael@0:   void ComputeStickyLimits(nsIFrame* aFrame, nsRect* aStick,
michael@0:                            nsRect* aContain) const;
michael@0: 
michael@0:   friend void DestroyStickyScrollContainer(void* aPropertyValue);
michael@0: 
michael@0:   nsIScrollableFrame* const mScrollFrame;
michael@0:   nsTArray<nsIFrame*> mFrames;
michael@0:   nsPoint mScrollPosition;
michael@0: };
michael@0: 
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif /* StickyScrollContainer_h */