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: #ifndef ACTIVELAYERTRACKER_H_
michael@0: #define ACTIVELAYERTRACKER_H_
michael@0: 
michael@0: #include "nsCSSProperty.h"
michael@0: 
michael@0: class nsIFrame;
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: /**
michael@0:  * This class receives various notifications about style changes and content
michael@0:  * changes that affect layerization decisions, and implements the heuristics
michael@0:  * that drive those decisions. It manages per-frame state to support those
michael@0:  * heuristics.
michael@0:  */
michael@0: class ActiveLayerTracker {
michael@0: public:
michael@0:   static void Shutdown();
michael@0: 
michael@0:   /*
michael@0:    * We track style changes to selected styles:
michael@0:    *   eCSSProperty_transform
michael@0:    *   eCSSProperty_opacity
michael@0:    *   eCSSProperty_left, eCSSProperty_top, eCSSProperty_right, eCSSProperty_bottom
michael@0:    * and use that information to guess whether style changes are animated.
michael@0:    */
michael@0: 
michael@0:   /**
michael@0:    * Notify aFrame's style property as having changed due to a restyle,
michael@0:    * and therefore possibly wanting an active layer to render that style.
michael@0:    * Any such marking will time out after a short period.
michael@0:    * @param aProperty the property that has changed
michael@0:    */
michael@0:   static void NotifyRestyle(nsIFrame* aFrame, nsCSSProperty aProperty);
michael@0:   /**
michael@0:    * Notify aFrame's left/top/right/bottom properties as having (maybe)
michael@0:    * changed due to a restyle, and therefore possibly wanting an active layer
michael@0:    * to render that style. Any such marking will time out after a short period.
michael@0:    */
michael@0:   static void NotifyOffsetRestyle(nsIFrame* aFrame);
michael@0:   /**
michael@0:    * Mark aFrame as being known to have an animation of aProperty.
michael@0:    * Any such marking will time out after a short period.
michael@0:    */
michael@0:   static void NotifyAnimated(nsIFrame* aFrame, nsCSSProperty aProperty);
michael@0:   /**
michael@0:    * Notify that a property in the inline style rule of aFrame's element
michael@0:    * has been modified.
michael@0:    * This notification is incomplete --- not all modifications to inline
michael@0:    * style will trigger this.
michael@0:    */
michael@0:   static void NotifyInlineStyleRuleModified(nsIFrame* aFrame, nsCSSProperty aProperty);
michael@0:   /**
michael@0:    * Return true if aFrame's aProperty style should be considered as being animated
michael@0:    * for constructing active layers.
michael@0:    */
michael@0:   static bool IsStyleAnimated(nsIFrame* aFrame, nsCSSProperty aProperty);
michael@0:   /**
michael@0:    * Return true if any of aFrame's offset property styles should be considered
michael@0:    * as being animated for constructing active layers.
michael@0:    */
michael@0:   static bool IsOffsetOrMarginStyleAnimated(nsIFrame* aFrame);
michael@0: 
michael@0:   /*
michael@0:    * We track modifications to the content of certain frames (i.e. canvas frames)
michael@0:    * and use that to make layering decisions.
michael@0:    */
michael@0: 
michael@0:   /**
michael@0:    * Mark aFrame's content as being active. This marking will time out after
michael@0:    * a short period.
michael@0:    */
michael@0:   static void NotifyContentChange(nsIFrame* aFrame);
michael@0:   /**
michael@0:    * Return true if this frame's content is still marked as active.
michael@0:    */
michael@0:   static bool IsContentActive(nsIFrame* aFrame);
michael@0: };
michael@0: 
michael@0: }
michael@0: 
michael@0: #endif /* ACTIVELAYERTRACKER_H_ */