ActiveLayerTracker.h (3843B)
1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* vim: set ts=8 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/. */ 6 7 #ifndef ACTIVELAYERTRACKER_H_ 8 #define ACTIVELAYERTRACKER_H_ 9 10 #include "NonCustomCSSPropertyId.h" 11 12 class nsIFrame; 13 class nsIContent; 14 class nsCSSPropertyIDSet; 15 class nsDOMCSSDeclaration; 16 17 namespace mozilla { 18 19 class nsDisplayListBuilder; 20 21 /** 22 * This class receives various notifications about style changes and content 23 * changes that affect layerization decisions, and implements the heuristics 24 * that drive those decisions. It manages per-frame state to support those 25 * heuristics. 26 */ 27 class ActiveLayerTracker { 28 public: 29 static void Shutdown(); 30 31 /* 32 * We track style changes to selected styles: 33 * eCSSProperty_transform, eCSSProperty_translate, 34 * eCSSProperty_rotate, eCSSProperty_scale 35 * eCSSProperty_offset_path, eCSSProperty_offset_distance, 36 * eCSSProperty_offset_rotate, eCSSProperty_offset_anchor, 37 * eCSSProperty_offset_position, eCSSProperty_opacity 38 * and use that information to guess whether style changes are animated. 39 */ 40 41 /** 42 * Notify aFrame's style property as having changed due to a restyle, 43 * and therefore possibly wanting an active layer to render that style. 44 * Any such marking will time out after a short period. 45 * @param aProperty the property that has changed 46 */ 47 static void NotifyRestyle(nsIFrame* aFrame, NonCustomCSSPropertyId aProperty); 48 49 /** 50 * Notify that a property in the inline style rule of aFrame's element 51 * has been modified. 52 */ 53 static void NotifyInlineStyleRuleModified(nsIFrame* aFrame, 54 NonCustomCSSPropertyId aProperty); 55 /** 56 * Notify that a frame needs to be repainted. This is important for layering 57 * decisions where, say, aFrame's transform is updated from JS, but we need 58 * to repaint aFrame anyway, so we get no benefit from giving it its own 59 * layer. 60 */ 61 static void NotifyNeedsRepaint(nsIFrame* aFrame); 62 /** 63 * Return true if aFrame's property style in |aPropertySet| should be 64 * considered as being animated for constructing active layers. 65 */ 66 static bool IsStyleAnimated(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame, 67 const nsCSSPropertyIDSet& aPropertySet); 68 /** 69 * Return true if aFrame's transform-like property, 70 * i.e. transform/translate/rotate/scale, is animated. 71 */ 72 static bool IsTransformAnimated(nsDisplayListBuilder* aBuilder, 73 nsIFrame* aFrame); 74 /** 75 * Return true if aFrame's transform style should be considered as being 76 * animated for pre-rendering. 77 */ 78 static bool IsTransformMaybeAnimated(nsIFrame* aFrame); 79 /** 80 * Return true if aFrame either has an animated scale now, or is likely to 81 * have one in the future because it has a CSS animation or transition 82 * (which may not be playing right now) that affects its scale. 83 */ 84 static bool IsScaleSubjectToAnimation(nsIFrame* aFrame); 85 86 /** 87 * Transfer the LayerActivity property to the frame's content node when the 88 * frame is about to be destroyed so that layer activity can be tracked 89 * throughout reframes of an element. Only call this when aFrame is the 90 * primary frame of aContent. 91 */ 92 static void TransferActivityToContent(nsIFrame* aFrame, nsIContent* aContent); 93 /** 94 * Transfer the LayerActivity property back to the content node's primary 95 * frame after the frame has been created. 96 */ 97 static void TransferActivityToFrame(nsIContent* aContent, nsIFrame* aFrame); 98 }; 99 100 } // namespace mozilla 101 102 #endif /* ACTIVELAYERTRACKER_H_ */