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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef ACTIVELAYERTRACKER_H_
#define ACTIVELAYERTRACKER_H_
#include "nsCSSPropertyID.h"
class nsIFrame;
class nsIContent;
class nsDisplayListBuilder;
class nsDOMCSSDeclaration;
namespace mozilla {
/**
* This class receives various notifications about style changes and content
* changes that affect layerization decisions, and implements the heuristics
* that drive those decisions. It manages per-frame state to support those
* heuristics.
*/
class ActiveLayerTracker {
public:
static void Shutdown();
/*
* We track style changes to selected styles:
* eCSSProperty_transform
* eCSSProperty_opacity
* eCSSProperty_left, eCSSProperty_top, eCSSProperty_right, eCSSProperty_bottom
* and use that information to guess whether style changes are animated.
*/
/**
* Notify aFrame's style property as having changed due to a restyle,
* and therefore possibly wanting an active layer to render that style.
* Any such marking will time out after a short period.
* @param aProperty the property that has changed
*/
static void NotifyRestyle(nsIFrame* aFrame, nsCSSPropertyID aProperty);
/**
* Notify aFrame's left/top/right/bottom properties as having (maybe)
* changed due to a restyle, and therefore possibly wanting an active layer
* to render that style. Any such marking will time out after a short period.
*/
static void NotifyOffsetRestyle(nsIFrame* aFrame);
/**
* Mark aFrame as being known to have an animation of aProperty.
* Any such marking will time out after a short period.
* aNewValue and aDOMCSSDecl are used to determine whether the property's
* value has changed.
*/
static void NotifyAnimated(nsIFrame* aFrame, nsCSSPropertyID aProperty,
const nsAString& aNewValue,
nsDOMCSSDeclaration* aDOMCSSDecl);
/**
* Notify aFrame as being known to have an animation of aProperty through an
* inline style modification during aScrollFrame's scroll event handler.
*/
static void NotifyAnimatedFromScrollHandler(nsIFrame* aFrame, nsCSSPropertyID aProperty,
nsIFrame* aScrollFrame);
/**
* Notify that a property in the inline style rule of aFrame's element
* has been modified.
* This notification is incomplete --- not all modifications to inline
* style will trigger this.
* aNewValue and aDOMCSSDecl are used to determine whether the property's
* value has changed.
*/
static void NotifyInlineStyleRuleModified(nsIFrame* aFrame, nsCSSPropertyID aProperty,
const nsAString& aNewValue,
nsDOMCSSDeclaration* aDOMCSSDecl);
/**
* Return true if aFrame's aProperty style should be considered as being animated
* for pre-rendering.
*/
static bool IsStyleMaybeAnimated(nsIFrame* aFrame, nsCSSPropertyID aProperty);
/**
* Return true if aFrame's aProperty style should be considered as being animated
* for constructing active layers.
*/
static bool IsStyleAnimated(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
nsCSSPropertyID aProperty);
/**
* Return true if any of aFrame's offset property styles should be considered
* as being animated for constructing active layers.
*/
static bool IsOffsetOrMarginStyleAnimated(nsIFrame* aFrame);
/**
* Return true if aFrame's background-position-x or background-position-y
* property is animated.
*/
static bool IsBackgroundPositionAnimated(nsDisplayListBuilder* aBuilder,
nsIFrame* aFrame);
/**
* Return true if aFrame either has an animated scale now, or is likely to
* have one in the future because it has a CSS animation or transition
* (which may not be playing right now) that affects its scale.
*/
static bool IsScaleSubjectToAnimation(nsIFrame* aFrame);
/**
* Transfer the LayerActivity property to the frame's content node when the
* frame is about to be destroyed so that layer activity can be tracked
* throughout reframes of an element. Only call this when aFrame is the
* primary frame of aContent.
*/
static void TransferActivityToContent(nsIFrame* aFrame, nsIContent* aContent);
/**
* Transfer the LayerActivity property back to the content node's primary
* frame after the frame has been created.
*/
static void TransferActivityToFrame(nsIContent* aContent, nsIFrame* aFrame);
/*
* We track modifications to the content of certain frames (i.e. canvas frames)
* and use that to make layering decisions.
*/
/**
* Mark aFrame's content as being active. This marking will time out after
* a short period.
*/
static void NotifyContentChange(nsIFrame* aFrame);
/**
* Return true if this frame's content is still marked as active.
*/
static bool IsContentActive(nsIFrame* aFrame);
/**
* Called before and after a scroll event handler is executed, with the
* scrollframe or nullptr, respectively. This acts as a hint to treat
* inline style changes during the handler differently.
*/
static void SetCurrentScrollHandlerFrame(nsIFrame* aFrame);
};
} // namespace mozilla
#endif /* ACTIVELAYERTRACKER_H_ */
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