The Tor Browser: layout/base/ActiveLayerTracker.h@6474c204b198

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

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

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

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

     5 #ifndef ACTIVELAYERTRACKER_H_

     6 #define ACTIVELAYERTRACKER_H_

     8 #include "nsCSSProperty.h"

    10 class nsIFrame;

    12 namespace mozilla {

    14 /**

    15  * This class receives various notifications about style changes and content

    16  * changes that affect layerization decisions, and implements the heuristics

    17  * that drive those decisions. It manages per-frame state to support those

    18  * heuristics.

    19  */

    20 class ActiveLayerTracker {

    21 public:

    22   static void Shutdown();

    24   /*

    25    * We track style changes to selected styles:

    26    *   eCSSProperty_transform

    27    *   eCSSProperty_opacity

    28    *   eCSSProperty_left, eCSSProperty_top, eCSSProperty_right, eCSSProperty_bottom

    29    * and use that information to guess whether style changes are animated.

    30    */

    32   /**

    33    * Notify aFrame's style property as having changed due to a restyle,

    34    * and therefore possibly wanting an active layer to render that style.

    35    * Any such marking will time out after a short period.

    36    * @param aProperty the property that has changed

    37    */

    38   static void NotifyRestyle(nsIFrame* aFrame, nsCSSProperty aProperty);

    39   /**

    40    * Notify aFrame's left/top/right/bottom properties as having (maybe)

    41    * changed due to a restyle, and therefore possibly wanting an active layer

    42    * to render that style. Any such marking will time out after a short period.

    43    */

    44   static void NotifyOffsetRestyle(nsIFrame* aFrame);

    45   /**

    46    * Mark aFrame as being known to have an animation of aProperty.

    47    * Any such marking will time out after a short period.

    48    */

    49   static void NotifyAnimated(nsIFrame* aFrame, nsCSSProperty aProperty);

    50   /**

    51    * Notify that a property in the inline style rule of aFrame's element

    52    * has been modified.

    53    * This notification is incomplete --- not all modifications to inline

    54    * style will trigger this.

    55    */

    56   static void NotifyInlineStyleRuleModified(nsIFrame* aFrame, nsCSSProperty aProperty);

    57   /**

    58    * Return true if aFrame's aProperty style should be considered as being animated

    59    * for constructing active layers.

    60    */

    61   static bool IsStyleAnimated(nsIFrame* aFrame, nsCSSProperty aProperty);

    62   /**

    63    * Return true if any of aFrame's offset property styles should be considered

    64    * as being animated for constructing active layers.

    65    */

    66   static bool IsOffsetOrMarginStyleAnimated(nsIFrame* aFrame);

    68   /*

    69    * We track modifications to the content of certain frames (i.e. canvas frames)

    70    * and use that to make layering decisions.

    71    */

    73   /**

    74    * Mark aFrame's content as being active. This marking will time out after

    75    * a short period.

    76    */

    77   static void NotifyContentChange(nsIFrame* aFrame);

    78   /**

    79    * Return true if this frame's content is still marked as active.

    80    */

    81   static bool IsContentActive(nsIFrame* aFrame);

    82 };

    84 }

    86 #endif /* ACTIVELAYERTRACKER_H_ */

The Tor Browser / file revision