summaryrefslogtreecommitdiffstats
path: root/layout/base/ActiveLayerTracker.h
diff options
context:
space:
mode:
Diffstat (limited to 'layout/base/ActiveLayerTracker.h')
-rw-r--r--layout/base/ActiveLayerTracker.h141
1 files changed, 141 insertions, 0 deletions
diff --git a/layout/base/ActiveLayerTracker.h b/layout/base/ActiveLayerTracker.h
new file mode 100644
index 000000000..145f5481e
--- /dev/null
+++ b/layout/base/ActiveLayerTracker.h
@@ -0,0 +1,141 @@
+/* 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_ */