Mark layers that can use LCD text based on layer transform and opacity.

cc/layer.h

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_LAYER_H_
 #define CC_LAYER_H_
 
 #include <public/WebFilterOperations.h>
 #include <string>
 #include <vector>
@@ skipping 122 matching lines @@
     DrawProperties<Layer, RenderSurface>& drawProperties() { return m_drawProperties; }
     const DrawProperties<Layer, RenderSurface>& drawProperties() const { return m_drawProperties; }
 
     // The following are shortcut accessors to get various information from m_drawProperties
     const gfx::Transform& drawTransform() const { return m_drawProperties.target_space_transform; }
     const gfx::Transform& screenSpaceTransform() const { return m_drawProperties.screen_space_transform; }
     float drawOpacity() const { return m_drawProperties.opacity; }
     bool drawOpacityIsAnimating() const { return m_drawProperties.opacity_is_animating; }
     bool drawTransformIsAnimating() const { return m_drawProperties.target_space_transform_is_animating; }
     bool screenSpaceTransformIsAnimating() const { return m_drawProperties.screen_space_transform_is_animating; }
+    bool screenSpaceOpacityIsAnimating() const { return m_drawProperties.screen_space_opacity_is_animating; }
     bool isClipped() const { return m_drawProperties.is_clipped; }
     const gfx::Rect& clipRect() const { return m_drawProperties.clip_rect; }
     const gfx::Rect& drawableContentRect() const { return m_drawProperties.drawable_content_rect; }
     const gfx::Rect& visibleContentRect() const { return m_drawProperties.visible_content_rect; }
     Layer* renderTarget() { DCHECK(!m_drawProperties.render_target || m_drawProperties.render_target->renderSurface()); return m_drawProperties.render_target; }
     const Layer* renderTarget() const { DCHECK(!m_drawProperties.render_target || m_drawProperties.render_target->renderSurface()); return m_drawProperties.render_target; }
     RenderSurface* renderSurface() const { return m_drawProperties.render_surface.get(); }
 
     void setScrollOffset(gfx::Vector2d);
     gfx::Vector2d scrollOffset() const { return m_scrollOffset; }
@@ skipping 33 matching lines @@
 
     void setDoubleSided(bool);
     bool doubleSided() const { return m_doubleSided; }
 
     void setPreserves3D(bool preserve3D) { m_preserves3D = preserve3D; }
     bool preserves3D() const { return m_preserves3D; }
 
     void setUseParentBackfaceVisibility(bool useParentBackfaceVisibility) { m_useParentBackfaceVisibility = useParentBackfaceVisibility; }
     bool useParentBackfaceVisibility() const { return m_useParentBackfaceVisibility; }
 
-    void setUseLCDText(bool);
-    bool useLCDText() const { return m_useLCDText; }
+    void setCanUseLCDText(bool);
+    bool canUseLCDText() const { return m_canUseLCDText; }
 
     virtual void setLayerTreeHost(LayerTreeHost*);
 
     bool hasContributingDelegatedRenderPasses() const { return false; }
 
     void setIsDrawable(bool);
 
     void setReplicaLayer(Layer*);
     Layer* replicaLayer() { return m_replicaLayer.get(); }
     const Layer* replicaLayer() const { return m_replicaLayer.get(); }
@@ skipping 83 matching lines @@
 protected:
     friend class LayerImpl;
     friend class TreeSynchronizer;
     virtual ~Layer();
 
     Layer();
 
     void setNeedsCommit();
     void setNeedsFullTreeSync();
 
+    // Called when LCD text setting is about to potentially change.
+    // If this function returns true, the setting is allowed to change.
+    // If it returns false, the setting is not changed.
+    virtual bool canUseLCDTextWillChange();

[enne (OOO), 2012/12/11 02:47:15]

Can you do this without adding more virtuals to Layer? I'm sorry to be picky,
but I feel like it's easy to dump things into the already overflowing base
class.

I'd really prefer a solution that encapsulated all of this inside of TiledLayer,
such as using some internal bool m_usingLCDText in TiledLayer (initialized to
true).  When updating a layer, you could check if canUseLCDText() is ever false
while m_usingLCDText is true, and then set it to false and invalidate.

[alokp, 2012/12/11 05:07:21]

I do not understand your solution but the reason I want to make the decision at
the ContentLayer level and not TiledLayer because other layer types (image,
video, etc) should not be invalidated because of a change in LCD text settings.
I will talk to you offline.

On 2012/12/11 02:47:15, enne wrote:

[alokp, 2012/12/12 17:42:24]

Done.

+    virtual void canUseLCDTextDidChange() { }
+
     // This flag is set when layer need repainting/updating.
     bool m_needsDisplay;
 
     // Tracks whether this layer may have changed stacking order with its siblings.
     bool m_stackingOrderChanged;
 
     // The update rect is the region of the compositor resource that was actually updated by the compositor.
     // For layers that may do updating outside the compositor's control (i.e. plugin layers), this information
     // is not available and the update rect will remain empty.
     // Note this rect is in layer space (not content space).
@@ skipping 50 matching lines @@
     skia::RefPtr<SkImageFilter> m_filter;
     WebKit::WebFilterOperations m_filters;
     WebKit::WebFilterOperations m_backgroundFilters;
     float m_anchorPointZ;
     bool m_isContainerForFixedPositionLayers;
     bool m_fixedToContainerLayer;
     bool m_isDrawable;
     bool m_masksToBounds;
     bool m_contentsOpaque;
     bool m_doubleSided;
-    bool m_useLCDText;
+    bool m_canUseLCDText;

[enne (OOO), 2012/12/11 02:47:15]

Can you move this to DrawProperties? I think it belongs there.

[alokp, 2012/12/11 05:07:21]

I considered doing that but I could think of a good way to invalidate layers
when this property changes. May be it will become clearer once I understand your
solution described above.

On 2012/12/11 02:47:15, enne wrote:

[alokp, 2012/12/12 17:42:24]

Done.

     bool m_preserves3D;
     bool m_useParentBackfaceVisibility;
     bool m_drawCheckerboardForMissingTiles;
     bool m_forceRenderSurface;
 
     gfx::Transform m_transform;
     gfx::Transform m_sublayerTransform;
 
     // Replica layer used for reflections.
     scoped_refptr<Layer> m_replicaLayer;
 
     // Transient properties.
     float m_rasterScale;
     bool m_automaticallyComputeRasterScale;
     bool m_boundsContainPageScale;
 
     gfx::Transform m_implTransform;
 
     WebKit::WebAnimationDelegate* m_layerAnimationDelegate;
     WebKit::WebLayerScrollClient* m_layerScrollClient;
 
     DrawProperties<Layer, RenderSurface> m_drawProperties;
 };
 
 void sortLayers(std::vector<scoped_refptr<Layer> >::iterator, std::vector<scoped_refptr<Layer> >::iterator, void*);
 
 }  // namespace cc
 
 #endif  // CC_LAYER_H_