This CL implements the first draft of Canvas 2D Context Attributes, aka getContext('2d', { alpha: f…

Source/core/html/canvas/CanvasRenderingContext2D.h

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 #ifndef CanvasRenderingContext2D_h
 #define CanvasRenderingContext2D_h
 
+#include "core/html/canvas/Canvas2DContextAttributes.h"
 #include "core/html/canvas/CanvasPathMethods.h"
 #include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/platform/graphics/Color.h"
 #include "core/platform/graphics/ColorSpace.h"
 #include "core/platform/graphics/DashArray.h"
 #include "core/platform/graphics/FloatSize.h"
 #include "core/platform/graphics/Font.h"
 #include "core/platform/graphics/GraphicsTypes.h"
 #include "core/platform/graphics/ImageBuffer.h"
 #include "core/platform/graphics/Path.h"
@@ skipping 14 matching lines @@
 class HTMLCanvasElement;
 class HTMLImageElement;
 class HTMLVideoElement;
 class ImageData;
 class TextMetrics;
 
 typedef int ExceptionCode;
 
 class CanvasRenderingContext2D : public CanvasRenderingContext, public CanvasPathMethods {
 public:
-    static PassOwnPtr<CanvasRenderingContext2D> create(HTMLCanvasElement* canvas, bool usesCSSCompatibilityParseMode)
+    static PassOwnPtr<CanvasRenderingContext2D> create(HTMLCanvasElement* canvas, const Canvas2DContextAttributes* attrs, bool usesCSSCompatibilityParseMode)
     {
-        return adoptPtr(new CanvasRenderingContext2D(canvas, usesCSSCompatibilityParseMode));
+        return adoptPtr(new CanvasRenderingContext2D(canvas, attrs, usesCSSCompatibilityParseMode));
     }
     virtual ~CanvasRenderingContext2D();
 
     CanvasStyle* strokeStyle() const;
     void setStrokeStyle(PassRefPtr<CanvasStyle>);
 
     CanvasStyle* fillStyle() const;
     void setFillStyle(PassRefPtr<CanvasStyle>);
 
     float lineWidth() const;
@@ skipping 137 matching lines @@
     void strokeText(const String& text, float x, float y);
     void strokeText(const String& text, float x, float y, float maxWidth);
     PassRefPtr<TextMetrics> measureText(const String& text);
 
     LineCap getLineCap() const { return state().m_lineCap; }
     LineJoin getLineJoin() const { return state().m_lineJoin; }
 
     bool webkitImageSmoothingEnabled() const;
     void setWebkitImageSmoothingEnabled(bool);
 
+    PassRefPtr<Canvas2DContextAttributes> getContextAttributes() const;
+
 private:
     struct State : FontSelectorClient {
         State();
         virtual ~State();
 
         State(const State&);
         State& operator=(const State&);
 
         virtual void fontsNeedUpdate(FontSelector*) OVERRIDE;
 
@@ skipping 27 matching lines @@
     };
 
     enum CanvasDidDrawOption {
         CanvasDidDrawApplyNone = 0,
         CanvasDidDrawApplyTransform = 1,
         CanvasDidDrawApplyShadow = 1 << 1,
         CanvasDidDrawApplyClip = 1 << 2,
         CanvasDidDrawApplyAll = 0xffffffff
     };
 
-    CanvasRenderingContext2D(HTMLCanvasElement*, bool usesCSSCompatibilityParseMode);
+    CanvasRenderingContext2D(HTMLCanvasElement*, const Canvas2DContextAttributes* attrs, bool usesCSSCompatibilityParseMode);
 
     State& modifiableState() { ASSERT(!m_unrealizedSaveCount); return m_stateStack.last(); }
     const State& state() const { return m_stateStack.last(); }
 
     void applyLineDash() const;
     void setShadow(const FloatSize& offset, float blur, RGBA32 color);
     void applyShadow();
     bool shouldDrawShadows() const;
 
     void didDraw(const FloatRect&, unsigned options = CanvasDidDrawApplyAll);
@@ skipping 28 matching lines @@
     void inflateStrokeRect(FloatRect&) const;
 
     template<class T> void fullCanvasCompositedFill(const T&);
     template<class T> void fullCanvasCompositedDrawImage(T*, ColorSpace, const FloatRect&, const FloatRect&, CompositeOperator);
 
     PassRefPtr<ImageData> getImageData(ImageBuffer::CoordinateSystem, float sx, float sy, float sw, float sh, ExceptionCode&) const;
     void putImageData(ImageData*, ImageBuffer::CoordinateSystem, float dx, float dy, float dirtyX, float dirtyY, float dirtyWidth, float dirtyHeight, ExceptionCode&);
 
     virtual bool is2d() const OVERRIDE { return true; }
     virtual bool isAccelerated() const OVERRIDE;
+    virtual bool hasAlpha() const OVERRIDE { return m_hasAlpha; }
 
     virtual bool isTransformInvertible() const { return state().m_invertibleCTM; }
 
     virtual PlatformLayer* platformLayer() const OVERRIDE;
 
     Vector<State, 1> m_stateStack;
     unsigned m_unrealizedSaveCount;
     bool m_usesCSSCompatibilityParseMode;
+    bool m_hasAlpha;
 };
 
 } // namespace WebCore
 
 #endif