2011-05-24 Ryuan Choi <ryuan.choi@samsung.com>

        Reviewed by Andreas Kling.

        [GTK] Implement GraphicsContextCairo::imageInterpolationQuality().
        https://bugs.webkit.org/show_bug.cgi?id=60827

        Implement getter/setter of imageInterpolationQuality and logic to change
        interpolation algorithm when drawing image.
        Mac and Qt already implemented it.

        * platform/graphics/cairo/GraphicsContextCairo.cpp:
        (WebCore::GraphicsContext::setImageInterpolationQuality):
        (WebCore::GraphicsContext::imageInterpolationQuality):
        * platform/graphics/cairo/GraphicsContextPlatformPrivateCairo.h:
        * platform/graphics/cairo/PlatformContextCairo.cpp:
        (WebCore::PlatformContextCairo::drawSurfaceToContext):
        * platform/graphics/cairo/PlatformContextCairo.h:
        (WebCore::PlatformContextCairo::setImageInterpolationQuality): Added.
        (WebCore::PlatformContextCairo::imageInterpolationQuality): Added.

Canonical link: https://commits.webkit.org/76731@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@87151 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/ChangeLog

@@ -1,3 +1,24 @@
+2011-05-24  Ryuan Choi  <ryuan.choi@samsung.com>
+
+        Reviewed by Andreas Kling.
+
+        [GTK] Implement GraphicsContextCairo::imageInterpolationQuality().
+        https://bugs.webkit.org/show_bug.cgi?id=60827
+
+        Implement getter/setter of imageInterpolationQuality and logic to change
+        interpolation algorithm when drawing image.
+        Mac and Qt already implemented it.
+
+        * platform/graphics/cairo/GraphicsContextCairo.cpp:
+        (WebCore::GraphicsContext::setImageInterpolationQuality):
+        (WebCore::GraphicsContext::imageInterpolationQuality):
+        * platform/graphics/cairo/GraphicsContextPlatformPrivateCairo.h:
+        * platform/graphics/cairo/PlatformContextCairo.cpp:
+        (WebCore::PlatformContextCairo::drawSurfaceToContext):
+        * platform/graphics/cairo/PlatformContextCairo.h:
+        (WebCore::PlatformContextCairo::setImageInterpolationQuality): Added.
+        (WebCore::PlatformContextCairo::imageInterpolationQuality): Added.
+
 2011-05-24  Leandro Gracia Gil  <leandrogracia@chromium.org>
 
         Reviewed by Tony Gentilcore.

Source/WebCore/platform/graphics/cairo/GraphicsContextCairo.cpp

@@ -1154,13 +1154,14 @@ void GraphicsContext::setPlatformShouldAntialias(bool enable)
     cairo_set_antialias(platformContext()->cr(), enable ? CAIRO_ANTIALIAS_DEFAULT : CAIRO_ANTIALIAS_NONE);
 }
 
-void GraphicsContext::setImageInterpolationQuality(InterpolationQuality)
+void GraphicsContext::setImageInterpolationQuality(InterpolationQuality quality)
 {
+    platformContext()->setImageInterpolationQuality(quality);
 }
 
 InterpolationQuality GraphicsContext::imageInterpolationQuality() const
 {
-    return InterpolationDefault;
+    return platformContext()->imageInterpolationQuality();
 }
 
 } // namespace WebCore

Source/WebCore/platform/graphics/cairo/GraphicsContextPlatformPrivateCairo.h

@@ -102,6 +102,7 @@ class GraphicsContextPlatformPrivate {
     Vector<float> layers;
     ContextShadow shadow;
     Vector<ContextShadow> shadowStack;
+    InterpolationQuality imageInterpolationQuality;
 
 #if PLATFORM(GTK)
     GdkEventExpose* expose;

Source/WebCore/platform/graphics/cairo/PlatformContextCairo.cpp

@@ -97,6 +97,20 @@ void PlatformContextCairo::drawSurfaceToContext(cairo_surface_t* surface, const
     // a pattern transformation on the image and draw the transformed pattern.
     // Test using example site at http://www.meyerweb.com/eric/css/edge/complexspiral/demo.html
     RefPtr<cairo_pattern_t> pattern = adoptRef(cairo_pattern_create_for_surface(surface));
+
+    switch (m_imageInterpolationQuality) {
+    case InterpolationNone:
+    case InterpolationLow:
+        cairo_pattern_set_filter(pattern.get(), CAIRO_FILTER_FAST);
+        break;
+    case InterpolationMedium:
+    case InterpolationHigh:
+        cairo_pattern_set_filter(pattern.get(), CAIRO_FILTER_BILINEAR);
+        break;
+    case InterpolationDefault:
+        cairo_pattern_set_filter(pattern.get(), CAIRO_FILTER_BILINEAR);
+        break;
+    }
     cairo_pattern_set_extend(pattern.get(), CAIRO_EXTEND_PAD);
 
     float scaleX = srcRect.width() / destRect.width();

Source/WebCore/platform/graphics/cairo/PlatformContextCairo.h

@@ -27,6 +27,7 @@
 #define PlatformContextCairo_h
 
 #include "ContextShadow.h"
+#include "GraphicsContext.h"
 #include "RefPtrCairo.h"
 
 namespace WebCore {
@@ -68,9 +69,13 @@ class PlatformContextCairo {
     void pushImageMask(cairo_surface_t*, const FloatRect&);
     void drawSurfaceToContext(cairo_surface_t*, const FloatRect& destRect, const FloatRect& srcRect, GraphicsContext*);
 
+    void setImageInterpolationQuality(InterpolationQuality quality) { m_imageInterpolationQuality = quality; }
+    InterpolationQuality imageInterpolationQuality() const { return m_imageInterpolationQuality; }
+
 private:
     RefPtr<cairo_t> m_cr;
     Vector<ImageMaskInformation> m_maskImageStack;
+    InterpolationQuality m_imageInterpolationQuality;
 };
 
 } // namespace WebCore