Implement InterpolationMedium to filter animated images

Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 285 matching lines @@
     if (!m_context->isAccelerated())
         return true;
 
     if (renderBox() && renderBox()->hasAcceleratedCompositing())
         return false;
 
     return true;
 }
 
 
-void HTMLCanvasElement::paint(GraphicsContext* context, const LayoutRect& r, bool useLowQualityScale)
+void HTMLCanvasElement::paint(GraphicsContext* context, const LayoutRect& r, InterpolationQuality interpolationQuality)

[Stephen White, 2014/03/18 17:26:43]

I believe this is only used when compositing the canvas into the page, not while
drawing elements into the canvas (and only in software rasterization, IIRC, not
for accelerated rendering).

I'm not sure if that changes what value we pass here.

[Alpha Left Google, 2014/03/18 22:59:13]

I don't think it matters functionally. If the argument stays a boolean then I
have to do an ugly convertion from bool -> InterpolationQuality in the
drawBlah() calls. Having the enum as parameter seems cleaner.

 {
     // Clear the dirty rect
     m_dirtyRect = FloatRect();
 
     if (context->paintingDisabled())
         return;
 
     if (m_context) {
         if (!paintsIntoCanvasBuffer() && !document().printing())
             return;
         m_context->paintRenderingResultsToCanvas();
     }
 
     if (hasImageBuffer()) {
         ImageBuffer* imageBuffer = buffer();
         if (imageBuffer) {
             CompositeOperator compositeOperator = !m_context || m_context->hasAlpha() ? CompositeSourceOver : CompositeCopy;
             if (m_presentedImage)
-                context->drawImage(m_presentedImage.get(), pixelSnappedIntRect(r), compositeOperator, DoNotRespectImageOrientation, useLowQualityScale);
+                context->drawImage(m_presentedImage.get(), pixelSnappedIntRect(r), compositeOperator, DoNotRespectImageOrientation, interpolationQuality);
             else
-                context->drawImageBuffer(imageBuffer, pixelSnappedIntRect(r), compositeOperator, blink::WebBlendModeNormal, useLowQualityScale);
+                context->drawImageBuffer(imageBuffer, pixelSnappedIntRect(r), compositeOperator, blink::WebBlendModeNormal, interpolationQuality);
         }
     }
 
     if (is3D())
         toWebGLRenderingContext(m_context.get())->markLayerComposited();
 }
 
 bool HTMLCanvasElement::is3D() const
 {
     return m_context && m_context->is3d();
@@ skipping 315 matching lines @@
 {
     return !originClean();
 }
 
 FloatSize HTMLCanvasElement::sourceSize() const
 {
     return FloatSize(width(), height());
 }
 
 }