[wip] image color correction

Source/platform/graphics/skia/NativeImageSkia.cpp

Index: Source/platform/graphics/skia/NativeImageSkia.cpp
diff --git a/Source/platform/graphics/skia/NativeImageSkia.cpp b/Source/platform/graphics/skia/NativeImageSkia.cpp
index f0db318605e4ca49e68ed556d327cfceab3492e5..df9ab4abcca6d88468a4e465110ec2e513fef3a8 100644
--- a/Source/platform/graphics/skia/NativeImageSkia.cpp
+++ b/Source/platform/graphics/skia/NativeImageSkia.cpp
@@ -36,9 +36,9 @@
 #include "platform/geometry/FloatPoint.h"
 #include "platform/geometry/FloatRect.h"
 #include "platform/geometry/FloatSize.h"
+#include "platform/graphics/DeferredImageDecoder.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/Image.h"
-#include "platform/graphics/DeferredImageDecoder.h"
 #include "platform/graphics/skia/SkiaUtils.h"
 #include "skia/ext/image_operations.h"
 #include "third_party/skia/include/core/SkMatrix.h"
@@ -347,12 +347,19 @@ static bool shouldDrawAntiAliased(GraphicsContext* context, const SkRect& destRe
     return destRect.width() * fabs(widthExpansion) < 1 || destRect.height() * fabs(heightExpansion) < 1;
 }
 
-void NativeImageSkia::draw(GraphicsContext* context, const SkRect& srcRect, const SkRect& destRect, PassRefPtr<SkXfermode> compOp) const
+void NativeImageSkia::draw(GraphicsContext* context, const SkRect& srcRect, const SkRect& destRect, PassRefPtr<SkXfermode> compOp, PassRefPtr<SkColorFilter> colorTransform) const
 {
     TRACE_EVENT0("skia", "NativeImageSkia::draw");
     SkPaint paint;
     paint.setXfermode(compOp.get());
-    paint.setColorFilter(context->colorFilter());
+    // FIXME: GraphicsContext only supports one filter, and here we ignore it and use the
+    // colorTransform argument instead (paint-time color correction).
+    // -- GraphicsContext needs a new api, setColorSpaceFilter.
+    // -- SkPaint needs a new api, paint.setColorSpaceFilter, to allow CSS or SVG
+    //    software filters to co-exist with the color space filter.

[Stephen White, 2014/07/03 18:38:17]

Actually I don't think CSS or SVG filters ever hit this particular path directly
-- they draw all images and text to a separate buffer and then apply filters to
that. So there should be no conflict with those.

For the existing color filters here, you should probably chat with fmalita@
about how to make them work. It could be done by turning them both into image
filters via SkColorFilterImageFilter adapters, and then concatenating them. That
would incur an extra pass, though, so you might want to only do that if both
filters are present.

+    // -- Skia can control the application of the filters, and in what order, which
+    //    is likely to be colorSpaceFilter first then colorFilter, during paint.
+    paint.setColorFilter(colorTransform.get() ? colorTransform.get() : context->colorFilter());
     paint.setAlpha(context->getNormalizedAlpha());
     paint.setLooper(context->drawLooper());
     paint.setAntiAlias(shouldDrawAntiAliased(context, destRect));
@@ -424,17 +431,10 @@ static SkBitmap createBitmapWithSpace(const SkBitmap& bitmap, int spaceWidth, in
     return result;
 }
 
-void NativeImageSkia::drawPattern(
-    GraphicsContext* context,
-    const FloatRect& floatSrcRect,
-    const FloatSize& scale,
-    const FloatPoint& phase,
-    CompositeOperator compositeOp,
-    const FloatRect& destRect,
-    blink::WebBlendMode blendMode,
-    const IntSize& repeatSpacing) const
+void NativeImageSkia::drawPattern(GraphicsContext* context, const FloatRect& srcRect, const FloatSize& scale,
+    const FloatPoint& phase, CompositeOperator compositeOp, const FloatRect& destRect, blink::WebBlendMode blendMode, const IntSize& repeatSpacing, PassRefPtr<SkColorFilter> colorTransform) const
 {
-    FloatRect normSrcRect = floatSrcRect;
+    FloatRect normSrcRect = srcRect;
     normSrcRect.intersect(FloatRect(0, 0, bitmap().width(), bitmap().height()));
     if (destRect.isEmpty() || normSrcRect.isEmpty())
         return; // nothing to draw
@@ -527,7 +527,9 @@ void NativeImageSkia::drawPattern(
     SkPaint paint;
     paint.setShader(shader.get());
     paint.setXfermode(WebCoreCompositeToSkiaComposite(compositeOp, blendMode).get());
-    paint.setColorFilter(context->colorFilter());
+    // FIXME: GraphicsContext only supports one filter, and here we ignore it and use the
+    // colorTransform argument instead (paint-time color correction).
+    paint.setColorFilter(colorTransform.get() ? colorTransform.get() : context->colorFilter());
     paint.setFilterLevel(convertToSkiaFilterLevel(useBicubicFilter, resampling));
 
     if (isLazyDecoded)