[poc] curve-filter

third_party/WebKit/Source/platform/graphics/ImagePattern.cpp

Index: third_party/WebKit/Source/platform/graphics/ImagePattern.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/ImagePattern.cpp b/third_party/WebKit/Source/platform/graphics/ImagePattern.cpp
index 1db843e4db952283a979b46c9f8a9d3936842774..089091a3fb3eac7a66372d34fa3797cbd92aaa26 100644
--- a/third_party/WebKit/Source/platform/graphics/ImagePattern.cpp
+++ b/third_party/WebKit/Source/platform/graphics/ImagePattern.cpp
@@ -4,9 +4,14 @@
 
 #include "platform/graphics/ImagePattern.h"
 
+#include "platform/graphics/BitmapImage.h"
+#include "platform/graphics/ColorSpaceFilter.h"
+#include "platform/graphics/ColorSpaceProfile.h"
+#include "platform/graphics/GraphicsScreen.h"
 #include "platform/graphics/Image.h"
 #include "platform/graphics/skia/SkiaUtils.h"
 #include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "third_party/skia/include/core/SkShader.h"
 #include "third_party/skia/include/core/SkSurface.h"
@@ -21,6 +26,7 @@ PassRefPtr<ImagePattern> ImagePattern::create(PassRefPtr<Image> image, RepeatMod
 ImagePattern::ImagePattern(PassRefPtr<Image> image, RepeatMode repeatMode)
     : Pattern(repeatMode)
     , m_tileImage(image->imageForCurrentFrame())
+    , m_image(image)
 {
     if (m_tileImage) {
         // TODO(fmalita): mechanism to extract the actual SkImageInfo from an SkImage?
@@ -30,14 +36,34 @@ ImagePattern::ImagePattern(PassRefPtr<Image> image, RepeatMode repeatMode)
     }
 }
 
+inline PassRefPtr<ColorSpaceProfile> sourceColorProfile(Image* image)
+{
+    return image->isBitmapImage() ? toBitmapImage(image)->colorProfile() : nullptr;
+}
+
 PassRefPtr<SkShader> ImagePattern::createShader()
 {
     if (!m_tileImage)
         return adoptRef(SkShader::CreateColorShader(SK_ColorTRANSPARENT));
 
+    // Patterns of tagged images (those that have a color profile) are drawn to sRGB
+    // on supported platforms. Note the only allowed caller is the <canvas> element.
+    RefPtr<SkColorFilter> colorTransform;
+    if (RefPtr<ColorSpaceProfile> source = sourceColorProfile(m_image.get())) {
+        RefPtr<ColorSpaceProfile> screen = screenColorProfile(currentScreenId());
+        colorTransform = createColorSpaceFilter(source.get(), screen.get());
+
+        if (currentScreenId()) {
+            fprintf(stderr, "ImagePattern::createShader has a non-zero page %ld\n", (long int)currentScreenId());
+            fflush(stderr);
+        }
+
+        RELEASE_ASSERT(!currentScreenId()); // Check caller is an HTML <canvas>.
+    }
+
     SkMatrix localMatrix = affineTransformToSkMatrix(m_patternSpaceTransformation);
 
-    if (isRepeatXY()) {
+    if (isRepeatXY() && !colorTransform.get()) {
         // Fast path: for repeatXY we just return a shader from the original image.
         return adoptRef(m_tileImage->newShader(SkShader::kRepeat_TileMode,
             SkShader::kRepeat_TileMode, &localMatrix));
@@ -58,18 +84,22 @@ PassRefPtr<SkShader> ImagePattern::createShader()
     // Create a transparent image 1 pixel wider and/or taller than the
     // original, then copy the orignal into it.
     // FIXME: Is there a better way to pad (not scale) an image in skia?
+    // since the drawing is noticably pixelated compared to drawing the
+    // same tiled image with Image:drawTiled (which is used to draw CSS
+    // background-image repeat tiles).
     RefPtr<SkSurface> surface = adoptRef(SkSurface::NewRasterN32Premul(
         m_tileImage->width() + expandW, m_tileImage->height() + expandH));
     if (!surface)
         return adoptRef(SkShader::CreateColorShader(SK_ColorTRANSPARENT));
-
     surface->getCanvas()->clear(SK_ColorTRANSPARENT);
+
     SkPaint paint;
+    paint.setColorFilter(colorTransform.get());
     paint.setXfermodeMode(SkXfermode::kSrc_Mode);
     surface->getCanvas()->drawImage(m_tileImage.get(), 0, 0, &paint);
-    RefPtr<SkImage> expandedImage = adoptRef(surface->newImageSnapshot());
 
-    return adoptRef(expandedImage->newShader(tileModeX, tileModeY, &localMatrix));
+    RefPtr<SkImage> image = adoptRef(surface->newImageSnapshot());
+    return adoptRef(image->newShader(tileModeX, tileModeY, &localMatrix));
 }
 
 bool ImagePattern::isTextureBacked() const