[wip] image color correction

Source/platform/graphics/skia/NativeImageSkia.cpp

 /*
  * Copyright (c) 2008, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 18 matching lines @@
  */
 
 #include "config.h"
 #include "platform/graphics/skia/NativeImageSkia.h"
 
 #include "platform/PlatformInstrumentation.h"
 #include "platform/TraceEvent.h"
 #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"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "third_party/skia/include/core/SkScalar.h"
 #include "third_party/skia/include/core/SkShader.h"
 
 #include <algorithm>
 #include <math.h>
 #include <limits>
@@ skipping 288 matching lines @@
     // discouraged. Always drawing with AA can negatively impact performance
     // though - that's why it's not always on.
     SkScalar widthExpansion, heightExpansion;
     if (totalMatrix.getType() & SkMatrix::kAffine_Mask)
         widthExpansion = totalMatrix[SkMatrix::kMSkewY], heightExpansion = totalMatrix[SkMatrix::kMSkewX];
     else
         widthExpansion = totalMatrix[SkMatrix::kMScaleX], heightExpansion = totalMatrix[SkMatrix::kMScaleY];
     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));
 
     bool isLazyDecoded = DeferredImageDecoder::isLazyDecoded(bitmap());
 
     InterpolationQuality resampling;
     if (context->isAccelerated()) {
         resampling = InterpolationLow;
     } else if (context->printing()) {
@@ skipping 51 matching lines @@
     info.fAlphaType = kPremul_SkAlphaType;
 
     SkBitmap result;
     result.allocPixels(info);
     result.eraseColor(SK_ColorTRANSPARENT);
     bitmap.copyPixelsTo(reinterpret_cast<uint8_t*>(result.getPixels()), result.rowBytes() * result.height(), result.rowBytes());
 
     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
 
     SkMatrix totalMatrix = context->getTotalMatrix();
     AffineTransform ctm = context->getCTM();
     SkScalar ctmScaleX = ctm.xScale();
     SkScalar ctmScaleY = ctm.yScale();
     totalMatrix.preScale(scale.width(), scale.height());
 
@@ skipping 72 matching lines @@
         } else {
             shader = adoptRef(SkShader::CreateBitmapShader(
                 createBitmapWithSpace(srcSubset, repeatSpacing.width() * ctmScaleX, repeatSpacing.height() * ctmScaleY),
                 SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode, &localMatrix));
         }
     }
 
     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)
         PlatformInstrumentation::didDrawLazyPixelRef(bitmap().getGenerationID());
 
     context->drawRect(destRect, paint);
 }
 
 bool NativeImageSkia::shouldCacheResampling(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const
 {
@@ skipping 61 matching lines @@
 SkIRect NativeImageSkia::ImageResourceInfo::rectInSubset(const SkIRect& otherScaledImageSubset)
 {
     if (!scaledImageSubset.contains(otherScaledImageSubset))
         return SkIRect::MakeEmpty();
     SkIRect subsetRect = otherScaledImageSubset;
     subsetRect.offset(-scaledImageSubset.x(), -scaledImageSubset.y());
     return subsetRect;
 }
 
 } // namespace WebCore