Removing the dependency on GraphicsContext for drawing images in 2D canvas

Source/platform/graphics/GraphicsContext.cpp

Index: Source/platform/graphics/GraphicsContext.cpp
diff --git a/Source/platform/graphics/GraphicsContext.cpp b/Source/platform/graphics/GraphicsContext.cpp
index 927f44dcd19cacd9bfdc402a17104ee63c637592..8ec315286ba9781e0212b7efa82b432615ca44cc 100644
--- a/Source/platform/graphics/GraphicsContext.cpp
+++ b/Source/platform/graphics/GraphicsContext.cpp
@@ -42,7 +42,6 @@
 #include "third_party/skia/include/core/SkRRect.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 #include "third_party/skia/include/effects/SkCornerPathEffect.h"
-#include "third_party/skia/include/effects/SkDropShadowImageFilter.h"
 #include "third_party/skia/include/effects/SkLumaColorFilter.h"
 #include "third_party/skia/include/effects/SkPictureImageFilter.h"
 #include "third_party/skia/include/utils/SkNullCanvas.h"
@@ -309,7 +308,7 @@ void GraphicsContext::setShadow(const FloatSize& offset, float blur, const Color
             setDrawLooper(drawLooperBuilder.release());
             return;
         }
-        clearShadow();
+        clearDrawLooper();
         return;
     }
 
@@ -318,18 +317,6 @@ void GraphicsContext::setShadow(const FloatSize& offset, float blur, const Color
         drawLooperBuilder->addUnmodifiedContent();
     }
     setDrawLooper(drawLooperBuilder.release());
-
-    if (shadowTransformMode == DrawLooperBuilder::ShadowIgnoresTransforms
-        && shadowAlphaMode == DrawLooperBuilder::ShadowRespectsAlpha) {
-        // This image filter will be used in place of the drawLooper created above but only for drawing non-opaque bitmaps;
-        // see preparePaintForDrawRectToRect().
-        SkColor skColor = color.rgb();
-        // These constants are from RadiusToSigma() from DrawLooperBuilder.cpp.
-        const SkScalar sigma = 0.288675f * blur + 0.5f;
-        SkDropShadowImageFilter::ShadowMode dropShadowMode = shadowMode == DrawShadowAndForeground ? SkDropShadowImageFilter::kDrawShadowAndForeground_ShadowMode : SkDropShadowImageFilter::kDrawShadowOnly_ShadowMode;
-        RefPtr<SkImageFilter> filter = adoptRef(SkDropShadowImageFilter::Create(offset.width(), offset.height(), sigma, sigma, skColor, dropShadowMode));
-        setDropShadowImageFilter(filter);
-    }
 }
 
 void GraphicsContext::setDrawLooper(PassOwnPtr<DrawLooperBuilder> drawLooperBuilder)
@@ -348,22 +335,6 @@ void GraphicsContext::clearDrawLooper()
     mutableState()->clearDrawLooper();
 }
 
-void GraphicsContext::setDropShadowImageFilter(PassRefPtr<SkImageFilter> imageFilter)
-{
-    if (contextDisabled())
-        return;
-
-    mutableState()->setDropShadowImageFilter(imageFilter);
-}
-
-void GraphicsContext::clearDropShadowImageFilter()
-{
-    if (contextDisabled())
-        return;
-
-    mutableState()->clearDropShadowImageFilter();
-}
-
 SkMatrix GraphicsContext::getTotalMatrix() const
 {
     // FIXME: this is a hack to avoid changing all call sites of getTotalMatrix() to not use this method.
@@ -450,7 +421,7 @@ void GraphicsContext::beginLayer(float opacity, SkXfermode::Mode xfermode, const
         SkRect skBounds = WebCoreFloatRectToSKRect(*bounds);
         saveLayer(&skBounds, &layerPaint);
     } else {
-        saveLayer(0, &layerPaint);
+        saveLayer(nullptr, &layerPaint);
     }
 
 #if ENABLE(ASSERT)
@@ -1032,7 +1003,41 @@ void GraphicsContext::drawImage(Image* image, const FloatRect& dest, const Float
 {
     if (contextDisabled() || !image)
         return;
-    image->draw(this, dest, src, op, shouldRespectImageOrientation);
+
+    SkPaint imagePaint = immutableState()->fillPaint();
+    imagePaint.setXfermodeMode(op);
+    imagePaint.setFilterQuality(getFilterQuality(image, dest, src));
+
+    image->draw(m_canvas, imagePaint, dest, src, shouldRespectImageOrientation);
+}
+
+SkFilterQuality GraphicsContext::getFilterQuality(Image* image, const FloatRect& dest, const FloatRect& src) const
+{
+    InterpolationQuality resampling;
+    if (printing()) {
+        resampling = InterpolationNone;
+    } else if (image->isLazyDecodedBitmap()) {
+        resampling = InterpolationHigh;
+    } else {
+        // Take into account scale applied to the canvas when computing sampling mode (e.g. CSS scale or page scale).

[f(malita), 2015/04/17 16:18:32]

Not new to this CL, but let's add a comment here: in SP we create GCs on the fly
when entering a new DisplayItemList scope, so relying on getTotalMatrix here is
not sound.

+        SkRect destRectTarget = dest;
+        SkMatrix totalMatrix = getTotalMatrix();
+        if (!(totalMatrix.getType() & (SkMatrix::kAffine_Mask | SkMatrix::kPerspective_Mask)))
+            totalMatrix.mapRect(&destRectTarget, dest);
+
+        resampling = computeInterpolationQuality(totalMatrix,
+            SkScalarToFloat(src.width()), SkScalarToFloat(src.height()),
+            SkScalarToFloat(destRectTarget.width()), SkScalarToFloat(destRectTarget.height()),
+            image->isImmutableBitmap());
+    }
+
+    if (resampling == InterpolationNone) {
+        // FIXME: This is to not break tests (it results in the filter bitmap flag
+        // being set to true). We need to decide if we respect InterpolationNone
+        // being returned from computeInterpolationQuality.
+        resampling = InterpolationLow;
+    }
+    return static_cast<SkFilterQuality>(limitInterpolationQuality(this, resampling));
 }
 
 void GraphicsContext::drawTiledImage(Image* image, const IntRect& destRect, const IntPoint& srcPoint, const IntSize& tileSize, SkXfermode::Mode op, const IntSize& repeatSpacing)
@@ -1075,23 +1080,6 @@ void GraphicsContext::writePixels(const SkImageInfo& info, const void* pixels, s
     m_canvas->writePixels(info, pixels, rowBytes, x, y);
 }
 
-void GraphicsContext::drawBitmapRect(const SkBitmap& bitmap, const SkRect* src,
-    const SkRect& dst, const SkPaint* paint)
-{
-    // Textures are bound to the blink main-thread GrContext, which can not be
-    // used on the compositor raster thread.
-    // FIXME: Mailbox support would make this possible in the GPU-raster case.
-    ASSERT(!isRecording() || !bitmap.getTexture());
-    if (contextDisabled())
-        return;
-
-    SkCanvas::DrawBitmapRectFlags flags =
-        immutableState()->shouldClampToSourceRect() ? SkCanvas::kNone_DrawBitmapRectFlag : SkCanvas::kBleed_DrawBitmapRectFlag;
-
-    ASSERT(m_canvas);
-    m_canvas->drawBitmapRectToRect(bitmap, src, dst, paint, flags);
-}
-
 void GraphicsContext::drawOval(const SkRect& oval, const SkPaint& paint)
 {
     if (contextDisabled())
@@ -1630,81 +1618,4 @@ SkPMColor GraphicsContext::antiColors2(int index)
 }
 #endif
 
-int GraphicsContext::preparePaintForDrawRectToRect(
-    SkPaint* paint,
-    const SkRect& srcRect,
-    const SkRect& destRect,
-    SkXfermode::Mode compositeOp,
-    bool isBitmapWithAlpha,
-    bool isLazyDecoded,
-    bool isDataComplete) const
-{
-    int initialSaveCount = m_canvas->getSaveCount();
-
-    paint->setColorFilter(this->colorFilter());
-    paint->setAlpha(this->getNormalizedAlpha());
-    bool usingImageFilter = false;
-    if (dropShadowImageFilter() && isBitmapWithAlpha) {
-        SkMatrix ctm = getTotalMatrix();
-        SkMatrix invCtm;
-        if (ctm.invert(&invCtm)) {
-            usingImageFilter = true;
-            // The image filter is meant to ignore tranforms with respect to
-            // the shadow parameters. The matrix tweaks below ensures that the image
-            // filter is applied in post-transform space. We use concat() instead of
-            // setMatrix() in case this goes into a recording canvas which may need to
-            // respect a parent transform at playback time.
-            m_canvas->save();
-            m_canvas->concat(invCtm);
-            SkRect bounds = destRect;
-            ctm.mapRect(&bounds);
-            SkRect filteredBounds;
-            dropShadowImageFilter()->computeFastBounds(bounds, &filteredBounds);
-            SkPaint layerPaint;
-            layerPaint.setXfermodeMode(compositeOp);
-            layerPaint.setImageFilter(dropShadowImageFilter());
-            m_canvas->saveLayer(&filteredBounds, &layerPaint);
-            m_canvas->concat(ctm);
-        }
-    }
-
-    if (!usingImageFilter) {
-        paint->setXfermodeMode(compositeOp);
-        paint->setLooper(this->drawLooper());
-    }
-
-    paint->setAntiAlias(shouldDrawAntiAliased(this, destRect));
-
-    InterpolationQuality resampling;
-    if (this->isAccelerated()) {
-        resampling = InterpolationLow;
-    } else if (this->printing()) {
-        resampling = InterpolationNone;
-    } else if (isLazyDecoded) {
-        resampling = InterpolationHigh;
-    } else {
-        // Take into account scale applied to the canvas when computing sampling mode (e.g. CSS scale or page scale).
-        SkRect destRectTarget = destRect;
-        SkMatrix totalMatrix = this->getTotalMatrix();
-        if (!(totalMatrix.getType() & (SkMatrix::kAffine_Mask | SkMatrix::kPerspective_Mask)))
-            totalMatrix.mapRect(&destRectTarget, destRect);
-
-        resampling = computeInterpolationQuality(totalMatrix,
-            SkScalarToFloat(srcRect.width()), SkScalarToFloat(srcRect.height()),
-            SkScalarToFloat(destRectTarget.width()), SkScalarToFloat(destRectTarget.height()),
-            isDataComplete);
-    }
-
-    if (resampling == InterpolationNone) {
-        // FIXME: This is to not break tests (it results in the filter bitmap flag
-        // being set to true). We need to decide if we respect InterpolationNone
-        // being returned from computeInterpolationQuality.
-        resampling = InterpolationLow;
-    }
-    resampling = limitInterpolationQuality(this, resampling);
-    paint->setFilterQuality(static_cast<SkFilterQuality>(resampling));
-
-    return initialSaveCount;
-}
-
 } // namespace blink