Change filter quality when scaling-down in drawImage

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

 /*
  * Copyright (C) 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 44 matching lines @@
     canvas->saveLayer(nullptr, &layerPaint);
 
     SkPaint imagePaint(paint);
     imagePaint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
     int imageAlpha = clampedAlphaForBlending(1 - m_percentage);
     imagePaint.setAlpha(imageAlpha > 255 ? 255 : imageAlpha);
     imagePaint.setAntiAlias(paint.isAntiAlias());
     // TODO(junov): This code should probably be propagating the RespectImageOrientationEnum
     // form CrossfadeGeneratedImage::draw. Code was written this way during refactoring to
     // avoid modifying existing behavior, but this warrants further investigation. crbug.com/472634
-    m_fromImage->draw(canvas, imagePaint, destRect, fromImageRect, DoNotRespectImageOrientation, clampMode);
+    m_fromImage->draw(canvas, imagePaint, destRect, fromImageRect, true, DoNotRespectImageOrientation, clampMode);
     imagePaint.setXfermodeMode(SkXfermode::kPlus_Mode);
     imageAlpha = clampedAlphaForBlending(m_percentage);
     imagePaint.setAlpha(imageAlpha > 255 ? 255 : imageAlpha);
-    m_toImage->draw(canvas, imagePaint, destRect, toImageRect, DoNotRespectImageOrientation, clampMode);
+    m_toImage->draw(canvas, imagePaint, destRect, toImageRect, true, DoNotRespectImageOrientation, clampMode);
 }
 
-void CrossfadeGeneratedImage::draw(SkCanvas* canvas, const SkPaint& paint, const FloatRect& dstRect, const FloatRect& srcRect, RespectImageOrientationEnum, ImageClampingMode clampMode)
+void CrossfadeGeneratedImage::draw(SkCanvas* canvas, const SkPaint& paint, const FloatRect& dstRect, const FloatRect& srcRect, bool imageSmoothingEnabled, RespectImageOrientationEnum, ImageClampingMode clampMode)
 {
     // Draw nothing if either of the images hasn't loaded yet.
     if (m_fromImage == Image::nullImage() || m_toImage == Image::nullImage())
         return;
 
     SkAutoCanvasRestore ar(canvas, true);
     canvas->clipRect(dstRect);
     canvas->translate(dstRect.x(), dstRect.y());
     if (dstRect.size() != srcRect.size())
         canvas->scale(dstRect.width() / srcRect.width(), dstRect.height() / srcRect.height());
     canvas->translate(-srcRect.x(), -srcRect.y());
 
-    drawCrossfade(canvas, paint, clampMode);
+    SkPaint adjustedPaint = paint;
+    if (!imageSmoothingEnabled && Image::isDrawScalingDown(srcRect, dstRect))
+        adjustedPaint.setFilterQuality(kLow_SkFilterQuality);
+
+    drawCrossfade(canvas, adjustedPaint, clampMode);
 }
 
 void CrossfadeGeneratedImage::drawTile(GraphicsContext& context, const FloatRect& srcRect)
 {
     // Draw nothing if either of the images hasn't loaded yet.
     if (m_fromImage == Image::nullImage() || m_toImage == Image::nullImage())
         return;
 
     SkPaint paint = context.fillPaint();
     paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
     paint.setAntiAlias(context.shouldAntialias());
     FloatRect destRect((FloatPoint()), FloatSize(m_crossfadeSize));
     paint.setFilterQuality(context.computeFilterQuality(this, destRect, srcRect));
     drawCrossfade(context.canvas(), paint, ClampImageToSourceRect);
 }
 
 } // namespace blink