2D canvas: pass unmodified primitive bounds to saveLayer().

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
@@ skipping 813 matching lines @@
     // CompositeSourceAtop and CompositeDestinationOut are not listed here as the platforms already
     // implement the specification's behavior.
     return op == SkXfermode::kSrcIn_Mode || op == SkXfermode::kSrcOut_Mode || op == SkXfermode::kDstIn_Mode || op == SkXfermode::kDstATop_Mode;
 }
 
 template<typename DrawFunc>
 void CanvasRenderingContext2D::compositedDraw(const DrawFunc& drawFunc, SkCanvas* c, CanvasRenderingContext2DState::PaintType paintType, CanvasRenderingContext2DState::ImageType imageType)
 {
     SkImageFilter* filter = state().getFilter(canvas(), accessFont());
     ASSERT(isFullCanvasCompositeMode(state().globalComposite()) || filter);
     SkMatrix ctm = c->getTotalMatrix();

[Justin Novosad, 2016/01/08 19:14:05]

Could you apply the same magic here as well?  Never mind conficts with my other
CL. I would like to re-write a fix on top of this awesomeness.

     c->resetMatrix();
     SkPaint compositePaint;
     compositePaint.setXfermodeMode(state().globalComposite());
     if (state().shouldDrawShadows()) {
         // unroll into two independently composited passes if drawing shadows
         SkPaint shadowPaint = *state().getPaint(paintType, DrawShadowOnly, imageType);
         int saveCount = c->getSaveCount();
         if (filter) {
             SkPaint filterPaint;
             filterPaint.setImageFilter(filter);
@@ skipping 456 matching lines @@
         widthExpansion = ctm[SkMatrix::kMScaleX], heightExpansion = ctm[SkMatrix::kMScaleY];
     return destRect.width() * fabs(widthExpansion) < 1 || destRect.height() * fabs(heightExpansion) < 1;
 }
 
 void CanvasRenderingContext2D::drawImageInternal(SkCanvas* c, CanvasImageSource* imageSource, Image* image, const FloatRect& srcRect, const FloatRect& dstRect, const SkPaint* paint)
 {
     int initialSaveCount = c->getSaveCount();
     SkPaint imagePaint = *paint;
 
     if (paint->getImageFilter()) {
-        SkMatrix ctm = c->getTotalMatrix();
         SkMatrix invCtm;
-        if (!ctm.invert(&invCtm)) {
+        if (!c->getTotalMatrix().invert(&invCtm)) {
             // There is an earlier check for invertibility, but the arithmetic
             // in AffineTransform is not exactly identical, so it is possible
             // for SkMatrix to find the transform to be non-invertible at this stage.
             // crbug.com/504687
             return;
         }
-        c->save();
-        c->concat(invCtm);
         SkRect bounds = dstRect;
-        ctm.mapRect(&bounds);
-        SkRect filteredBounds;
-        paint->getImageFilter()->computeFastBounds(bounds, &filteredBounds);
         SkPaint layerPaint;
         layerPaint.setXfermode(paint->getXfermode());
-        layerPaint.setImageFilter(paint->getImageFilter());
-        c->saveLayer(&filteredBounds, &layerPaint);
-        c->concat(ctm);
+        SkAutoTUnref<SkImageFilter> localFilter(paint->getImageFilter()->newWithLocalMatrix(invCtm));
+        layerPaint.setImageFilter(localFilter);
+        c->saveLayer(&bounds, &layerPaint);
         imagePaint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
         imagePaint.setImageFilter(nullptr);
     }
 
     if (!imageSource->isVideoElement()) {
         imagePaint.setAntiAlias(shouldDrawImageAntialiased(dstRect));
         image->draw(c, imagePaint, dstRect, srcRect, DoNotRespectImageOrientation, Image::DoNotClampImageToSourceRect);
     } else {
         c->save();
         c->clipRect(dstRect);
@@ skipping 994 matching lines @@
         if (imageType == CanvasRenderingContext2DState::NonOpaqueImage)
             return;
         if (alpha < 0xFF)
             return;
     }
 
     canvas()->buffer()->willOverwriteCanvas();
 }
 
 } // namespace blink