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

Source/core/svg/graphics/SVGImage.cpp

 /*
  * Copyright (C) 2006 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. 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.
@@ skipping 176 matching lines @@
     if (intrinsicSize.isEmpty())
         intrinsicSize = rootElement->currentViewBoxRect().size();
 
     if (!intrinsicSize.isEmpty())
         return expandedIntSize(intrinsicSize);
 
     // As last resort, use CSS replaced element fallback size.
     return IntSize(300, 150);
 }
 
-void SVGImage::drawForContainer(GraphicsContext* context, const FloatSize containerSize, float zoom, const FloatRect& dstRect,
-    const FloatRect& srcRect, SkXfermode::Mode compositeOp)
+void SVGImage::drawForContainer(SkCanvas* canvas, const SkPaint& paint, const FloatSize containerSize, float zoom, const FloatRect& dstRect,
+    const FloatRect& srcRect)
 {
     if (!m_page)
         return;
 
     // Temporarily disable the image observer to prevent changeInRect() calls due re-laying out the image.
     ImageObserverDisabler imageObserverDisabler(this);
 
     IntSize roundedContainerSize = roundedIntSize(containerSize);
     setContainerSize(roundedContainerSize);
 
     FloatRect scaledSrc = srcRect;
     scaledSrc.scale(1 / zoom);
 
     // Compensate for the container size rounding by adjusting the source rect.
     FloatSize adjustedSrcSize = scaledSrc.size();
     adjustedSrcSize.scale(roundedContainerSize.width() / containerSize.width(), roundedContainerSize.height() / containerSize.height());
     scaledSrc.setSize(adjustedSrcSize);
 
-    draw(context, dstRect, scaledSrc, compositeOp, DoNotRespectImageOrientation);
+    bool shouldClampToSourceRect = true;
+    draw(canvas, paint, dstRect, scaledSrc, DoNotRespectImageOrientation, shouldClampToSourceRect);
 }
 
 bool SVGImage::bitmapForCurrentFrame(SkBitmap* bitmap)
 {
     if (!m_page)
         return false;
 
     OwnPtr<ImageBuffer> buffer = ImageBuffer::create(size());
     if (!buffer)
         return false;
 
-    drawForContainer(buffer->context(), size(), 1, rect(), rect(), SkXfermode::kSrcOver_Mode);
+    SkPaint paint;
+    drawForContainer(buffer->canvas(), paint, size(), 1, rect(), rect());
 
     *bitmap = buffer->bitmap();
     return true;
 }
 
 void SVGImage::drawPatternForContainer(GraphicsContext* context, const FloatSize containerSize,
     float zoom, const FloatRect& srcRect, const FloatSize& tileScale, const FloatPoint& phase,
     SkXfermode::Mode compositeOp, const FloatRect& dstRect,
     const IntSize& repeatSpacing)
 {
     // Tile adjusted for scaling/stretch.
     FloatRect tile(srcRect);
     tile.scale(tileScale.width(), tileScale.height());
 
     // Expand the tile to account for repeat spacing.
     FloatRect spacedTile(tile);
     spacedTile.expand(repeatSpacing);
 
     SkPictureBuilder patternPicture(spacedTile);
     {
         DrawingRecorder patternPictureRecorder(patternPicture.context(), *this, DisplayItem::Type::SVGImage, spacedTile);
         if (!patternPictureRecorder.canUseCachedDrawing()) {
             // When generating an expanded tile, make sure we don't draw into the spacing area.
             if (tile != spacedTile)
                 patternPicture.context().clip(tile);
-            drawForContainer(&patternPicture.context(), containerSize, zoom, tile, srcRect, SkXfermode::kSrcOver_Mode);
+            SkPaint paint;
+            drawForContainer(patternPicture.context().canvas(), paint, containerSize, zoom, tile, srcRect);
         }
     }
     RefPtr<const SkPicture> tilePicture = patternPicture.endRecording();
 
     SkMatrix patternTransform;
     patternTransform.setTranslate(phase.x() + spacedTile.x(), phase.y() + spacedTile.y());
     RefPtr<SkShader> patternShader = adoptRef(SkShader::CreatePictureShader(
         tilePicture.get(), SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode,
         &patternTransform, nullptr));
 
     SkPaint paint;
     paint.setShader(patternShader.get());
     paint.setXfermodeMode(compositeOp);
     paint.setColorFilter(context->colorFilter());
     context->drawRect(dstRect, paint);
 }
 
-void SVGImage::draw(GraphicsContext* context, const FloatRect& dstRect, const FloatRect& srcRect, SkXfermode::Mode compositeOp, RespectImageOrientationEnum)
+static bool drawNeedsLayer(const SkPaint& paint)
+{
+    if (SkColorGetA(paint.getColor()) < 255)
+        return true;
+
+    SkXfermode::Mode xfermode;
+    if (SkXfermode::AsMode(paint.getXfermode(), &xfermode)) {
+        if (xfermode != SkXfermode::kSrcOver_Mode)
+            return true;
+    }
+
+    return false;
+}
+
+void SVGImage::draw(SkCanvas* canvas, const SkPaint& paint, const FloatRect& dstRect, const FloatRect& srcRect, RespectImageOrientationEnum, bool /*shouldClampToSourceRect*/)
 {
     if (!m_page)
         return;
 
-    float opacity = context->getNormalizedAlpha() / 255.f;
-
     FrameView* view = frameView();
     view->resize(containerSize());
 
     // Always call scrollToFragment, even if the url is empty, because
     // there may have been a previous url/fragment that needs to be reset.
     view->scrollToFragment(m_url);
 
+    SkPictureBuilder imagePicture(dstRect);
     {
-        DisplayItemListContextRecorder contextRecorder(*context);
-        GraphicsContext& paintContext = contextRecorder.context();
-
-        ClipRecorder clipRecorder(paintContext, *this, DisplayItem::ClipNodeImage, LayoutRect(enclosingIntRect(dstRect)));
-
-        bool hasCompositing = compositeOp != SkXfermode::kSrcOver_Mode;
-        OwnPtr<CompositingRecorder> compositingRecorder;
-        if (hasCompositing || opacity < 1)
-            compositingRecorder = adoptPtr(new CompositingRecorder(paintContext, *this, compositeOp, opacity));
+        ClipRecorder clipRecorder(imagePicture.context(), *this, DisplayItem::ClipNodeImage, LayoutRect(enclosingIntRect(dstRect)));
 
         // We can only draw the entire frame, clipped to the rect we want. So compute where the top left
         // of the image would be if we were drawing without clipping, and translate accordingly.
         FloatSize scale(dstRect.width() / srcRect.width(), dstRect.height() / srcRect.height());
         FloatSize topLeftOffset(srcRect.location().x() * scale.width(), srcRect.location().y() * scale.height());
         FloatPoint destOffset = dstRect.location() - topLeftOffset;
         AffineTransform transform = AffineTransform::translation(destOffset.x(), destOffset.y());
         transform.scale(scale.width(), scale.height());
-        TransformRecorder transformRecorder(paintContext, *this, transform);
+        TransformRecorder transformRecorder(imagePicture.context(), *this, transform);
 
         view->updateLayoutAndStyleForPainting();
-        view->paint(&paintContext, enclosingIntRect(srcRect));
+        view->paint(&imagePicture.context(), enclosingIntRect(srcRect));
         ASSERT(!view->needsLayout());
     }
 
+    {
+        SkAutoCanvasRestore ar(canvas, false);
+        if (drawNeedsLayer(paint)) {
+            SkRect layerRect = dstRect;
+            canvas->saveLayer(&layerRect, &paint);
+        }
+        RefPtr<const SkPicture> recording = imagePicture.endRecording();
+        canvas->drawPicture(recording.get());
+    }
+
     if (imageObserver())
         imageObserver()->didDraw(this);
 
     // Start any (SMIL) animations if needed. This will restart or continue
     // animations if preceded by calls to resetAnimation or stopAnimation
     // respectively.
     startAnimation();
 }
 
 LayoutBox* SVGImage::embeddedContentBox() const
@@ skipping 146 matching lines @@
 
     return m_page;
 }
 
 String SVGImage::filenameExtension() const
 {
     return "svg";
 }
 
 }