Make SVG painting independent of GraphicsContext's alpha state

Source/core/rendering/svg/RenderSVGResourcePaintServer.cpp

 /*
  * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 30 matching lines @@
     , m_color(Color::black)
 {
 }
 
 SVGPaintServer::SVGPaintServer(PassRefPtr<Pattern> pattern)
     : m_pattern(pattern)
     , m_color(Color::black)
 {
 }
 
-void SVGPaintServer::apply(GraphicsContext& context, RenderSVGResourceMode resourceMode, GraphicsContextStateSaver* stateSaver)
+void SVGPaintServer::apply(GraphicsContext& context, RenderSVGResourceMode resourceMode, const SVGRenderStyle& svgStyle, GraphicsContextStateSaver& stateSaver)

[fs, 2015/02/03 10:08:49]

According to my doctrine this would rather be 'float paintAlpha' or some such.
(And I do find having to pass RenderSVGResourceMode here at all a bit of a
nuisance...)
(Only to consider if you do end up making other changes anyway though...)

[pdr., 2015/02/04 04:04:31]

Done

 {
     ASSERT(resourceMode == ApplyToFillMode || resourceMode == ApplyToStrokeMode);
-    if (stateSaver && (m_gradient || m_pattern))
-        stateSaver->saveIfNeeded();
+
+    if (m_gradient || m_pattern)
+        stateSaver.saveIfNeeded();
 
     if (resourceMode == ApplyToFillMode) {
         if (m_pattern)
-            context.setFillPattern(m_pattern);
+            context.setFillPattern(m_pattern, svgStyle.fillOpacity());
         else if (m_gradient)
-            context.setFillGradient(m_gradient);
+            context.setFillGradient(m_gradient, svgStyle.fillOpacity());
         else
-            context.setFillColor(m_color);
+            context.setFillColor(GraphicsContext::combineWithAlpha(m_color.rgb(), svgStyle.fillOpacity()));

[f(malita), 2015/02/03 00:33:28]

Implicit SkColor -> Color conversion seems fragile. OTOH this is probably not
the only place where we do this. Methinks Color needs to die a quick death.

[pdr., 2015/02/04 04:04:31]

+1

     } else {
         if (m_pattern)
-            context.setStrokePattern(m_pattern);
+            context.setStrokePattern(m_pattern, svgStyle.strokeOpacity());
         else if (m_gradient)
-            context.setStrokeGradient(m_gradient);
+            context.setStrokeGradient(m_gradient, svgStyle.strokeOpacity());
         else
-            context.setStrokeColor(m_color);
+            context.setStrokeColor(GraphicsContext::combineWithAlpha(m_color.rgb(), svgStyle.strokeOpacity()));
     }
 }
 
 void SVGPaintServer::prependTransform(const AffineTransform& transform)
 {
     ASSERT(m_gradient || m_pattern);
     if (m_pattern)
         m_pattern->setPatternSpaceTransform(transform * m_pattern->patternSpaceTransform());
     else
         m_gradient->setGradientSpaceTransform(transform * m_gradient->gradientSpaceTransform());
@@ skipping 104 matching lines @@
 RenderSVGResourcePaintServer::~RenderSVGResourcePaintServer()
 {
 }
 
 SVGPaintDescription RenderSVGResourcePaintServer::requestPaintDescription(const RenderObject& renderer, const RenderStyle* style, RenderSVGResourceMode resourceMode)
 {
     return requestPaint(renderer, style, resourceMode);
 }
 
 }