[SVG2] Add support for marker orient="auto-start-reverse".

Source/core/rendering/svg/RenderSVGResourceMarker.cpp

 /*
  * Copyright (C) 2004, 2005, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) Research In Motion Limited 2009-2010. 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 97 matching lines @@
     SVGMarkerElement* marker = toSVGMarkerElement(element());
     ASSERT(marker);
 
     float angle = -1;
     if (marker->orientType()->currentValue()->enumValue() == SVGMarkerOrientAngle)
         angle = marker->orientAngle()->currentValue()->value();
 
     return angle;
 }
 
-AffineTransform RenderSVGResourceMarker::markerTransformation(const FloatPoint& origin, float autoAngle, float strokeWidth) const
+AffineTransform RenderSVGResourceMarker::markerTransformation(const FloatPoint& origin, float autoAngle, float strokeWidth, bool isStartMarker) const
 {
     SVGMarkerElement* marker = toSVGMarkerElement(element());
     ASSERT(marker);
 
     float markerAngle = angle();
     bool useStrokeWidth = marker->markerUnits()->currentValue()->enumValue() == SVGMarkerUnitsStrokeWidth;
-
+    if (markerAngle == -1) {
+        markerAngle = autoAngle;
+        if (isStartMarker && marker->orientType()->currentValue()->enumValue() == SVGMarkerOrientAutoStartReverse)
+            markerAngle += 180;

[fs, 2014/09/09 12:18:21]

I'm curious if this (adjustment) would be nicer in the SVGMarkerData-helper
(i.e. pass an auto-start-reverse flag to it, and then compute different
(auto-)angle in currentAngle(StartMarker) instead. That ought to cut
RenderSVGResourceMarker out of the patch entirely.

+    }
     AffineTransform transform;
     transform.translate(origin.x(), origin.y());
-    transform.rotate(markerAngle == -1 ? autoAngle : markerAngle);
+    transform.rotate(markerAngle);
     transform = markerContentTransformation(transform, referencePoint(), useStrokeWidth ? strokeWidth : -1);
     return transform;
 }
 
 void RenderSVGResourceMarker::draw(PaintInfo& paintInfo, const AffineTransform& transform)
 {
     clearInvalidationMask();
 
     // An empty viewBox disables rendering.
     SVGMarkerElement* marker = toSVGMarkerElement(element());
@@ skipping 39 matching lines @@
     SVGMarkerElement* marker = toSVGMarkerElement(element());
     ASSERT(marker);
 
     SVGLengthContext lengthContext(marker);
     float w = marker->markerWidth()->currentValue()->value(lengthContext);
     float h = marker->markerHeight()->currentValue()->value(lengthContext);
     m_viewport = FloatRect(0, 0, w, h);
 }
 
 }