Add helper for computing the reflected control point for smooth segments

Source/core/svg/SVGPathParser.cpp

 /*
  * Copyright (C) 2002, 2003 The Karbon Developers
  * Copyright (C) 2006 Alexander Kellett <lypanov@kde.org>
  * Copyright (C) 2006, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2007, 2009 Apple Inc. All rights reserved.
  * 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
@@ skipping 125 matching lines @@
         point2 += m_currentPoint;
         targetPoint += m_currentPoint;
     }
     m_consumer->curveToCubic(point1, point2, targetPoint, AbsoluteCoordinates);
 
     m_controlPoint = point2;
     m_currentPoint = targetPoint;
     return true;
 }
 
+static FloatPoint reflectedPoint(const FloatPoint& reflectIn, const FloatPoint& pointToReflect)
+{
+    return FloatPoint(2 * reflectIn.x() - pointToReflect.x(), 2 * reflectIn.y() - pointToReflect.y());
+}
+
 bool SVGPathParser::parseCurveToCubicSmoothSegment()
 {
     FloatPoint point2;
     FloatPoint targetPoint;
     if (!m_source->parseCurveToCubicSmoothSegment(point2, targetPoint))
         return false;
 
     if (m_pathParsingMode == UnalteredParsing) {
         m_consumer->curveToCubicSmooth(point2, targetPoint, m_mode);
         return true;
     }
     if (m_lastCommand != PathSegCurveToCubicAbs
         && m_lastCommand != PathSegCurveToCubicRel
         && m_lastCommand != PathSegCurveToCubicSmoothAbs
         && m_lastCommand != PathSegCurveToCubicSmoothRel)
         m_controlPoint = m_currentPoint;
 
-    FloatPoint point1 = m_currentPoint;
-    point1.scale(2, 2);
-    point1.move(-m_controlPoint.x(), -m_controlPoint.y());
+    FloatPoint point1 = reflectedPoint(m_currentPoint, m_controlPoint);
     if (m_mode == RelativeCoordinates) {
         point2 += m_currentPoint;
         targetPoint += m_currentPoint;
     }
 
     m_consumer->curveToCubic(point1, point2, targetPoint, AbsoluteCoordinates);
 
     m_controlPoint = point2;
     m_currentPoint = targetPoint;
     return true;
@@ skipping 39 matching lines @@
     if (m_pathParsingMode == UnalteredParsing) {
         m_consumer->curveToQuadraticSmooth(targetPoint, m_mode);
         return true;
     }
     if (m_lastCommand != PathSegCurveToQuadraticAbs
         && m_lastCommand != PathSegCurveToQuadraticRel
         && m_lastCommand != PathSegCurveToQuadraticSmoothAbs
         && m_lastCommand != PathSegCurveToQuadraticSmoothRel)
         m_controlPoint = m_currentPoint;
 
-    FloatPoint cubicPoint = m_currentPoint;
-    cubicPoint.scale(2, 2);
-    cubicPoint.move(-m_controlPoint.x(), -m_controlPoint.y());
+    FloatPoint cubicPoint = reflectedPoint(m_currentPoint, m_controlPoint);
     FloatPoint point1(m_currentPoint.x() + 2 * cubicPoint.x(), m_currentPoint.y() + 2 * cubicPoint.y());
     FloatPoint point2(targetPoint.x() + 2 * cubicPoint.x(), targetPoint.y() + 2 * cubicPoint.y());
     if (m_mode == RelativeCoordinates) {
         point2 += m_currentPoint;
         targetPoint += m_currentPoint;
     }
     point1.scale(gOneOverThree, gOneOverThree);
     point2.scale(gOneOverThree, gOneOverThree);
 
     m_consumer->curveToCubic(point1, point2, targetPoint, AbsoluteCoordinates);
@@ skipping 234 matching lines @@
         point2 = targetPoint;
         point2.move(t * sinEndTheta, -t * cosEndTheta);
 
         m_consumer->curveToCubic(pointTransform.mapPoint(point1), pointTransform.mapPoint(point2),
                                  pointTransform.mapPoint(targetPoint), AbsoluteCoordinates);
     }
     return true;
 }
 
 }