[SVG] Paint unnormalized paths

third_party/WebKit/Source/core/svg/SVGPathBuilder.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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "core/svg/SVGPathBuilder.h"
 
-#include "core/svg/SVGPathData.h"
 #include "platform/graphics/Path.h"
 
 namespace blink {
 
+FloatPoint SVGPathBuilder::smoothControl(bool isCompatibleSegment) const
+{
+    // The control point is assumed to be the reflection of the control point on
+    // the previous command relative to the current point. If there is no previous
+    // command or if the previous command was not a [quad/cubic], assume the control
+    // point is coincident with the current point.
+    // [https://www.w3.org/TR/SVG/paths.html#PathDataCubicBezierCommands]
+    // [https://www.w3.org/TR/SVG/paths.html#PathDataQuadraticBezierCommands]
+    FloatPoint controlPoint = m_currentPoint;
+    if (isCompatibleSegment)
+        controlPoint += m_currentPoint - m_lastControlPoint;
+
+    return controlPoint;
+}
+
+void SVGPathBuilder::emitClose()
+{
+    m_path.closeSubpath();
+
+    // At the end of the [closepath] command, the new current
+    // point is set to the initial point of the current subpath.
+    // [https://www.w3.org/TR/SVG/paths.html#PathDataClosePathCommand]
+    m_currentPoint = m_subpathPoint;
+}
+
+void SVGPathBuilder::emitMoveTo(const FloatPoint& p)
+{
+    m_path.moveTo(p);
+
+    // If a "closepath" is followed immediately by a "moveto", then
+    // the "moveto" identifies the start point of the next subpath.
+    // [https://www.w3.org/TR/SVG/paths.html#PathDataClosePathCommand]
+    if (m_lastCommand == PathSegClosePath)
+        m_subpathPoint = p;
+
+    m_currentPoint = p;
+}
+
+void SVGPathBuilder::emitLineTo(const FloatPoint& p)
+{
+    m_path.addLineTo(p);
+    m_currentPoint = p;
+}
+
+void SVGPathBuilder::emitQuadTo(const FloatPoint& c0, const FloatPoint& p)
+{
+    m_path.addQuadCurveTo(c0, p);
+    m_lastControlPoint = c0;
+    m_currentPoint = p;
+}
+
+void SVGPathBuilder::emitSmoothQuadTo(const FloatPoint& p)
+{
+    bool lastWasQuadratic = m_lastCommand == PathSegCurveToQuadraticAbs
+        || m_lastCommand == PathSegCurveToQuadraticRel
+        || m_lastCommand == PathSegCurveToQuadraticSmoothAbs
+        || m_lastCommand == PathSegCurveToQuadraticSmoothRel;
+
+    emitQuadTo(smoothControl(lastWasQuadratic), p);
+}
+
+void SVGPathBuilder::emitCubicTo(const FloatPoint& c0, const FloatPoint& c1, const FloatPoint& p)
+{
+    m_path.addBezierCurveTo(c0, c1, p);
+    m_lastControlPoint = c1;
+    m_currentPoint = p;
+}
+
+void SVGPathBuilder::emitSmoothCubicTo(const FloatPoint& c1, const FloatPoint& p)
+{
+    bool lastWasCubic = m_lastCommand == PathSegCurveToCubicAbs
+        || m_lastCommand == PathSegCurveToCubicRel
+        || m_lastCommand == PathSegCurveToCubicSmoothAbs
+        || m_lastCommand == PathSegCurveToCubicSmoothRel;
+
+    emitCubicTo(smoothControl(lastWasCubic), c1, p);
+}
+
+void SVGPathBuilder::emitArcTo(const FloatPoint& p, const FloatSize& r, float rotate,
+    bool largeArc, bool sweep)
+{
+    m_path.addArcTo(p, r, rotate, largeArc, sweep);
+    m_currentPoint = p;
+}
+
 void SVGPathBuilder::emitSegment(const PathSegmentData& segment)
 {
     switch (segment.command) {
+    case PathSegClosePath:
+        emitClose();
+        break;
     case PathSegMoveToAbs:
-        m_path.moveTo(segment.targetPoint);
+        emitMoveTo(
+            segment.targetPoint);
+        break;
+    case PathSegMoveToRel:
+        emitMoveTo(
+            m_currentPoint + segment.targetPoint);
         break;
     case PathSegLineToAbs:
-        m_path.addLineTo(segment.targetPoint);
+        emitLineTo(
+            segment.targetPoint);
         break;
-    case PathSegClosePath:
-        m_path.closeSubpath();
+    case PathSegLineToRel:
+        emitLineTo(
+            m_currentPoint + segment.targetPoint);
+        break;
+    case PathSegLineToHorizontalAbs:
+        emitLineTo(
+            FloatPoint(segment.targetPoint.x(), m_currentPoint.y()));
+        break;
+    case PathSegLineToHorizontalRel:
+        emitLineTo(
+            m_currentPoint + FloatSize(segment.targetPoint.x(), 0));
+        break;
+    case PathSegLineToVerticalAbs:
+        emitLineTo(
+            FloatPoint(m_currentPoint.x(), segment.targetPoint.y()));
+        break;
+    case PathSegLineToVerticalRel:
+        emitLineTo(
+            m_currentPoint + FloatSize(0, segment.targetPoint.y()));
+        break;
+    case PathSegCurveToQuadraticAbs:
+        emitQuadTo(
+            segment.point1,
+            segment.targetPoint);
+        break;
+    case PathSegCurveToQuadraticRel:
+        emitQuadTo(
+            m_currentPoint + segment.point1,
+            m_currentPoint + segment.targetPoint);
+        break;
+    case PathSegCurveToQuadraticSmoothAbs:
+        emitSmoothQuadTo(
+            segment.targetPoint);
+        break;
+    case PathSegCurveToQuadraticSmoothRel:
+        emitSmoothQuadTo(
+            m_currentPoint + segment.targetPoint);
         break;
     case PathSegCurveToCubicAbs:
-        m_path.addBezierCurveTo(segment.point1, segment.point2, segment.targetPoint);
+        emitCubicTo(
+            segment.point1,
+            segment.point2,
+            segment.targetPoint);
+        break;
+    case PathSegCurveToCubicRel:
+        emitCubicTo(
+            m_currentPoint + segment.point1,
+            m_currentPoint + segment.point2,
+            m_currentPoint + segment.targetPoint);
+        break;
+    case PathSegCurveToCubicSmoothAbs:
+        emitSmoothCubicTo(
+            segment.point2,
+            segment.targetPoint);
+        break;
+    case PathSegCurveToCubicSmoothRel:
+        emitSmoothCubicTo(
+            m_currentPoint + segment.point2,
+            m_currentPoint + segment.targetPoint);
+        break;
+    case PathSegArcAbs:
+        emitArcTo(
+            segment.targetPoint,
+            toFloatSize(segment.arcRadii()),
+            segment.arcAngle(),
+            segment.largeArcFlag(),
+            segment.sweepFlag());
+        break;
+    case PathSegArcRel:
+        emitArcTo(
+            m_currentPoint + segment.targetPoint,
+            toFloatSize(segment.arcRadii()),
+            segment.arcAngle(),
+            segment.largeArcFlag(),
+            segment.sweepFlag());
         break;
     default:
         ASSERT_NOT_REACHED();
     }
+
+    m_lastCommand = segment.command;
 }
 
 }