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com.hfg xml, html, svg, and bioinformatics utility library
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package com.hfg.svg.path;

import java.awt.geom.GeneralPath;
import java.awt.geom.Path2D;
import java.awt.geom.Point2D;
import java.util.List;
                        
//------------------------------------------------------------------------------
/**
 * Object representation of an SVG (Scalable Vector Graphics) path smooth curveTo ('S' or 's') command.
 *
 * @author J. Alex Taylor, hairyfatguy.com
 */
//------------------------------------------------------------------------------
// com.hfg XML/HTML Coding Library
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// J. Alex Taylor, President, Founder, CEO, COO, CFO, OOPS hairyfatguy.com
// [email protected]
//------------------------------------------------------------------------------
               
public class SvgPathSmoothCurveToCmd extends SvgPathCurveToCmd
{
   private Point2D.Float mPrevCmdSecondControlPoint;

   //---------------------------------------------------------------------------
   public SvgPathSmoothCurveToCmd()
   {
      super('S');
   }


   //---------------------------------------------------------------------------
   @Override
   public SvgPathSmoothCurveToCmd setRawNumbers(List inValue)
   {
      if (inValue.size()%4 != 0)
      {
         throw new SvgPathDataException("A pair of points per command must be given to a smooth curveTo path command!");
      }

      setNumSteps(inValue.size()/4);

      super.setRawNumbers(inValue);
      return this;
   }

   //---------------------------------------------------------------------------
   public void setPrevCmdSecondControlPoint(Point2D.Float inValue)
   {
      mPrevCmdSecondControlPoint = inValue;
   }


   //--------------------------------------------------------------------------
   // From http://www.w3.org/TR/SVG/paths.html
   //
   // Draws a cubic Bézier curve from the current point to (x,y).
   // The first control point is assumed to be the reflection of the second control point on the previous command relative
   // to the current point. (If there is no previous command or if the previous command was not an C, c, S or s, assume
   // the first control point is coincident with the current point.) (x2,y2) is the second control point (i.e., the
   // control point at the end of the curve). S (uppercase) indicates that absolute coordinates will follow;
   // s (lowercase) indicates that relative coordinates will follow. Multiple sets of coordinates may be specified to draw a polybézier.
   // At the end of the command, the new current point becomes the final (x,y) coordinate pair used in the polybézier.
   public Point2D.Float draw(Path2D.Float inPolyline)
   {
      List rawNumbers = getRawNumbers();
      int numIndex = 0;

      Point2D.Float currentPoint = getStartingPoint();

      while (numIndex < rawNumbers.size() - 1)
      {
         Point2D.Float point1 = new Point2D.Float(rawNumbers.get(numIndex++), rawNumbers.get(numIndex++));
         Point2D.Float point2 = new Point2D.Float(rawNumbers.get(numIndex++), rawNumbers.get(numIndex++));

         if (isRelative())
         {
            point1.setLocation(point1.getX() + currentPoint.getX(), point1.getY() + currentPoint.getY());
            point2.setLocation(point2.getX() + currentPoint.getX(), point2.getY() + currentPoint.getY());
         }

         Point2D.Float firstCtrlPoint = currentPoint;
         if (mPrevCmdSecondControlPoint != null)
         {
            // Calculate reflection of the prev second control point
            firstCtrlPoint = new Point2D.Float((float) (currentPoint.getX() + (2 * (currentPoint.getX() - mPrevCmdSecondControlPoint.getX()))),
                                               (float) (currentPoint.getY() + (2 * (currentPoint.getY() - mPrevCmdSecondControlPoint.getY()))));
         }

         inPolyline.curveTo(firstCtrlPoint.getX(), firstCtrlPoint.getY(), point1.getX(), point1.getY(), point2.getX(), point2.getY());

         setSecondControlPoint(point2);

         currentPoint = point2;
      }

      // Return the last point.
      return currentPoint;
   }
}