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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.Path2D;
import java.awt.geom.Point2D;
import java.util.List;
                        
//------------------------------------------------------------------------------
/**
 * Object representation of an SVG (Scalable Vector Graphics) path smooth quadratic curveTo ('T' or 't') 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 SvgPathSmoothQuadCurveToCmd extends SvgPathQuadCurveToCmd
{
   private Point2D.Float mPrevCmdControlPoint;

   //---------------------------------------------------------------------------
   public SvgPathSmoothQuadCurveToCmd()
   {
      super('T');
   }


   //---------------------------------------------------------------------------
   @Override
   protected int getExpectedNumPoints()
   {
      return 2;
   }

   //---------------------------------------------------------------------------
   public void setPrevCmdControlPoint(Point2D.Float inValue)
   {
      mPrevCmdControlPoint = inValue;
   }


   //--------------------------------------------------------------------------
   // From http://www.w3.org/TR/SVG/paths.html
   //
   // Draws a quadratic Bézier curve from the current point to (x,y).
   // 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 Q, q, T or t, assume the control point is coincident
   // with the current point.) T (uppercase) indicates that absolute coordinates will follow; t (lowercase) indicates that
   // relative coordinates will follow. 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 point = new Point2D.Float(rawNumbers.get(numIndex++), rawNumbers.get(numIndex++));

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

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

         inPolyline.quadTo(ctrlPoint.getX(), ctrlPoint.getY(), point.getX(), point.getY());

         setControlPoint(ctrlPoint);

         currentPoint = point;
      }

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