intersect Line2D and Shape - Java 2D Graphics

Java examples for 2D Graphics:Line

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Description

intersect Line2D and Shape

Demo Code

/* ------------------------------------------------------------------------
 * PlantUML : a free UML diagram generator
 * ------------------------------------------------------------------------
 *
 * (C) Copyright 2009, Arnaud Roques//from w w w  .  j  a v a 2s  .co  m
 *
 * Project Info:  http://plantuml.sourceforge.net
 * 
 * This file is part of PlantUML.
 *
 * PlantUML is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * PlantUML 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 General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * Original Author:  Arnaud Roques
 *
 * Revision $Revision: 4236 $
 * 
 */
import java.awt.Shape;
import java.awt.geom.CubicCurve2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;

public class Main {
  public static Point2D intersect(Line2D.Double orig, Shape shape) {
    final Line2D.Double copy = new Line2D.Double(orig.x1, orig.y1, orig.x2, orig.y2);
    final boolean contains1 = shape.contains(copy.x1, copy.y1);
    final boolean contains2 = shape.contains(copy.x2, copy.y2);
    if (contains1 ^ contains2 == false) {
      // return new Point2D.Double(orig.x2, orig.y2);
      throw new IllegalArgumentException();
    }
    while (true) {
      final double mx = (copy.x1 + copy.x2) / 2;
      final double my = (copy.y1 + copy.y2) / 2;
      final boolean containsMiddle = shape.contains(mx, my);
      if (contains1 == containsMiddle) {
        copy.x1 = mx;
        copy.y1 = my;
      } else {
        copy.x2 = mx;
        copy.y2 = my;
      }
      if (dist(copy) < 0.1) {
        if (contains1) {
          return new Point2D.Double(copy.x2, copy.y2);
        }
        if (contains2) {
          return new Point2D.Double(copy.x1, copy.y1);
        }
        throw new IllegalStateException();
      }
    }
  }

  static double dist(CubicCurve2D.Double seg) {
    return Point2D.distance(seg.x1, seg.y1, seg.x2, seg.y2);
  }

  static double dist(Line2D.Double seg) {
    return Point2D.distance(seg.x1, seg.y1, seg.x2, seg.y2);
  }

}

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