Compute the distance between a point and a segment. - Java java.lang

Java examples for java.lang:Math Trigonometric Function

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Description

Compute the distance between a point and a segment.

Demo Code

/* /* w w  w . ja v a 2s. c  o m*/
 * $Id$
 * 
 * Copyright (C) 2010-2011 Janus Core Developers
 * Copyright (C) 2012 St?phane GALLAND
 * 
 * This program 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.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

public class Main{
    /** Compute the distance between a point and a segment.
     *
     * @param p position of the point.
     * @param s1 position of the first point of the segment.
     * @param s2 position of the second point of the segment.
     * @return the distance beetween the point and the segment.
     */
    public static final float distancePointToSegment(Point2f p, Point2f s1,
            Point2f s2) {
        float r_denomenator = (s2.getX() - s1.getX())
                * (s2.getX() - s1.getX()) + (s2.getY() - s1.getY())
                * (s2.getY() - s1.getY());
        if (r_denomenator == 0f)
            return p.distance(s1);
        float r_numerator = (p.getX() - s1.getX())
                * (s2.getX() - s1.getX()) + (p.getY() - s1.getY())
                * (s2.getY() - s1.getY());
        float ratio = r_numerator / r_denomenator;

        if (ratio <= 0.) {
            return (float) Math.sqrt((p.getX() - s1.getX())
                    * (p.getX() - s1.getX()) + (p.getY() - s1.getY())
                    * (p.getY() - s1.getY()));
        }

        if (ratio >= 1f) {
            return (float) Math.sqrt((p.getX() - s2.getX())
                    * (p.getX() - s2.getX()) + (p.getY() - s2.getY())
                    * (p.getY() - s2.getY()));
        }

        float s = ((s1.getY() - p.getY()) * (s2.getX() - s1.getX()) - (s1
                .getX() - p.getX()) * (s2.getY() - s1.getY()))
                / r_denomenator;
        return (float) (Math.abs(s) * Math.sqrt(r_denomenator));
    }
}

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