Returns the distance of p3 to the segment defined by p1,p2. - Java java.lang

Java examples for java.lang:Math Geometry Distance

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Description

Returns the distance of p3 to the segment defined by p1,p2.

Demo Code


//package com.java2s;
import java.awt.geom.*;

public class Main {
    /**/*w ww.  jav  a2s  . c o m*/
     * Returns the distance of p3 to the segment defined by p1,p2.
     * http://local.wasp.uwa.edu.au/~pbourke/geometry/pointline/
     * Wrapper function for distanceToSegment.
     * @param x3
     * @param y3
     * @param x1
     * @param y1
     * @param x2
     * @param y2
     * @return
     */
    public static double distanceToSegment(double x3, double y3, double x1,
            double y1, double x2, double y2) {
        final Point2D p3 = new Point2D.Double(x3, y3);
        final Point2D p1 = new Point2D.Double(x1, y1);
        final Point2D p2 = new Point2D.Double(x2, y2);
        return distanceToSegment(p1, p2, p3);
    }

    /**
     * Returns the distance of p3 to the segment defined by p1,p2.
     * http://local.wasp.uwa.edu.au/~pbourke/geometry/pointline/
     * @param p1 First point of the segment
     * @param p2 Second point of the segment
     * @param p3  Point to which we want to know the distance of the segment
     * defined by p1,p2
     * @return The distance of p3 to the segment defined by p1,p2
     */
    public static double distanceToSegment(Point2D p1, Point2D p2,
            Point2D p3) {

        final double xDelta = p2.getX() - p1.getX();
        final double yDelta = p2.getY() - p1.getY();

        if ((xDelta == 0) && (yDelta == 0)) {
            throw new IllegalArgumentException(
                    "p1 and p2 cannot be the same point");
        }

        final double u = ((p3.getX() - p1.getX()) * xDelta + (p3.getY() - p1
                .getY()) * yDelta)
                / (xDelta * xDelta + yDelta * yDelta);

        final Point2D closestPoint;
        if (u < 0) {
            closestPoint = p1;
        } else if (u > 1) {
            closestPoint = p2;
        } else {
            closestPoint = new Point2D.Double(p1.getX() + u * xDelta,
                    p1.getY() + u * yDelta);
        }

        return closestPoint.distance(p3);
    }
}

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