Calculates the intersection location of the line formed by (x1, y1), (x2, y2) and the line segment formed by (x3, y3), (x4, y4). - Java java.lang

Java examples for java.lang:Math Geometry Line

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Description

Calculates the intersection location of the line formed by (x1, y1), (x2, y2) and the line segment formed by (x3, y3), (x4, y4).

Demo Code

/*/* w  ww .  java  2 s  .  c  om*/
 * Copyright (c) JenSoft API
 * This source file is part of JenSoft API, All rights reserved.
 * JENSOFT PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
//package com.java2s;

public class Main {
    public static final Object PARALLEL = new Object();
    public static final Object INTERSECT = new Object();

    /**
     * Calculates the intersection location of the line formed by (x1, y1), (x2,
     * y2) and the line segment formed by (x3, y3), (x4, y4). If the line and
     * line segment are determined to be parallel, then Geom.PARALLEL is
     * returned and no further computations are done. If the line segment does
     * not cross the line, then null is returned and no further computations are
     * done. Otherwise the intersection location is stored in index locations 0
     * and 1 of the specified array. The parametric value with respect to the
     * line segment is stored in index location 2. If there in an intersection
     * then the returned value is Geom.INTERSECT.
     */
    public static Object getLineSegIntersection(double x1, double y1,
            double x2, double y2, double x3, double y3, double x4,
            double y4, double[] result) {
        double bx = x2 - x1;
        double by = y2 - y1;
        double dx = x4 - x3;
        double dy = y4 - y3;

        double b_dot_d_perp = bx * dy - by * dx;

        if (b_dot_d_perp == 0) {
            return PARALLEL;
        }

        double cx = x3 - x1;
        double cy = y3 - y1;

        double u = (cx * by - cy * bx) / b_dot_d_perp;
        if (u < 0 || u > 1) {
            return null;
        }

        if (result != null) {
            result[0] = x3 + u * dx;
            result[1] = y3 + u * dy;
            result[2] = u;
        }

        return INTERSECT;
    }
}

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