Java Line Intersect intersect(Point a, Point b, Point c, Point d)

Description

intersect

License

Apache License

Declaration

public static Point intersect(Point a, Point b, Point c, Point d) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.awt.Point;

public class Main {
    public static Point intersect(Point a, Point b, Point c, Point d) {
        float[] rv = intersect(new float[] { a.x, a.y, b.x, b.y, c.x, c.y, d.x, d.y });
        if (rv == null)
            return null;
        return new Point((int) rv[0], (int) rv[1]);
    }/*  w ww  .  ja  v  a2s . c om*/

    public static float[] intersect(float[] points) {
        float[] l1 = getAffineFunction(points[0], points[1], points[2], points[3]);
        float[] l2 = getAffineFunction(points[4], points[5], points[6], points[7]);
        float[] crossing;
        if (l1 == null && l2 == null) {
            return null;
        } else if (l1 == null && l2 != null) {
            crossing = intersect(l2[0], l2[1], points[0]);
        } else if (l1 != null && l2 == null) {
            crossing = intersect(l1[0], l1[1], points[4]);
        } else {
            crossing = intersect(l1[0], l1[1], l2[0], l2[1]);
        }
        if (crossing == null) {
            return null;
        }
        if (!(inBounds(points[0], points[1], points[2], points[3], crossing[0], crossing[1])
                && inBounds(points[4], points[5], points[6], points[7], crossing[0], crossing[1])))
            return null;
        return crossing;
    }

    public static float[] intersect(float m1, float b1, float m2, float b2) {
        if (m1 == m2) {
            return null;
        }
        float x = (b2 - b1) / (m1 - m2);
        float y = m1 * x + b1;
        return new float[] { x, y };
    }

    public static float[] intersect(float m1, float b1, float x) {
        return new float[] { x, m1 * x + b1 };
    }

    public static float[] getAffineFunction(float x1, float y1, float x2, float y2) {
        if (x1 == x2)
            return null;
        float m = (y1 - y2) / (x1 - x2);
        float b = y1 - m * x1;
        return new float[] { m, b };
    }

    public static boolean inBounds(float bx1, float by1, float bx2, float by2, float x, float y) {
        if (bx1 < bx2) {
            if (x < bx1 || x > bx2)
                return false;
        } else {
            if (x > bx1 || x < bx2)
                return false;
        }
        if (by1 < by2) {
            if (y < by1 || y > by2)
                return false;
        } else {
            if (y > by1 || y < by2)
                return false;
        }
        return true;
    }
}

Related

1. intersect(int xa, int ya, int xb, int yb, int xc, int yc, int xd, int yd)
2. intersect(Shape shape1, Shape shape2)
3. intersectClip(final Graphics2D g2d, final Shape clip)
4. intersection(Line2D a, Line2D b)
5. intersection(Line2D lineA, Line2D lineB)