get Line Rectangle Intersection - Java 2D Graphics

Java examples for 2D Graphics:Rectangle

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Description

get Line Rectangle Intersection

Demo Code

/* /*from w  w w  .ja  va 2  s  . c  o m*/
 * Copyright 2008 Tom Huybrechts and hudson.dev.java.net
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * 
 *    http://www.apache.org/licenses/LICENSE-2.0 
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or 
 * implied. See the License for the specific language governing 
 * permissions and limitations under the License.  
 * 
 */
//package com.java2s;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;

public class Main {
    public static boolean getLineRectangleIntersection(
            Rectangle2D.Double rect, Line2D.Double line,
            Point2D.Double intersection) {

        Line2D.Double top = new Line2D.Double(rect.x, rect.y, rect.x
                + rect.width, rect.y);
        Line2D.Double bottom = new Line2D.Double(rect.x, rect.y
                + rect.height, rect.x + rect.width, rect.y + rect.height);
        Line2D.Double left = new Line2D.Double(rect.x, rect.y, rect.x,
                rect.y + rect.height);
        Line2D.Double right = new Line2D.Double(rect.x + rect.width,
                rect.y, rect.x + rect.width, rect.y + rect.height);

        return getLineLineIntersection(line, top, intersection)
                || getLineLineIntersection(line, bottom, intersection)
                || getLineLineIntersection(line, left, intersection)
                || getLineLineIntersection(line, right, intersection);
    }

    public static boolean getLineLineIntersection(Line2D.Double l1,
            Line2D.Double l2, Point2D.Double intersection) {
        if (!l1.intersectsLine(l2))
            return false;

        double x1 = l1.getX1(), y1 = l1.getY1(), x2 = l1.getX2(), y2 = l1
                .getY2(), x3 = l2.getX1(), y3 = l2.getY1(), x4 = l2.getX2(), y4 = l2
                .getY2();

        intersection.x = det(det(x1, y1, x2, y2), x1 - x2,
                det(x3, y3, x4, y4), x3 - x4)
                / det(x1 - x2, y1 - y2, x3 - x4, y3 - y4);
        intersection.y = det(det(x1, y1, x2, y2), y1 - y2,
                det(x3, y3, x4, y4), y3 - y4)
                / det(x1 - x2, y1 - y2, x3 - x4, y3 - y4);

        return true;
    }

    public static double det(double a, double b, double c, double d) {
        return a * d - b * c;
    }
}

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