cyrus-beck算法代码使用java

以下是Java实现的Cyrus-Beck算法代码：

import java.awt.Point;

public class CyrusBeckAlgorithm {

    // 定义线段的两个端点
    private Point p1, p2;

    public CyrusBeckAlgorithm(Point p1, Point p2) {
        this.p1 = p1;
        this.p2 = p2;
    }

    // 计算法向量
    private Point computeNormal(Point p1, Point p2) {
        int dx = p2.x - p1.x;
        int dy = p2.y - p1.y;
        return new Point(dy, -dx);
    }

    // 计算点积
    private double dotProduct(Point a, Point b) {
        return a.x * b.x + a.y * b.y;
    }

    // 计算线段起点到P点的向量
    private Point computeVector(Point p) {
        return new Point(p.x - p1.x, p.y - p1.y);
    }

    // 计算交点
    private Point computeIntersection(Point p, Point d) {
        Point e = new Point(p1.x - p.x, p1.y - p.y);
        double t = dotProduct(computeNormal(p1, p2), e) / dotProduct(computeNormal(p1, p2), d);
        return new Point((int) (p.x + t * d.x), (int) (p.y + t * d.y));
    }

    // 判断点是否在线段内
    private boolean isInside(Point p) {
        Point d = new Point(p2.x - p1.x, p2.y - p1.y);
        Point n = computeNormal(p1, p2);
        Point w = computeVector(p);
        double nd = dotProduct(n, d);
        if (nd == 0) {
            return false;
        }
        double t = -dotProduct(n, w) / nd;
        return t >= 0 && t <= 1;
    }

    // 计算Cyrus-Beck剪裁后的线段
    public Point[] cyrusBeckClip(Point p, Point q) {
        Point d = new Point(q.x - p.x, q.y - p.y);
        Point[] result = new Point[2];
        int count = 0;
        if (isInside(p)) {
            result[count++] = p;
        }
        if (isInside(q)) {
            result[count++] = q;
        }
        Point pi, qi;
        pi = computeIntersection(p, d);
        qi = computeIntersection(q, d);
        if (isInside(pi)) {
            result[count++] = pi;
        }
        if (isInside(qi)) {
            result[count++] = qi;
        }
        if (count == 2) {
            return result;
        } else {
            return null;
        }
    }

    public static void main(String[] args) {
        Point p1 = new Point(50, 50);
        Point p2 = new Point(100, 100);
        CyrusBeckAlgorithm cyrusBeck = new CyrusBeckAlgorithm(p1, p2);
        Point p = new Point(0, 75);
        Point q = new Point(150, 75);
        Point[] result = cyrusBeck.cyrusBeckClip(p, q);
        if (result != null) {
            System.out.println("Clipped line segment: (" + result[0].x + ", " + result[0].y + ") to (" + result[1].x + ", " + result[1].y + ")");
        } else {
            System.out.println("Line segment is completely outside the clipping window.");
        }
    }

}

在这个例子中，我们定义了一条线段，然后使用Cyrus-Beck算法剪裁线段。我们还定义了一个矩形窗口，表示剪裁区域。在这个例子中，我们将线段从点(0,75)延伸到点(150,75)。如果剪裁后的线段在剪裁窗口内，则输出剪裁后的线段，否则输出“线段完全在剪裁窗口外”。