用c++实现liang-Barsky二维裁剪算法

Liang-Barsky二维裁剪算法是一种用于在二维平面上裁剪线段的算法。下面是一个C语言实现的例子:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define min(a,b) (((a)<(b))?(a):(b))
#define max(a,b) (((a)>(b))?(a):(b))

// 定义线段
typedef struct {
    double x1, y1, x2, y2;
} Line;

// 定义矩形
typedef struct {
    double xmin, ymin, xmax, ymax;
} Rect;

// 计算线段和矩形的交点
int LiangBarsky(Line line, Rect rect, double *x, double *y) {
    double dx = line.x2 - line.x1;
    double dy = line.y2 - line.y1;
    double p[4], q[4];
    double u1 = 0.0, u2 = 1.0;

    p[0] = -dx; q[0] = line.x1 - rect.xmin;
    p[1] = dx; q[1] = rect.xmax - line.x1;
    p[2] = -dy; q[2] = line.y1 - rect.ymin;
    p[3] = dy; q[3] = rect.ymax - line.y1;

    for (int i = 0; i < 4; i++) {
        if (p[i] == 0 && q[i] < 0)
            return 0;
        else {
            double r = q[i] / p[i];
            if (p[i] < 0) {
                if (r > u1) u1 = r;
            }
            else {
                if (r < u2) u2 = r;
            }
        }
    }

    if (u1 > u2) return 0;
    *x = line.x1 + u1 * dx;
    *y = line.y1 + u1 * dy;
    return 1;
}

int main() {
    Line line = { 0, 0, 10, 10 };
    Rect rect = { 5, 5, 15, 15 };
    double x, y;
    if (LiangBarsky(line, rect, &x, &y))
        printf("(%lf, %lf)\n", x, y);
    else
        printf("no intersection\n");
    return 0;
}

该程序将给出一条线段(x1,y1)到(x2,y2)和一个矩形(xmin,y