liang-barsky算法c语言

以下是 Liang-Barsky 算法的 C 语言实现：

#include <stdio.h>

void LiangBarsky(int x1, int y1, int x2, int y2, int xmin, int ymin, int xmax, int ymax) 
{
    int dx = x2 - x1;
    int dy = y2 - y1;
    float p1 = -dx;
    float p2 = dx;
    float p3 = -dy;
    float p4 = dy;
    float q1 = x1 - xmin;
    float q2 = xmax - x1;
    float q3 = y1 - ymin;
    float q4 = ymax - y1;

    float posarr[5], negarr[5];
    int posind = 1, negind = 1;
    posarr[0] = 1;
    negarr[0] = 0;

    if ((p1 == 0 && q1 < 0) || (p3 == 0 && q3 < 0)) 
    {
        printf("Line is outside the clipping window\n");
        return;
    }

    if (p1 != 0)
    {
        float r1 = q1 / p1;
        float r2 = q2 / p2;
        if (p1 < 0)
        {
            negarr[negind++] = r1; 
            posarr[posind++] = r2; 
        }
        else
        {
            negarr[negind++] = r2; 
            posarr[posind++] = r1; 
        }
    }

    if (p3 != 0)
    {
        float r3 = q3 / p3;
        float r4 = q4 / p4;
        if (p3 < 0)
        {
            negarr[negind++] = r3; 
            posarr[posind++] = r4; 
        }
        else
        {
            negarr[negind++] = r4; 
            posarr[posind++] = r3; 
        }
    }

    float xn1, yn1, xn2, yn2;
    float rn1 = 0, rn2 = 1;

    for (int i = 1; i < posind; i++)
    {
        float rn = posarr[i];
        if (rn < rn2)
        {
            rn2 = rn;
        }
    }

    for (int i = 1; i < negind; i++)
    {
        float rn = negarr[i];
        if (rn > rn1)
        {
            rn1 = rn;
        }
    }

    xn1 = x1 + rn1 * dx;
    yn1 = y1 + rn1 * dy;
    xn2 = x1 + rn2 * dx;
    yn2 = y1 + rn2 * dy;

    printf("The coordinates of the clipped line are: (%.2f, %.2f) and (%.2f, %.2f)\n", xn1, yn1, xn2, yn2);
}

int main()
{
    int x1 = 50, y1 = 50, x2 = 200, y2 = 200;
    int xmin = 100, ymin = 100, xmax = 300, ymax = 300;
    LiangBarsky(x1, y1, x2, y2, xmin, ymin, xmax, ymax);
    return 0;
}

这个程序假设输入的线段的起点和终点坐标分别为 (x1, y1) 和 (x2, y2)，裁剪窗口的四个边界坐标分别为 xmin, ymin, xmax 和 ymax。函数 `LiangBarsky` 的输出为经过裁剪后的线段的两个端点的坐标。