CG-Lab/program8.c at main · golu19102003/CG-Lab · GitHub

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// write a c program for  Cohen Sutherland 2D line clipping and Windowing
#include<stdio.h>
#include<conio.h>
#include<graphics.h>

#define INSIDE 0
#define LEFT 1
#define RIGHT 2
#define BOTTOM 4
#define TOP 8

int xmin, ymin, xmax, ymax;

int computeCode(int x, int y) {
    int code = INSIDE;
    if (x < xmin) code |= LEFT;
    else if (x > xmax) code |= RIGHT;
    if (y < ymin) code |= BOTTOM;
    else if (y > ymax) code |= TOP;
    return code;
}

void cohenSutherlandClip(int x1, int y1, int x2, int y2) {
    int code1 = computeCode(x1, y1);
    int code2 = computeCode(x2, y2);
    int accept = 0;

    while (1) {
        if ((code1 == 0) && (code2 == 0)) {
            accept = 1;
            break;
        } else if (code1 & code2) {
            break;
        } else {
            int codeOut, x, y;
            if (code1 != 0) codeOut = code1;
            else codeOut = code2;

            if (codeOut & TOP) {
                x = x1 + (x2 - x1) * (ymax - y1) / (y2 - y1);
                y = ymax;
            } else if (codeOut & BOTTOM) {
                x = x1 + (x2 - x1) * (ymin - y1) / (y2 - y1);
                y = ymin;
            } else if (codeOut & RIGHT) {
                y = y1 + (y2 - y1) * (xmax - x1) / (x2 - x1);
                x = xmax;
            } else if (codeOut & LEFT) {
                y = y1 + (y2 - y1) * (xmin - x1) / (x2 - x1);
                x = xmin;
            }

            if (codeOut == code1) {
                x1 = x;
                y1 = y;
                code1 = computeCode(x1, y1);
            } else {
                x2 = x;
                y2 = y;
                code2 = computeCode(x2, y2);
            }
        }
    }

    if (accept) {
        setcolor(GREEN);
        line(x1, y1, x2, y2);
    }
}

void main() {
    int gd = DETECT, gm;
    int x1, y1, x2, y2;
     initgraph(&gd, &gm, "C:\\turboc3\\BGI");
    printf("Enter Window (xmin, ymin, xmax, ymax): ");
    scanf("%d %d %d %d", &xmin, &ymin, &xmax, &ymax);
    printf("Enter Line (x1, y1, x2, y2): ");
    scanf("%d %d %d %d", &x1, &y1, &x2, &y2);


    rectangle(xmin, ymin, xmax, ymax);

    setcolor(RED);
    line(x1, y1, x2, y2);

    cohenSutherlandClip(x1, y1, x2, y2);
    getch();
    closegraph();
}