computer-graphics/PolyClip.cpp at master · murlis97/computer-graphics · GitHub

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#include <stdio.h>
#include <graphics.h>
#include <conio.h>
#include <math.h>
#include <process.h>
#define TRUE 1
#define FALSE 0
typedef unsigned int outcode;
outcode CompOutCode(float x,float y);
enum  {  TOP = 0x1,
         BOTTOM = 0x2,
         RIGHT = 0x4,
         LEFT = 0x8
      };
float xmin,xmax,ymin,ymax;
void clip(float x0,float y0,float x1,float y1)
{
    outcode outcode0,outcode1,outcodeOut;
    int accept = FALSE,done = FALSE;
    outcode0 = CompOutCode(x0,y0);
    outcode1 = CompOutCode(x1,y1);
    do
    {
        if(!(outcode0|outcode1))
        {
            accept = TRUE;
            done = TRUE;
        }
        else if(outcode0 & outcode1)
            done = TRUE;
        else
        {
            float x,y;

            outcodeOut = outcode0?outcode0:outcode1;
            if(outcodeOut & TOP)
            {
                x = x0+(x1-x0)*(ymax-y0)/(y1-y0);
                y = ymax;
            }
            else if(outcodeOut & BOTTOM)
            {
                x = x0+(x1-x0)*(ymin-y0)/(y1-y0);
                y = ymin;
            }
            else if(outcodeOut & RIGHT)
            {
                y = y0+(y1-y0)*(xmax-x0)/(x1-x0);
                x = xmax;
            }
            else
            {
                y = y0+(y1-y0)*(xmin-x0)/(x1-x0);
                x = xmin;
            }
            if(outcodeOut==outcode0)
            {
                x0 = x;
                y0 = y;
                outcode0 = CompOutCode(x0,y0);
            }
            else
            {
                x1 = x;
                y1 = y;
                outcode1 = CompOutCode(x1,y1);
            }
        }
    }
    while(done==FALSE);
    if(accept)
        line(x0,y0,x1,y1);
    outtextxy(150,20,"POLYGON AFTER CLIPPING");
    rectangle(xmin,ymin,xmax,ymax);
}
outcode CompOutCode(float x,float y)
{
    outcode code = 0;
    if(y>ymax)
        code|=TOP;
    else if(y<ymin)
        code|=BOTTOM;
    if(x>xmax)
        code|=RIGHT;
    else if(x<xmin)
        code|=LEFT;
    return code;
}
int main( )
{
    float x1,y1,x2,y2;
    int gdriver = DETECT, gmode, n,poly[14],i;
    int X[]= {80,80,80,240,240,240,240,80,80,140,140,80,128,240,240,128};
    int Y[]= {80,200,200,200,200,80,80,80,80,140,140,200,152,152,128,128};
    n=16;
    for(i=0; i<2*n; i++)
    {
        if(i%2 == 0)
            poly[i] = X[i/2];
        else
            poly[i] = Y[i/2];
    }
    poly[2*n]=poly[0];
    poly[2*n+1]=poly[1];
    printf("Enter the rectangular coordinates of clipping window\n");
    scanf("%f%f%f%f",&xmin,&ymin,&xmax,&ymax);
    initgraph(&gdriver, &gmode, "");
    outtextxy(150,20,"POLYGON BEFORE CLIPPING");
    drawpoly(n+1,poly);
    rectangle(xmin,ymin,xmax,ymax);
    Sleep(5000);
    cleardevice();
    for(i=0; i<n; i++)
        clip(poly[2*i],poly[(2*i)+1],poly[(2*i)+2],poly[(2*i)+3]);
    Sleep(5000);
}