Line Clipping - Cohen Sutherland Line Clipping Algorithm - Graphics.h in Ubuntu - C++ Program

Line Clipping 

Cohen Sutherland Line Clipping Algorithm  

Graphics & Multimedia Lab - C++ Program

Program:

#include<iostream>
#include<graphics.h>
using namespace std;

const int TOP=8,BOTTOM=4,RIGHT=2,LEFT=1;

typedef int outcode;

outcode compute(int x, int y , int xmax, int ymax, int xmin, int ymin)
{
 outcode oc=0;
 if(x<xmin)
 oc|=LEFT;
 else if(x>xmax)
 oc|=RIGHT;
 if(y>ymax)
 oc|=TOP;
 else if(y<ymin)
 oc|=BOTTOM;
 
 return oc;

}

void coh(int x1,int y1,int x2,int y2, int xmin,int ymin, int xmax, int ymax)
{
 bool accept = false, done=false;double m;
 outcode o1,o2,ot;
 o1=compute(x1,y1,xmax,ymax,xmin,ymin);
 o2=compute(x2,y2,xmax,ymax,xmin,ymin);
 do{
  
  if(!(o1 | o2))
  {
   done=true;
   accept=true;
  }
  else if(o1&o2)
  {
   done=true;
   
  }
  else
  {
   int x,y;
   ot=o1?o1:o2;
   if(ot & TOP)
   {
    y=ymax;
    x = x1 + (x2-x1)*(ymax-y1)/(y2-y1);
   } 
   else if(ot & BOTTOM)
   {
    y=ymin;
    x = x1 + (x2 - x1) * (ymin - y1) / (y2 - y1);
   }
   else if(ot & RIGHT)
   {
    x=xmax;
    y = y1 + (y2 - y1) * (xmax - x1) / (x2 - x1);
   }
   else if(ot & LEFT)
   {
    x=xmin;
     y = y1 + (y2 - y1) * (xmin - x1) / (x2 - x1);
    
   }
   if(ot==o1)
   {
    
    x1=x;
    y1=y;
    o1=compute(x1,y1,xmax,ymax,xmin,ymin);
   }
   else
   {
    
    x2=x;
    y2=y;
    o2=compute(x2,y2,xmax,ymax,xmin,ymin);
   }
 
  }
 }while(done==false);
   
 if(accept==true)
 {
  line(x1,y1,x2,y2);
 }

}

int main()
{
 int gd=DETECT,gm,x,y,j,i;
 initgraph(&gd,&gm,NULL);
 
 outtextxy(150,15, "Cohen Sutherland");


 int xmx=200,ymx=200,xmn=100,ymn=100;
 
 int ax1=50,ay1=75,bx1=50,by1=325;
 int ax2=150,ay2=75,bx2=150,by2=325;
 int ax3=250,ay3=75,bx3=250,by3=325;
 int ax4=50,ay4=75,bx4=250,by4=75;
 int ax5=50,ay5=175,bx5=250,by5=175; 
 int ax6=50,ay6=275,bx6=250,by6=275;
 int ax7=50,ay7=75,bx7=275,by7=275;
 int ax8=250,ay8=75,bx8=75,by8=275;

 line(ax1,ay1,bx1,by1);
 line(ax2,ay2,bx2,by2);
 line(ax3,ay3,bx3,by3);
 line(ax4,ay4,bx4,by4);
 line(ax5,ay5,bx5,by5);
 line(ax6,ay6,bx6,by6);
 line(ax7,ay7,bx7,by7);
 line(ax8,ay8,bx8,by8);
 setcolor(4);
 rectangle(xmn,ymn,xmx,ymx);
 delay(1000);
 
 cleardevice(); 
 
 setcolor(4);
 rectangle(xmn,ymn,xmx,ymx);
 
 setcolor(15);
 coh(ax1,ay1,bx1,by1,xmn,ymn,xmx,ymx);
 coh(ax2,ay2,bx2,by2,xmn,ymn,xmx,ymx);
 coh(ax3,ay3,bx3,by3,xmn,ymn,xmx,ymx);
 coh(ax4,ay4,bx4,by4,xmn,ymn,xmx,ymx);
 coh(ax5,ay5,bx5,by5,xmn,ymn,xmx,ymx);
 coh(ax6,ay6,bx6,by6,xmn,ymn,xmx,ymx);
 coh(ax7,ay7,bx7,by7,xmn,ymn,xmx,ymx);
 coh(ax8,ay8,bx8,by8,xmn,ymn,xmx,ymx);
 delay(1000);
 
 
 getch();
 closegraph();
 return 0;
}

Output: