cg_ass10.cpp

//cohen sutherland window clipping
#include<iostream>
#include<stdlib.h>
#include<math.h>
#include<graphics.h>
//#include<dos.h>
using namespace std;
class Coordinate
{
public:
int x,y;
char code[4];
};
class Lineclip
{
public:
Coordinate PT;
void drawwindow();
void drawline(Coordinate p1,Coordinate p2);
Coordinate setcode(Coordinate p);
int visibility(Coordinate p1,Coordinate p2);
Coordinate resetendpt(Coordinate p1,Coordinate p2);
};
int main()
{
Lineclip lc;
int gd = DETECT,v,gm;
Coordinate p1,p2,p3,p4,ptemp;

cout<<"\n Enter x1 and y1\n";
cin>>p1.x>>p1.y;
cout<<"\n Enter x2 and y2\n";
cin>>p2.x>>p2.y;

initgraph(&gd,&gm,NULL);
lc.drawwindow();
delay(2000);

lc.drawline (p1,p2);
delay(2000);
cleardevice();

delay(2000);
p1=lc.setcode(p1);
p2=lc.setcode(p2);
v=lc.visibility(p1,p2);
delay(2000);

switch(v)
{
case 0: lc.drawwindow();
delay(2000);
lc.drawline(p1,p2);
break;
   case 1:lc.drawwindow();
        delay(2000);
        break;
   case 2:p3=lc.resetendpt(p1,p2);
      p4=lc.resetendpt(p2,p1);
      lc.drawwindow();
      delay(2000);
      lc.drawline(p3,p4);
      break;

    }
     delay(2000);
     closegraph();
 }
 
 
 void Lineclip::drawwindow()
 {
  line(150,100,450,100);
  line(450,100,450,350);
  line(450,350,150,350);
  line(150,350,150,100);
 
 }
 
 void Lineclip::drawline(Coordinate p1,Coordinate p2)
 {
  line(p1.x,p1.y,p2.x,p2.y);
 }

Coordinate Lineclip::setcode(Coordinate p)

{
Coordinate ptemp;


if(p.y<100)
   ptemp.code[0]='1';
else
   ptemp.code[0]='0';
   
if(p.y>350)
ptemp.code[1]='1';
else
ptemp.code[1]='0';


if(p.x>450)
ptemp.code[2]='1';
else
ptemp.code[2]='0';

if(p.x<150)
ptemp.code[3]='1';
else
ptemp.code[3]='0';


ptemp.x=p.x;
ptemp.y=p.y;

return(ptemp);

};


int Lineclip:: visibility(Coordinate p1,Coordinate p2)
{
int i,flag=0;

for(i=0;i<4;i++)
{
if(p1.code[i]!='0' || (p2.code[i]=='1'))
 flag='0';
}

if(flag==0)
return(0);

for(i=0;i<4;i++)
{
if(p1.code[i]==p2.code[i] && (p2.code[i]=='1'))
flag='0';
}

if(flag==0)
return(1);


return(2);
}

Coordinate Lineclip::resetendpt(Coordinate p1,Coordinate p2)
{
Coordinate temp;
int x,y,i;
float m,k;


if(p1.code[3]=='1')
x=150;
if(p1.code[2]=='1')
x=450;
if((p1.code[3]=='1') || (p1.code[2])=='1')
{


m=(float)(p2.y-p1.y)/(p2.x-p1.x);
k=(p1.y+(m*(x-p1.x)));
temp.y=k;
temp.x=x;

for(i=0;i<4;i++)
temp.code[i]=p1.code[i];

   if(temp.y<=350 && temp.y>=100)
    return (temp);
}


if(p1.code[0]=='1')
y=100;
if(p1.code[1]=='1')
y=350;
if((p1.code[1]=='1') || (p1.code[1]=='1'))
{
m=(float)(p2.y-p1.y)/(p2.x-p1.x);
k=(float)p1.x+(float)(y-p1.y)/m;
temp.x=k;
temp.y=y;

for(i=0;i<4;i++)
temp.code[i]=p1.code[i];

return(temp);


}
else
return(p1);


}

/*
Input :

X1 , Y1:
100
200

X2, Y2 :
500
100
*/