Write C++ program to implement Cohen Southerland line clipping algorithm.
Computer Graphics Assignment 2
Write C++ program to implement Cohen Southerland line clipping algorithm.
Code :
#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,"");
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
Output :
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