# Cohen Sutherland Line Clipping Algorithm in C Program | CS1355-Graphics & Multimedia Lab

Computer Graphics LC->line clipping algorithm is method of eliminate lines of outside area of the object .so outside of object viewing is removed .These line clipping was performed by the line function from graphics.h header file.Source code programming
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
void clip(float,float,float);
int i,j=0,n;
int rx1,rx2,ry1,ry2;
float x1[8],y1[8];
void main()
{
int gd=DETECT,gm;
int i,n;
float x[8],y[8],m;
clrscr();
initgraph(&gd,&gm,"");
printf("coordinates for rectangle : ");
scanf("%d%d%d%d",&rx1,&ry1,&rx2,&ry2);
printf("no. of sides for polygon : ");
scanf("%d",&n);
printf("coordinates : ");
for(i=0;i<n;i++)
{
scanf("%f%f",&x[i],&y[i]);
}
cleardevice();
outtextxy(10,10,"Before clipping");
outtextxy(10,470,"Press any key....");
rectangle(rx1,ry1,rx2,ry2);
for(i=0;i<n-1;i++)
line(x[i],y[i],x[i+1],y[i+1]);
line(x[i],y[i],x[0],y[0]);
getch();
cleardevice();
for(i=0;i<n-1;i++)
{
m=(y[i+1]-y[i])/(x[i+1]-x[i]);
clip(x[i],y[i],m);
}
clip(x[0],y[0],m);
outtextxy(10,10,"After clipping");
outtextxy(10,470,"Press any key....");
rectangle(rx1,ry1,rx2,ry2);
for(i=0;i<j-1;i++)
line(x1[i],y1[i],x1[i+1],y1[i+1]);
getch();
}

void clip(float e,float f,float m)
{
while(e<rx1 e>rx2 f<ry1 f>ry2)
{
if(e<rx1)
{
f+=m*(rx1-e);
e=rx1;
}
else if(e>rx2)
{
f+=m*(rx2-e);
e=rx1;
}
if(f<ry1)
{
e+=(ry1-f)/m;
f=ry1;
}
else if(f>ry2)
{
e+=(ry2-f)/m;
f=ry2;
}
x1[j]=e;
y1[j]=f;
j++;
}
}
//# Author: J.Ajai
//#Mail-id- ajay.compiler@gmail.com
//# PH:+91-9790402155
OUTPUT

Enter the x1 & y1 coordinates:
X1 : 70
Y1 : 80
Enter the x2 & y2 coordinates:
X2 : 250
Y2 : 280