Question

Write A program To implement Cohen sutherland Line Clipping Algorithm

Answer 1

#include<stdio.h>
	#include<conio.h>
	#include<stdlib.h>
	#include<dos.h>
	#include<math.h>
	#include<graphics.h>
 	typedef struct coordinate
	{
	int x,y;
	char code[4];
	}PT;
	void drawwindow();
	void drawline (PT p1,PT p2,int cl);
	PT setcode(PT p);
	int visibility (PT p1,PT p2);
	PT resetendpt (PT p1,PT p2);
	main()
	{
	int gd=DETECT, gm,v;
	PT p1,p2,ptemp;
	initgraph(&gd,&gm,"\\tc\\bgi");
	cleardevice();
	printf("\n\n\t\tENTER END-POINT 1 (x,y): ");
	scanf("%d,%d",&p1.x,&p1.y);
	printf("\n\n\t\tENTER END-POINT 2 (x,y): ");
	scanf("%d,%d",&p2.x,&p2.y);
	cleardevice();
	drawwindow();
	getch();
	drawline(p1,p2,15);
	getch();
	p1=setcode(p1);
	p2=setcode(p2);
	v=visibility(p1,p2);
	switch(v)
		{
		case 0:	cleardevice(); /* Line completely visible*/
				drawwindow();
				drawline(p1,p2,15);
				break;
		case 1:	cleardevice(); /* Line completely invisible */
				drawwindow();
				break;
		case 2:	cleardevice(); 	/* line partly visible */
				p1=resetendpt (p1,p2);
				p2=resetendpt(p2,p1);
				drawwindow();
				drawline(p1,p2,15);
				break;
		}
	getch();
	closegraph();
	return(0);
	}
 void drawwindow()
	{
	setcolor(RED);
	line(150,100,450,100);
	line(450,100,450,350);
	line(450,350,150,350);
	line(150,350,150,100);
	}
 	void drawline (PT p1,PT p2,int cl)
	{
	setcolor(cl);
	line(p1.x,p1.y,p2.x,p2.y);
	}
     PT setcode(PT p)
	{
	PT ptemp;
	if(p.y<100)
	ptemp.code[0]='1'; /* TOP */
	else
	ptemp.code[0]='0';
	if(p.y>350)
	ptemp.code[1]='1'; /* BOTTOM */
	else
	ptemp.code[1]='0';
	if (p.x>450)
	ptemp.code[2]='1'; /* RIGHT */
	else
	ptemp.code[2]='0';
	if (p.x<150) /* LEFT */
	ptemp.code[3]='1';
	else
	ptemp.code[3]='0';
	ptemp.x=p.x;
	ptemp.y=p.y;
	return(ptemp);
	}
	 int visibility (PT p1,PT p2)
	{
	int i,flag=0;
	for(i=0;i<4;i++)
	{
	if((p1.code[i]!='0')||(p2.code[i]!='0'))
	flag=1;
	}
	if(flag==0)
	return(0);
	for(i=0;i<4;i++)
	{
	if((p1.code[i]==p2.code[i]) &&(p1.code[i]=='1'))
	flag=0;
	}
	if(flag==0)
	return(1);
	return(2);
	}
 	PT resetendpt (PT p1,PT p2)
	{
	PT temp;
	int x,y,i;
	float m,k;
	if( p1.code[3]=='1') /* Cutting LEFT Edge  */
	x=150;
	if(p1.code[2]=='1')  /* Cutting RIGHT Edge */
	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')  /* Cutting TOP Edge */
	y=100;
	if(p1.code [1]=='1') /* Cutting BOTTOM Edge */
	y=350;
	if((p1.code[0]=='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);
	}