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);
    }