C Program for Bresenham line drawing algorithm

ALGORITHM:

1.      Start

2.      Get the values of the end points as (x1,y1) and (x2,y2)

3.      Initialize the graphics mode.

4.      calculate dx=abs(x2-x1) dy=abs(y2-y1)

5.      Initialize starting point x=x1,y=y1

6.      e= 2*dy-dx

7.      i=1

8.      plot(x,y)

9.      y=y+1

10.  e=e-2dx

11.  repeat 9&10  until e>=0

12.  x=x+1

13.  e=e+2dy

14.  i=i+1

15.  If i<dx then go to step 8.

PROGRAM:

#include<stdio.h>

#include<math.h>

#include<graphics.h>

int main()

{

int dx,dy,p,tdy,tdydx,xa,xb,ya,yb;

int x,y,xend;

int gd=DETECT,gm;

initgraph(&gd,&gm," ");

printf("\nEnter the value of x1,y1:\t");

scanf("%d\t%d",&xa,&ya);

printf("\nEnter the value of x2,y2:\t");

scanf("%d\t%d",&xb,&yb);

dx=abs(xa-xb);

dy=abs(ya-yb);

p=2*dy-dx;

tdy=2*dy;

tdydx=2*(dy-dx);

if(xa>xb)

{

x=xb;

y=yb;

xend=xa;

}

else

{

x=xa;

y=ya;

xend=xb;

}

putpixel(x,y,11);

outtextxy(xa,ya,"(xa,ya)");

outtextxy(xb,yb,"(xb,yb)");

while(x<xend)

{

x++;

if(p<0)

{

p=p+tdy;

}

else

{

y++;

p=p+tdydx;

}

putpixel(x,y,11);

delay(50);

}

closegraph();

}

Posted in: C / C++ Program,learning