Bresenham’s algorithm for line coding and example

BRESENHAM’S ALGORITHM


AIM :

     To  implement the Bresenham’s  algorithm for line using a c coding.


LINE :


ALGORITHM :

   Step 1 : Start.
   
   Step 2 : Initialize the graphics header files and functions.

   Step 3 : Declare the required variables and functions.

   Step 4 : Get the four points for drawing a line namely x1,x2,y1,y2.

   Step 5 : Draw the line using the algorithm.

   Step  6 : Display the output.

   Step 7 : stop.






PROGRAM :

#include "stdio.h"
#include "conio.h"
#include "math.h"
#include "graphics.h"
main()
{
    int gd=DETECT,gm;
    int xa,xb,ya,yb;
    int dx,dy,x,y,xend,p;
    initgraph(&gd,&gm,"c:\\tc\\bgi");
    printf("Enter The Two Left Endpoints(xa,ya):\n");
    scanf("%d%d",&xa,&ya);
    printf("Enter The Two Right Endpoints(xb,yb):\n");
    scanf("%d%d",&xb,&yb); 

    dx=abs(xa-xb);
    dy=abs(ya-yb);
    p=2*dy-dx;
    if(xa>xb)
    {
      x=xb;
      y=yb;
      xend=xa;
    }
  else
{  
    x=xa;
      y=ya;
      xend=xb;
}
      putpixel(x,y,6);
     while(x<xend)
      {
      x=x+1;
      if(p<0)
      {
      p=p+2*dy;
      }
  
      else    
      {
      y=y+1;
      p=p+2*(dy-dx);    
      }
      putpixel(x,y,6);
      }
   getch();
   return(0);
}






OUTPUT :

Enter The Two Left Endpoints(xa,ya):    234  124

Enter The Two Right Endpoints(xb,yb):  578  321