Implementation of Bresenhams algorithm

Implementation of Bresenhams algorithm 

Enginer's Portal 

 1.a.) Implementation of Bresenhams algorithm - 

Program :


// This program will work for all input ....  0<m<1 and m>1 
// where 'm' is slope


#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,dxt,dyt,slope_pos,yend;
initgraph(&gd,&gm,"H:\\TC\\BGI");
printf("Enter the First End points(xa,ya):\n");
scanf("%d%d",&xa,&ya);
printf("Enter the Second End points(xb,yb):\n");
scanf("%d%d",&xb,&yb);


dxt=xb-xa;
dyt=yb-ya;
dx=abs(xb-xa);
dy=abs(yb-ya);


slope_pos=(dxt>0);
if(dyt<0)
slope_pos=!slope_pos;


if(dx>dy)   // slope => 0<m<1
{
p=2*dy-dx;
if(xa>xb)
{
x=xb;
y=yb;
xend=xa;
}
else
{
x=xa;
y=ya;
xend=xb;
}


    while(x<xend)
      {
      x=x+1;
      if(p<0)
      {
      p=p+2*dy;
      }
      else
      {
      if(slope_pos)
      y=y+1;
      else
      y=y-1;
      p=p+2*(dy-dx);
      }
      putpixel(x,y,6);
      }
      }
      else   // slope => m>1
      {
p=2*dx-dy;
if(ya>yb)
{
x=xb;
y=yb;
yend=ya;
}
else
{
x=xa;
y=ya;
yend=yb;
}
    while(y<yend)
      {
      y=y+1;
      if(p<0)
      {
      p=p+2*dx;
      }
      else
      {
      if(slope_pos)
      x=x+1;
      else
      x=x-1;
      p=p+2*(dx-dy);
      }
      putpixel(x,y,6);
      }
      }
    putpixel(xa,ya,4);
    putpixel(xb,yb,4);
   getch();
   return(0);
}


Output :

Enter The Two Left Endpoints(xa,ya):       50    60

Enter The Two Right Endpoints(xb,yb):    150 360

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