Bresenham’s Line Drawing Algorithm

#include<graphics.h>

#include<iostream.h>

#include<dos.h>

#include<stdio.h>

#include<stdlib.h>

#include<conio.h>

#include<math.h>

class Line

{

      public:

      int x1,x2,y1,y2;

      int dx,dy,x,y,xend,p;

      int xa,ya,xb,yb;

      void input();

      void draw(int,int, int,int);

};

void Line :: input()

{

      cout<<"Enter the points x1,y1:";

      cin>>x1>>y1;

      cout<<"Enter the points x2,y2:";

      cin>>x2>>yb;

draw(x1,y1,x2,y2);

}

void Line :: draw(xa,ya,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,1);

     

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,1);

                  sleep(1);

                 

      }

}

void main()

{

      int gd=DETECT,gm;

      initgraph(&gd,&gm,"");

      Line b;

      b.input();

      closegraph();

      getch();

}

input:   

Enter the points x1,y1:200

300

Enter the points x2,y2:400

350