Experiment-2 Computer Graphics (Bresenham's Line Drawing Algorithm).cpp

#include <iostream.h>
#include <conio.h>
#include <math.h>
#include <stdlib.h>
#include <dos.h>
#include <graphics.h>

void bresenhamsthick (int x1,int y1, int x2, int y2);
void bresenhamsthick (int x1,int y1, int x2, int y2)
{
 int dx,dy,p0,pk;
 dx=(x2-x1);
 dy=(y2-y1);
 p0 =2*dy-dx;
 int x,y;
 x=x1;
 y=y1;
 pk=p0;
 putpixel(x,y,WHITE);
 while(x<=x2){
   if(pk<0){
     x=x+1;
     y=y;
    putpixel(x,y,WHITE);
     pk=pk+2*dy;
   }
   else{
     x=x+1;
     y=y+1;
     putpixel(x,y,WHITE);
     pk=pk+(2*(dy-dx));

   }

 }
}

void bresenhamsdotted (int x1,int y1, int x2, int y2);
void bresenhamsdotted (int x1,int y1, int x2, int y2)
{
 int dx,dy,p0,pk;
 dx=(x2-x1);
 dy=(y2-y1);
 p0=2*dy-dx;
 int x,y;
 x=x1;
 y=y1;
 pk=p0;
 putpixel(x,y,WHITE);
 int i=0;
 while(x<=x2){
   if(pk<0){
     x=x+1;
     y=y;
     if(i%2!=0)
     {
	putpixel(x,y,WHITE);
     }
     pk=pk+2*dy;
   }
   else{
     x=x+1;
     y=y+1;
     if(i%2!=0)
     {
	putpixel(x,y,WHITE);
     }
     pk=pk+(2*(dy-dx));

   }
   i++;
 }
}

void bresenhamsdashed (int x1,int y1, int x2, int y2);
void bresenhamsdashed (int x1,int y1, int x2, int y2)
{
 int dx,dy,p0,pk;
 dx=(x2-x1);
 dy=(y2-y1);
 p0 =2*dy-dx;
 int x,y;
 x=x1;
 y=y1;
 pk=p0;
 putpixel(x,y,WHITE);
 int i=0;
 while(x<=x2){
   if(pk<0){
     x=x+1;
     y=y;
     if(i%8!=0)
     {
	putpixel(x,y,WHITE);
     }
     pk=pk+2*dy;
   }
   else{
     x=x+1;
     y=y+1;
     if(i%8!=0)
     {
	putpixel(x,y,WHITE);
     }
     pk=pk+(2*(dy-dx));

   }
   i++;
 }
}


void main()
{
 int gd=DETECT,gm;
 int x1,y1,x2,y2,option;
 initgraph(&gd,&gm,"C:\\TURBOC3\\BGI");
 cleardevice();
 cout<< "Bresenham's Line Generation Algorithm";
 cout<<"\n Enter the starting co-ordinates for drawing a line";
 cin>>x1>>y1;
 cout<<"\n Enter the ending co-ordinates";
 cin>>x2>>y2;
 cout<<"\n1) Thick\n2) Dotted \n3) Dashed\nEnter your options: \n";
 cin>>option;
 //switch case
  switch(option){
    case 1: bresenhamsthick(x1,y1,x2,y2);
    break;
    case 2:bresenhamsdotted(x1,y1,x2,y2);
    break;
    case 3:bresenhamsdashed(x1,y1,x2,y2);
    break;
    default: cout<<"\n Invalid option";
    break;
  }


 getch();
 closegraph();
 }