Midpoint Line Algorithm - Line Drawing C++ program - Graphics & Multimedia Lab

Midpoint Line Algorithm 

Line Drawing C++ program - Graphics & Multimedia Lab

Sourcecode:

//MIDPOINT ALGORITHM



#include<graphics.h>

#include<iostream>

using namespace std;


int count,points[1000];

int i=0;

int gd=DETECT,gm;

int np;



void midLine(int x0,int y0,int x1,int y1)

 {

 int maxy=getmaxy();

 int dx=x1-x0;

 int dy=y1-y0;

 int d=2*dy-dx;

 int incE=2*dy;

 int incNE=2*(dy-dx);

 int x=x0;

 int y=y0;



 putpixel(x,(maxy-y),WHITE);

 points[i]=x;

 points[i+1]=y;

 i+=2;

 while(x<x1)

  {

  if(d<=0)

   {

   d=d+incE;

   x++;

   }

  else

   {

   d=d+incNE;

   x++;

   y++;

   }

  putpixel(x,(maxy-y),WHITE);

  points[i]=x;

  points[i+1]=y;

  i+=2;

  }

 }



main()

 {
  int x0,y0,x1,y1;

 FILE *fp;

 initgraph(&gd,&gm,NULL);



 fp=fopen("inlpoints.txt","r");

 if(fp==NULL)

  {

  printf("ERROR IN READING FILE !");

  getch();

  exit(0);

  }



 fscanf(fp,"%d",&x0);

 fscanf(fp,"%d",&y0);

 fscanf(fp,"%d",&x1);

 fscanf(fp,"%d",&y1);

 fclose(fp);



 midLine(x0,y0,x1,y1);

 fp=fopen("outlpoints.txt","w");

 fprintf(fp,"%s","Plotted points are:-\n");



 count=i;

 np=0;

 for(i=0;i<count;i+=2)

  {

  fprintf(fp,"(%d, %d) ",points[i],points[i+1]);

  np++;

  if(np==5) { fprintf(fp,"\n"); np=0; }

  }

 fclose(fp);



 getch();

 closegraph();

 return(0);

 }

Output:

nn@linuxmint ~ $ g++ lab2.cpp -lgraph
nn@linuxmint ~ $ ./a.out

"inlpoints.txt"

22 22 72 40

"outlpoints.txt"

Plotted points are:-
(22, 22) (23, 22) (24, 23) (25, 23) (26, 23) 
(27, 24) (28, 24) (29, 25) (30, 25) (31, 25) 
(32, 26) (33, 26) (34, 26) (35, 27) (36, 27) 
(37, 27) (38, 28) (39, 28) (40, 28) (41, 29) 
(42, 29) (43, 30) (44, 30) (45, 30) (46, 31) 
(47, 31) (48, 31) (49, 32) (50, 32) (51, 32) 
(52, 33) (53, 33) (54, 34) (55, 34) (56, 34) 
(57, 35) (58, 35) (59, 35) (60, 36) (61, 36) 
(62, 36) (63, 37) (64, 37) (65, 37) (66, 38) 
(67, 38) (68, 39) (69, 39) (70, 39) (71, 40) 
(72, 40)