C implementation of Midpoint Ellipse Drawing Algorithm

Hi friends ,this time I am posting a program for Midpoint Ellipse Drawing Algorithm in C implemented during my Computer Graphics studies.Note that the output or screenshot shown is REAL and taken using a Virtual Machine.Program written is very simple and can be understood easily.Anyways do leave a comment to us if you got any queries .

PROGRAM CODE

#include<stdio.h>

#include<conio.h>

#include<graphics.h>

int gdriver=DETECT, gmode,i,x,y;

void main()

{

long d1,d2,rx,ry,rxsq,rysq,trxsq,trysq,dx,dy;

printf("\nPlease enter the x radius of the ellipse\n");

scanf("%ld",&rx);

printf("Please enter the y radius of the ellipse\n");

scanf("%ld",&ry);

initgraph(&gdriver,&gmode,"c:\\tc\\bgi");

int xmid,ymid;

xmid=getmaxx()/2;

ymid=getmaxy()/2;

line(xmid+rx+10,ymid-ry,xmid+rx+10,ymid);

line(xmid,ymid-ry-10,xmid+rx,ymid-ry-10);

char ch[20];

sprintf(ch,"%c",17);

outtextxy(xmid,ymid-ry-13,ch);

sprintf(ch,"%c",16);

outtextxy(xmid+rx-6,ymid-ry-13,ch);

sprintf(ch,"%c",30);

outtextxy(xmid+rx+7,ymid-ry,ch);

sprintf(ch,"%c",31);

outtextxy(xmid+rx+7,ymid-6,ch);

sprintf(ch,"%d",rx);

outtextxy(xmid+(rx/2)-5,ymid-ry-20,ch);

sprintf(ch,"%d",ry);

outtextxy(xmid+rx+20,ymid-(ry/2)-1,ch);

outtextxy(getmaxx()-450,getmaxy()-20,"MidPoint Ellipse Algorithm :Program By 1st Kinecteers");

rectangle(getmaxx()-455,getmaxy()-25,getmaxx()-30,getmaxy()-7);

rxsq=rx*rx;

rysq=ry*ry;

trxsq=2*rxsq;

trysq=2*rysq;

x=0;

y=ry;

d1=rysq-rxsq*ry+(0.25*rxsq);

dx=trysq*x;

dy=trxsq*y;

do

{

putpixel(xmid+x,ymid+y,15);

putpixel(xmid-x,ymid-y,15);

putpixel(xmid+x,ymid-y,15);

putpixel(xmid-x,ymid+y,15);

if(d1<0){

x=x+1;

y=y;

dx=dx+trysq;

d1=d1+dx+rysq;

}

else{

x=x+1;

y=y-1;

dx=dx+trysq;

dy=dy-trxsq;

d1=d1+dx-dy+rysq;

}}

while(dx<dy);

d2=rysq*(x+0.5)*(x+0.5)+rxsq*(y-1)*(y-1)-rxsq*rysq;

do

{

putpixel(xmid+x,ymid+y,15);

putpixel(xmid-x,ymid-y,15);

putpixel(xmid+x,ymid-y,15);

putpixel(xmid-x,ymid+y,15);

if(d2>0){

x=x;

y=y-1;

dy=dy-trxsq;

d2=d2-dy+rxsq;

}

else{

x=x+1;

y=y-1;

dy=dy-trxsq;

dx=dx+trysq;

d2=d2+dx-dy+rxsq;

}}

while(y>0);

getch();

}

OUTPUT: