Midpoint ellipse algorithms uses symmetry property of an ellipse in order draw it. It plots points . Here is the program to draw an ellipse using midpoint ellipse drawing algorithm.
Program to draw ellipse using Midpoint Ellipse Algorithm in C
Program:
#include<stdio.h> #include<graphics.h> void main(){ long x,y,x_center,y_center; long a_sqr,b_sqr, fx,fy, d,a,b,tmp1,tmp2; int g_driver=DETECT,g_mode; clrscr(); initgraph(&g_driver,&g_mode,"C:\\TURBOC3\\BGI"); printf("********* MID POINT ELLIPSE ALGORITHM *********"); printf("\n\n Enter coordinate x and y = "); scanf("%ld%ld",&x_center,&y_center); printf("\n Now enter constants a and b = "); scanf("%ld%ld",&a,&b); x=0; y=b; a_sqr=a*a; b_sqr=b*b; fx=2*b_sqr*x; fy=2*a_sqr*y; d=b_sqr-(a_sqr*b)+(a_sqr*0.25); do { putpixel(x_center+x,y_center+y,1); putpixel(x_center-x,y_center-y,1); putpixel(x_center+x,y_center-y,1); putpixel(x_center-x,y_center+y,1); if(d<0) { d=d+fx+b_sqr; } else { y=y-1; d=d+fx+-fy+b_sqr; fy=fy-(2*a_sqr); } x=x+1; fx=fx+(2*b_sqr); delay(10); } while(fx<fy); tmp1=(x+0.5)*(x+0.5); tmp2=(y-1)*(y-1); d=b_sqr*tmp1+a_sqr*tmp2-(a_sqr*b_sqr); do { putpixel(x_center+x,y_center+y,1); putpixel(x_center-x,y_center-y,1); putpixel(x_center+x,y_center-y,1); putpixel(x_center-x,y_center+y,1); if(d>=0) d=d-fy+a_sqr; else { x=x+1; d=d+fx-fy+a_sqr; fx=fx+(2*b_sqr); } y=y-1; fy=fy-(2*a_sqr); } while(y>0); getch(); closegraph(); }
Input:
X= 300, Y=300
a = 100, b=150
Output:
Input:
X=300,Y=300
a=200,b=100
Output:
thank you so much.. this code really works..! it helped a lot