Mid Point Ellipse Drawing Algorithm

This program is for implementing Mid Point Ellipse Drawing Algorithm. This is a part of Mumbai University MCA Colleges Computer Graphics CG MCA Sem 2


#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<graphics.h>

void plot(int xc,int yc,int x,int y)
{
            putpixel(x+xc,y+yc,1);
            putpixel(x+xc,-y+yc,1);
            putpixel(-x+xc,y+yc,1);
            putpixel(-x+xc,-y+yc,1);
}

void myellipse(int xc,int yc,int rx,int ry)
{
            long rx2,ry2,px,py,tworx2,twory2,p;
            float x,y;
            x=0;
            y=ry;
            rx2=rx*rx;
            ry2=ry*ry;
            tworx2=2*rx2;
            twory2=2*ry2;
            px=0;
            py=tworx2*y;
//Printing the initial point
            plot(xc,yc,x,y);
            p=(int)(ry2-(rx2*ry)+(0.25*rx2));
            while(px<py)
            {
                        x++;
                        px+=twory2;
                        if(p<0)
                                    p+=px+ry2;
                        else
                        {
                                    y=y-1;
                                    py-=tworx2;
                                    p+=ry2+px-py;
                        }
                        plot(xc,yc,x,y);
            }
            p=(int)((ry2*(x+0.5)*(x+0.5)+rx2*(y-1)*(y-1)-rx2*ry2));
            while(y>0)
            {
                        y--;
                        py-=tworx2;
                        if(p>0)
                                    p+=rx2-py;
                        else
                        {
                                    x++;
                                    px+=twory2;
                                    p+=rx2-py+px;
                        }
                        plot(xc,yc,x,y);
            }
}

void main()
{
            int gd,gm;
            int xc,yc,rx,ry;
            clrscr();
            gd=DETECT;
            detectgraph(&gd,&gm);
            printf("Enter values of centre of ellipse\n");
            scanf("%d%d",&xc,&yc);
            printf("Enter the x radius and y radius\n");
            scanf("%d%d",&rx,&ry);
            initgraph(&gd,&gm,"c:\\tc\\bgi");
            myellipse(xc,yc,rx,ry);
            getch();
}



Hope this Program is useful to you in some sense or other. Keep on following this blog for more Mumbai University MCA College Programs. Happy Programming and Studying.

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