Program to Draw an Ellipse using Mid - Point Algorithm --- Computer Graphics Lab

Program to Draw an Ellipse using Mid - Point Algorithm  --- Computer Graphics Lab

/*** Program to Draw an Ellipse using Mid - Point Algorithm ***/

#include <stdio.h>

#include <dos.h>

#include <graphics.h>

void ellipseMidpoint(float, float, float, float);

void drawEllipse(float, float, float, float);

void main()

{

float xc, yc, rx, ry;

int gd = DETECT, gm;

initgraph(&gd, &gm, "");

printf("\nEnter the center coordinates of ellipse: ");

scanf("%f %f", &xc, &yc);

printf("\nEnter x-radius coordinate: ");

scanf("%f", &rx);

printf("\nEnter y-radius coordiante: ");

scanf("%f", &ry);

ellipseMidpoint(xc, yc, rx, ry);

getch();

}

void ellipseMidpoint(float xc, float yc, float rx, float ry)

{

float rxSq = rx * rx;

float rySq = ry * ry;

float x = 0, y = ry, p;

float px = 0, py = 2 * rxSq * y;

drawEllipse(xc, yc, x, y);

//Region 1

p = rySq - (rxSq * ry) + (0.25 * rxSq);

while (px < py)

{

x++;

px = px + 2 * rySq;

if (p < 0)

p = p + rySq + px;

else

{

y--;

py = py - 2 * rxSq;

p = p + rySq + px - py;

}

drawEllipse(xc, yc, x, y);

delay(30);

}

//Region 2

p = rySq*(x+0.5)*(x+0.5) + rxSq*(y-1)*(y-1) - rxSq*rySq;

while (y > 0)

{

y--;

py = py - 2 * rxSq;

if (p > 0)

p = p + rxSq - py;

else

{

x++;

px = px + 2 * rySq;

p = p + rxSq - py + px;

}

drawEllipse(xc, yc, x, y);

delay(30);

}

}

void drawEllipse(float xc, float yc, float x, float y)

{

putpixel(xc+x, yc+y, RED);

putpixel(xc-x, yc+y, RED);

putpixel(xc+x, yc-y, RED);

putpixel(xc-x, yc-y, RED);

}

--

Don't ever give up.

Even when it seems impossible,

Something will always

pull you through.

The hardest times get even

worse when you lose hope.

As long as you believe you can do it, You can.

But When you give up,

You lose !

I DONT GIVE UP.....!!!

with regards

prem sasi kumar arivukalanjiam