CS2405 Two Dimensional transformations - Translation, Rotation, Scaling, Reflection, Shear.

CS2405 Two Dimensional transformations - Translation, Rotation, Scaling, Reflection, Shear.

ELLIPSE DRAWING

AIM:

               To write a program to draw a ellipse using Bresenham’s ellipse drawing Algorithm.

FUNCTIONS USED:

initgraph().

       This function takes thee arguments and they are

         i).the video driver to be used (gd).

         ii).the graphics mode (gm).

         iii).the path name.

Syntax:

       Initgraph(gd,gm,path)

Putpixel ()

      The function putpixel() is used to place a pixel at particular coordinate

Syntax:

         Putpixel(x,y,color)

ALGORITHM:

Step 1: Start

Step 2: Get the center point as(x1, y1)

Step 3: Get the length of semi-major, semi-minor axes as r1 & r2

Step 4: Calculate t=pi/180

Step 5: Initialise i=0;

Step 6: Compute d=i*t

Step 7: Compute x=x1+y1*sin(d), y=y1+r2*cos(d).

Step 8: Put a pixel on(x,y)

Step 9: Increment I by 1

Step 10: Repeat steps(6) to (9) until i<360

Step 11: Stop

PROGRAM:

#include<iostream.h>

#include<graphics.h>

#include<conio.h>

#include<math.h>

void main()

{

int gd=DETECT,gm,x1=0,y1=0,r1=0,r2=0;

float x=0,y=0,t,d,i;

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

cout<<"enter the center co-or:";

cin>>x1>>y1;

cout<<"enter  the radius1:";

cin>>r1;

cout<<"enter radius2:";

cin>>r2;

for(i=0;i<360;i++)

{

t=3.14/180;

d=i*t;

x=x1+ceil(r1*sin(d));

y=y1+ceil(r2*cos(d));

putpixel(x,y,15);

}

getch();

closegraph();

}

INPUT:

Enter the center co-or:100 150

Enter the radius1:40

Enter radius2:20

OUTPUT:

RESULT:

             Thus the program is executed and verified.