Implementation of Line, Circle and ellipse Attributes

CIRCLE DRAWING

AIM:

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

FUNCTIONS USED:

Circle()

      The function circle() is used to draw a circle using(x,y) as centre point.

 Syntax:

         circle (x,y,radius)

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 (xc,yc),get the radius as r.

Step 3: Assign y=r,x=0

Step 4: Calculate p=3-2r

Step 5: If p<0,p=p+4x+6 else p=p+10+4(x-y) and y=y-1

Step 6: Increment x by 1

Step 7: Do steps (9) to (16)

Step 8: Repeat steps (5) to (9) until x<=y

Step 9: Put a pixel on (xc+x,yc+y,15);

Step 10: Put a pixel on (xc+x,yc-y,15);

Step 11: Put a pixel on (xc-x,yc+y,15);

Step 12: Put a pixel on (xc-x, yc-y, 15);

Step 13: Put a pixel on (xc+y,yc+x,15);

Step14: Put a pixel on (xc+y, yc-x, 15);

Step 15: Put a pixel on (xc-y, yc+x, 15);

Step 16: Put a pixel on (xc-y, yc-x, 15);

Step 17: Stop

PROGRAM:

#include<iostream.h>

#include<graphics.h>

#include<conio.h>

#include<math.h>

void my_circle(int,int,int);

void plot(int,int,int,int);

void main()

{

int gd=DETECT,gm;

int xc,yc,r;

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

cout<<"enter X-Axis----->";

cin>>xc;

cout<<"enter  Y-Axis----->";

cin>>yc;

cout<<"enter radius----->";

cin>>r;

my_circle(xc,yc,r);

getch();

closegraph();

}

void my_circle(int xc,int yc,int r)

{

int x,y,p;

p=3-2*r;

x=0;

y=r;

while(x<=y)

{

if(p<0)

p=p+(4*x+6);

else

{

p=p+10+4*(x-y);

y=y-1;

}

plot(xc,yc,x,y);

x=x+1;

}

}

void plot(int xc,int yc,int x,int y)

{

putpixel(xc+x,yc+y,15);

putpixel(xc+x,yc-y,15);

putpixel(xc-x,yc+y,15);

putpixel(xc-x,yc-y,15);

putpixel(xc+y,yc+x,15);

putpixel(xc+y,yc-x,15);

putpixel(xc-y,yc+x,15);

putpixel(xc-y,yc-x,15);

}

INPUT:

Enter X-Axis----->:100

Enter Y-Axis----->:200

Enter radius----->: 40

OUTPUT:

 

:

    

RESULT:

                         Thus the program is executed and verified.