Computer Graphics Lab

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

int L=0;

void ddaline(int x1,int y1,int x2,int y2)
{

int s,dx,dy,m,c=0;
float xi,yi,x,y;

dx=x2-x1;
dy=y2-y1;

if(abs(dx)>abs(dy))
s=abs(dx);
else
s=abs(dy);

xi=dx/(float)s;
yi=dy/(float)s;

x=x1;
y=y1;

putpixel(x1+0.5,y1+0.5,15);
for(m=0;m<s;m++)
{
x+=xi;
y+=yi;
if(getpixel(x+0.5,y+0.5)==4)
{
c++;
continue;
}
if(c%2==0)
{
putpixel(x+0.5,y+0.5,15);
}
}
}


void plotpoints(int x,int y,int cx,int cy,int s)
{
if(s==0)
{
if(L%20==0)
{
ddaline(cx-x,cy-y,cx+x,cy+y);
ddaline(cx-y,cy+x,cx+y,cy-x);
ddaline(cx-y,cy-x,cx+y,cy+x);
ddaline(cx-x,cy+y,cx+x,cy-y);
}
L++;
}
putpixel(cx+x,cy+y,4);
putpixel(cx-x,cy+y,4);
putpixel(cx+x,cy-y,4);
putpixel(cx-x,cy-y,4);
putpixel(cx+y,cy+x,4);
putpixel(cx-y,cy+x,4);
putpixel(cx+y,cy-x,4);
putpixel(cx-y,cy-x,4);
}


void mcircle(int cx,int cy,int r,int s)
{
int x=0,y,p;

y=r;
p=1-r;

while(x<=y)
{
plotpoints(x,y,cx,cy,s);
x++;
if(p<0)
p+=2*x+1;
else
{
y--;
p+=2*(x-y)+1;
}
}

}

void main()
{
int gd=DETECT,gm=DETECT;
initgraph(&gd,&gm,"");

mcircle(300,250,20,1);
mcircle(300,250,100,0);

getch();
}