1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include "hp2648.h"
void
circle(int xc, int yc, int r)
{
double costheta,sintheta,x,y,xn;
int xi,yi;
if(r<1){
point(xc,yc);
return;
}
sintheta = 1.0/r;
costheta = pow(1-sintheta*sintheta,0.5);
xi = x = r;
yi = y = 0;
do {
point(xc+xi,yc+yi);
xn = x;
xi = x = x*costheta + y*sintheta;
yi = y = y*costheta - xn*sintheta;
} while( ! (yi==0 && xi >= r-1));
}
|
