4.3BSD - /usr/src/usr.lib/libplot/hp2648/circle.c

   1: /*
   2:  * Copyright (c) 1980 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #ifndef lint
   8: static char sccsid[] = "@(#)circle.c	5.1 (Berkeley) 5/7/85";
   9: #endif not lint
  10: 
  11: #include "hp2648.h"
  12: 
  13: circle (xc,yc,r)
  14: int xc,yc,r;
  15: {
  16:     double costheta,sintheta,x,y,xn;
  17:     int xi,yi;
  18: 
  19:     if(r<1){
  20:         point(xc,yc);
  21:         return;
  22:     }
  23:     sintheta = 1.0/r;
  24:     costheta = pow(1-sintheta*sintheta,0.5);
  25:     xi = x = r;
  26:     yi = y = 0;
  27:     do {
  28:         point(xc+xi,yc+yi);
  29:         xn = x;
  30:         xi = x = x*costheta + y*sintheta;
  31:         yi = y = y*costheta - xn*sintheta;
  32:     } while( ! (yi==0 && xi >= r-1));
  33: }

Defined functions

Defined variables