Message-ID: <37AC37B8.B29A3614@unb.ca>
From: Endlisnis <s257m AT unb DOT ca>
X-Mailer: Mozilla 4.61 [en] (Win98; U)
X-Accept-Language: en
MIME-Version: 1.0
Newsgroups: comp.os.msdos.djgpp,comp.programming
Subject: Re: Circle Drawing Algorithms
References: <7oh04k$3vb$1 AT newsreader2 DOT core DOT theplanet DOT net>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 44
Date: Sat, 07 Aug 1999 13:43:40 GMT
NNTP-Posting-Host: 209.226.124.244
X-Trace: news20.bellglobal.com 934033420 209.226.124.244 (Sat, 07 Aug 1999 09:43:40 EDT)
NNTP-Posting-Date: Sat, 07 Aug 1999 09:43:40 EDT
Organization: Sympatico
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Andy Kilner wrote:

> What is the fastest circle algorithm available at the moment?

This is a snip of code from my graphics library.  It only draws 1/8th of the
circle and reflects the rest.  Also, no multiplication or trig is done and
only integers are used.

void _GraphixBase::Circle(short X, short Y, short Radius, byte Clr)
{
 short x=0;
 short y=Radius;
 short step=1-y;

 while(y>=x)
 {
  Pset(X+x, Y+y, Clr);
  Pset(X+y, Y+x, Clr);
  Pset(X+y, Y-x, Clr);
  Pset(X+x, Y-y, Clr);
  Pset(X-x, Y-y, Clr);
  Pset(X-y, Y-x, Clr);
  Pset(X-y, Y+x, Clr);
  Pset(X-x, Y+y, Clr);

  if (step<0) step += x+x+3;
  else
  {
   step += ((x-y)<<1)+5;
   y--;
   }
  x++;
  }
 }



--
     (\/) Endlisnis (\/)
          s257m AT unb DOT ca
          Endlisnis AT HotMail DOT com
          ICQ: 32959047