Bresenham Line Algorithm

 BBS: Inland Empire Archive
Date: 07-28-92 (12:56)             Number: 107
From: BRIAN DESSENT                Refer#: NONE
  To: SIMON KIRBY                   Recvd: NO  
Subj: Bresenham Line Algorithm       Conf: (1) 80xxx

 >  BD> I also have source for an all-integer math circle drawing routine...

 > YES!  I want it too!  I have sort of made my own, except I can't
 > seem to make it work the proper dots per size etc..  THANKS!

Okay, again, this isn't asm, so I apologize for being off
topic, but maybe someone can translate this into ASM and
post it :-)

circle (int xc, yc, radius)   ; center coordinates, radius

  int x, y, d

  x = 0
  y = radius
  d = 2 * (1 - radius)
  while y > x
    plot dot at (xc + x, yc + y)  ; I think there's only 4, but
    plot dot at (xc - x, yc + y)  ; there may be 8 plotdot routines
    plot dot at (xc + x, yc - y)
    plot dot at (xc - x, yc - y)
    if d + y > 0 then
      y = y + 1
      d = d - 2 * y + 1
    endif
    if x > d then
      x = x + 1
      d = d + 2 * x + 1
    endif
  endwhile
done

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