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Groups > comp.graphics.algorithms > #931

Re: decorative random colors algorithm

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JohnF <john@please.see.sig.for.email.com> wrote:
> 
> I think I got your (and Foley,van Dam's) algorithms right,
> but have included the updated function below. For example,
> I didn't have your limtab, and just clipped your single
> r,g,b's to 1.0. Don't think that accounts for
> any of the "diff difference".

I realized that my snippet of clipping code
  >  double  r = l+u+u,  g = l-u+v,  b = l-u-v;
  >  double  rgbmax = (r>g? (r>b?r:b) : (g>b?g:b));
  >  if ( rgbmax > 1.0 ) {
  >    r /= rgbmax;  g /= rgbmax;  b /= rgbmax; }
  >  red    = (int)(255.0*r + 0.5);
  >  green  = (int)(255.0*g + 0.5);
  >  blue   = (int)(255.0*b + 0.5);
which I inferred from
your Section 4.3 discussion
  Proportional clipping
  improves the quality
  m=max(r,g,b)
  If m>255 Then
  Begin
  s=255/m
  r=Round(r*s)
  g=Round(g*s)
  b=Round(b*s)
  End
can't possibly be equivalent to your table clipping
that you're doing in Section 8
  rb:=LimTab^[ri]; { Limiter by table }
  gb:=LimTab^[gi];
  bb:=LimTab^[bi];
since you're clipping each component independently,
i.e., if LimTab^[ri] < ri gets clipped, the other
two aren't (necessarily) affected at all.
-- 
John Forkosh  ( mailto:  j@f.com  where j=john and f=forkosh )

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decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-01 12:15 +0000
  Re: decorative random colors algorithm gernot.hoffmann@hs-emden-leer.de - 2012-07-01 07:59 -0700
    Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-02 07:58 +0000
      Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-02 12:29 +0000
  Re: decorative random colors algorithm Nobody <nobody@nowhere.com> - 2012-07-01 16:25 +0100
    Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-02 08:28 +0000
  Re: decorative random colors algorithm gernot.hoffmann@hs-emden-leer.de - 2012-07-03 01:17 -0700
    Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-03 10:27 +0000
  Re: decorative random colors algorithm gernot.hoffmann@hs-emden-leer.de - 2012-07-03 21:50 -0700
    Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-04 05:15 +0000
      Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-04 08:01 +0000
  Re: decorative random colors algorithm gernot.hoffmann@hs-emden-leer.de - 2012-07-04 02:20 -0700
    Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-04 09:51 +0000
      Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-04 10:59 +0000
        Re: decorative random colors algorithm Wally W. <ww84wa@aim.com> - 2012-07-04 09:03 -0400
          Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-04 13:46 +0000
            Re: decorative random colors algorithm Wally W. <ww84wa@aim.com> - 2012-07-04 12:39 -0400
  Re: decorative random colors algorithm gernot.hoffmann@hs-emden-leer.de - 2012-07-04 07:10 -0700
    Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-04 15:05 +0000
  Re: decorative random colors algorithm gernot.hoffmann@hs-emden-leer.de - 2012-07-04 09:12 -0700
    Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-05 03:18 +0000
      Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-05 05:54 +0000
        Re: decorative random colors algorithm John Forkosh <forkosh@panix.com> - 2012-07-05 12:23 +0000
  Re: decorative random colors algorithm "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-07-05 07:48 +0200
    Re: decorative random colors algorithm JohnF <john@please.see.sig.for.email.com> - 2012-07-05 06:14 +0000
    Re: decorative random colors algorithm Wally W. <ww84wa@aim.com> - 2012-07-05 07:30 -0400

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