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Re: decorative random colors algorithm

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gernot.hoffmann@hs-emden-leer.de wrote:
> John,
> 
> as stated in my doc, I'm not the inventor of the HLStoRGBf-algorithm.
> 'f' stands for 'Foley,van Dam, Computer Graphics' (famous book), and 
> I had coded this in several programming languages, even Intel Assembly.

Sorry for the misattribution. I saw your pascal comment about that,
but didn't quite appreciate that it referred to the particular algorithm
rather than to the general mathematics.

> On the other hand, I had recognized early, that this color space 
> suffers much from a disadvantage: The saturation on the surface of 
> the double cone is S=1. On the vertical axis we have S=0. Near to poles
> we have in vicinity S=1 and S=0, which is in my opinion a not acceptable
> discontinuity. In order to resolve this problem I had developed my own
> HLS space, which uses S as a true cylinder coordinate - small S for 
> small radius. At that time, trigonometric functions were sufficiently 
> fast, using the standard floating point unit.  

Okay, I'll add your Section 8 code to my C function, along with
an option to use either the "standard" or "hoffmann" method
(yours will become the default, of course:).

> Mainly, I wanted to clarify, that I'm not the inventor of the tricky 
> algorithm.

Right. I always try to be very careful giving credit where credit
is due (sometimes even where it's not due). It's very embarrassing
to look like you're claiming credit for someone else's work. Sorry
for reading your hlscone doc too carelessly to realize the correct
attribution.

> Thanks for the interesting discussion!
> Best regards --Gernot Hoffmann

Thank you very much for originally providing the ps line interpolation
code, and now pointing out the hls model and providing that code, too.
-- 
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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