Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!news-out.readnews.com!transit3.readnews.com!panix!not-for-mail From: JohnF Newsgroups: comp.graphics.algorithms Subject: Re: decorative random colors algorithm Date: Wed, 4 Jul 2012 15:05:29 +0000 (UTC) Organization: PANIX Public Access Internet and UNIX, NYC Lines: 66 Message-ID: References: <86781430-5454-4e19-8eaa-3961622f5054@googlegroups.com> NNTP-Posting-Host: panix3.panix.com X-Trace: reader1.panix.com 1341414329 26815 166.84.1.3 (4 Jul 2012 15:05:29 GMT) X-Complaints-To: abuse@panix.com NNTP-Posting-Date: Wed, 4 Jul 2012 15:05:29 +0000 (UTC) User-Agent: tin/2.0.0-20110823 ("Ardenistiel") (UNIX) (NetBSD/5.1.2 (i386)) Xref: csiph.com comp.graphics.algorithms:923 gernot.hoffmann@hs-emden-leer.de wrote: > > John, > > to be honest, the older version (kind of pastel) looked for me more > esthetical than the one between (didn't see the last one). That's pretty much still available, though I forget its exact parameters. I've uploaded forkosh.com/decorative5.ps that's a pretty much random "color wheel", which was the version originally intended for maximum "decorativeness". By the way, although named .ps, it's eps, see below. The forkosh.com/decorative4.ps now runs through 0<=h<=360 just once around its entire circumference (rather than the three times for ngon=3 earlier). That's controlled by the (new) huesteps=0 attribute for once around, or omit the huesteps attribute entirely for the original "three times around". That's arguably not as decorative, but its intent was to be a little more informative, in a somewhat decorative way, or something like that. The older more decorative stuff is still all available, just by running the cgi with an appropriate query string eps&attribute1=value1&etc. I haven't "disabled" any functionality, just added new stuff and demonstrated it. Using any old file's %title line for the cgi's query string should reproduce that old file (unless I've goofed). > Here, *.PS files are automatically converted into PDF by Acrobat. > If you could send PDF, then everybody could use the free Adobe Reader > or Acrobat. > > If you used *.EPS instead of *.PS, then we could view them immediately > by other Adobe programs (Photoshop, InDesign, Illustrator). Already done. Just replace that leading ps&etc attribute with eps&etc. That was actually in the program all along. I just didn't think to mention it. The only differences are the top two lines, 1,2c1 < %!PS-Adobe EPSF-3.0 < %%BoundingBox: 0 0 612 792 --- > %!PS and the (absence of the) last line preceding the %%EOF 465a465 [or some other line#, depending on the graphic] > showpage I hope that's all that's needed. When I originally wrote the program and read some online pages about ps, that's all that seemed necessary. So I coded it that way, but never really checked the correctness of the results beyond the fact that gv doesn't complain. > Yes, this HLS<-->RGB conversion is really tricky. Maybe it's only an > approximation (I forgot the algorithm), but this dates back perhaps 35 > years, where trigonometric functions were very time consuming. Yeah, antique slide rules on ebay sell for a lot these days. The angles of the rotated rgb axes all seem to be 45 degrees wrt the sl-plane, but I still couldn't immediately see how you're getting all the projections so easily. But it's all hidden in the function, and can be easily changed if needed, completely transparent to the rest of the program. > Best regards --Gernot Hoffmann Thanks again. -- John Forkosh ( mailto: j@f.com where j=john and f=forkosh )