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Article #568

236 color GIF's on Windows? 20 more colors, please!

#568
From: In Sik Rhee
Date: Mon, 05 Nov 1990 10:21
35 lines
2482 bytes
After hacking away for 13 straight hours today, I finished my GifImp code
finally...  Surprise, surprise, the pre-release ships tomorrow (actually,
today... yawn!).  but I haven't quite perfected it, so I'm asking for some
advice/tips/help...

As I have it now, I am importing a GIF and creating a DIB (Device-Independant
Bitmap) which, in turn, becomes a Metafile... now, the problem I face is 
that with a 256 color GIF image, I create a logical palette... but when
I select and realize it, windows will not let me take precedence over its
20 primary colors in the system palette... so essentially, it will only 
give me 236 color indices... (or am I doing something wrong?)  so for now,
I am setting the last 20 colors the value of the 236th color (usually works
out since most 256 color vga shots are digitized pics which have very close
color values for closely mapped values) and you really cant tell the 
difference unless you looked for it.  

But I'm a purist, so I want to know how I can incorporate all my 256 colors
(or as many as possible) for my application.   

I have one hypothesis that I think may work... In addition to selecting
and realizing the logical palette, I can pass literal RGB values to the
DIB instead of color indices... Wouldn't that give me the same results for
the 236 colors already defined?  and as for the last 20 colors, since 
windows palette manager will use a "best-match" algorithm, wouldn't they
be mapped to the nearest possible pre-defined colors?  so that way,
instead of having them all be the 236th color, they'll be the closest 
color out of the 236 colors (+20 system colors)

Can someone help me out?  Am I making any sense?  I'd like to get this 
problem solved so I can go onto bigger problems at hand (like trying to
get Word for Windows and Microsoft PowerPoint to use my filter correctly)

Thanks in advance for any comments...

					InSik Rhee
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Message-ID: <1990Nov5.102146.27535@agate.berkeley.edu>
Path: arc1-ca.pugleaf.net!utzoo!utgpu!watserv1!watmath!att!att!emory!wuarchive!julius.cs.uiuc.edu!apple!agate!e260-3f!c60c-3fz

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!watserv1!watmath!att!att!emory!wuarchive!julius.cs.uiuc.edu!apple!agate!e260-3f!c60c-3fz
From: c60c-3fz@e260-3f.berkeley.edu (In Sik Rhee)
Newsgroups: comp.windows.ms.programmer
Subject: 236 color GIF's on Windows?  20 more colors, please!
Summary: GIF, BMP, Metafile for Windows 3.0
Keywords: GIF BMP METAFILE VGA
Message-ID: <1990Nov5.102146.27535@agate.berkeley.edu>
Date: 5 Nov 90 10:21:46 GMT
Sender: usenet@agate.berkeley.edu (USENET Administrator)
Organization: University of California, Berkeley
Lines: 35