Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!bloom-beacon!INTELLICORP.COM!TRANLE
From: TRANLE@INTELLICORP.COM (Minh Tran-Le)
Newsgroups: comp.windows.x
Subject: Re: How does the X protocol deal with colors ?
Message-ID: <8907262013.AA05801@expo.lcs.mit.edu>
Date: 26 Jul 89 21:13:37 GMT
References: <8907261834.AA20315@expire.lcs.mit.edu>
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
Lines: 29

>>    Does it use the 2 colormap entries (pixel value) or does it use the rgb
>>    values to do the logical combination ?
> 
> *All* graphics ops (even those in windows) are based purely on pixel values.
> (Another hint of this for pixmaps: pixmaps don't *have* visuals or colormaps.
> 

What is the correct way to do consistent color operation across platforms ?

This is because I am building and application that will run different
platforms using black&white or color displays.  And I have seen that a 
black pixel is usually 0 on a B&W display but on my color PS2 it is also 0 
while on my color vax decwindows display it is 252.

Should I use only logical functions that always do the same thing on all the
displays like GXclear, GXcopy, GXnoop and GXset. But that is pretty 
restrictive about what you can do with these operations.

Should I use my own colormap where I would know where all the colormap
entries are .  But some machines will not allow you to install multiple 
colormaps. And also it would interfere with the other applications running 
on the same display.


Thanks, Tran Le.

Internet: tranle@intellicorp.com
uucp:   ..sun!icmv!mtranle
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