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From: jim@EXPO.LCS.MIT.EDU (Jim Fulton)
Newsgroups: comp.windows.x
Subject: Re: color map question
Message-ID: <8806161400.AA24624@EXPO.LCS.MIT.EDU>
Date: 16 Jun 88 14:00:00 GMT
References: <460@ole.UUCP>
Sender: daemon@bloom-beacon.MIT.EDU
Organization: X Consortium, MIT Laboratory for Computer Science
Lines: 43


>> [the allocating colors misexample]
>
> There is a bit of misunderstanding here.

To say the least.  For reference, the indicated code was attempting to allocate
ncells*2^nplanes = 256*2^8 = 65536 color cells.  Ugh.


> [this was asking about why XGetStandardColormap wasn't working]
>
> I would appreciate it if anyone out there could point out what
> we are doing wrong.

Two things:

    1.  The publicly-available window managers don't create any standard
	colormaps, so there aren't any to fetch.  Unless you have created
	a special program to load the colormaps, XGetStandardColormap
	won't work.  See Section 9.2 of the Xlib manual and the ICCCM 
	for more detailed information.

    2.  You were passing the colormap property type (XA_RGB_COLOR_MAP)
	instead of one of the standard colormap property names listed in
	Section 9.2.2 of the Xlib manual:

		XA_RGB_DEFAULT_MAP
			a "nice" collection of commonly-used colors

		XA_RGB_BEST_MAP
			the widest distribution of colors

		XA_RGB_RED_MAP
		XA_RGB_GREEN_MAP
		XA_RGB_BLUE_MAP
			ramps of the indicated colors

		XA_RGB_GRAY_MAP
			ramps of gray



Jim Fulton
MIT X Consortium