Patrick O'Donnell pao at
Wed Apr 8 06:09:35 PDT 2009

>Date: Tue, 07 Apr 2009 20:05:08 -0400
>From: Peter Harris <pharris at>
>Unless you need to maintain support for legacy (PseudoColor)
>displays, ...
>Yes, PseudoColor is a pain. ... Fortunately, PseudoColor seems to be
>mostly dead these days.

Please don't write off PseudoColor quite yet.  A writable color map is 
a boon for those of us with complicated layered graphics to draw.  It
greatly simplifies the maintenance of separate layers.

> ...Even if you do need to work on a PseudoColor display, you're far
>better off allocating a new Colormap[1] and calling XStoreColors once
>(to fill the whole Colormap with exactly the colors you need) for
>this sort of thing.

But for nearly all systems, allocating a new colormap for specific
windows creates color flashing when the windows change focus.  When
there are enough color slots avilable in the default colormap,
XAllocColors (note the plural) gives a much more pleasing effect.
(Though, I just really noticed the the "million".  That could indeed
change the balance.)

		- Patrick

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