PseudoColor and DirectColor visuals (was Re: Documentation?)

Peter Harris pharris at
Thu Apr 9 09:48:00 PDT 2009

Patrick O'Donnell wrote:
>> The RENDER extension already has mechanisms for copying PseudoColor
>> pixmaps to TrueColor displays, but it does not allow you to use your own
>> colormap.
> This sounds a bit more promising, though.  I guess I'll have to read
> up on RENDER.  Could you clarify "it does not allow you to use your own
> colormap"?  Is there a default PseudoColor colormap (writable) that is
> uses, or is it a fixed colormap, and it's thus not really PseudoColor
> conversion that it's doing but StaticColor.

If the default visual is PseudoColor, there will be a few writable color
cells left in the default colormap. But in that case, you've already got
a PseudoColor visual and don't need RENDER. If the default visual is not
PseudoColor, every RENDER format that has a colormap will have one that
is fully pre-allocated. That makes it effectively, as you say, StaticColor.

Hence the part you trimmed about needing to improve RENDER slightly
before it would be useful for your purposes.

Peter Harris
               Open Text Connectivity Solutions Group
Peter Harris          
Research and Development        Phone: +1 905 762 6001
pharris at            Toll Free: 1 877 359 4866

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