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From: JONESD@kcgl1.eng.ohio-state.edu (David Jones)
Newsgroups: comp.windows.x
Subject: Re: XY and Z formats
Message-ID: <2880@quanta.eng.ohio-state.edu>
Date: 23 Aug 89 05:18:55 GMT
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Newsgroups: comp.windows.x
Subject: Re: XY and Z formats
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>    What was the rationale or precedent for these names?
>
>It is well known that I am terrible at making up names, and that's being kind.
>Geez, after all, it *is* called "X".  Unfortunately, too many people let me get
>away with it when X11 was being designed, and you're stuck with it now.  I
>doubt I can give you a rationale for how things were named.

My guess would have been that the naming of XY versus Z format was a reflection
of the fact that the X server loads and unloads the images as streams of bits.
If you picture the bit planes of a screen as a 3 dimensional grid, 'Z' format
indicates that successive bits in the image represent successive bits in the
z direction, i.e. successive bit planes.  Likewise, the 'XY' format indicates
that successive bits fill successive bits in the x, then y directions.

David L. Jones               |      Phone:    (614) 292-6929
Ohio State Unviversity       |      Internet:
1971 Neil Ave. Rm. 406       |               jonesd@kcgl1.eng.ohio-state.edu
Columbus, OH 43210           |               jones-d@eng.ohio-state.edu

Disclaimer: A repudiation of a claim.