[Patches] [ python-Patches-874358 ] imageop on little-endian systems uses reversed byte order

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Patches item #874358, was opened at 2004-01-10 11:47
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Category: Modules
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Sjoerd Mullender (sjoerd)
Assigned to: Guido van Rossum (gvanrossum)
Summary: imageop on little-endian systems uses reversed byte order

Initial Comment:
The format of the string data used in the imageop
module is described as "This is the same format as used
by gl.lrectwrite() and the imgfile module."  This
implies a certain byte order in multi-byte pixel formats.
However, the code was originally written on an SGI
(big-endian) and *uses* the fact that bytes are stored
in a particular order in ints.  This means that the
code uses and produces different byte order on
little-endian systems.
The attached patch adds a module-level flag
"backward_compatible" (default not set, and if not set,
behaves as if set to 1--i.e. backward compatible) that
can be used on a little-endian system to use the same
byte order as the SGI.  Using this flag it is then
possible to prepare SGI-compatible images on a
little-endian system.

This patch is the result of a (small) discussion on
python-dev.

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