This is really intresting.  I have spent some time in reproducing this,
and finally succeeded (as in, it fails.)

Maybe this is an ubuntu-specific issue after all?

I'd have to actually run dspdfviewer's GUI on a powerpc machine to test
that.  When I run it in the emulator, the colors are *completely* messed
up.  For example, the black background is rendered as blue, since ARGB
ff000000 (as in, opaque black) becomes 000000ff (as in, transparent
blue) but the alpha value gets ignored, resulting in opaque blue.


Oh and one more thing:  The colors are already messed up on the Qt
Standard "Choose a File" dialog.

This may be a legitimate Bug, or an issue with the emulator not
translating byte orders on an X connection correctly.

Which brings me to the point:  Are the Ubuntu powerpc builds run *on
actual PowerPCs* or on qemu-based emulators?  How about Debian?  (Maybe
there's the difference why Debian's ppc build did not fail)

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The messed-up colors are not specific to dspdfviewer, but seem to be
reproducible in the qt4-demo application.  Try this:

(host) pbuilder-dist xenial powerpc create
(host) xhost +
(host) pbuilder-dist xenial powerpc login
(guest) apt install qt4-demos
(guest) /usr/lib/powerpc-linux-gnu/qt4/bin/qtdemo

The window is mainly blue-ish, it should be grey (try it on your host
native)


So this could be a limitation of the emulator, in which case I can't fix
it.  Or, it could be a legitimate bug.

How do we find out?

----

Any recommendations on how to proceeed?