Actually, if "plug-in" means something like a fill pattern that could
be user-specified in the same way as the splash screen, I think it
would be possible to implement everything Peter has specified here --
including the opacity slider -- using the "scratch image" framework
I've been experimenting with.
There is one aspect of this specification that seems problematic to
me, though. If the user closes the final image by clicking the "X" in
the upper right corner of the window, we must close that window or we
violate a fundamental rule of window handling. We can create a new
window if we feel the need to, but we must close the original window.
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