Jeremy White wrote:
(1) It appears that the '-background' option was never intended to
work with windows (Win32::GUI::Window, Win32::GUI::Dialog) and that
the only way to change the background colour of a window is using the
-class option with a coloured brush. It might be possible to extend
the WM_PAINT and/or WM_ERASEBKGND handlers to cope with this - is it
work exploring?
I've just had a look at the Visual .Net environment and you can specify
the backcolor of a window (and the background image)
It would be possible to allow the -background option to take a
Win32::GUI::Brush as a value. This would allow bitmaps as patterns for
the background; but it would start to be very confusing for controls,
where -background also specifies the text background colour. I don't
propose to do this - if you really want it use a class.
The
problem with using a class to set the background is that you can't
change it during runtime.
I hadn't spotted this.
Setting the background of a window does seem to crop up now and again -
and I've been stung with it several times - so a solution would be nice
- but how much work would be involved with the fiddling of
WM_PAINT/WM_ERASEBKGND? Is there a risk of it breaking other things?
Performance?
From what I've seen I don't think it would be hard, but I would be
concerned about regression testing, as I don't yet have enough
experience in this area to be confident of understanding the behaviour
of everything.
Performance - you'd only take a hit if you had the -background option
set, and the background needs erasing anyway - it's just a question of
whether Win32::GUI does it of it's done by DefWindowProc.
I'll have a look at implementing this.
BTW I've got the fix for class backgrounds not working in perl's 5.8 and
higher.
Regards,
Rob.
