Re: transparent gtkwindow

[Tor Lillqvist <tml iki fi>]

> > How to create a transparent gtkwindow with alpha values on Windows and
> > Linux?

Presumably you mean with the X11 backend (which is in no way Linux
specific) when you say "on Linux"?

> gtk_widget_shape_combine_mask () could be what you want.

No, it wouldn't. That sets the shape of a window. That's nothing new,
it has been in GTK+ since ages. It does work on both X11 (as long as
the X server has the SHAPE extension, which I guess they practically
all do) and Windows.

Instead, take a look at testgtk.c in recent GTK+ distributions. Look
for the create_alpha_window() function.

But I'm afraid that this doesn't work on Windows. Sorry. The Windows
API one has to use to fully support per-pixel alpha is horribly broken
by design, and making gdk/win32 use it seems rather impossible. (I
spent one weekend looking into it, so trust me, this isn't just a gut
feeling. I would love to be proved wrong, of course.)

Using just one fixed alpha value for a whole window is much easier in
the Windows API, but then there is no API to request that in GTK+. I
probably should add a feature request for that to Bugzilla and maybe
even implement it.

--tml