[maemo-developers] How to get a transparent GtkWindow (fremantle)

[From: Kimmo Hämäläinen]

On Thu, 2009-11-12 at 17:21 +0100, ext Luca Donaggio wrote:
> Thanks a lot Kimmo!
> 
> At least, now I know what's happening!
> Now, what to do to solve the problem? If HildonAppMenu behaves like
> this by design (and if the bug regards only the fact that it is first
> mapped and then unmapped while it shouldn't be mapped at all), is
> there a way to create a floating top level widget on top of a
> HildonWindow or it is somewhat forbidden by the actual implementation?
> I don't want to continue the development in the wrong direction, maybe
> it's better if I stop here and redisign my app to not include the
> "offending" widget and find another way to present the same
> informations to the user - but let me say that I grew somewhat fond of
> my transparent-overlayed-unobtrusive-image-details-window!

I think the cleanest (and most risk-free) solution is that you create
the transparent window as a child window of the main window right from
the beginning. But I'm not sure how Gtk allows that. Better solution
would be fixing the WM so that it allows rgba in dialogs, but that can
be more work...

-Kimmo

> 
> What do you think?
> 
> --
> Luca Donaggio
> 
> 2009/11/11 Kimmo Hämäläinen <kimmo.hamalainen at nokia.com>
>         On Wed, 2009-11-11 at 08:28 +0100, Hamalainen Kimmo (Nokia-
>         D/Helsinki)
>         wrote:
>         > On Tue, 2009-11-10 at 16:15 +0100, ext Luca Donaggio wrote:
>         > > I thought it was somewhat related to transparency because
>         doing this:
>         > >
>         > > gdk_window_reparent(win->window,gtk_widget_get_window
>         (GTK_WIDGET
>         > > (mainwin)),300,200);
>         > >
>         > > makes the HildonAppMenu work again at the price of loosing
>         the
>         > > transparency effect (modified code attached).
>         >
>         > Reparenting 'win->window' makes it a child of 'mainwin'.
>         That is
>         > completely different ballgame than the original code, which
>         keeps 'win-
>         > >window' a top-level window (child of the root).  When the
>         window is not
>         > top-level, it's not managed by the window manager anymore,
>         but it could
>         > also cause something in Gtk/Hildon (at least I have checked
>         all places
>         > deleting windows in hildon-desktop to no avail).
>         
>         
>         Finally I found the reason for hiding the menu!  It's in
>         libhildon
>         function hildon_app_menu_find_intruder. It thinks that the
>         window with
>         the "This is an RGBA window" label is an "intruder" (such as
>         dialog
>         etc.) and closes the menu as soon as it is mapped.  This seems
>         like a
>         bug since the menu should not be mapped in the first place if
>         this
>         "intruder" is already there at mapping time.
>         
>         To summarize: this is libhildon bug and hildon-desktop is
>         completely
>         innocent (at last...)!  ;)
>         
>         -Kimmo
>         
>         
>         >
>         > -Kimmo
>         >
>         > > --
>         > > Luca Donaggio
>         > >
>         > > 2009/11/10 Kimmo Hämäläinen <kimmo.hamalainen at nokia.com>
>         > >         On Tue, 2009-11-10 at 14:12 +0100, ext Luca
>         Donaggio wrote:
>         > >         > Hi Kimmo,
>         > >         >
>         > >         > I'm sorry to bother you again, but the problem
>         I'm facing is
>         > >         not how
>         > >         > to get a transparent window, but that if I
>         create such a
>         > >         window the
>         > >         > HildonAppMenu of its parent HildonWindow doesn't
>         show
>         > >         anymore.
>         > >         > I (slightly) modified your code to exemplify my
>         situation.
>         > >
>         > >
>         > >         Ah, yes, I can see it.  Looks like the menu is
>         unmapped
>         > >         immediately when
>         > >         it is shown. It's weird, I'm not yet sure what
>         unmaps it...
>         > >          Now it
>         > >         looks like hildon-desktop is not unmapping it, so
>         it could be
>         > >         widget
>         > >         side problem also. I'll try to find out.
>         > >
>         > >         BTW. this problem is not related to the
>         transparency: opaque
>         > >         window does
>         > >         the same.
>         > >
>         > >         -Kimmo
>         > >
>         > >
>         > >         >
>         > >         >
>         > >         > Thanks for your time,
>         > >         >
>         > >         > Luca Donaggio
>         > >         >
>         > >         > 2009/11/10 Kimmo Hämäläinen
>         <kimmo.hamalainen at nokia.com>
>         > >         >         Hi,
>         > >         >
>         > >         >         Sorry, took some time, I was busy with
>         some bug
>         > >         fixing...  I
>         > >         >         started
>         > >         >         with the Home applet example and managed
>         to whip up
>         > >         a small
>         > >         >         example
>         > >         >         (attached) that shows a transparent pop-
>         up window.
>         > >         >
>         > >         >         -Kimmo
>         > >         >
>         > >         >
>         > >
>         > >
>         > >
>         >
>         
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