donaggio at gmail
Oct 30, 2009, 8:00 AM
Post #7 of 21
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Re: How to get a transparent GtkWindow (fremantle)
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Thanks Kimmo, somehow I haven't seen it in the manual page!
But... I found it's not necessary: the thing which was preventing the
transparency effect to work as expected was this instruction:
gdk_window_reparent(myapp->imgparamwin->window,gtk_widget_get_window(GTK_WIDGET
(myapp->mainwin)),offset,offset);
Without it I can get the transparent background just as Conny suggested, BUT
... without it the HildonAppMenu stops working: it shows up and immediately
disappear!
Luca Donaggio
2009/10/30 Kimmo Hämäläinen <kimmo.hamalainen [at] nokia>
> On Fri, 2009-10-30 at 14:36 +0100, ext Luca Donaggio wrote:
> > Thanks Conny and Kimmo,
> >
> > here are my progresses:
> >
> > I'm able to draw to the GtkWindow using Cairo only if I do it in a
> > callback attached to the expose event of the window itself, but I'm
> > still getting no transparency!
> > I'm sure this is the problem with the window manager that Kimmo
> > pointed out, but I don't know how to set the override-redirect flag
> > apart from passing the correct value inside a GdkWindowAttr struct
> > when manually creating a GdkWindow with gdk_window_new(), but I'm not
> > doing this manually, so I'm lost here!
>
> gdk_window_set_override_redirect () sets it. You need to set it after
> realizing (gtk_widget_realize ()) your window but before showing it.
> gtk_widget_get_window () returns GdkWindow of your widget.
>
> -Kimmo
>
> >
> > Luca Donaggio
> >
> > 2009/10/30 Kimmo Hämäläinen <kimmo.hamalainen [at] nokia>
> > On Thu, 2009-10-29 at 17:29 +0100, ext Luca Donaggio wrote:
> > > I'm trying to create a transparent, non-decorated popup
> > GtkWindow on
> > > top af my app HildonWindow and draw something on its
> > underlying
> > > GdkWindow object using cairo.
> > > All I was able to obtain so far is a black (or whatever is
> > the
> > > background colour of the selected theme) rectangle -ie it's
> > not
> > > transparent and everything I paint in its GdkWindow with
> > Cairo is not
> > > showed at all.
> >
> >
> > You may hit (at least) this hard-coded limitation:
> > http://maemo.gitorious.org/fremantle-hildon-
> > desktop/libmatchbox2/blobs/master/matchbox/core/mb-wm-
> > client.c#line173
> >
> > Currently alpha in dialogs and application windows is ignored
> > because it
> > allows for optimisations in the compositor. But if you set the
> > override-
> > redirect flag for the window, that should go around that
> > (because the
> > type of your window would be MBWMClientTypeOverride).
> >
> > -Kimmo
> >
> >
> > > Here is the code I'm using:
> > >
> > > void create_image_details(GtkWidget *callerobj,app_data_t
> > *myapp) {
> > > PangoLayout *textbuff;
> > > cairo_t *cr;
> > > gint x0, y0, r, txtwidth, txtheight;
> > >
> > > /* For the widget itself let's use a GtkWindow */
> > > if ((myapp->imgparamwin != NULL) & GTK_IS_WINDOW(myapp-
> > > >imgparamwin)) gtk_widget_destroy(myapp->imgparamwin);
> > > myapp->imgparamwin = gtk_window_new(GTK_WINDOW_POPUP);
> > > gtk_window_set_decorated(GTK_WINDOW (myapp-
> > >imgparamwin),FALSE);
> > > gtk_window_set_opacity(GTK_WINDOW (myapp-
> > >imgparamwin),0);
> > > gtk_widget_set_app_paintable(myapp->imgparamwin,TRUE);
> > > gtk_widget_realize(myapp->imgparamwin);
> > > /* gdk_window_set_back_pixmap(myapp->imgparamwin-
> > > >window,NULL,FALSE); */
> > > /* Get the Cairo context */
> > > cr = gdk_cairo_create(GDK_DRAWABLE (myapp->imgparamwin-
> > >window));
> > > textbuff = pango_cairo_create_layout(cr);
> > > pango_layout_set_markup(textbuff,myapp->imgparam,-1);
> > > pango_layout_get_pixel_size
> > (textbuff,&txtwidth,&txtheight);
> > > /* Draw a rounded rectangle */
> > >
> > > [cairo stuff is here]
> > >
> > > cairo_destroy(cr);
> > > g_object_unref(textbuff);
> > > /* Show the widget */
> > > gtk_window_resize(GTK_WINDOW (myapp-
> > >imgparamwin),txtwidth + (r *
> > > 2),txtheight + (r * 2));
> > > gtk_window_move(GTK_WINDOW (myapp->imgparamwin),30,30);
> > > gdk_window_reparent(myapp->imgparamwin->window,myapp-
> > >image-
> > > >window,30,30);
> > > gtk_widget_show_all(myapp->imgparamwin);
> > > }
> > >
> > > The window dimension after the gtk_window_resize() are
> > correct -ie the
> > > dimension of the PangoLayout containing the text to be
> > rendered, so
> > > something is definitely going on under the hood... but
> > nothing is
> > > displayed!
> > > If I add some widget to the popoup window (for example a
> > GtkLabel with
> > > some text in it), it's rendered correctly, but, of course
> > it's not
> > > transparent!
> > >
> > > Any help, as always, is much appreciated!
> > >
> > > Luca Donaggio
> >
> >
> >
>
>
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rgba-window-example.c
