Thanks Kimmo, somehow I haven't seen it in the manual page!<br>But... I found it's not necessary: the thing which was preventing the transparency effect to work as expected was this instruction:<br><br>gdk_window_reparent(myapp->imgparamwin->window,gtk_widget_get_window(GTK_WIDGET (myapp->mainwin)),offset,offset);<br>
<br>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!<br><br>Luca Donaggio<br><br><div class="gmail_quote">
2009/10/30 Kimmo Hämäläinen <span dir="ltr"><<a href="mailto:kimmo.hamalainen@nokia.com">kimmo.hamalainen@nokia.com</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="im">On Fri, 2009-10-30 at 14:36 +0100, ext Luca Donaggio wrote:<br>
> Thanks Conny and Kimmo,<br>
><br>
> here are my progresses:<br>
><br>
> I'm able to draw to the GtkWindow using Cairo only if I do it in a<br>
> callback attached to the expose event of the window itself, but I'm<br>
> still getting no transparency!<br>
> I'm sure this is the problem with the window manager that Kimmo<br>
> pointed out, but I don't know how to set the override-redirect flag<br>
> apart from passing the correct value inside a GdkWindowAttr struct<br>
> when manually creating a GdkWindow with gdk_window_new(), but I'm not<br>
> doing this manually, so I'm lost here!<br>
<br>
</div>gdk_window_set_override_redirect () sets it. You need to set it after<br>
realizing (gtk_widget_realize ()) your window but before showing it.<br>
gtk_widget_get_window () returns GdkWindow of your widget.<br>
<font color="#888888"><br>
-Kimmo<br>
</font><div><div></div><div class="h5"><br>
><br>
> Luca Donaggio<br>
><br>
> 2009/10/30 Kimmo Hämäläinen <<a href="mailto:kimmo.hamalainen@nokia.com">kimmo.hamalainen@nokia.com</a>><br>
> On Thu, 2009-10-29 at 17:29 +0100, ext Luca Donaggio wrote:<br>
> > I'm trying to create a transparent, non-decorated popup<br>
> GtkWindow on<br>
> > top af my app HildonWindow and draw something on its<br>
> underlying<br>
> > GdkWindow object using cairo.<br>
> > All I was able to obtain so far is a black (or whatever is<br>
> the<br>
> > background colour of the selected theme) rectangle -ie it's<br>
> not<br>
> > transparent and everything I paint in its GdkWindow with<br>
> Cairo is not<br>
> > showed at all.<br>
><br>
><br>
> You may hit (at least) this hard-coded limitation:<br>
> <a href="http://maemo.gitorious.org/fremantle-hildon-" target="_blank">http://maemo.gitorious.org/fremantle-hildon-</a><br>
> desktop/libmatchbox2/blobs/master/matchbox/core/mb-wm-<br>
> client.c#line173<br>
><br>
> Currently alpha in dialogs and application windows is ignored<br>
> because it<br>
> allows for optimisations in the compositor. But if you set the<br>
> override-<br>
> redirect flag for the window, that should go around that<br>
> (because the<br>
> type of your window would be MBWMClientTypeOverride).<br>
><br>
> -Kimmo<br>
><br>
><br>
> > Here is the code I'm using:<br>
> ><br>
> > void create_image_details(GtkWidget *callerobj,app_data_t<br>
> *myapp) {<br>
> > PangoLayout *textbuff;<br>
> > cairo_t *cr;<br>
> > gint x0, y0, r, txtwidth, txtheight;<br>
> ><br>
> > /* For the widget itself let's use a GtkWindow */<br>
> > if ((myapp->imgparamwin != NULL) & GTK_IS_WINDOW(myapp-<br>
> > >imgparamwin)) gtk_widget_destroy(myapp->imgparamwin);<br>
> > myapp->imgparamwin = gtk_window_new(GTK_WINDOW_POPUP);<br>
> > gtk_window_set_decorated(GTK_WINDOW (myapp-<br>
> >imgparamwin),FALSE);<br>
> > gtk_window_set_opacity(GTK_WINDOW (myapp-<br>
> >imgparamwin),0);<br>
> > gtk_widget_set_app_paintable(myapp->imgparamwin,TRUE);<br>
> > gtk_widget_realize(myapp->imgparamwin);<br>
> > /* gdk_window_set_back_pixmap(myapp->imgparamwin-<br>
> > >window,NULL,FALSE); */<br>
> > /* Get the Cairo context */<br>
> > cr = gdk_cairo_create(GDK_DRAWABLE (myapp->imgparamwin-<br>
> >window));<br>
> > textbuff = pango_cairo_create_layout(cr);<br>
> > pango_layout_set_markup(textbuff,myapp->imgparam,-1);<br>
> > pango_layout_get_pixel_size<br>
> (textbuff,&txtwidth,&txtheight);<br>
> > /* Draw a rounded rectangle */<br>
> ><br>
> > [cairo stuff is here]<br>
> ><br>
> > cairo_destroy(cr);<br>
> > g_object_unref(textbuff);<br>
> > /* Show the widget */<br>
> > gtk_window_resize(GTK_WINDOW (myapp-<br>
> >imgparamwin),txtwidth + (r *<br>
> > 2),txtheight + (r * 2));<br>
> > gtk_window_move(GTK_WINDOW (myapp->imgparamwin),30,30);<br>
> > gdk_window_reparent(myapp->imgparamwin->window,myapp-<br>
> >image-<br>
> > >window,30,30);<br>
> > gtk_widget_show_all(myapp->imgparamwin);<br>
> > }<br>
> ><br>
> > The window dimension after the gtk_window_resize() are<br>
> correct -ie the<br>
> > dimension of the PangoLayout containing the text to be<br>
> rendered, so<br>
> > something is definitely going on under the hood... but<br>
> nothing is<br>
> > displayed!<br>
> > If I add some widget to the popoup window (for example a<br>
> GtkLabel with<br>
> > some text in it), it's rendered correctly, but, of course<br>
> it's not<br>
> > transparent!<br>
> ><br>
> > Any help, as always, is much appreciated!<br>
> ><br>
> > Luca Donaggio<br>
><br>
><br>
><br>
<br>
</div></div></blockquote></div><br>