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 callback attached to the expose event of the window itself, but I'm still getting no transparency!<br>
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!<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 Thu, 2009-10-29 at 17:29 +0100, ext Luca Donaggio wrote:<br>
> I'm trying to create a transparent, non-decorated popup GtkWindow on<br>
> top af my app HildonWindow and draw something on its underlying<br>
> GdkWindow object using cairo.<br>
> All I was able to obtain so far is a black (or whatever is the<br>
> background colour of the selected theme) rectangle -ie it's not<br>
> transparent and everything I paint in its GdkWindow with Cairo is not<br>
> showed at all.<br>
<br>
</div>You may hit (at least) this hard-coded limitation:<br>
<a href="http://maemo.gitorious.org/fremantle-hildon-%0Adesktop/libmatchbox2/blobs/master/matchbox/core/mb-wm-client.c#line173" target="_blank">http://maemo.gitorious.org/fremantle-hildon-<br>
desktop/libmatchbox2/blobs/master/matchbox/core/mb-wm-client.c#line173</a><br>
<br>
Currently alpha in dialogs and application windows is ignored because it<br>
allows for optimisations in the compositor. But if you set the override-<br>
redirect flag for the window, that should go around that (because the<br>
type of your window would be MBWMClientTypeOverride).<br>
<font color="#888888"><br>
-Kimmo<br>
</font><div><div></div><div class="h5"><br>
> Here is the code I'm using:<br>
><br>
> void create_image_details(GtkWidget *callerobj,app_data_t *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->imgparamwin),FALSE);<br>
> gtk_window_set_opacity(GTK_WINDOW (myapp->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->window));<br>
> textbuff = pango_cairo_create_layout(cr);<br>
> pango_layout_set_markup(textbuff,myapp->imgparam,-1);<br>
> pango_layout_get_pixel_size(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->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->image-<br>
> >window,30,30);<br>
> gtk_widget_show_all(myapp->imgparamwin);<br>
> }<br>
><br>
> The window dimension after the gtk_window_resize() are correct -ie the<br>
> dimension of the PangoLayout containing the text to be rendered, so<br>
> something is definitely going on under the hood... but nothing is<br>
> displayed!<br>
> If I add some widget to the popoup window (for example a GtkLabel with<br>
> some text in it), it's rendered correctly, but, of course it's not<br>
> transparent!<br>
><br>
> Any help, as always, is much appreciated!<br>
><br>
> Luca Donaggio<br>
<br>
</div></div></blockquote></div><br>