Re: Transparency ?

[Owen Taylor <otaylor redhat com>]

On Tue, 2003-02-04 at 08:51, StÃphane Konstantaropoulos wrote:
> Le lun 03/02/2003 Ã 20:10, Stephane Wirtel a Ãcrit :
> > Is there to have a background transparent for a Widget ? by example a
> > GtkEventBox ?
> >
> > because i found a python code, and this application show a transparent
> > GtkWidget.
> >
> > thanks
> To my knowledge, there is no alpha channel in the colours attributed to
> widgets, each colour has RGB attributes, not RGBA.
>
> Anybody has something better to say?
>
> Hey QT does it (hardware with XRender)...
>
> Can you post the code somewhere so that I can have a look?

Widget's can certainly draw with alpha - though only widgets that 
are drawing on their parent's widgets windows... windows can't
be transparent.

The only graphics primitive in GTK+ that supports alpha, however
is drawing GdkPixbuf (gdk_draw_pixbuf() in 2.2, it has a different
name in 2.0). 

So, the main examples you'll find of translucent widgets are:

 - The GtkImage widget
 - The pixbuf theme engine in gtk-engines. (Some themes on 
   art.gnome.org use alpha fairly extensively.)

It's likely that a future version of GTK+ will have a full set
of antialiased and alpha-blended primitives, but that will be
a ways off.

Regards,
                                    Owen