Re: Generating widget images offscreen?

[Tristan Van Berkom <tristan van berkom gmail com>]

On Mon, 11 Oct 2004 15:07:08 -0700, Joshua Outwater
<joshua outwater sun com> wrote:
> Hi,
>         I am trying to create an application that will create an instance of a
> widget (GtkButton, GtkLabel, ...), set a particular state, and then take
> a snapshot of the widget.  So far I am assuming I would use
> gtk_widget_set_state with the particular state I want to widget to
> render in.

You should be able to do something like

/* create an offscreen drawable */
GdkPixmap *pixmap = gdk_pixmap_new(...);

/* copy the widget's rendered data to your pixmap */
gdk_draw_drawable ( ... GDK_DRAWABLE( widget->winodw) ,
                                      GDK_DRAWABLE(pixmap) ... );

Then there should be a function that allows you to make a 
GdkPixbuf from a GdkDrawable (which I cant remember the name...),
and then you have gdk_pixbuf_save (...) .

Note that you should use widget->allocation to specify which source 
coordinates and dimentions you are going to copy, widget->window
is sometimes a parent window in the case of GTK_NO_WINDOW widgets
(in which case widget->allocation.[xy] will not always be 0)

Cheers,
                                           -Tristan