GtkOffscreenWindow is strictly intended to be used for obtaining
snapshots of widgets that are not part of a normal widget hierarchy.
Since #GtkOffscreenWindow is a toplevel widget you cannot obtain
snapshots of a full window with it since you cannot pack a toplevel
widget in another toplevel.
The idea is to take a widget and manually set the state of it,
add it to a GtkOffscreenWindow and then retrieve the snapshot
as a #cairo_surface_t or #GdkPixbuf.
GtkOffscreenWindow derives from #GtkWindow only as an implementation
detail. Applications should not use any API specific to #GtkWindow
to operate on this object. It should be treated as a #GtkBin that
has no parent widget.
When contained offscreen widgets are redrawn, GtkOffscreenWindow
will emit a #GtkWidget::damage-event signal.
GtkOffscreenWindow is strictly intended to be used for obtaining snapshots of widgets that are not part of a normal widget hierarchy. Since #GtkOffscreenWindow is a toplevel widget you cannot obtain snapshots of a full window with it since you cannot pack a toplevel widget in another toplevel.
The idea is to take a widget and manually set the state of it, add it to a GtkOffscreenWindow and then retrieve the snapshot as a #cairo_surface_t or #GdkPixbuf.
GtkOffscreenWindow derives from #GtkWindow only as an implementation detail. Applications should not use any API specific to #GtkWindow to operate on this object. It should be treated as a #GtkBin that has no parent widget.
When contained offscreen widgets are redrawn, GtkOffscreenWindow will emit a #GtkWidget::damage-event signal.