Re: Routing scroll events in a Gtk.Overlay

[Paul Davis <paul linuxaudiosystems com>]

On Wed, Jun 4, 2014 at 10:53 PM, Robert Schroll <rschroll gmail com> wrote:

Hi all,

I'm working on a Gtk project (3.10, Python 2 for the prototype, if that matters) using a Gtk.Overlay [1].  

You should know that GTK's design more or less does not cater to overlapping GtkWidgets. It is not completely clear if you are actually doing this, but it certainly sounds as if you are. The API allows you to create overlapping widgets, but nothing else in the API (though I admit to knowing GTK3 not as well as I should) defines event handling when this happens. Z-axis (or "stacking) ordering needs to be defined for this to be done rationally. GTK does not provide this as far as I know (GTK2 definitely does not and I don't think GTK3 changed this).

Such things are normally done using "scene graphs" or "canvases", and there is no "blessed" Gtk implementation of such a thing at this time (nor has there been for many years). there are a variety of attempts to implement such a thing; several of them do not provide support for normal widgets within the scene graph/canvas. some do.