Gets emitted to move the viewport.
The move_viewport signal is a [keybinding signal](class.SignalAction.html), which can be bound to key combinations to allow the user to move the viewport, i.e. change what part of the text view is visible in a containing scrolled window.
There are no default bindings for this signal.
| step |
the granularity of the movement, as a `GtkScrollStep` |
| count |
the number of |