# I mean basically a re-render fundamentally is just a call of app.redraw().
# We do that for every gtk signal after all state-changes by the signal have run
# through:
      proc valueChangedEventCallback(
        widget: GtkWidget,
        data: ptr EventObj[proc(newValue: float)]
      ) {.cdecl.} =
        let scaleValue: float = gtk_range_get_value(widget).float
        ScaleState(data[].widget).value = scaleValue
        data[].callback(scaleValue)
        data[].redraw()
 ```
As an example