+FilmViewer::update_position_slider ()
+{
+ if (!_film) {
+ _slider->SetValue (0);
+ return;
+ }
+
+ DCPTime const len = _film->length ();
+
+ if (len.get ()) {
+ int const new_slider_position = 4096 * _position.get() / len.get();
+ if (new_slider_position != _slider->GetValue()) {
+ _slider->SetValue (new_slider_position);
+ }
+ }
+}
+
+void
+FilmViewer::update_position_label ()