rem: d += 5;
add: d += adj->step_increment;
context: totem_volume_button_scroll (GtkWidget      * widget,			    GdkEventScroll * event){  TotemVolumeButton *button = TOTEM_VOLUME_BUTTON (widget);  GtkAdjustment *adj = gtk_range_get_adjustment (GTK_RANGE (button->scale));  float d;  if (event->type != GDK_SCROLL)    return FALSE;  d = totem_volume_button_get_value (button);  if (event->direction == GDK_SCROLL_UP) {    d += 5;    if (d > adj->upper)      d = adj->upper;  } else {    d -= 5;    if (d < adj->lower)      d = adj->lower;  }  totem_volume_button_set_value (button, d);  return TRUE;}