on-scroll

Called when the value of one of the canvas's scrollbars changes. A wx:command-event% argument provides information about the scroll action.

The get-selection method of event returns the value of the scrollbar.

The get-selection-type method of of event returns either wx:const-horizontal or wx:const-vertical.

The get-event-type method of event returns one of:

• wx:const-event-type-scroll-linedown -- called when the scrollbar is incremented by a line, by clicking on the bottom arrow of a vertical scrollbar or right-hand arrow of a horizontal scrollbar
• wx:const-event-type-scroll-lineup -- called when the scrollbar is decremented by a line, by clicking on the top arrow of a vertical scrollbar or left-hand arrow of a horizontal scrollbar
• wx:const-event-type-scroll-pagedown -- called when the scrollbar is incremented by a page
• wx:const-event-type-scroll-pageup -- called when the scrollbar is decremented by a page
• wx:const-event-type-scroll-top -- called when the scrollbar is set to the top
• wx:const-event-type-scroll-bottom -- called when the scrollbar is set to the bottom
• wx:const-event-type-scroll-thumbtrack -- called when the the scrollbar is being dragged

• (send a-wx:canvas on-scroll event) -> void
      event : wx:command-event% object

  Calls on-paint.