UIHANDLER OnUpdate

Invoked when drawing the user interface (many times per second). (self, elapsed)

• self : - The updated widget.
• elapsed : - The time in seconds since the last OnUpdate dispatch, but excluding time when the user interface was not being drawn such as while zoning into the game world

• Preceeded by handlers associated with processing user input.
• Blocked by a frame or its parent.
• OnUpdate is resource intensive because it fires as often as the client can draw new frames -- potentially hundreds of FPS with modern computers.
• It is usually better to substitute or to skip frames, or to apply an for animating a widget.
• Alternatively, throttle slower parts of an OnUpdate handler by measuring the passage of time and only performing work as often as reasonably necessary.

Throttles a workload no more than once every 0.05 seconds:

Executes a workload 20 times per second. If FPS is slower than 20, the workload repeats until caught up.