UPDATE(9) Kernel Developer's Manual UPDATE(9)

update - flush graphics

update ?options?

Changes made via Tk commands do not become visible until a call to update. Update flushes any pending changes to the screen. The following options are supported:

-disable
If this option is given, all updates are disabled. This is useful to enable a program to stop mouse movement causing automatic updates while it is making changes to the window.
-enable
This reverses a previous update -enable invocation.

Changes that affect window sizes are visible immediately.