Clear_Window(Color)
Clear_Window is a call that allows the user to clear the entire window to a particular color.
Note: A graphics window must be open when Clear_Window is called or a run-time error will occur.
Note: If Freeze_Graph_Window has been called, the window will not be cleared until a subsequent call to Unfreeze_Graph_Window or Update_Graph_Window is reached.
Examples:
Clear_Window(Red)
clears the window and fills in red