WINDOWAVAILABLE

Name

WindowAvailable

Purpose

This function returns a 1 if the specified window index number is
currently open or available. It returns a 0 if the window is currently
closed or unavailable.

Author

FANNING SOFTWARE CONSULTING
David Fanning, Ph.D.
1645 Sheely Drive
Fort Collins, CO 80526 USA
Phone: 970-221-0438
E-mail: david@idlcoyote.com
Coyote's Guide to IDL Programming: http://www.idlcoyote.com

Calling Sequence

available = WindowAvaiable(windowIndexNumber)

Inputs

windowIndexNumber: The window index number of the window you wish to
know is available or not.

Keywords

None.

Notes

The window vector obtained from the DEVICE command is not always the same length. It
is normally (on my machine) 65 elements long, but can be much longer if you have lots
of IDL windows open (by calling PickColorName, for example). But if no windows with
index numbers greater than 65 are open, IDL shinks the larger vector to the smaller one
as part of its housekeeping operations, which means it happens on their timetable, not yours.
This can result in the user having "stale" index numbers greater than 65, but no larger vector
to check them against. I have modified the code to return a 0 in this case, assuming that
whatever window your index number points to is long gone. I have not experience any ill effects
by doing this, but I STRONGLY advice you to ALWAYS know what window you are drawing into
when you issue a graphics command.

Modification History

Written by David W. Fanning, June 2005.
Modified to return 0 if the window index number is larger than the number of elements
in the WINDOW_STATE array. 25 June 2008. DWF.