coyote: IMAGE_DIMENSIONS

Description
The purpose of this function is to return the various dimensions of the image,
and also to extract relevant image information via output keywords. The
function works only with 2D and 3D (24-bit) images, with or without alpha
channels.
Categories
Utilities
Returns
A vector containing the size of each dimension of the image. It is equivalent
to calling the SIZE function with the DIMENSIONS keyword set.
Params
image:  in, optional, type=various
    The image variable from which information is to be obtained.
Keywords
alphachannel: out, optional, type=boolean
   This keyword is set to 1 if there is an alpha channel in the image. Otherwise,
   the keyword is set to 0. 
trueindex: out, optional, type=integer
   The position of the "true color" index in the return value. Is -1 for 2D images.
xindex: out, optional, type=integer
   The index (position) of the X dimension in the return value.
xsize: out, optional, type=integer
   The X size of the image.
yindex: out, optional, type=integer
   The index (position) of the Y dimension in the return value.
ysize: out, optional, type=integer
   The Y size of the image.
Examples
To load open a window of the appropriate size and display a 24-bit image::
   dims = Image_Dimensions(image24, XSize=xsize, YSize=ysize, TrueIndex=trueindex)
   Window, XSIZE=xsize, YSIZE=ysize
   TV, image24, TRUE=trueindex
Author
FANNING SOFTWARE CONSULTING::
    David W. Fanning 
    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/
History
Modification History::
   Written by:  David W. Fanning, 5 March 2003.
   Added support for alpha channel images, include ALPHACHANNEL keyword. 13 May 2009. DWF.
Copyright
Copyright (c) 2003-2011, Fanning Software Consulting, Inc.