PRO test_image, imdata, status, imxsize, imysize, imtype

; Description: This module tests that the parameter "imdata" contains image data. In other
;              words, it checks that "imdata" is non-empty, contains numbers of any of the 
;              types BYTE, INTEGER, LONG, FLOAT, DOUBLE, UINT, ULONG, LONG64 or ULONG64, 
;              and has exactly two dimensions. If the module finds that "imdata" does 
;              indeed contain image data, then it also determines the image size and saves 
;              this information in the parameters "imxsize" and "imysize". Finally, the
;              module also returns the IDL type code of the parameter "imdata".
;
; Input Parameters:
;
;   imdata - ANY - The parameter to be tested whether or not it satisfies the properties 
;                  that an image array would have.
;
; Output Parameters:
;
;   status - INTEGER - The parameter "status" is set to "1" if the parameter "imdata" is a
;                      non-empty array of numbers of any of the types BYTE, INTEGER, LONG, 
;                      FLOAT, DOUBLE, UINT, ULONG, LONG64 or ULONG64, with exactly two 
;                      dimensions. Otherwise, the module sets the value of "status" to "0".
;   imxsize - LONG - The image size along the x-axis (pix). This parameter is only calculated
;                    if "status" is set to "1".
;   imysize - LONG - The image size along the y-axis (pix). This parameter is only calculated
;                    if "status" is set to "1".
;   imtype - INTEGER - The IDL type code of the pixel values stored in "imdata". Note that IDL 
;                      type codes of 1, 2, 3, 4, 5, 12, 13, 14 and 15 correspond to variable 
;                      types of BYTE, INTEGER, LONG, FLOAT, DOUBLE, UINT, ULONG, LONG64 and 
;                      ULONG64, respectively.
;
; Author: Dan Bramich (dmb@ing.iac.es)
;
; History:
;
;   14/08/2008 - Module created (dmb)

;Determine the IDL type code for "imdata"

;Check that "imdata" has two dimensions

;If "imdata" is two-dimensional and contains numbers of any of the types BYTE, INTEGER, LONG, FLOAT,
;DOUBLE, UINT, ULONG, LONG64 or ULONG64, then set the value of "status" to "1" and determine the
;image size