Name

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      IMLIST

Purpose

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      Display pixel values on an image surrounding a specified X,Y center.

Explanation

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      IMLIST is similar to TVLIST but the center pixel is supplied directly by
      the user, rather than being read off of the image display

Calling Sequence

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      IMLIST, Image, Xc, Yc, [ TEXTOUT = , DX = , DY = ,WIDTH = ,DESCRIP = ]

Inputs

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      Image - Two-dimensional array containing the image
      Xc - X pixel value at which to center the display, integer scalar
      Yc - Y pixel value at which to center the display, integer scalar
  OPTIONAL INPUTS KEYWORDS:
      TEXTOUT - Scalar number (1-7) or string which determines output device.
              (see TEXTOPEN) The following dev/file is opened for output.
              textout=1 TERMINAL using /more option
              textout=2 TERMINAL without /more option
              textout=3 <program>.prt
              textout=4 laser.tmp
              textout=5 user must open file
              textout=7 same as 3 but text is appended to <program>.prt
                              if file already exists
              textout = filename (default extension of .prt)
      DX -Integer scalar giving the number of pixels inthe X direction
              to be displayed. If omitted then DX = 18 for byte images, and
              DX = 14 for integer images. IMLIST will display REAL data
              with more significant figures if more room is available to
              print.
      DY - Same as DX, but in Y direction. If omitted, then DY = DX
      WIDTH - Integer scalar giving the character width of the output device.
              Default is 80 characters.
      DESCRIP = Scalar string which will be written as a description over
              the output pixel values. If DESCRIP is not supplied, and the
              output device specified by TEXTOUT is not a terminal, then the
              user will be prompted for a description.
      OFFSET - 2 element numeric vector giving an offset to apply to the
              display of the X,Y coordinates of the image (e.g. if the
              supplied image array is a subarray of a larger image).

Outputs

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      None.

Procedure

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      Corresponding region of image is then displayed at
      the terminal. If necessary, IMLIST will divide all pixel values
      in a REAL*4 image by a (displayed) factor of 10 to make a pretty format.

System Variables

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      If the keyword TEXTOUT is not supplied, then the non-standard system
      variable !TEXTOUT will be read. (The procedure ASTROLIB can be
      used to add the non-standard system variables.)

Restrictions

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      IMLIST may not be able to correctly format all pixel values if the
      dynamic range of the values near the center pixel is very large

Example

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      Display the pixel values of an image array IM in the vicinity of 254,111
      IDL> imlist, IM, 254, 111

Procedures Used

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      TEXTOPEN, F_FORMAT(), TEXTCLOSE

Revision History

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      Written, W. Landsman June, 1991
      Added DESCRIP keyword W. Landsman December, 1991
      Treat LONG image as integer when possible, call TEXTOPEN with /STDOUT
      keyword, W. Landsman April, 1996
      Use SYSTIME() instead of !STIME August 1997
      Converted to IDL V5.0 W. Landsman September 1997
      Recognize new integer types, added OFFSET keyword W. Landsman Jan. 2000
      Replace DATATYPE() with size(/TNAME) W. Landsman Nov. 2001
      Handle NAN values in output display W. Landsman June 2004
      Use V6.0 notation W. Landsman April 2011