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Cursor controlled listing of image pixel values in a window.

Calling Sequence

TVLIST, [image, dx, dy, TEXTOUT=, OFFSET= , ZOOM= ]

Optional Inputs

IMAGE - Array containing the image currently displayed on the TV.
If omitted, the byte pixel intensities are read from the TV
If the array does not start at position (0,0) on the window then
the OFFSET keyword should be supplied.
DX -Integer scalar giving the number of pixels in the X direction
to be displayed. If omitted then DX = 18 for byte images, and
DX = 14 for integer images. TVLIST will display REAL data
with more significant figures if more room is availble to
DY - Same as DX, but in Y direction. If omitted, then DY = DX

Optional Input Keywords

      OFFSET - 2 element vector giving the location of the image pixel (0,0)
on the window display. OFFSET can be positive (e.g if the
image is centered in a larger window) or negative (e.g. if the
only the central region of an image much larger than the window
is being displayed.
Default value is [0,0], or no offset.
ZOOM - Scalar specifying the magnification of the window with respect
to the image variable. Use, for example, if image has been
REBINed before display.
TEXTOUT - Optional keyword that determines output device.
The following dev/file is opened for output.
textout=1 TERMINAL using /more option (default)
textout=2 TERMINAL without /more option
textout=3 <program>.prt
textout=4 laser.tmp
textout=5 user must open file
textout=7 Append to an existing <program>.prt file if it
textout = filename (default extension of .prt)
If TEXTOUT > 3 or set to a filename, then TVLIST will prompt for a
brief description to be included in the output file




Program prompts user to place cursor on region of interest in
image display. Corresponding region of image is then displayed at
the terminal. A compression factor between the image array and the
displayed image is determined using the ratio of image sizes. If
necessary, TVLIST will divide all pixel values in a REAL*4 image by a
(displayed) factor of 10^n (n=1,2,3...) to make a pretty format.

System Variable

The nonstandard system variable !TEXTOUT is used as an alternative to
the keyword TEXTOUT. The procedure ASTROLIB can be used to define
!TEXTOUT (and !TEXTUNIT) if necessary.


TVLIST may not be able to correctly format all pixel values if the
dynamic range near the cursor position is very large.
      Probably does not work under Mac IDL which does not allow the cursor
      to be positioned with TVCRS

Procedures Called


Revision History

Written by rhc, SASC Tech, 3/14/86.
Added textout keyword option, J. Isensee, July, 1990
Check for readable pixels W. Landsman May 1992
Use integer format statement from F_FORMAT W. Landsman Feb 1994
Added OFFSET, ZOOM keywords W. Landsman Mar 1996
More intelligent formatting of longword, call TEXTOPEN with /STDOUT
W. Landsman April, 1996
Added check for valid dx value W. Landsman Mar 1997
Converted to IDL V5.0 W. Landsman September 1997
      Major rewrite to call IMLIST, recognize new integer data types
                                          W. Landsman Jan 2000
      Remove all calls to !TEXTUNIT W. Landsman Sep 2000
      Always call UNZOOM_XY for MOUSSE compatibility W. Landsman Sep. 2004

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