UNZOOM_XY

      Converts X, Y position on the image display to the the X,Y position
      on the corresponding image array.  (These  positions are identical
      only for an unroamed, unzoomed image with with pixel (0,0) of the
      image placed at position (0,0) on the TV.)

      UNZoom_XY, Xtv,Ytv,Xim,Yim, [ OFFSET =, ZOOM = ]

      XTV - Scalar or vector giving X position(s) as read on the image
            display (e.g. with CURSOR,XTV,YTV,/DEVICE)
      XTV - Scalar or vector giving Y position(s) on the image display.
      If only 2 parameters are supplied then XTV and YTV will be modfied
      on output to contain the image array coordinates.

      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.

      XIM,YIM - X and Y coordinates of the image corresponding to the
            cursor position on the TV display.

       If present, ZOOM_XY will use the TV and IMAGE common blocks which are
       defined in the MOUSSE software system (see
        http://archive.stsci.edu/uit/analysis.html)   If the user is not using
       the MOUSSE software (which keeps track of the offset and zoom in each
       window) then the common blocks are ignored.

       The integer value of a pixel is assumed to refer to the *center*
       of a pixel.

       Adapted from MOUSSE procedure  W. Landsman       March 1996
       Converted to IDL V5.0   W. Landsman   September 1997
       Proper handling of offset option          S. Ott/W. Landsman May 2000
       Put back common blocks for MOUSSE compatibility    September 2004

[Home Page] [Software, Documentation] [IDL Documentation] [Quick Reference] [Feedback]