% @(#)zoom_over.hlq	19.1 (ESO-IPG) 02/25/03 14:03:52 
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1990 European Southern Observatory
%.IDENT      zoom_over.hlq
%.AUTHOR     KB, IPG/ESO
%.KEYWORDS   MIDAS, help files, ZOOM/OVERLAY
%.PURPOSE    On-line help file for the command: ZOOM/OVERLAY
%.VERSION    1.0  30-JUN-1991 : Creation, KB
%----------------------------------------------------------------
\se
SECTION./OVER
\es\co
ZOOM/OVERLAY						30-JUN-1991  KB
\oc\su
ZOOM/OVERLAY [zoom_fact] [center]
	zoom image + overlay together
\us\pu
Purpose:
          Zoom image interactively and also the overlay plane.
\up\sy
Syntax:  
          ZOOM/OVERLAY [zoom_factor] [center]
\ys\pa
          zoom_fact = integer zoom factor;
\\
              if zoom_fact is omitted, zoom the image + overlay on image display
              according to size of rectangle formed by the two cursors (a);
\\
              maximum of the zoom factors in x and y is taken, so that equal
              magnification in x and y is assured;
\\
              this is the default;
\\
              if zoom factor is given, zoom the image + overlay with explicit
              zoom factor in interval [1,8] (b);
\\
              if zoom_factor = UP or DOWN (c), zoom up or down continuously:
\\
              Every time the ENTER button is pressed on the cursor box, the
              image + overlay is zoomed with the next higher (lower) zoom
              factor. Control returns to the terminal when highest (=8) or
              lowest (=1) zoom factors are reached, or if ENTER is pressed with
              cursor off.
\ap\pa
          center = only for option (b) above: x,y-screen coords. of center pixel
              for zooming;
\\
              if center is omitted, use cursor to choose center of zoom
\ap\sa
See also:
          CLEAR/ZOOM, ZOOM/CHANNEL, CLEAR/OVERLAY
\as\no
Note:
          On workstations with X-Windows the overlay channel/plane is
          emulated in software. Therefore ZOOM/OVERLAY is not supported
          on workstations in MIDAS.
\on\exs
Examples:
\ex
          ZOOM/OVER
            Modify size of cursor rectangle to determine the zoom factor and 
            move it over part of image which should remain on display, press 
            ENTER to magnify image + overlay.
\xe\ex
          ZOOM/OVER 4
            Move cursor to pixel which should remain fixed on display, press
            ENTER to magnify image + overlay by a factor of 4.
\xe \sxe
