NavPak

                    SCREEN OVERLAY METAFILE
    A metafile is a vector overlay which records all your drawing, plotting
and text, and redraw it as you scroll.  The screen metafile uses memory buffers
to paint the screen and write disk files.  These buffers are structured as follows:

     1. Lines drawn using the "Line" function in the Draw menu, and lines
        plotted using items in the Tools and Celestial menus, share a
        buffer which will store 610 lines.
     2. The text buffer stores 62 strings of 16 characters each.
     3. "Sketch / Boundary"  buffer will record 1200 line segments.
     4. "Chain / Boundary"   buffer will record 1200 line segments.
     5. Color fill buffer will store 62 fill operations.
     6. Marker buffer will record 304 markers.

  These items can be deleted by deincrementing the buffer using "Undo"
located in the Edit menu. All of the above buffers can be cleared using
"Clear Screen Metafile", located in the Screen menu.  When one of the buffers
fills up, a message box will appear to notify you.

  A program to edit and print metafiles is available to registered users of
NavPak, on request.  This program is available in 16 and 32 bit versions.      
 

                      DISK METAFILE
  Screen metafiles previously saved on disk can be displayed alone, with a
bitmap image, or with other metafiles.   The most recently loaded metafile
will be repainted after scrolling, the previously loaded metafiles will
scroll, but will not be repainted when cropped by scrolling.

  The screen metafile, disk metafile and the bitmap will be continuously
repainted after scrolling (persistent graphics).  While you have disk
metafiles loaded and displayed, the screen metafile is keeping track of your
plotting, and can be saved under any name.

  A disk metafile can be over-written by saving a screen metafile as the
same name, and a dialog box will appear to verify that you want to
over-write the file.  The default extension for a metafile is .wmf.

  If you load a metafile from disk, when a bitmap is not present,  the
horizontal and vertical scroll bars are set to 2000 pixels, otherwise they
will be set to the size of the bitmap.

 Loading a metafile from disk does not initiate the script file for auto
setup.  If a metafile is drawn as an overlay on a bitmap, the script file
associated with the bitmap will automatically setup the reference points,
scale, and variation, when the bitmap is loaded.   If the metafile was
created on a bitmap, then load the bitmap to start the script file.

 If the metafile is intended to be used without a bitmap, such as a plotting
sheet, then setup the screen coordinates, scale, and variation manually.
To facilitate manual setup, draw a reference meridian and parallel on the
metafile using the "Line" function located in the "Draw" menu.  Where these
lines intersect, show the lat/lon using the "Text" function located in the
"Draw" menu.  Also show the scale and magnetic variation with the "Text"
function.  Then when you load the metafile from disk later, the necessary
information will be there for manual setup.  The manual setup routine is
explained in: "NavPak.txt".

  After a metafile or bitmap is displayed, it can be viewed for
information.  Before doing any serious plotting, it is important to verify
that the screen position and scale have been accurately setup with the
script file.  See "SCREEN POSITION AND SCALE", located in "NavPak.txt.

               /********  End MetaFile.txt  **********/