PLT2PIC    AutoCAD Binary PLot File to Psion Pic Converter    [TW] Ver. 1.0
                 (c) Tim Williamson, October 1993.

Files:      PLTPIC10.ZIP
            containing:
               PLT2PIC.EXE  45,760 bytes  Main program file
               PLT2LIC.TXT  4,859 bytes   (see PLT2PIC.TXT)
               LILSHOP.PLT  7,4032 bytes  Sample plot file

Author:     (c) Tim Williamson (TimW@cix.compulink.co.uk)

Version:    1.0 (October 1993)

Platform:   DOS with VGA display

Precis:     DOS Utility for converting AutoCAD plot files to Psion
            Series 3 or 3a PIC files.

Release:    May be freely distributed and used on a non-profit basis.
            If you find it useful, a small contribution to relieve the
            author's poverty would be greatly appreciated.

Description:
This program converts a plot file created by AutoCad into a Psion PIC
file. It was created to allow a simple way of getting a copy of CAD
drawings onto a Series 3 or Series 3a, allowing you to specify the size
of the image created, and to preview it before saving to make sure you
have enough detail left to be useful.

The only way I could find to do this before writing this program was to
create a GIF file using AutoCAD version 12 then converting this to a PIC
using a Psion based utility, which proved to be slow and difficult to
ensure the resultant image was showing the right information.

You can adjust the size of the PIC created by specifying the width in
pixels. The height is then automatically calculated, to save wasted
pixels at the bottom of the image. If you exceed the maximum image size
(64K bytes, about 850 x 600 pixels depending on the aspect ratio) the
program automatically re-calculates to create an image of the maximum
possible size.


How To Use This:
1. Redefine the PLOT output format of AutoCAD to and ADI Binary File
   format, for version 11, starting at the main menu, select:

      5 - Configure AutoCAD
      5 - Configure Plotter
      3 - ADI plotter
      1 - Binary File
         multiple pens              - Yes, 2 pens
         Multiple dashed lines?     - No
         Variable Speed?            - No
         plot size in mm?           - No

      all the rest are default values, until you get

         Write the plot to a file?  - Yes

      then your normal default.

2. Create a drawing

3. Plot out the drawing to a file, e.g. TEST.PLT

4. Shell out to DOS

5. run PLT2PIC TEST

6. When the plot file has been rasterised, pan and zoom round the image
   to see if it's what you want.

   hit I to get info. on the file and the size of PIC file that'll be created.
   hit R to re-load the data with a new image width if needed.
   hit S to save the image to a PIC file.
   press <Esc> when done to exit.

7. Exit back to AutoCAD.


How It Works:
The AutoCAD binary plot file contains purely vector information, i.e.
loads of lines. All higher level objects, such as circles, hatching,
text etc. are converted into vectors. This means that PLT2PIC will
handle perspective views, hidden views and the like with no problems.

The plot file is first scanned to determine the effective size of the
image and it's aspect ratio. Any blank space around the image is
ignored by offsetting the vectors, then a scale factor is calculated.

Given an image width, the image height is calculated from the aspect
ratio, and each vector is scaled and rasterised into the image. The more
vectors you have in the plot file, the longer the rasterisation process
will take, regardless of the image size.

Once created, you can pan and zoom around it, or re-load it using a new
image width, then save it as a PIC file. By default it uses the same
name as the source file but with a .PIC extention. This can then be
downloaded to a Psion.


Limitations:
This program will only view an image on a VGA screen (virtually
obligatory for anyone running AutoCAD) due to the rather obscure video
mode used.

Multiple layers are not supported yet. If there is any interest, version
2 will allow plotter pens 1 and 2 to be converted to the black and grey
layers of a PIC.

Depending on the detail in your plot file, you may not be able to
resolve enough detail in the PIC. Try plotting a smaller area, or, if
you are working with a schematic, re-arrange things to be closer
together.

The outputs of AutoCAD version 11 and 12 have been tested and work ok. It
hasn't been tested on earlier versions but, assuming that the plot
format is supported, you shouldn't have any problems.

The program can be modified to work with pure vector outputs of other CAD
packages, such as HP7475 format. If there is sufficient demand, I will
modify the program. There are no plans to support DXF files at the
moment.