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                           A MacPaint to PostScript
                              Conversion Utility

                            Michael P. Kaczmarczik
                                June 26th, 1986
                       The University of Texas at Austin
                              Computation Center
                                 Austin, Texas
Introduction                                                             Page 1

1. Introduction

1.1 Overview

MacPs  is  a utility to convert Macintosh MacPaint files into a format suitable
for printing on the  Apple  LaserWriter,  and  other  printers  which  use  the
PostScript  language.    It  is written in Rutgers Pascal and is the product of
inspiration from many sources.

An important feature of MacPs is its ability to  produce  files  which  may  be
included  in a Scribe document with the @Picture command.  The image bitmap may
be centered and sized to fit exactly in the specified space on the page, giving
a fine degree of control over the final picture.

1.2 Credits

MacPs  is  based  on EXTRACT_TOP.C, by J.W. Peterson of the University of Utah,
and MACQMS.PAS by E. Lavitsky at Rutgers.  EXTRACT_TOP, written in C, would not
work  on  our  system  (the  C  I/O package we have uses 7-bit bytes, and 8 are
necessary), so I recoded the extraction code from EXTRACT_TOP and added TOPS-20
argument  parsing  in the same style as MACQMS.  This documentation also owes a
large debt to E. Lavitsky's excellent documentation for MACQMS.

1.3 System Requirements

You will need the following to use MacPs:

   - Macintosh Computer
   - Macintosh diskette with MacKermit and System Folder
   - Macintosh diskette with MacPaint documents
   - Connection (modem, Micom line) to the DEC-20
   - User account and access to the KERMIT-20 program on the DEC-20
   - Access to an Apple LaserWriter printer

1.4 Disclaimer

MacPS is supplied as unsupported software, so you take your own risks when  you
use  it.  However, please feel free to send comments, suggestions, and so forth
to Mic Kaczmarczik (  Especially useful would
be suggestions for improving the dialogue and defaults that are currently used.
Getting files to the DEC-20                                              Page 2

2. Getting files to the DEC-20

2.1 On the Macintosh

NOTE:This section describes file transfer using MacKermit V0.8 or later.

When  you prepare MacPaint images for transmission to the DEC-20, be aware that
if you want to extract an image smaller than the entire MacPaint page the image
must  be  in the top left corner of the MacPaint document.  If the image is not
there already, select "Show Page" from the "Goodies" menu, drag  the  image  to
the top left corner, then save the document.

When  printed  on  the LaserWriter, areas of black will tend to be faded in the
center.  If this is undesireable, use patterns with less black in them.

If you have a two-drive system, a convenient way to perform the  file  transfer
is  to  have  Kermit  on  the  system  diskette (in the internal drive) and the
diskette with MacPaint files on the external drive.)  That way, you do not have
to switch diskettes while transferring files.

Start  Kermit  and  choose  "File Defaults" from the File menu. Select "Binary"
transfer mode and "Data" as the default file fork, and  click  "OK".  Selecting
the data fork assures that the MacKermit will offer MacPaint files when you try
to send them.  (This is a bug in this version of MacKermit.)

Select "Communications" from the File menu and make the following settings:

   - Set the baud rate to the appropriate value for your connection to the
     DEC-20  (the faster the better).  XON/XOFF flow control 1 stop bit NO

You should now be able to connect to the DEC-20.  Dial up, select class  codes,
hit  carriage returns, and do whatever is necessary to get the attention of the

2.2 Transferring the files

Log in to the DEC-20. Once you are at the "@" prompt, start up DEC-20 Kermit by


The 20 will respond with the KERMIT-20> prompt.

The  Macintosh,  along  with many other computer systems, stores information in
8-bit bytes.  The DEC-20, however, usually stores them in 7-bit bytes.    Since
all the bits of information from the MacPaint document are necessary, type in


to tell the DEC-20 to use 8-bit bytes for the file transfer.

Now you are ready to send files.  Type in
Transferring the files                                                   Page 3

    KERMIT-20>RECIEVE filename

to  tell  KERMIT-20  to  wait for a file from the Macintosh.  On the Macintosh,
select "Send" from the File menu, select the MacPaint file  you  wish  to  send
from  the  dialogue box, then click on "Send" to start the transfer.  MacKermit
will inform you of the progress of the file  transfer  until  it  is  complete.
When complete, click the mouse button once to remove the dialogue box.  You may
then send another MacPaint file, or type 


to return to the TOPS-20 prompt.
MacPs Parameters                                                         Page 4

3. MacPs Parameters

Now that the MacPaint file has been transferred to the DEC-20, you may  convert
it into one ready for insertion into a Scribe document.

3.1 Scribe Image Parameters

MacPs  has  a  number  of  settable parameters which control the height, color,
horizontal centering, and vertical positioning of the image:

3.1.1 Image Height

The height parameter is the height you want the image to be.  This value should
exactly  match  the  "Size"  attribute  you  plan to use in the Scribe @Picture

3.1.2 Column Width

The Scribe column width should match the column width of your Scribe  document.
This will assure that the rectangular area extracted from the MacPaint document
is centered on the output page.

3.1.3 Upward Translation

The upward translation parameter allows you to move the image vertically.   Its
main usefulness is for centering images vertically as well as horizontally.

For  example,  if  you  desire  a  3  inch tall image and also want at least .5
binches of space around it, specify a picture size of 4 (= 3 + 1) inches in the
@Picture  command,  then  specify an upward translation of .5 inches. This will
center the image in the 4 inch tall area.

3.1.4 Inverted Image

Inverting the image means making white dots black and black dots white.    This
is  useful for special effects.  Remember that inverting an image with a lot of
blank area may case the center of the area to wash out somewhat.

3.2 Document Parameters

The nature of the encoding of the  MacPaint  image  requires  MacPs  to  always
extract  a  rectangular  area from a MacPaint document.  By default, the entire
MacPaint page, starting from the top left corner, is extracted, but the  number
of scan lines and the width of the scan lines may changed:

3.2.1 Vertical Scan Lines

The  number  of  vertical  scan  lines  determines  the  relative height of the
picture.  The maximum number is 720 (the height of the MacPaint page)  and  the
minimum  is  1  (the  top  scan  line of the image).  The MacPaint window has a
height of 240 scan lines.
Horizontal Line Width                                                    Page 5

3.2.2 Horizontal Line Width

The horizontal line width determines the relative width of the  picture.    The
maximum  is  72  bytes  (576 bits), while the MacPaint window has a width of 52
bytes (420 bits).

The image is always taken from the top left corner of  the  MacPaint  document.
Thus if you wish to extract an image smaller than the entire MacPaint page, you
must select Show Page from the Goodies menu of MacPaint and  move  the  desired
image to an appropriate spot at the top left of the page before transferring it
to the DEC-20.
Running MacPs                                                            Page 6

4. Running MacPs

Here is an example run of MacPs, using the file PIC.MPT as the input file.

            MacPs -- MacPaint to Postscript converter
            Mac filename: PIC.MPT
            Output filename: PIC.PS
            Change Scribe page parameters? YES
            Image height: 5
            Scribe column width: 6.5
            Upward translation: 0
            Change MacPaint image parameters? Yes
            Vertical scan lines: 240
            Horizontal Line Width: 52
            Inverted image? NO
            Processing file PIC.PS [OK]

In this example, a rectangular bitmap with the dimensions of a MacPaint  window
(240  bits  high  by  52*8  bits  wide),  located at the top left corner of the
MacPaint page, was extracted.  The rectangular area  this  represents  will  be
centered  in a column 6.5 inches wide, and is to be 5 inches tall. The width of
the image will be adjusted so that it has the proper proportions.)
Running Scribe                                                           Page 7

5. Running Scribe

After processing by MacPs, your MacPaint image is finally ready  for  insertion
in a Scribe document.

At  the  beginning  of  your  document,  use the @Device(PostScript) command to
inform Scribe that you wish to generate output for the Apple LaserWriter.

At the point you want the image to appear in the  Scribe  document,  enter  the
@Figure, @FullPageFigure, or @Equation environment and use the @Picture command
to insert the MacPaint image:

    @Comment[Must use device type "PostScript"]
    ...... Scribe commands and text ......
    @Picture(Size = 5 inches, ScaleAbleLaser = "PIC.PS")
    @Caption(<Whatever may be appropriate>)
    ...... more Scribe commands and text ......

The @Picture command may only be used inside the @Figure, @FullPageFigure,  and
@Equation  environments.    However,  these  environnments are available in any
Scribe document type that has  a  Table  Of  Contents  (e.g.  Report,  Article,
Thesis, etc.).

Now  run  Scribe  and  print  the  output  file (for example, PICTURE.MSS would
generate PICTURE.PS as the output file) on the Apple LaserWriter.  Consult your
local guru on how to print the resulting file on the LaserWriter.
Table of Contents                                                        Page i

                               Table of Contents

1. Introduction                                                               1

   1.1 Overview                                                               1
   1.2 Credits                                                                1
   1.3 System Requirements                                                    1
   1.4 Disclaimer                                                             1

2. Getting files to the DEC-20                                                2

   2.1 On the Macintosh                                                       2
   2.2 Transferring the files                                                 2

3. MacPs Parameters                                                           4

   3.1 Scribe Image Parameters                                                4
       3.1.1 Image Height                                                     4
       3.1.2 Column Width                                                     4
       3.1.3 Upward Translation                                               4
       3.1.4 Inverted Image                                                   4
   3.2 Document Parameters                                                    4
       3.2.1 Vertical Scan Lines                                              4
       3.2.2 Horizontal Line Width                                            5

4. Running MacPs                                                              6

5. Running Scribe                                                             7