From: shiva@well.sf.ca.us (Kenneth Porter)
Subject: (29may91) FAQ 1.06: Frequently Asked Questions about PostScript
Keywords: FAQ
Organization: Logical Solutions for Industry
Date: Fri, 9 Oct 1992 22:31:10 GMT

Frequently Asked Questions in comp.lang.postscript

Version 1.06 Last Changed 5-29-91

No warranty is made as to the validity of the answers below.
I don't work for any of these companies, and I've used only
some of these products, so there will probably be minor
errors.  I welcome corrections.

If you think of questions appropiate for this FAQ, or would
like to improve on an answer, please email me at the address
below.

If you manage an FTP PostScript repository, please leave a
copy of this there as I don't have FTP access.

================================================================

What is EPS?
How do I convert PS to EPS?
How can I convert PS to [other graphics format]?
How can I convert [other graphics format] to PS?
How can I convert ASCII text to PS?
How can I display PS on my [brand x] computer?
Should I leave my printer on?
How do I suppress the power-on start page?
How do I remove a persistent ("permanent") downloaded font?
How do I reset the printer without power-cycling?
What documentation is available on the PostScript language?
How do I get bitmap representations of Adobe fonts?
What FTP resources are available?
How do I get in touch with Adobe?
Where can I get official documentation?
How do I get the physical size of a page?

================================================================

What is EPS?
How do I convert PS to EPS?

An Encapsulated PostScript file (EPSF) is a standard format for
importing and exporting PostScript language files in all
environments. It is usually a single page PostScript language
program that describes an illustration. The purpose of the EPS
file is to be included as an illustration in other PostScript
language page descriptions. The EPS file can contain any
combination of text, graphics, and images. An EPS file is the
same as any other PostScript language page description, with
some restrictions.

An EPS file must be a conforming file, that is, it must conform
to the  document structuring conventions (DSC). At a minimum,
it must include a header comment, %!PS-Adobe-3.0 EPSF-3.0, and
a bounding box comment, %%BoundingBox: llx lly urx ury, that
describes the bounds of the illustration.  (The specification
does not require the EPSF version, but many programs will
reject a file that does not have it.)

The EPS program must not use operators that initialize or
permanently change the state of the machine in a manner that
cannot be undone by the enclosing application's use of save and
restore (eg. the operators starting with "init" like
initgraphics).  As a special case, the EPS program may use the
showpage operator.  The importing application is responsible
for disabling the normal effects of showpage.

The EPS program should make no environment-sensitive decisions
(the importing application may be trying to attain some special
effect, and the EPS program shouldn't screw this up), although
it can use some device-dependent tricks to improve appearance
such as a snap-to-pixel algorithm.

The complete EPS specification is available from Adobe (see
below).

A variation of EPS embeds the PS text in a binary file which
contains a header and either a TIFF or MetaFile preview image.
The header defines where in the file each section (EPS, TIFF,
or MetaFile) starts and ends.  On the Macintosh, the preview
is stored as a PICT in the file's resource fork.

To convert from PS to EPS, one must guarantee that the PS file
meets the above requirements.  If the actual program conforms
to the programming requirements, then one can simply add the
required comments at the top of the file saying that the file
is EPS and giving its BoundingBox dimensions.

================================================================

How can I convert PS to [other graphics format]?
How can I display PS on my [brand x] computer?

Since PostScript is not just a picture-description language,
but in fact a complete programming language, one needs a
complete PostScript interpreter to convert or display a
PostScript graphic. Adobe PostScript interpreters are available
for some machines (notably those using the NextStep GUI).

Numerous PostScript interpreter clones, both commercial and
free, are available for other machines.  Not all clone
interpreters know how to handle Adobe's encrypted Type 1 fonts,
and some have other incompatibilities.  Clone interpreters will
not have Adobe's proprietary rendering technology which
interprets font hints to improve the appearance of fonts shown
at small sizes on low-resolution devices.

Ghostscript, a freeware product associated with the GNU
project, is available for PC's, Sun's, X servers, and other
architectures.  Source is included.  For more information about
Ghostscript, read the gnu.ghostscript.bug newsgroup, or contact
the author at ghost@aladdin.com (L. Peter Deutsch).

Sun OpenWindows users can preview PostScript on-screen using a
program called "pageview".  Or they can print postscript on any
raster printer using the NeWSprint product which uses the same
PostScript interpreter found in OpenWindows.

AmigaDOS users can use PixelScript, a commercial product from
Pixelations, and Post, which is freely redistributable and is
available on Compuserve..

MSDOS users can use Go-Script, QMS UltraScript-PC, or Freedom
of the Press.  File format conversion is available with
Hijack-PS.

================================================================

How can I convert [other graphics format] to PS?
How can I convert ASCII text to PS?

A list of text-to-PS software is available from Howard Gayle
(howard@hal.com, phone 1(408)379-7000 ext 1080), including his
cz package.

Under Unix, you can use Adobe's TranScript package.

To convert various bitmap formats to EPS, see the frequently
asked questions posting in comp.graphics.

================================================================

What documentation is available on the PostScript language?

Adobe has written numerous manuals, sometimes referred to
by PostScript gurus by the color of the cover.  These books
are published by Addison-Wesley.  They are listed here in
order of (my) suggested reading:

PostScript Language Tutorial & Cookbook, Adobe Systems
Incorporated Addison Wesley 1985, 1990 (The "Blue" Book)

PostScript Language Reference Manual, Second Edition, Adobe
Systems Incorporated, Addison Wesley 1985, 1990 (The New "Red" Book
(really Red and White))

PostScript Language Program Design, Adobe Systems Incorporated
Addison Wesley 1988 (The "Green" Book)

Adobe Type 1 Font Format ("The Black Book")

----------------------------------------------------------------

Other books include:

Thinking in PostScript, Glenn C. Reid, Addison-Wesley, 1989

Understanding PostScript, David A. Holzgang, Sybex, 1988

Display PostScript Programming, David A. Holzgang, Addison Wesley, 1990

Mastering Adobe Illustrator, David A. Holzgang, Addison Wesley, 1988

Learning PostScript, A Visual Approach, Ross Smith, Peachpit Press, 1990

Real World PostScript, Stephen F. Roth Addison Wesley, 1988
("The Orange Book")

Graphic Design With PostScript, Gerard Kunkel Scott, Foresman and
Company, 1990

A PostScript Cookbook, Barry Thomas Van Nostrand Reinhold, 1988

Inside PostScript, Frank Merritt Braswell, Systems of Merritt &
Peachpit Press 1989

The Verbum Book of PostScript Illustration, Michael Gosney, Janet
Ashford, Linnea Dayton
M&T Books, 1990

Mastering Adobe Illustrator 88, Deke McClelland, Craig Danuloff
Publishing Resources Inc.-Dow Jones Irwin 1989.

Adobe Illustrator 88, The Official Handbook for Designers, Tony Bove,
Cheryl Rhodes, Fred Davis , Bantam Computer Books 1987

Encapsulated PostScript, Peter Vollenweider, Prentice Hall 1990.

Running PostScript from MS-DOS, Gary Glover, Windcrest Books, 1989,
ISBN 0-8306-2998-X

================================================================

Should I leave my printer on?
How do I suppress the power-on start page?
How do I remove a persistent ("permanent") downloaded font?
How do I reset the printer without power-cycling?

The general consensus seems to be that most computer equipment
lasts longer if left on.  This presents less thermal stress to
the components.  Disabling the start page is described in your
printer's PostScript supplement.  The most common sequence is
"serverdict begin 0 exitserver statusdict begin false
dostartpage end".

One trick for removing a persistent font (this requires that
you knew you would need to remove it before you downloaded it)
is to issue a "serverdict begin 0 exitserver /magic-cookie save
def" before downloading and sending "serverdict begin 0
exitserver magic-cookie restore" when you want to reclaim all
VM used since the first download.  The downside of this is that
is uses up a save level, but this is usually not a problem.

Most printers can be reset by issuing "serverdict begin 0
exitserver systemdict /quit get exec".

================================================================

How do I get bitmap representations of Adobe fonts?

Use the Font Foundary program included with the font.  If you
don't have it, contact Adobe for an upgrade.

================================================================

What FTP resources are available?

There are bitmaps of many Adobe fonts in the info-mac archives
on sumex-aim.stanford.edu.   They are available in TeX form,
with the encoding expected by dvips, on ftp.cs.umb.edu
[192.12.26.23], in pub/tex/ps-screenfonts.tar.Z.

================================================================

How do I get in touch with Adobe?
Where can I get official documentation?

Adobe Systems Incorporated
1585 Charleston Road
P.O. Box 7900
Mountain View, CA 94039-7900

Phones:
Main:           (415)961-4400
Tech Support:   (415)961-0911
Developers Line & Tech Docs (voice mail):
                (415)961-4111
Sales:          (800)344-8335

A selection of technical documents is available from Adobe's
file server, including the aforementioned EPS specification.
For more information on this, send the one-word message "help"
to ps-file-server@adobe.com.  These documents are also
available by mail; call the Developers Line and ask for the
documents catalog.

================================================================

How do I get the physical size of a page?

The initial clipping path gives you the size of the imagable
area. Use "clippath pathbbox" to get these coordinates.  If you
*must* know the size of the device's imageable area, use the
sequence "gsave initclip clippath pathbbox grestore", but this
will prevent an enclosing application from using the clippath
to achieve some special effects (such as multiple pages per
page).

================================================================

Who has helped fixed errors in earlier drafts?

I am indebted to the following people for adding functionality
to this document:

wet!icv (Ilsa VanHook)
skdutta@cs.tamu.edu (Saumen K Dutta)
howard@hal.com (Howard Gayle)
tneff@bfmny0.BFM.COM (Tom Neff)
orthlieb@adobe (Carl Orthlieb)
naughton@Eng.Sun.COM (Patrick Naughton)
flar@Eng.Sun.COM (Jim Graham)
cwitty@cs.Stanford.EDU (Carl Witty)
squash@math.ufl.edu (Jonathan)
rsmith@well.sf.ca.us (Ross Smith)
u12570@uicvm.uic.edu (Edward A. Garay)
karl@ai.mit.edu (Karl Berry)
kwb@betasvm2.vnet.ibm.com (Ken Borgendale)
us267388@web.mmc.mmmg.com (Bradley D. Rhoades)

Ver  Date     Reason
----------------------------------------------------------------
1.00 12-18-90 Creation
1.01  1- 8-91
1.02  1-25-91
1.03  2-26-91
1.04  3-28-91
1.05  4-30-91
1.06  5-29-91 expanded on EPS explanation, new email address for
              Howard Gayle, added version numbering

================================================================

Ken (shiva@well.sf.ca.us)
"Pay no attention to that man behind the curtain!"