|
This document presents an overview of Postscript printing
(with soft fonts downloaded to a Postscript printer).
Postscript is an interpretive language like Basic, Java and
PCL. The postscript program and data can be downloaded from the
host to the device and the device interprets line by line and
executes the commands. Postscript language is device independent
and supported by a lot of printer manufacturers. Using a
postscript printer and Morovia business fonts, you can print
barcodes, OCR/MICR characters from any an operating system - no
matter it is a UNIX, Macintosh or AS/400.
A Postscript language font program should be a 7-bit ASCII
stream when it is sent a PosctScript interpreter. However, the
programs are not always stored in ASCII. They are referred as
different Postscript font format. Among these different types,
type 1 font is most commonly used and supported by a variety of
computer platforms ranging from microcomputers to mainframes.
The files are normally identified by their extensions .AFM, .PFM,
.PFB or .PFA.
AFM (Adobe Font Metrics). The AFM files contain
general font information and font metrics information, including
the encodings, character widths, bounding boxes, ligature, and
kerning tables as is needed to format text for the screen or
printer. AFM files are generally only direct used in UNIX. This
is an ASCII readable file.
PFM (Printer Font Metrics). This is the binary
equivalent of the AFM font metric file used in Windows and
Macintosh platforms.
PFB (Printer Font Binary). This is a Type 1 font
outline file stored in a compressed binary format intended for
PC or Macintosh platforms. Macintosh uses a different binary
storage format known as POST resources. Therefore, the PEB file
in PC is different than the one in MAC. The PEB file must be
unpacked to ASCII before it is sent to the printer.
PFA (Printer Font ASCII). This is the unpacked version
of the PEB file. It can be sent directly to a Postscript printer
for interpretation.
For each font style, matching PFM and PFB PostScript files
are needed to install a font on Windows or Macintosh
environments; Unix platforms require matching AFM and PFA files.
These matching files are usually identified by filenames
identical except for the extension.
In Windows and Macintosh platforms the operating systems rely
on the PostScript drivers to prepare the PostScript contents
sent to the printer. On the other side, print servers on UNIX
platforms usually only send a PostScript file to the printer
without further processing. You can send the font with a print
job, or make the font persistent. Postscript fonts are
referenced by their type face names.
In UNIX environment you invoke download command to download a
Postscript font to the printer.
Adobe Technical Notes
Technical Note #5040.
Supporting Downloadable PostScript Language Fonts
Technical Note #5075.
Supporting Fonts in the PostScript Language Environment
Adobe PostScript Information
Adobe Type Information -
http://partners.adobe.com/asn/developer/technotes.html
PostScript F.A.Q.
ftp://wilma.cs.brown.edu/pub/comp.lang.postscript/
|
