Installing Fonts for Use with PostScript Printing
Products : VW7.1 and later
Platforms: ALL
Keywords : printing, font, graphics
Released: 6/23/97
Last Revised: 7/30/03
This document presents an overview of PostScript printing and fonts and
answers the question of how new PostScript fonts are installed and used
with VisualWorks. A patch and application is attached to simplify VW font
installation and to download soft fonts to a printer.
What is PostScript?
Like Java, PostScript is a language of executable content whereby PostScript
programs and data may be downloaded and run on any device with a PostScript
interpreter. In fact, PostScript was the first language that popularized
executable content. The purpose of the PostScript language is to compose
the graphic elements of text, graphics, and scanned images on a page of
a printer or other output device. It is device independent and takes full
advantage of the capabilities built into the device in rendering graphics
and text.
Type 1 PostScript Font Files
The most common PostScript font format for type display on PostScript printers
and displays is the Type 1. The Type 1 font is a specialized form of the
PostScript language and is the only digital type format recognized on every
computer platform from microcomputers to mainframes. Hundreds of companies
around the world have designed and released more than 30,000 Type 1 fonts.
PostScript Type 1 fonts are distributed in a few different file formats
and two files are usually all that are needed to install and use PostScript
fonts. The files are normally identified by their .AFM, .PFM, .PFB, or
.PFA file extensions.
AFM (Adobe Font Metrics) This is an ASCII readable file with
the font metric information for the PostScript font. Every style of a font
family has a corresponding AFM file. The font metric information includes
the encodings, character widths, bounding boxes, ligature, and kerning
tables as is needed to format text for the screen or printer. A font metric
file specifies character widths to calculate line widths and text placement,
as well as character bounding boxes that can be used for placing accents
and determination of clipping regions. An AFM font metric file is needed
for each PostScript printer font defined in VW for printer text placement.
Once installed in VW the font metrics appear in instances of PostScriptFontBody.
PFM (Printer Font Metrics) This is the binary equivalent of the
font AFM font metric file as is usually distributed for the Windows and
Macintosh environments. AFM files are seldom used on Windows and Mac 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 a POST resource.
Mac PFB files are therefore not compatible with PC PFB files. Because PFB
files include binary data they cannot in general be sent directly to a
PostScript printer. Instead, a print driver unpacks the font to ASCII before
sending to the printer.
PFA (Printer Font ASCII) This is the ASCII PostScript equivalent
of an unpacked PFB file. It can be sent directly to a PostScript printer
for interpretation. Any binary data present in a former PFB file is stored
as "ASCII hex"--meaning each byte of binary data is turned into two ASCII
characters representing the hexadecimal value. Stand alone conversion utilities
exist to convert PFB files to PFA files such as what most Windows print
drivers do.
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.
If the PFA font file is not available in a package but the PFB file
is then you can create the PFA file using any of the conversion utilities
pfa2pfb, pfb2pfa, pfatopfb, fbtopfa, ft1ascii, t1binary, or t1utils available
by FTP. The reference section below cites a location where t1utils for
the PC is available.
PostScript Printing Primer
Windows and Mac platforms rely heavily on their individual PostScript drivers
to construct the PostScript content sent to the printer. This means appropriate
application calls by applications such as MS Word need only tell the platform
resident PostScript print driver what soft fonts to include and the driver
then does the remaining processing. When an application requests a font
the print driver compares the font request to a list of fonts known to
be installed in the printer. If it determines that a font to be included
in the document is not resident on the printer, the driver finds the required
font or an appropriate substitute installed on the operating system, extracts
its content, translates it to PostScript, and includes its content in the
current print job.
Print servers on Unix platforms on the other hand usually only send
a PostScript file to the printer as is with no further processing. VisualWorks
assumes the lowest common denominator exists between platforms and takes
the responsibility to construct the entire PostScript file itself. Once
VisualWorks constructs a PostScript file it sends the file to the operating
system's PostScript print spooler. It does this without knowledge whether
the fonts required by the document are missing from the PostScript printer
and is not enabled to download the soft fonts the document needs.
PostScript Font Types Compatible with VW
To be used with VW the PostScript font must satisfy the following conditions:
-
It must be a Type 1 font.
-
The AFM font file should be available written with the line end convention
of the platform it is installed to (i.e. LF for Unix, CR for Mac platforms,
and CRLF for Windows platforms).
-
It should have AdobeStandardEncoding, HRomanEncoding, or FontSpecific encoding
types. These are the encoding schemes currently recognized by VW. If you
are not certain what encoding the font has look inside the font AFM file
for the tag 'EncodingScheme' where it is specified.
-
If the font needs to be downloaded as a soft font to a PostScript printer
its PFA file must be available.
These restrictions are a trade-off between the existing VW coding to interpret
PostScript fonts and the requirement that VW operate on multiple platforms.
How to Display and Print PostScript Fonts in VW
To display PostScript fonts in VW you need only to install and setup these
fonts for the operating system. When you add PostScript fonts to the operating
system follow the instructions of the font manufacturer for installation.
For MS Windows, you will need to install Adobe Type Manager so Windows
can display PostScript as well as TrueType fonts. Once the operating system
can utilize PostScript fonts VW will display them. To see a sample of all
fonts VW can display file in and run the Font2Example VW application available
from the online example files.
To print PostScript fonts from VW requires that the PostScript AFM font
file is installed in VW and that the printer has the font installed. It
is not enough that VW has the font defined, the printer must either have
the font defined internally or have it downloaded in advance as a soft
font. If the font is referenced but not available on the printer it will
substitute a default font, usually Courier, in place of it.
For a listing of all PostScript fonts VW recognizes and can print evaluate
the following with 'print it' in VW:
PostScriptFontBody fontNames
The majority of all Apple and HP PostScript laser printers have all
these VW default fonts defined internally with the exception of the following
font variations of Helvetica:
Helvetica-Black
Helvetica-BlackOblique
Helvetica-Condensed
Helvetica-Condensed-Oblique
Helvetica-Condensed-Bold
Helvetica-Condensed-BoldObl
Helvetica-Light
Helvetica-LightOblique
Since few if any printers have these font styles installed these fonts
will be printed using a default font (e.g. Courier). Fortunately, Helvetica
bold or italic fonts are good substitutes and there is seldom a need to
use a Helvetica font choice from the list above.
The remaining sections of this document will describe how to download
soft fonts to a PostScript printer to either make them persist on the printer
or to be used for a single-use print job. A VW patch and application is
also presented to simplify font installation and implement font download
for VW PostScript print jobs.
Making PostScript Soft Fonts Persistent in Printer Volatile Memory
PostScript soft fonts can be downloaded to a PostScript printer and made
available for use indefinitely. Few if any Windows PostScript printer drivers
still provide this ability however.
The comp.lang.PostScript FAQ contains instructions on how to make a
font persistent. This amounts to appending a font PFA file to a PostScript
header and downloading it to the printer. To remove a persistent font the
only reliable method in PostScript Level 1 is to restart the printer. Of
course, the real solution is just to not download persistent fonts unless
you really want them available indefinitely. If you want them only for
one job, you should download them as part of the job.
Downloading Soft Fonts for Use During a Print Job
You can download a font manually for use during a print job by just including
the PFA source for all fonts needed by the document prior to the document
PostScript content. This is as easy as prepending all the PFA font files
needed in the document before the PostScript document file and printing
the combination. The document file must be at the end of the combined file.
For example, given a PostScript document created by VW as VWsource.ps
and the PFA file font.pfa the resulting file to print, VWoutput.ps,
could be created in a DOS Shell by executing
copy font.pfa+VWsource.ps VWoutput.ps
in the command line.
Evaluating
'VWoutput.ps' asFilename printPSFile
in VW should print the document with the soft font. Append other PFA
font files to the beginning of the combined output file as necessary for
each soft font used.
VW PostScript Printing Goodie
Instead of prepending PostScript fonts to a document manually for each
print job requiring a soft font, this goodie adds functionality to the
PostScriptFontBody and PostScriptFile classes to do this automatically.
PostScript fonts are installed in VW by means of processing the AFM files
in the Fontmets subdirectory. Each font installed will reference an instance
of PostScriptFontBody in the class variable PostScriptFonts in PostScriptFontBody.
What the patch adds to the PostScriptFontBody class is an instance variable
'fontSource' which, if defined for an instance, references the Filename
instance on the font's PFA file. The PostScriptFile method #close has also
been changed so that before a PostScript file created by VW is closed all
fonts needed in the document are matched to PostScriptFontBody instances.
If a PostScriptFontBody instance has a filename defined for 'fontSource'
the PFA font file is read and appended to the beginning of the document.
The resulting PostScript file, larger by the font files appended to it,
can be directed to the printer or left on the disk.
VW Font Installation Application
An application aid to install PostScript fonts into VW and reference the
font PFA files appears below. The application has two lists--an Available
list of fonts available to install and an Installed list of fonts installed
in VW. The FontInstaller application fills the Available list with all
fonts that are available to install from AFM and PFA font files omitting
those fonts already installed in VW that appear in the Installed list.
Fonts with matching AFM and PFA font files appear in green whereas fonts
found from only AFM metric files are in black. The user can select fonts
to install or remove installed fonts. The application also can print a
test page of all installed fonts. See the Help option for the application
for more details or read on.
There are two parcels and their accompanying source files (.pst) in
this application:
| PSFontDeply |
Parcel to add PostScript font printing to an image. |
| PSFontPrinting |
Application to setup and test PostScript printer fonts to an image.
Unload this parcel to prepare a deployment image. Autoloads PSFontDeploy
parcel. |
Follow the steps below to make new PostScript fonts available to print
from your image.
-
Parcel in the PSFontPrinting parcel.
-
Copy the AFM and PFA font files for all fonts you wish to include in the
installation to the Fontmets subdirectory you specify for your VW installation.
By default, these files are expected to appear in Utils/Fontmets as a subdirectory
of VW. For case dependent operating systems (e.g. Unix) the AFM and PFA
filenames should match in case and their extensions should be in lower
case (i.e. "afm" and "pfa").
-
Open the Settings Tool and select the tab named "PS Fonts" or execute "FontInstaller
open".
-
Modify or add the specification of your font directory in step 2 above.
Once this is completed the Available list of the PostScript Font Installer
window should include the names of all fonts you installed files for in
green. Font names that appear in black have an AFM file but no matching
PFA file was found. If you add font files to either of these directories
while the Installer is running select the 'Update' option from the Available
list pop up menu.
-
Select a font that you wish to install in the Available list and push the
">>" button. The font you selected is installed and its name should be
moved from the Available list to the Installed list.
To print a sample of all PostScript fonts installed in VW select the Installer's
'Print all' option in the Installed list.
If you want to remove PostScript printer fonts from the image select
a font name in the Installed list and press the "<<" button. The
font will be withdrawn from the Installed list and placed in the Available
list.
To distribute an image using the PostScript printer fonts unload the
PSFontPrinting parcel and save the image with the PSFontDeply parcel
and settings. Then, when you distribute an image you need to have the end
user install the PFA files to the same directory you used for any fonts
you installed using the Installer above. If the image is distributed to
an operating system with case dependent file names (e.g. Unix) and the
image was developed from an operating system with case independent file
names (e.g. Windows) be certain that the AFM and PFA file names distributed
are in lower case. If not, the end user will see VW pop up a dialog asking
for a correct path and file name for the needed PFA file when the font
is used. Also, if you distribute the image you must obey the font manufacturer's
fair use policy for those fonts you distribute with the image.
Sample Font Download
A ZIP archive of sample PostScript font files ready for use with the PSFontPrinting
parcel is available for download from
http://www.cincomsmalltalk.com:8080/CincomSmalltalkWiki/DOWNLOAD/CODE/fontmets.zip
Install the files from the archive to Utils/Fontmets as a subdirectory
of VW. Or install the files to another directory and specify that
directory to the Settings Tool "PS Fonts" page as noted in the previous
section. The archive also includes Adobe AFM files previously distributed
with VW2.5.2. The font metrics of these files are defined already
in a VW image by default and the files are only needed if you use the Settings
Tool "PS Fonts" page to remove the font then later wish to restore it .
References
PostScript Font Sources
PostScript fonts are available either as freeware, shareware, or commericial
products. Free or shareware font listings originate from AOL, Compuserve,
several Web or FTP sites, and CD-ROMs. A number of Linux user groups have
compiled PostScript fonts and utilities for use with this product.
Here are a few sites for information on PostScript fonts and font sources:
http://www.math.utah.edu/~beebe/fonts/postscript-type-1-fonts.html
http://yoyo.cc.monash.edu.au/~wigs/postscript/
http://www.cs.indiana.edu/docproject/programming/postscript/postscript.html
The full set of public domain PostScript font files for the Computer
Modern Roman set is available at
http://www.ams.org/tex/type1-cm-fonts.html
Type 1 Font Conversion Utilities
For DOS and Windows, t1utils1.zip:
http://garbo.uwasa.fi/pc/fonts.html
The t1ascii.exe executable may be used to convert a PFB file to PFA
file in DOS.
Usenet newsgroup comp.lang.postscript FAQ
ftp://wilma.cs.brown.edu/pub/comp.lang.postscript/
Adobe Technical Notes (in Adobe PDF format)
Technical Note #5040. Supporting Downloadable PostScript Language Fonts
Technical Note #5075. Supporting Fonts in the PostScript Language Environment
Adobe PostScript and Typographic Information
Documents on PostScript font styles, metrics, terminology, and an overview
of PostScript may be found at http://partners.adobe.com/asn/developer/technotes.html
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