source: trunk/third/transcript/man/afm.7p @ 9217

.TH AFM 7 "19 August 1992" "Adobe Systems"
\" Copyright (c) 1985,1987,1992 Adobe Systems Incorporated. All Rights Reserved.
\" ATTN GOVERNMENT END USERS: See notice of rights in file XPSLIBDIRX/Notice
\" RCSID: $Header: /afs/dev.mit.edu/source/repository/third/transcript/man/afm.7p,v 1.2 1996-10-14 05:09:39 ghudson Exp $
.ds PS P\s-2OST\s+2S\s-2CRIPT\s+2
.ds TS T\s-2RAN\s+2S\s-2CRIPT\s+2
.SH NAME
AFM \- Adobe font metrics file format
.SH DESCRIPTION
AFM files are a standard interchange format for communicating 
Type 1 font metric information to people and programs.
The format is ASCII encoded (for both human and machine
readability), machine independent, extensible, simple to
parse, and simple to generate.
AFM files are available for all of Adobe Systems'
\*(PS font programs.
.PP
While somewhat verbose, the format is intended to be easily 
parsed, with the ability for applications to quickly
skip over items that are not of interest.  It should be
possible to create simple line-oriented
parsing programs, or tools based on
awk(1)
or 
sed(1).
.PP
Each AFM file contains the information for only one font
face.  The file begins with global information about the
font, followed by sections with character metrics.  The file
format is line-oriented, each line beginning with a property
(key) name, followed by the values for that property.  The
general idea is to give key-value tuples.
.PP
The format is:
.RS
Key [value value ...]
.RE
Key names are case-sensitive.  All keys beginning with a
capital letter are reserved by Adobe Systems.
The standard keys are detailed below, but other keys should
be allowed and safely ignored by programs not recognizing
them.  All standard keys begin with a capital letter.
User-defined nonstandard entries should begin with a lowercase letter.
.PP
The file begins with the line:
.RS
StartFontMetrics 
.I version
.RE
The version described here is 1.0.
The last line of the file is:
.RS
EndFontMetrics
.RE
.PP
The following global font keys are defined.
Many of them are defined as in the top level or
FontInfo subdictionary of a \*(PS font dictionary.
All numeric values are in the
(1000 unit per em) character coordinate system.
.TP 1.5i
.BI FontName " string"
the name of the font as presented to the
findfont
operator.
.TP
.BI FullName " string"
the "print name" of the font.
.TP
.BI FamilyName " string"
the font family name.
.TP
.BI Weight " string"
the weight of the font.
.TP
.BI ItalicAngle " real"
the angle (in degrees counter-clockwise 
from the vertical) of the dominant staffs of the font.
.TP
.BI IsFixedPitch " boolean"
indicates monospaced (typewriter) fonts.
.TP
.BI FontBBox " llx lly urx ury"
four integers giving the lower left
corner and the upper right corner of the font bounding box.
.B Note:
the bounding box given here is that of the flattened
paths, not of the Bezier curve descriptions.
.TP
.BI UnderlinePosition " number"
the position (from the baseline) to place
an underline.
.TP
.BI UnderlineThickness " number"
thickness of an underline stroke.
.TP
.BI Version " string"
font version identifier.
.TP
.BI Notice " string"
font name trademark or copyright notice.
.TP
.BI Comment " string"
comment strings may be ignored.
.TP
.BI EncodingScheme " string"
a string indicating the default encoding
vector for this font.  The most common one is
AdobeStandardEncoding.
Special fonts may simply state
"FontSpecific".  In the future, other schemes may be
employed.
.TP
.BI CapHeight " number"
top of capital H.
.TP
.BI XHeight " number"
top of lower case x.
.TP
.BI Ascender " number"
top of lower case d.
.TP
.BI Descender " number"
bottom of lower case p.
.PP
The individual character metrics are surrounded with the lines
StartCharMetrics and EndCharMetrics and consist of a list of
keys and values separated by semicolons.  The characters are
sorted (numeric ascending) by character code.  Unencoded characters
follow all the encoded ones and are distinguished by
having character code \-1.  Each character gets one line
of description. Standard keys are:
.TP 1.5i
.BI C " number"
decimal value of default
character code (\-1 if unencoded).
.TP
.BI WX " width-x"
character width in \fIx\fP (y is 0).
.TP
.BI W " width-x width-y"
character width vector.
.TP
.BI N " name"
character name.
.TP
.BI B " llx lly urx ury"
the character bounding box.
.TP
.BI L " successor ligature"
a ligature sequence;  The current
character may join with the character named \fIsuccessor\fP to
form the character named \fIligature\fP.  Note that characters
may have more than one such entry.
.PP
Most western language fonts have WX rather than W entries.
Note that keys are one letter for brevity.  Here, too,
the set is extensible, with unknown entries ignored.  (This leaves room for 
the addition of new information, for example.)
A future revision of this format will have a specification for
kerning information.
.SH FILES
.TP 1.5i
XPSLIBDIRX/*.afm
AFM files in the \*(TS distribution
.SH "SEE ALSO"
transcript(1), psfonts(1), awk(1), sed(1)
.SH AUTHOR
Adobe Systems Incorporated
.SH NOTES
\*(PS is a registered trademark of Adobe Systems Incorporated.
.br
\*(TS is a trademark of Adobe Systems Incorporated.