diff options
Diffstat (limited to 'man/groff_font.5.man')
| -rw-r--r-- | man/groff_font.5.man | 1114 |
1 files changed, 1114 insertions, 0 deletions
diff --git a/man/groff_font.5.man b/man/groff_font.5.man new file mode 100644 index 0000000..0ee1d9a --- /dev/null +++ b/man/groff_font.5.man @@ -0,0 +1,1114 @@ +.TH groff_font @MAN5EXT@ "@MDATE@" "groff @VERSION@" +.SH Name +groff_font \- GNU +.I roff +device and font description files +. +. +.\" ==================================================================== +.\" Legal Terms +.\" ==================================================================== +.\" +.\" Copyright (C) 1989-2021 Free Software Foundation, Inc. +.\" +.\" This file is part of groff (GNU roff), which is a free software +.\" project. +.\" +.\" You can redistribute it and/or modify it under the terms of the GNU +.\" General Public License as published by the Free Software Foundation, +.\" either version 2 of the License, or (at your option) any later +.\" version. +.\" +.\" You should have received a copy of the GNU General Public License +.\" along with this program. If not, see +.\" <http://www.gnu.org/licenses/gpl-2.0.html>. +. +. +.\" Save and disable compatibility mode (for, e.g., Solaris 10/11). +.do nr *groff_groff_font_5_man_C \n[.cp] +.cp 0 +. +.\" Define fallback for groff 1.23's MR macro if the system lacks it. +.nr do-fallback 0 +.if !\n(.f .nr do-fallback 1 \" mandoc +.if \n(.g .if !d MR .nr do-fallback 1 \" older groff +.if !\n(.g .nr do-fallback 1 \" non-groff *roff +.if \n[do-fallback] \{\ +. de MR +. ie \\n(.$=1 \ +. I \%\\$1 +. el \ +. IR \%\\$1 (\\$2)\\$3 +. . +.\} +.rr do-fallback +. +. +.\" ==================================================================== +.SH Description +.\" ==================================================================== +. +.\" BEGIN Keep parallel with groff.texi node "Device and Font Files". +The +.I groff +font and output device description formats are slight +extensions of those used by AT&T device-independent +.IR troff . \" AT&T +. +In distinction to the AT&T implementation, +.I groff +lacks a binary format; +all files are text files. +. +(Plan\~9 +.I troff \" Plan 9 +has also abandoned the binary format.) +. +The device and font description files for a device +.I name +are stored in a +.IR dev name +directory. +. +The device description file is called +.IR DESC , +and, +for each font supported by the device, +a font description file is +.RI called\~ f, +where +.IR f \~is +usually an abbreviation of a font's name and/or style. +. +For example, +the +.B ps +(PostScript) +device has +.I groff +font description files for Times roman +.RB ( TR ) +and Zapf Chancery Medium italic +.RB ( ZCMI ), +among many others, +while the +.B utf8 +device +(for terminal emulators) +has only font descriptions for the roman, +italic, +bold, +and bold-italic styles +.RB ( R , +.BR I , +.BR B , +and +.BR BI , +respectively). +. +. +.P +Device and font description files are read by the formatter, +.IR @g@troff , +and by output drivers. +. +The programs typically delegate these files' processing to an internal +library, +.IR libgroff , +ensuring their consistent interpretation. +. +. +.\" ==================================================================== +.SH "\f[I]DESC\f[] file format" +.\" ==================================================================== +. +The +.I DESC +file contains a series of directives; +each begins a line. +. +Their order is not important, +with two exceptions: +(1) the +.B res +directive must precede any +.B \%papersize +directive; +and +(2) the +.B charset +directive must come last +(if at all). +. +If a directive name is repeated, +later entries in the file override previous ones +(except that the paper dimensions are computed based on the +.B res +directive last seen when +.B \%papersize +is encountered). +. +Spaces and/or tabs separate words and are ignored at line boundaries. +. +Comments start with the +.RB \[lq] # \[rq] +character and extend to the end of a line. +. +Empty lines are ignored. +. +. +.TP +.BI family\~ fam +The default font family is +.IR fam . +. +. +.TP +.BI fonts\~ "n F1"\~\c +.RI .\|.\|.\&\~ Fn +Fonts +.IR F1 ", \|.\|.\|.\|, " Fn +are mounted at font positions +.IR m "\|+\|1, \|.\|.\|., " m \|+\| n +where +.I m +is the number of +.B styles +(see below). +. +This directive may extend over more than one line. +. +A font name +.RB of\~ 0 +causes no font to be mounted at the corresponding position. +. +. +.TP +.BI hor\~ n +The horizontal motion quantum is +.IR n \~basic +units. +. +Horizontal quantities are rounded to multiples +.RI of\~ n. +. +. +.TP +.BI image_generator\~ program +Use +.I program +to generate PNG images from PostScript input. +. +Under GNU/Linux, +this is usually +.MR gs 1 , +but under other systems +(notably Cygwin) +it might be set to another name. +. +The +.MR grohtml @MAN1EXT@ +driver uses this directive. +. +. +.TP +.BI paperlength\~ n +The vertical dimension of the output medium is +.IR n \~basic +units +(deprecated: +use +.B \%papersize +instead). +. +. +.TP +.BI papersize\~ format-or-dimension-pair-or-file-name\c +\~.\|.\|. +The dimensions of the output medium are as according to the +argument, +which is either +a standard paper format, +a pair of dimensions, +or the name of a plain text file containing either of the foregoing. +. +Recognized paper formats are the ISO and DIN formats +.BR A0 \[en] A7 , +.BR B0 \[en] B7 , +.BR C0 \[en] C7 , +and +.BR D0 \[en] D7 ; +.\" XXX: tmac/papersize.tmac does not support [ABCD]7. +the U.S.\& formats +.BR letter , +.BR legal , +.BR tabloid , +.BR ledger , +.BR statement , +and +.BR executive ; +and the envelope formats +.BR com10 , +.BR monarch , +and +.BR DL . +. +Matching is performed without regard for lettercase. +. +. +.IP +Alternatively, +the argument can be a custom paper format +.IB length , width +(with no spaces before or after the comma). +. +Both +.I length +and +.I width +must have a unit appended; +valid units are +.RB \[lq] i \[rq] +for inches, +.RB \[lq] c \[rq] +for centimeters, +.RB \[lq] p \[rq] +for points, +and +.RB \[lq] P \[rq] +for picas. +. +Example: +.RB \[lq] 12c,235p \[rq]. +. +An argument that starts with a digit is always treated as a custom paper +format. +. +. +.IP +Finally, +the argument can be a file name +(e.g., +.IR /etc/papersize ); +if the file can be opened, +the first line is read and a match attempted against each other form. +. +No comment syntax is supported. +. +. +.IP +More than one argument can be specified; +each is scanned in turn and the first valid paper specification used. +. +. +.TP +.BI paperwidth\~ n +The horizontal dimension of the output medium is +.IR n \~basic +units +(deprecated: +use +.B \%papersize +instead). +. +. +.TP +.B pass_filenames +Direct +.I @g@troff +to emit the name of the source file being processed. +. +This is achieved with the intermediate output command +.RB \[lq] "x F" \[rq], +which +.I \%grohtml +interprets. +. +. +.TP +.BI postpro\~ program +Use +.I program +as the postprocessor. +. +. +.TP +.BI prepro\~ program +Use +.I program +as a preprocessor. +. +The +.B html +and +.B xhtml +output devices use this directive. +. +. +.TP +.BI print\~ program +Use +.I program +as the print spooler. +. +If omitted, +.IR groff 's +.B \-l +and +.B \-L +options are ignored. +. +. +.TP +.BI res\~ n +The device resolution is +.I n +basic units per inch. +. +. +.TP +.BI sizes\~ s1\~\c +.RI .\|.\|.\&\~ sn\~\c +.B 0 +The device has fonts at +.IR s1 , +\&.\|.\|., +.I sn +scaled points +(see below). +. +The list of sizes must be terminated by +.RB a\~ 0 . +. +Each +.I si +can also be a range of sizes +.IR m \[en] n . +. +The list can extend over more than one line. +. +. +.TP +.BI sizescale\~ n +A typographical point +is subdivided into +.IR n \~scaled +points. +. +The default +.RB is\~ 1 . +. +. +.TP +.BI styles\~ S1\~\c +.RI .\|.\|.\&\~ Sm +The +.RI first\~ m +font mounting positions are associated with styles +.IR S1 , +\&.\|.\|., +.IR Sm . +. +. +.TP +.B tcommand +The postprocessor can handle the +.B t +.RB and\~ u +intermediate output commands. +. +. +.TP +.B unicode +The output device supports the complete Unicode repertoire. +. +This directive is useful only for devices which produce character +entities instead of glyphs. +. +. +.IP +If +.B unicode +is present, +no +.B charset +section is required in the font description files since the Unicode +handling built into +.I groff +is used. +. +However, +if there are entries in a font description file's +.B charset +section, +they either override the default mappings for those particular +characters or add new mappings +(normally for composite characters). +. +. +.IP +The +.BR utf8 , +.BR html , +and +.B xhtml +output devices use this directive. +. +. +.TP +.BI unitwidth\~ n +Quantities in the font description files are in basic units for fonts +whose type size is +.IR n \~scaled +points. +. +. +.TP +.B unscaled_charwidths +Make the font handling module always return unscaled glyph widths. +. +The +.I \%grohtml +driver uses this directive. +. +. +.TP +.B use_charnames_in_special +.I @g@troff +should encode named glyphs inside device control commands. +. +The +.I \%grohtml +driver uses this directive. +. +. +.TP +.BI vert\~ n +The vertical motion quantum is +.IR n \~basic +units. +. +Vertical quantities are rounded to multiples +.RI of\~ n. +. +. +.TP +.B charset +This directive and the rest of the file are ignored. +. +It is recognized for compatibility with other +.I troff \" generic +implementations. +. +In GNU +.IR troff , \" GNU +character set repertoire is described on a per-font basis. +. +. +.P +.I @g@troff +recognizes but ignores the directives +.BR spare1 , +.BR spare2 , +and +.BR biggestfont . +. +. +.P +The +.BR res , +.BR unitwidth , +.BR fonts , +and +.B sizes +lines are mandatory. +. +Directives not listed above are ignored by +.I @g@troff +but may be used by postprocessors to obtain further information about +the device. +. +. +.\" ==================================================================== +.SH "Font description file format" +.\" ==================================================================== +. +On typesetting output devices, +each font is typically available at multiple sizes. +. +While paper measurements in the device description file are in absolute +units, +measurements applicable to fonts must be proportional to the type size. +. +.I groff +achieves this using the precedent set by AT&T device-independent +.IR troff : \" AT&T +one font size is chosen as a norm, +and all others are scaled linearly relative to that basis. +. +The \[lq]unit width\[rq] is the number of basic units per point when the +font is rendered at this nominal size. +. +. +.P +For instance, +.IR groff 's +.B lbp +device uses a +.B unitwidth +of\~800. +. +Its Times roman font +.RB (\[lq] TR \[rq]) +has a +.B spacewidth +of\~833; +this is also the width of its comma, +period, +centered period, +and mathematical asterisk, +while its \[lq]M\[rq] is 2,963 basic units. +. +Thus, +an \[lq]M\[rq] on the +.B lbp +device is 2,963 basic units wide at a notional type size of 800\~points. +. +(800-point type is not practical for most purposes, +but using it enables the quantities in the font description files to be +expressed as integers.) +. +. +.P +A font description file has two sections. +. +The first is a sequence of directives, +and is parsed similarly to the +.I DESC +file described above. +. +Except for the directive names that begin the second section, +their ordering is immaterial. +. +Later directives of the same name override earlier ones, +spaces and tabs are handled in the same way, +and the same comment syntax is supported. +. +Empty lines are ignored throughout. +. +. +.TP +.BI name\~ F +The name of the font +.RI is\~ F . +. +.RB \[lq] DESC \[rq] +is an invalid font name. +. +Simple integers are valid, +but their use is discouraged. +. +.RI ( groff +requests and escape sequences interpret non-negative font names as +mounting positions instead. +. +Further, +a font named +.RB \[lq] 0 \[rq] +cannot be automatically mounted by the +.B fonts +directive of a +.I DESC +file.) +. +. +.TP +.BI spacewidth\~ n +The width of an unadjusted inter-word space is +.IR n \~basic +units. +. +. +.P +The directives above must appear in the first section; +those below are optional. +. +. +.TP +.BI slant\~ n +The font's glyphs have a slant of +.IR n \~degrees; +a positive +.I n +slants in the direction of text flow. +. +. +.TP +.BI ligatures\~ lig1\~\c +.RI .\|.\|.\&\~ lign\~\c +.RB [ 0 ] +Glyphs +.IR lig1 , +\&.\|.\|., +.I lign +are ligatures; +possible ligatures are +.BR ff , +.BR fi , +.BR fl , +.BR ffi , +and +.BR ffl . +. +For compatibility with other +.I troff +implementations, +the list of ligatures may be terminated with +.RB a\~ 0 . +. +The list of ligatures must not extend over more than one line. +. +. +.TP +.B special +The font is +.IR special : +when a glyph is requested that is not present in the current font, +it is sought in any mounted fonts that bear this property. +. +. +.P +Other directives in this section are ignored by +.IR @g@troff , +but may be used by postprocessors to obtain further information about +the font. +. +. +.P +The second section contains one or two subsections. +. +These can appear in either order; +the first one encountered commences the second section. +. +Each starts with a directive on a line by itself. +. +A +.B charset +subsection is mandatory unless the associated +.I DESC +file contains the +.B unicode +directive. +. +Another subsection, +.BR \%kernpairs , +is optional. +. +. +.P +The directive +.B charset +starts the character set subsection. +. +(For typesetter devices, +this directive is misnamed since it starts a list of glyphs, +not characters.) +. +It precedes a series of glyph descriptions, +one per line. +. +Each such glyph description comprises a set of fields separated by +spaces or tabs and organized as follows. +. +. +.IP +.I name metrics type code +.RI [ entity-name ] +.RB [ \-\- +.IR comment ] +. +. +.P +.I name +identifies the glyph: +if +.I name +is a printable +.RI character\~ c , +it corresponds to the +.I troff \" generic +ordinary +.RI character\~ c . +. +If +.I name +is a multi-character sequence not beginning with +.BR \[rs] , +it corresponds to the GNU +.I troff \" GNU +special character escape sequence +\[lq]\c +.BI \[rs][ name ]\c +\[rq]. +. +A name consisting of three minus signs, +.RB \[lq] \-\-\- \[rq], +indicates that the glyph is unnamed: +such glyphs can be accessed only by the +.B \[rs]N +escape sequence in +.IR troff . \" generic; \N is portable +. +A special character named +.RB \[lq] \-\-\- \[rq] +can still be defined using +.B .char +and similar requests. +. +The +.I name +.RB \[lq] \[rs]\- \[rq] +defines the minus sign glyph. +. +.\" TODO: Withdraw support for this. No one seems to use it. +Finally, +.I name +can be the horizontal motion escape sequences, +.B \[rs]| +and +.B \[rs]\[ha] +(\[lq]thin\[rq] and \[lq]hair\[rq] spaces, +respectively), +in which case only the width metric described below is applied; +a font can thus customize the widths of these spaces. +.\" XXX: For exhaustivity purposes...you can define "\whatever", which +.\" has to be accessed with \C'\\whatever' or \[\\whatever], but the +.\" parser matches predefined escape sequences before looking up special +.\" characters. Most such definitions are inaccessible from the +.\" language, because nearly every '\x', where 'x' is a Unicode basic +.\" Latin character, is a predefined groff escape sequence. +. +. +.br +.ne 4v \" Keep next paragraph together with (possibly 2-line) synopsis. +.P +The form of the +.I metrics +field is as follows +(on one line; +it may be broken here for readability). +. +. +.IP +.\" XXX: Turning off adjustment is ugly; thanks to meter-long specimens +.\" like this, we need an escape sequence that selectively disables +.\" adjustment at the end of a word. +.na +.I width\/\c +.RI [\fB,\fP[ \:height\/\c +.RI [\fB,\fP[ \:depth\/\c +.RI [\fB,\fP[ \:\%italic-correction\/\c +.RI [\fB,\fP[ \:\%left-italic-correction\/\c +.RI [\fB,\fP[ \:\%subscript-correction ]]]]]]]]]] +.ad \*[AD] +. +. +.P +There must not be any spaces, +tabs, +or newlines between these +.I subfields, +. +which are in basic units expressed as decimal integers. +. +Unspecified subfields default +.RB to\~ 0 . +. +Since there is no associated binary format, +these values are not required to fit into the C language data type +.B char +as they are in AT&T device-independent +.IR troff . \" AT&T +. +. +.P +The +.I width +subfield gives the width of the glyph. +. +The +.I height +subfield gives the height of the glyph +(upwards is positive); +if a glyph does not extend above the baseline, +it should be given a zero height, +rather than a negative height. +. +The +.I depth +subfield gives the depth of the glyph, +that is, +the distance below the baseline to which the glyph extends +(downwards is positive); +if a glyph does not extend below the baseline, +it should be given a zero depth, +rather than a negative depth. +. +Italic corrections are relevant to glyphs in italic or oblique styles. +. +The +.I italic-correction +is the amount of space that should be added after an oblique glyph to be +followed immediately by an upright glyph. +. +The +.I left-italic-correction +is the amount of space that should be added before an oblique glyph to +be preceded immediately by an upright glyph. +. +The +.I +subscript-correction +is the amount of space that should be added after an oblique glyph to be +followed by a subscript; +it should be less than the italic correction. +. +. +.P +For fonts used with typesetting devices, +the +.I type +field gives a featural description of the glyph: +it is a bit mask recording whether the glyph is an ascender, +descender, +both, +or neither. +. +When a +.B \[rs]w +escape sequence is interpolated, +these values are bitwise or-ed together +for each glyph +and stored in the +.B ct +register. +. +In font descriptions for terminal devices, +all glyphs might have a type of zero, +regardless of their appearance. +. +. +.TP +0 +means the glyph lies entirely between the baseline and +a horizontal line at the \[lq]x-height\[rq] of the font, +as with \[lq]a\[rq], +\[lq]c\[rq], +and +\[lq]x\[rq]; +. +. +.TP +1 +means the glyph descends below the baseline, +like \[lq]p\[rq]; +. +. +.TP +2 +means the glyph ascends above the font's x-height, +like \[lq]A\[rq] or +\[lq]b\[rq]); +and +. +. +.TP +3 +means the glyph is both an ascender and a descender\[em]this is true of +parentheses in some fonts. +. +. +.P +The +.I code +field gives a numeric identifier that the postprocessor uses to render +the glyph. +. +The glyph can be specified to +.I troff \" generic +using this code by means of the +.B \[rs]N +escape sequence. +. +The code can be any integer +(that is, +any integer parsable by the C standard library's +.MR strtol 3 +function). +. +. +.P +The +.I entity-name +field defines an identifier for the glyph that the postprocessor +uses to print the +.I @g@troff +glyph +.IR name . +. +This field is optional; +it was introduced so that the +.I \%grohtml +output driver could encode its character set. +. +For example, +the glyph +.B \[rs][Po] +is represented by +.RB \[lq] £ \[rq] +in HTML 4.0. +. +For efficiency, +these data are now compiled directly into +.IR \%grohtml . +. +.I grops +uses the field to build sub-encoding arrays for PostScript fonts +containing more than 256 glyphs. +. +Anything on the line after the +.I entity-name +field or +.RB \[lq] \-\- \[rq] +is ignored. +. +. +.P +A line in the +.B charset +section can also have the form +. +.RS +.IB name\~ \[dq] +.RE +. +identifying +.I name +as another name for the glyph mentioned in the preceding line. +. +Such aliases can be chained. +. +. +.P +The directive +.B \%kernpairs +starts a list of kerning adjustments to be made to adjacent glyph pairs +from this font. +. +It contains a sequence of lines formatted as follows. +. +.RS +.I g1 g2 n +.RE +. +The foregoing means that when glyph +.I g1 +is typeset immediately before +.IR g2 , +the space between them should be increased +.RI by\~ n . +. +Most kerning pairs should have a negative value +.RI for\~ n . +.\" END Keep parallel with groff.texi node "Device and Font Files". +. +. +.br +.ne 4v +.\" ==================================================================== +.SH Files +.\" ==================================================================== +. +.TP +.IR @FONTDIR@/\:\%dev name /\:DESC +describes the output device +.IR name . +. +. +.TP +.IR @FONTDIR@/\:\%dev name / F +describes the font known +.RI as\~ F +on device +.IR name . +. +. +.\" ==================================================================== +.SH "See also" +.\" ==================================================================== +. +.IR "Groff: The GNU Implementation of troff" , +by Trent A.\& Fisher and Werner Lemberg, +is the primary +.I groff +manual. +. +You can browse it interactively with \[lq]info groff\[rq]. +. +. +.P +\[lq]Troff User's Manual\[rq] +by Joseph F.\& Ossanna, +1976 +(revised by Brian W.\& Kernighan, +1992), +AT&T Bell Laboratories Computing Science Technical Report No.\& 54, +widely called simply \[lq]CSTR\~#54\[rq], +documents the language, +device and font description file formats, +and device-independent output format +referred to collectively in +.I groff +documentation as +.RI \[lq]AT&T\~ troff \[rq]. +. +. +.P +\[lq]A Typesetter-independent TROFF\[rq] +by Brian W.\& Kernighan, +1982, +AT&T Bell Laboratories Computing Science Technical Report No.\& 97, +provides additional insights into the +device and font description file formats +and device-independent output format. +. +. +.P +.MR groff @MAN1EXT@ , +subsection \[lq]Utilities\[rq], +lists programs available for describing fonts in a variety of formats +such that +.I groff +output drivers can use them. +. +. +.P +.MR @g@troff @MAN1EXT@ +documents the default device and font description file search path. +. +. +.P +.MR groff_out @MAN5EXT@ , +.MR addftinfo @MAN1EXT@ +. +. +.\" Restore compatibility mode (for, e.g., Solaris 10/11). +.cp \n[*groff_groff_font_5_man_C] +.do rr *groff_groff_font_5_man_C +. +. +.\" Local Variables: +.\" fill-column: 72 +.\" mode: nroff +.\" End: +.\" vim: set filetype=groff textwidth=72: |