/contrib/groff/src/devices/grolj4/lj4_font.man

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  3Copyright (C) 2004 Free Software Foundation, Inc.
  4
  5Permission is granted to make and distribute verbatim copies of
  6this manual provided the copyright notice and this permission notice
  7are preserved on all copies.
  8
  9Permission is granted to copy and distribute modified versions of this
 10manual under the conditions for verbatim copying, provided that the
 11entire resulting derived work is distributed under the terms of a
 12permission notice identical to this one.
 13
 14Permission is granted to copy and distribute translations of this
 15manual into another language, under the above conditions for modified
 16versions, except that this permission notice may be included in
 17translations approved by the Free Software Foundation instead of in
 18the original English.
 19..
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 27.TH LJ4_FONT @MAN5EXT@ "@MDATE@" "Groff Version @VERSION@"
 28.\" --------------------------------------------------------------------------
 29.SH NAME
 30.\" --------------------------------------------------------------------------
 31lj4_font \- groff fonts for use with devlj4
 32.\" --------------------------------------------------------------------------
 33.SH DESCRIPTION
 34.\" --------------------------------------------------------------------------
 35Nominally, all Hewlett-Packard LaserJet~4\(enseries and newer printers
 36have the same internal fonts: 45 scalable fonts and one bitmapped
 37Lineprinter font.
 38The scalable fonts are available in sizes between 0.25 point and 999.75
 39points, in 0.25-point increments; the Lineprinter font is available only
 40in 8.5-point size.
 41.LP
 42The LaserJet font files included with
 43.B groff
 44assume that all printers since the LaserJet~4 are identical.
 45There are some differences between fonts in the earlier and more recent
 46printers, however.
 47The LaserJet~4 printer used Agfa Intellifont technology for 35 of the
 48internal scalable fonts; the remaining 10 scalable fonts were TrueType.
 49Beginning with the LaserJet~4000\(enseries printers introduced in 1997,
 50all scalable internal fonts have been TrueType.
 51The number of printable glyphs differs slightly between Intellifont and
 52TrueType fonts (generally, the TrueType fonts include more glyphs), and
 53there are some minor differences in glyph metrics.
 54Differences among printer models are described in the
 55.I "PCL~5 Comparison Guide"
 56and the
 57.I "PCL~5 Comparison Guide Addendum"
 58(for printers introduced since approximately 2001).
 59.LP
 60LaserJet printers reference a glyph by a combination of a 256-glyph
 61symbol set and an index within that symbol set.
 62Many glyphs appear in more than one symbol set; all combinations of
 63symbol set and index that reference the same glyph are equivalent.
 64For each glyph,
 65.BR hpftodit (@MAN1EXT@)
 66searches a list of symbol sets, and selects the first set that contains
 67the glyph.
 68The printing code generated by
 69.BR hpftodit (@MAN1EXT@)
 70is an integer that encodes a numerical value for the symbol set in the
 71high byte(s), and the index in the low byte.
 72See
 73.BR groff_font (@MAN5EXT@)
 74for a complete description of the font file format; symbol sets are
 75described in greater detail in the
 76.IR "PCL~5 Printer Language Technical Reference Manual" .
 77.LP
 78Two of the scalable fonts, Symbol and Wingdings, are bound to
 79256-glyph symbol sets; the remaining scalable fonts, as well as the
 80Lineprinter font, support numerous symbol sets, sufficient to enable
 81printing of more than 600 glyphs.
 82.LP
 83The metrics generated by
 84.BR hpftodit (@MAN1EXT@)
 85assume that the DESC file contains values of 1200 for res and 6350 for
 86unitwidth (or any combination (e.g., 2400 and 3175) for which
 87res~\(mu~unitwidth~=~7\|620\|000).
 88Although HP PCL~5 LaserJet printers support an internal resolution of
 897200 units per inch, they use a 16-bit signed integer for cursor
 90positioning; if
 91.B devlj4
 92is to support U.S. ledger paper (11\(sd~\(mu~17\(sd), the maximum usable
 93resolution is 32\|767~/~17, or 1927, units per inch, which rounds down to
 941200 units per inch.
 95If the largest required paper size is less (e.g., 8.5\(sd~\(mu~11\(sd or
 96A5), a greater resolution (and lesser unitwidth) can be specified.
 97.\" --------------------------------------------------------------------------
 98.SH LIMITATIONS
 99.\" --------------------------------------------------------------------------
100Font metrics for Intellifont fonts were provided by Tagged Font Metric
101(TFM) files originally developed by Agfa/Compugraphic.
102The TFM files provided for these fonts supported 600+ glyphs and
103contained extensive lists of kern pairs.
104.LP
105To accommodate developers who had become accustomed to TFM files, HP also
106provided TFM files for the 10 TrueType fonts included in the LaserJet~4.
107The TFM files for TrueType fonts generally included less information
108than the Intellifont TFMs, supporting fewer glyphs, and in most cases,
109providing no kerning information.
110By the time the LaserJet~4000 printer was introduced, most
111developers had migrated to other means of obtaining font metrics,
112and support for new TFM files was very limited.
113The TFM files provided for the TrueType fonts in the LaserJet~4000
114support only the Latin 2 (ISO 8859-2) symbol set, and include no kerning
115information; consequently, they are of little value for any but the most
116rudimentary documents.
117.LP
118Because the Intellifont TFM files contain considerably more information,
119they generally are preferable to the TrueType TFM files even for use
120with the TrueType fonts in the newer printers.
121The metrics for the TrueType fonts are very close, though not identical,
122to those for the earlier Intellifont fonts of the same names.
123Although most output using the Intellifont metrics with the newer
124printers is quite acceptable, a few glyphs may fail to print as
125expected.
126The differences in glyph metrics may be particularly noticeable with
127composite parentheses, brackets, and braces used by
128.BR eqn (@MAN1EXT@) .
129A script, located in
130.BR @FONTDIR@/devlj4/generate ,
131can be used to adjust the metrics for these glyphs in the special font S
132for use with printers that have all TrueType fonts.
133.LP
134At the time HP last supported TFM files, only Version 1 of the Unicode
135standard was available.
136Consequently, many glyphs lacking assigned code points were assigned by
137HP to the Private Use Area (PUA).
138Later versions of the Unicode standard included code points outside the
139PUA for many of these glyphs.
140The HP-supplied TrueType TFM files use the PUA assignments;
141TFM files generated from more recent TrueType font files require the
142later Unicode values to access the same glyphs.
143Consequently, two different mapping files may be required: one for the
144HP-supplied TFM files, and one for more recent TFM files.
145.\" --------------------------------------------------------------------------
146.SH FILES
147.\" --------------------------------------------------------------------------
148.Tp \w'\fB@FONTDIR@/devlj4/DESC'u+2n
149.B @FONTDIR@/devlj4/DESC
150Device description file.
151.TP
152.BI @FONTDIR@/devlj4/ F
153Font description file for font
154.IR F .
155.\" --------------------------------------------------------------------------
156.SH "SEE ALSO"
157.\" --------------------------------------------------------------------------
158.ad 0
159.BR groff (@MAN1EXT@),
160.BR groff_diff (@MAN1EXT@),
161.BR hpftodit (@MAN1EXT@),
162.BR grolj4 (@MAN1EXT@),
163.BR groff_font (@MAN5EXT@)
164.
165.\" Local Variables:
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167.\" End: