1LJ4_FONT(5) File Formats Manual LJ4_FONT(5)
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6 lj4_font - groff fonts for use with devlj4
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9 Nominally, all Hewlett-Packard LaserJet 4–series and newer printers
10 have the same internal fonts: 45 scalable fonts and one bitmapped
11 Lineprinter font. The scalable fonts are available in sizes between
12 0.25 point and 999.75 points, in 0.25-point increments; the Lineprinter
13 font is available only in 8.5-point size.
14 The LaserJet font files included with groff assume that all printers
16 since the LaserJet 4 are identical. There are some differences between
17 fonts in the earlier and more recent printers, however. The LaserJet 4
18 printer used Agfa Intellifont technology for 35 of the internal scal‐
19 able fonts; the remaining 10 scalable fonts were TrueType. Beginning
20 with the LaserJet 4000–series printers introduced in 1997, all scalable
21 internal fonts have been TrueType. The number of printable glyphs dif‐
22 fers slightly between Intellifont and TrueType fonts (generally, the
23 TrueType fonts include more glyphs), and there are some minor differ‐
24 ences in glyph metrics. Differences among printer models are described
25 in the PCL 5 Comparison Guide and the PCL 5 Comparison Guide Addendum
26 (for printers introduced since approximately 2001).
27 LaserJet printers reference a glyph by a combination of a 256-glyph
29 symbol set and an index within that symbol set. Many glyphs appear in
30 more than one symbol set; all combinations of symbol set and index that
31 reference the same glyph are equivalent. For each glyph, hpftodit(1)
32 searches a list of symbol sets, and selects the first set that contains
33 the glyph. The printing code generated by hpftodit(1) is an integer
34 that encodes a numerical value for the symbol set in the high byte(s),
35 and the index in the low byte. See groff_font(5) for a complete
36 description of the font file format; symbol sets are described in
37 greater detail in the PCL 5 Printer Language Technical Reference Man‐
38 ual.
39 Two of the scalable fonts, Symbol and Wingdings, are bound to 256-glyph
41 symbol sets; the remaining scalable fonts, as well as the Lineprinter
42 font, support numerous symbol sets, sufficient to enable printing of
43 more than 600 glyphs.
44 The metrics generated by hpftodit(1) assume that the DESC file contains
46 values of 1200 for res and 6350 for unitwidth (or any combination
47 (e.g., 2400 and 3175) for which res × unitwidth = 7620000). Although
48 HP PCL 5 LaserJet printers support an internal resolution of 7200 units
49 per inch, they use a 16-bit signed integer for cursor positioning; if
50 devlj4 is to support U.S. ledger paper (11″ × 17″), the maximum usable
51 resolution is 32767 / 17, or 1927, units per inch, which rounds down to
52 1200 units per inch. If the largest required paper size is less (e.g.,
53 8.5″ × 11″ or A5), a greater resolution (and lesser unitwidth) can be
54 specified.
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57 Font metrics for Intellifont fonts were provided by Tagged Font Metric
58 (TFM) files originally developed by Agfa/Compugraphic. The TFM files
59 provided for these fonts supported 600+ glyphs and contained extensive
60 lists of kern pairs.
61 To accommodate developers who had become accustomed to TFM files, HP
63 also provided TFM files for the 10 TrueType fonts included in the
64 LaserJet 4. The TFM files for TrueType fonts generally included less
65 information than the Intellifont TFMs, supporting fewer glyphs, and in
66 most cases, providing no kerning information. By the time the Laser‐
67 Jet 4000 printer was introduced, most developers had migrated to other
68 means of obtaining font metrics, and support for new TFM files was very
69 limited. The TFM files provided for the TrueType fonts in the Laser‐
70 Jet 4000 support only the Latin 2 (ISO 8859-2) symbol set, and include
71 no kerning information; consequently, they are of little value for any
72 but the most rudimentary documents.
73 Because the Intellifont TFM files contain considerably more informa‐
75 tion, they generally are preferable to the TrueType TFM files even for
76 use with the TrueType fonts in the newer printers. The metrics for the
77 TrueType fonts are very close, though not identical, to those for the
78 earlier Intellifont fonts of the same names. Although most output
79 using the Intellifont metrics with the newer printers is quite accept‐
80 able, a few glyphs may fail to print as expected. The differences in
81 glyph metrics may be particularly noticeable with composite parenthe‐
82 ses, brackets, and braces used by eqn(1). A script, located in
83 /usr/share/groff/1.20.1/font/devlj4/generate, can be used to adjust the
84 metrics for these glyphs in the special font S for use with printers
85 that have all TrueType fonts.
86 At the time HP last supported TFM files, only Version 1 of the Unicode
88 standard was available. Consequently, many glyphs lacking assigned
89 code points were assigned by HP to the Private Use Area (PUA). Later
90 versions of the Unicode standard included code points outside the PUA
91 for many of these glyphs. The HP-supplied TrueType TFM files use the
92 PUA assignments; TFM files generated from more recent TrueType font
93 files require the later Unicode values to access the same glyphs. Con‐
94 sequently, two different mapping files may be required: one for the HP-
95 supplied TFM files, and one for more recent TFM files.
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98 /usr/share/groff/1.20.1/font/devlj4/DESC
99 Device description file.
100 /usr/share/groff/1.20.1/font/devlj4/F
102 Font description file for font F.
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105 groff(1), groff_diff(1), hpftodit(1), grolj4(1), groff_font(5)
106Groff Version 1.20.1 9 January 2009 LJ4_FONT(5)