LJ4_FONT(5)            (9 September 2021)             LJ4_FONT(5)

          lj4_font - groff fonts for use with devlj4

          Nominally, all Hewlett-Packard LaserJet~4-series and newer
          printers have the same internal fonts: 45 scalable fonts and
          one bitmapped Lineprinter font.  The scalable fonts are
          available in sizes between 0.25 points and 999.75 points, in
          0.25-point increments; the Lineprinter font is available
          only in 8.5-point size.

          The LaserJet font files included with groff assume that all
          printers since the LaserJet~4 are identical.  There are some
          differences between fonts in the earlier and more recent
          printers, however.  The LaserJet~4 printer used Agfa Intel-
          lifont technology for 35 of the internal scalable fonts; the
          remaining 10 scalable fonts were TrueType.  Beginning with
          the LaserJet~4000-series printers introduced in 1997, all
          scalable internal fonts have been TrueType.  The number of
          printable glyphs differs slightly between Intellifont and
          TrueType fonts (generally, the TrueType fonts include more
          glyphs), and there are some minor differences in glyph met-
          rics.  Differences among printer models are described in the
          PCL~5 Comparison Guide and the PCL~5 Comparison Guide
          Addendum (for printers introduced since approximately 2001).

          LaserJet printers reference a glyph by a combination of a
          256-glyph symbol set and an index within that symbol set.
          Many glyphs appear in more than one symbol set; all combina-
          tions of symbol set and index that reference the same glyph
          are equivalent.  For each glyph, hpftodit(1) searches a list
          of symbol sets, and selects the first set that contains the
          glyph.  The printing code generated by hpftodit is an inte-
          ger that encodes a numerical value for the symbol set in the
          high byte(s), and the index in the low byte.  See
          groff_font(5) for a complete description of the font file
          format; symbol sets are described in greater detail in the
          PCL~5 Printer Language Technical Reference Manual.  .}f

          Two of the scalable fonts, Symbol and Wingdings, are bound
          to 256-glyph symbol sets; the remaining scalable fonts, as
          well as the Lineprinter font, support numerous symbol sets,
          sufficient to enable printing of more than 600 glyphs.

          The metrics generated by hpftodit assume that the DESC file
          contains values of 1200 for res and 6350 for unitwidth, or
          any combination (e.g., 2400 and 3175) for which
          res~[tmu]~unitwidth~=~7620000.  Although HP PCL~5 LaserJet
          printers support an internal resolution of 7200 units per
          inch, they use a 16-bit signed integer for cursor

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     LJ4_FONT(5)            (9 September 2021)             LJ4_FONT(5)

          positioning; if devlj4 is to support U.S. ledger paper
          (11~in~[mu]~17~in; in = inch), the maximum usable resolution
          is 32767~[di]~17, or 1927 units per inch, which rounds down
          to 1200 units per inch.  If the largest required paper size
          is less (e.g., 8.5~in~[mu]~11~in, or A5), a greater res (and
          lesser unitwidth) can be specified.

          Font metrics for Intellifont fonts were provided by Tagged
          Font Metric (TFM) files originally developed by
          Agfa/Compugraphic.  The TFM files provided for these fonts
          supported 600+ glyphs and contained extensive lists of kern-
          ing pairs.

          To accommodate developers who had become accustomed to TFM
          files, HP also provided TFM files for the 10 TrueType fonts
          included in the LaserJet~4.  The TFM files for TrueType
          fonts generally included less information than the Intelli-
          font TFMs, supporting fewer glyphs, and in most cases, pro-
          viding no kerning information.  By the time the Laser-
          Jet~4000 printer was introduced, most developers had
          migrated to other means of obtaining font metrics, and sup-
          port for new TFM files was very limited.  The TFM files pro-
          vided for the TrueType fonts in the LaserJet~4000 support
          only the Latin 2 (ISO 8859-2) symbol set, and include no
          kerning information; consequently, they are of little value
          for any but the most rudimentary documents.

          Because the Intellifont TFM files contain considerably more
          information, they generally are preferable to the TrueType
          TFM files even for use with the TrueType fonts in the newer
          printers.  The metrics for the TrueType fonts are very
          close, though not identical, to those for the earlier Intel-
          lifont fonts of the same names.  Although most output using
          the Intellifont metrics with the newer printers is quite
          acceptable, a few glyphs may fail to print as expected.  The
          differences in glyph metrics may be particularly noticeable
          with composite parentheses, brackets, and braces used by
          eqn(1).  A script, located in
          /usr/:share/:groff/:1.22.4/:font/:devlj4/:generate, .el
          /usr/:share/:groff/:1.22.4/:font/:devlj4/:generate can be
          used to adjust the metrics for these glyphs in the special
          font [lq]S[rq] for use with printers that have all TrueType

          At the time HP last supported TFM files, only version 1.0 of
          the Unicode standard was available.  Consequently, many
          glyphs lacking assigned code points were assigned by HP to
          the Private Use Area (PUA).  Later versions of the Unicode
          standard included code points outside the PUA for many of
          these glyphs.  The HP-supplied TrueType TFM files use the
          PUA assignments; TFM files generated from more recent

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     LJ4_FONT(5)            (9 September 2021)             LJ4_FONT(5)

          TrueType font files require the later Unicode values to
          access the same glyphs.  Consequently, two different mapping
          files may be required: one for the HP-supplied TFM files,
          and one for more recent TFM files.

               device description file


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