LJ4_FONT(5)                                         LJ4_FONT(5)



NAME
       lj4_font - groff fonts for use with devlj4

DESCRIPTION
       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  point  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 Intellifont 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 dif-
       fers  slightly  between  Intellifont  and TrueType fonts
       (generally, the TrueType fonts include more glyphs), and
       there are some minor differences in glyph metrics.  Dif-
       ferences 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  combinations 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(1) is an integer 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  Man-
       ual.

       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(1) 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  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  positioning; if devlj4 is to support U.S. ledger
       paper  (11  17),  the  maximum  usable  resolution   is
       32767 / 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  11 or A5), a greater resolu-
       tion (and lesser unitwidth) can be specified.

LIMITATIONS
       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 pairs.

       To accommodate developers who had become  accustomed  to
       TFM  files,  HP also provided TFM files for the 10 True-
       Type fonts included in the LaserJet 4.   The  TFM  files
       for  TrueType  fonts generally included less information
       than the Intellifont TFMs, supporting fewer glyphs,  and
       in most cases, providing no kerning information.  By the
       time the  LaserJet 4000  printer  was  introduced,  most
       developers had migrated to other means of obtaining font
       metrics, and support for new TFM files was very limited.
       The  TFM  files  provided  for the TrueType fonts in the
       LaserJet 4000 support only the Latin 2 (ISO 8859-2) sym-
       bol  set,  and  include  no  kerning information; conse-
       quently, 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  Intellifont  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           c:/pro-
       gra 1/groff/share/groff/1.20/font/devlj4/generate,   can
       be used to adjust the metrics for these  glyphs  in  the
       special font S for use with printers that have all True-
       Type fonts.

       At the time HP last supported TFM files, only Version  1
       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 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.

FILES
       c:/progra 1/groff/share/groff/1.20/font/devlj4/DESC
              Device description file.

       c:/progra 1/groff/share/groff/1.20/font/devlj4/F
              Font description file for font F.

SEE ALSO
       groff(1), groff_diff(1), hpftodit(1), grolj4(1),
       groff_font(5)



Groff Version 1.20       5 January 2009             LJ4_FONT(5)
