File: groff.info,  Node: Selecting Fonts,  Next: Font Families,  Prev: Using_Fonts.php">Using Fonts,  Up: Using_Fonts.php">Using Fonts

5.19.1 Selecting Fonts
----------------------

We use "font" to refer to any of several means of identifying a font: by
mounting position ('3'), by abstract style ('B'), or by its identifier
('TB').

 -- Request: .ft [font]
 -- Escape sequence: \ff
 -- Escape sequence: \f(fn
 -- Escape sequence: \f[font]
 -- Register: \n[.fn]
     The 'ft' request selects the typeface FONT.  If the argument is
     absent or 'P', it selects the previously chosen font.  If FONT is a
     non-negative integer, it is interpreted as mounting position; the
     font mounted there is selected.  If that position refers to an
     abstract style, it is combined with the default family (see 'fam'
     and '\F' below) to make a resolved font name.  If the mounting
     position is not a style and no font is mounted there, GNU 'troff'
     emits a warning in category 'font' and ignores the request.

     If FONT matches a style name, it is combined with the current
     family to make a resolved font name.  Otherwise, FONT is assumed to
     already be a resolved font name.

     The resolved font name is subject to translation (see request 'ftr'
     below).  Next, the (possibly translated) font name's mounting
     position is looked up; if not mounted, FONT is sought on the file
     system as a font description file and, if located, automatically
     mounted at the next available position (see register '.fp' below).
     If the font was mounted using an identifier different from its font
     description file name (see request 'fp' below), that file name is
     then looked up.  If a font description file for the resolved font
     name is not found, GNU 'troff' emits a warning in category 'font'
     and ignores the request.

     The '\f' escape sequence is similar, using one-character name (or
     mounting position) F, two-character name FN, or a name FONT of
     arbitrary length.  '\f[]' selects the previous font.  The syntax
     form '\fP' is supported for backward compatibility, and '\f[P]' for
     consistency.

          eggs, bacon,
          .ft I
          spam,
          .ft
          and sausage.
          .br
          eggs, bacon, \fIspam,\fP and sausage.
              => eggs, bacon, spam, and sausage
              => eggs, bacon, spam, and sausage

     The current and previously selected fonts are properties of the
     environment (*note Environments::).

     The read-only string-valued register '.fn' contains the resolved
     font name of the selected font.

     '\f' doesn't produce an input token in GNU 'troff'; it thus can be
     used in requests that expect a single-character argument.  We can
     assign a font to a margin character as follows (*note
     Miscellaneous::).

          .mc \f[I]x\f[]

 -- Request: .ftr f [g]
     Translate font F to font G.  Whenever a font named F is referred to
     in a '\f' escape sequence, in the 'F' and 'S' conditional
     operators, or in the 'ft', 'ul', 'bd', 'cs', 'tkf', 'special',
     'fspecial', 'fp', or 'sty' requests, font G is used.  If G is
     missing or equal to F the translation is undone.

     Font translations cannot be chained.

          .ftr XXX TR
          .ftr XXX YYY
          .ft XXX
              error-> warning: can't find font 'XXX'

 -- Request: .fzoom f [zoom]
 -- Register: \n[.zoom]
     Set magnification of font F to factor ZOOM, which must be a
     non-negative integer multiple of 1/1000th.  This request is useful
     to adjust the optical size of a font in relation to the others.  In
     the example below, font 'CR' is magnified by 10% (the zoom factor
     is thus 1.1).

          .fam P
          .fzoom CR 1100
          .ps 12
          Palatino and \f[CR]Courier\f[]

     A missing or zero value of ZOOM is the same as a value of 1000,
     which means no magnification.  F must be a resolved font name, not
     an abstract style.

     The magnification of a font is completely transparent to GNU
     'troff'; a change of the zoom factor doesn't cause any effect
     except that the dimensions of glyphs, (word) spaces, kerns, etc.,
     of the affected font are adjusted accordingly.

     The zoom factor of the current font is available in the read-only
     register '.zoom', in multiples of 1/1000th.  It returns zero if
     there is no magnification.