Font Families (The GNU Troff Manual)

+Next: Font Positions, Previous: Selecting Fonts, Up: Using Fonts [Contents][Index]

5.19.2 Font Families

+ + + + + +

To accommodate the wide variety of fonts available, GNU troff +distinguishes font families and font styles. A resolved +font name is the catenation of a font family and a style. Selecting an +abstract style causes GNU troff to combine it with the default +font family. +

You can thus compose a document using abstract styles exclusively for +its body or running text, selecting a specific family only for titles or +examples, for instance, and change the default family on the command +line (recall Options). +

Fonts for the devices ps, pdf, dvi, lj4, +lbp, and the X11 devices support this mechanism. By default, +GNU troff uses the Times family with the four styles ‘R’, +‘I’, ‘B’, and ‘BI’. +

Request: .fam [family] ¶

Escape sequence: \Ff ¶

Escape sequence: \F(fm ¶

Escape sequence: \F[family] ¶

+ +

Set the default font family, used in combination with abstract styles to +construct a resolved font name, to family (one-character +name f, two-character name fm). If no argument is +given, GNU troff selects the previous font family; if there none, +is it falls back to the device’s default⁷⁶ or its own (‘T’). +

The \F escape sequence works similarly. In disanalogy to +\f, ‘\FP’ makes ‘P’ the default family. Use +‘\F[]’ to select the previous default family. The default font +family is available in the read-only string-valued register .fam; +it is associated with the environment (see Environments). +

spam,     \" startup defaults are T (Times) R (roman)
+.fam H    \" make Helvetica the default family
+spam,     \" family H + style R = HR
+.ft B     \" family H + style B = HB
+spam,
+.ft CR    \" Courier roman (default family not changed)
+spam,
+.ft       \" back to Helvetica bold
+spam,
+.fam T    \" make Times the default family
+spam,     \" family T + style B = TB
+.ft AR    \" font AR (not a style)
+baked beans,
+.ft R     \" family T + style R = TR
+and spam.
+

+ +

\F doesn’t produce an input token in GNU troff. As a +consequence, it can be used in requests like mc (which expects +a single character as an argument) to change the font family on the fly. +

.mc \F[P]x\F[]
+

+ +

Request: .sty n style ¶

+ + + + + + + + + +

Associate an abstract style style with mounting +position n, which must be a non-negative integer. If the +requests cs, bd, tkf, uf, or fspecial +are applied to an abstract style, they are instead applied to the member +of the current family corresponding to that style. +

+ + +

The default family can be set with the -f option (see Options). The styles command in the DESC file controls +which font positions (if any) are initially associated with abstract +styles rather than fonts. +

Caution: The style argument is not validated. +Errors may occur later, when the formatter attempts to construct a +resolved font name, or format a character for output. +

.nr BarPos \n[.fp]
+.sty \n[.fp] Bar
+.fam Foo
+.ft \n[BarPos]
+.tm .f=\n[.f]
+A
+    error→ error: no font family named 'Foo' exists
+    error→ .f=41
+    error→ error: cannot format glyph: no current font
+

+ +

When an abstract style has been selected, the read-only string-valued +register ‘.sty’ interpolates its name; this datum is associated +with the environment (see Environments). Otherwise, ‘.sty’ +interpolates nothing. +

+ + +