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There are a number of requests and escape sequences for artificially
creating fonts. These are largely vestiges of the days when output
devices did not have a wide variety of fonts, and when nroff and
troff were separate programs. Most of them are no longer
necessary in GNU troff. Nevertheless, they are supported.
'height''+height''-height'Change (increment, decrement) the height of the current font, but not the width. If height is zero, restore the original height. Default scaling unit is ‘z’.
The read-only register .height contains the font height as set by
\H.
Currently, only the -Tps and -Tpdf devices support this feature.
\H 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 on the fly:
.mc \H'+5z'x\H'0'
In compatibility mode, gtroff behaves differently: If an
increment or decrement is used, it is always taken relative to the
current type size and not relative to the previously selected font
height. Thus,
.cp 1 \H'+5'test \H'+5'test
prints the word ‘test’ twice with the same font height (five points larger than the current font size).
'slant'Slant the current font by slant degrees. Positive values slant to the right. Only integer values are possible.
The read-only register .slant contains the font slant as set by
\S.
Currently, only the -Tps and -Tpdf devices support this feature.
\S 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 on the fly:
.mc \S'20'x\S'0'
This escape is incorrectly documented in the AT&T
troff manual; the slant is always set to an absolute value.
The ul request normally underlines subsequent lines if a TTY
output device is used. Otherwise, the lines are printed in italics
(only the term ‘underlined’ is used in the following). The single
argument is the quantity of input lines to be underlined; with no
argument, the next line is underlined. If lines is zero or
negative, stop the effects of ul (if it was active). Requests
and empty lines do not count for computing the number of underlined
input lines, even if they produce some output like tl. Lines
inserted by macros (e.g., invoked by a trap) do count.
At the beginning of ul, the current font is stored and the
underline font is activated. Within the span of a ul request, it
is possible to change fonts, but after the last line affected by
ul the saved font is restored.
This number of lines still to be underlined is associated with the
environment (see Environments). The underline font can be changed
with the uf request.
The ul request does not underline spaces.
The cu request is similar to ul but underlines spaces as
well (if a TTY output device is used).
Set the underline font (globally) used by ul and cu. By
default, this is the font at position 2. font can be either
a non-negative font position or the name of a font.
Embolden font by overstriking its glyphs offset by offset units minus one.
Two syntax forms are available.
font can be either a non-negative font position or the name of a font.
offset is available in the .b read-only register if a
special font is active; in the bd request, its default unit is
‘u’.
This affects special fonts only (either set up with the special
command in font files or with the fspecial request).
Switch to and from constant glyph space mode. If activated, the
width of every glyph is width/36 ems. The em size is given
absolutely by em-size; if this argument is missing, the em value
is taken from the current font size (as set with the ps request)
when the font is effectively in use. Without second and third argument,
constant glyph space mode is deactivated.
Default scaling unit for em-size is ‘z’; width is an integer.
Next: Ligatures and Kerning, Previous: Special Fonts, Up: Using Fonts [Contents][Index]