Previous: Intermediate Output Examples, Up: gtroff Output [Contents][Index]
The intermediate output language of AT&T troff
was
first documented in the UNIX troff manual, with later
additions documented in A Typesetter-indenpendent TROFF, written
by Brian Kernighan.
The gtroff
intermediate output format is compatible with this
specification except for the following features.
groff
devices are also fundamentally different from the ones
in AT&T troff
. For example, the AT&T
POSTSCRIPT device is called post
and has a resolution of
only 720 units per inch, suitable for printers 20 years ago, while
groff
’s ps
device has a resolution of 72000 units per
inch. Maybe, by implementing some rescaling mechanism similar to the
classical quasi device independence, groff
could emulate
AT&T’s post
device.
gtroff
, while
AT&T troff
has point (‘p’). This isn’t an
incompatibility but a compatible extension, for both units coincide for
all devices without a sizescale
parameter in the DESC
file, including all postprocessors from AT&T and
groff
’s text devices. The few groff
devices with a
sizescale
parameter either do not exist for AT&T
troff
, have a different name, or seem to have a different
resolution. So conflicts are very unlikely.
gtroff
used this
feature it is kept for compatibility reasons.
Previous: Intermediate Output Examples, Up: gtroff Output [Contents][Index]