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   groff_out    ( 5 )

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Описание (Description)

The fundamental operation of the troff(1) formatter is the
       translation of the groff(7) input language into a device-
       independent form, described here, primarily concerned with what
       has to be written or drawn at specific positions on the output
       device.  This language is simple and imperative.  In the
       following discussion, the term command always refers to this
       intermediate output language, and never to the groff(7) language
       intended for direct use by document authors.  Intermediate output
       commands comprise several categories: glyph output; font, color,
       and text size selection; motion of the printing position; page
       advancement; drawing of geometric primitives; and device control
       commands, a catch-all for operations not easily classified as any
       of the foregoing, such as directives to start and stop output,
       identify the intended output device, or place URL hyperlinks in
       supported output formats.

       As the GNU roff processor groff(1) is a wrapper program around
       troff that automatically calls a postprocessor, this output does
       not show up normally.  This is why it is called intermediate
       within the groff system.  The groff program provides the option
       -Z to inhibit postprocessing, such that the produced intermediate
       output is sent to standard output just like calling troff
       manually.

       In this document, the term troff output describes what is output
       by the GNU troff program, while intermediate output refers to the
       language that is accepted by the parser that prepares this output
       for the postprocessors.  This parser is smarter on whitespace and
       implements obsolete elements for compatibility, otherwise both
       formats are the same.  Both formats can be viewed directly with
       gxditview(1).

       The main purpose of the intermediate output concept is to
       facilitate the development of postprocessors by providing a
       common programming interface for all devices.  It has a language
       of its own that is completely different from the groff(7)
       language.  While the groff language is a high-level programming
       language for text processing, the intermediate output language is
       a kind of low-level assembler language by specifying all
       positions on the page for writing and drawing.

       The pre-groff roff versions are denoted as classical troff.  The
       intermediate output produced by groff is fairly readable, while
       classical troff output was hard to understand because of strange
       habits that are still supported, but not used any longer by GNU
       troff.