groff: Suppressing output
5.27 Suppressing output
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-- Escape: \Onum
Disable or enable output depending on the value of NUM:
'\O0'
Disable any glyphs from being emitted to the device driver,
provided that the escape occurs at the outer level (see
'\O[3]' and '\O[4]'). Motion is not suppressed so effectively
'\O[0]' means _pen up_.
'\O1'
Enable output of glyphs, provided that the escape occurs at
the outer level.
'\O0' and '\O1' also reset the four registers 'opminx', 'opminy',
'opmaxx', and 'opmaxy' to -1. ⇒Register Index. These four
registers mark the top left and bottom right hand corners of a box
that encompasses all written glyphs.
For example the input text:
Hello \O[0]world \O[1]this is a test.
produces the following output:
Hello this is a test.
'\O2'
Provided that the escape occurs at the outer level, enable
output of glyphs and also write out to 'stderr' the page
number and four registers encompassing the glyphs previously
written since the last call to '\O'.
'\O3'
Begin a nesting level. At start-up, 'gtroff' is at outer
level. The current level is contained within the read-only
register '.O'. ⇒Built-in Registers.
'\O4'
End a nesting level. The current level is contained within
the read-only register '.O'. ⇒Built-in Registers.
'\O[5PFILENAME]'
This escape is 'grohtml' specific. Provided that this escape
occurs at the outer nesting level write the 'filename' to
'stderr'. The position of the image, P, must be specified and
must be one of 'l', 'r', 'c', or 'i' (left, right, centered,
inline). FILENAME is associated with the production of the
next inline image.
Info Catalog
groff: Environments
groff: gtroff Reference
groff: Colors