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GROFF_OUT
!!!GROFF_OUT
NAME
DESCRIPTION
SEE ALSO
----
!!NAME


groff_out - groff intermediate output format
!!DESCRIPTION


This manual page describes the format output by GNU troff.
The output format used by GNU troff is very similar to that
used by Unix device-independent troff. Only the differences
are documented here.


The argument to the __s__ command is in scaled points
(units of ''points/''n'','' where ''n'' is the
argument to the __sizescale__ command in the DESC file.)
The argument to the __x Height__ command is also in
scaled points.


The first three output commands are guaranteed to
be:


__x T__ ''device''__
x res__ ''n h v''__
x init__


If the __tcommand__ line is present in the DESC file,
troff will use the following two commands


__t__''xxx''


''xxx'' is any sequence of characters terminated by a
space or a newline; the first character should be printed at
the current position, the the current horizontal position
should be increased by the width of the first character, and
so on for each character. The width of the character is that
given in the font file, appropriately scaled for the current
point size, and rounded so that it is a multiple of the
horizontal resolution. Special characters cannot be printed
using this command.


__u__''n xxx''


This is same as the __t__ command except that after
printing each character, the current horizontal position is
increased by the sum of the width of that character and
''n''.


Note that single characters can have the eighth bit set, as
can the names of fonts and special characters.


The names of characters and fonts can be of arbitrary
length; drivers should not assume that they will be only two
characters long.


When a character is to be printed, that character will
always be in the current font. Unlike device-independent
troff, it is not necessary for drivers to search special
fonts to find a character.


The __x__ device control command has been
extended.


__x u__ ''n''


If ''n'' is 1, start underlining of spaces. If ''n''
is 0, stop underlining of spaces. This is needed for the
__cu__ request in nroff mode and is ignored
otherwise.


The __D__ drawing command has been extended. These
extensions will not be used by GNU pic if the __-n__
option is given.


__Df__ ''n''n


Set the shade of gray to be used for filling solid objects
to ''n''; ''n'' must be an integer between 0 and 1000,
where 0 corresponds solid white and 1000 to solid black, and
values in between correspond to intermediate shades of gray.
This applies only to solid circles, solid ellipses and solid
polygons. By default, a level of 1000 will be used. Whatever
color a solid object has, it should completely obscure
everything beneath it. A value greater than 1000 or less
than 0 can also be used: this means fill with the shade of
gray that is currently being used for lines and text.
Normally this will be black, but some drivers may provide a
way of changing this.


__DC__ ''d''n


Draw a solid circle with a diameter of ''d'' with the
leftmost point at the current position.


__DE__ ''dx dy''n


Draw a solid ellipse with a horizontal diameter of ''dx''
and a vertical diameter of ''dy'' with the leftmost point
at the current position.


__Dp__ ''dx'' 1
''dy'' 1 ''dx''
2 ''dy''
2 ... ''dx
n dy
n'' n


Draw a polygon with, for ''i''=1,...,''n''+1, the
''i''-th vertex at the current position +
''ij''-=
11 (''dx
j'' ,''dy
j'' ). At the moment, GNU
pic only uses this command to generate triangles and
rectangles.


__DP__ ''dx'' 1
''dy'' 1 ''dx''
2 ''dy''
2 ... ''dx
n dy
n'' n


Like __Dp__ but draw a solid rather than outlined
polygon.


__Dt__ ''n''n


Set the current line thickness to ''n'' machine units.
Traditionally Unix troff drivers use a line thickness
proportional to the current point size; drivers should
continue to do this if no __Dt__ command has been given,
or if a __Dt__ command has been given with a negative
value of ''n''. A zero value of ''n'' selects the
smallest available line thickness.


A difficulty arises in how the current position should be
changed after the execution of these commands. This is not
of great importance since the code generated by GNU pic does
not depend on this. Given a drawing command of the
form


__D__''c x'' 1 ''y''
1 ''x''
2 ''y''
2 ... ''x
n y
n''


where ''c'' is not one of __c__, __e__, __l__,
__a__ or __~__, Unix troff will treat each of the ''x
i'' as a horizontal
quantity, and each of the ''y
i'' as a vertical quantity
and will assume that the width of the drawn object is
''i''=''n''1
''x i'' , and that the
height is
''i''=''n''1
''y i'' . (The assumption
about the height can be seen by examining the __st__ and
__sb__ registers after using such a __D__ command in a
w escape sequence.) This rule also holds for all the
original drawing commands with the exception of __De__.
For the sake of compatibility GNU troff also follows this
rule, even though it produces an ugly result in the case of
the __Df__, __Dt__, and, to a lesser extent, __DE__
commands. Thus after executing a __D__ command of the
form


__D__''c x'' 1 ''y''
1 ''x''
2 ''y''
2 ... ''x
n y
n'' n


the current position should be increased by (
''i''=''n''1
''x i'' ,
''ni''=
1 ''y i''
).


There is a continuation convention which permits the
argument to the __x X__ command to contain newlines: when
outputting the argument to the __x X__ command, GNU troff
will follow each newline in the argument with a __+__
character (as usual, it will terminate the entire argument
with a newline); thus if the line after the line containing
the __x X__ command starts with __+__, then the
newline ending the line containing the __x X__ command
should be treated as part of the argument to the __x X__
command, the __+__ should be ignored, and the part of the
line following the __+__ should be treated like the part
of the line following the __x X__ command.
!!SEE ALSO


groff_font(5)
----
12 pages link to groff_out(5):
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Last edited on Monday, June 3, 2002 6:55:56 pm by "perry"
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