GROFF_OUT(5)                                                      GROFF_OUT(5)



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

       txxx   xxx is any sequence of characters terminated by a space or a
              newline; the first character should be printed at the current
              position, 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.

       un 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 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.  delim $$

       Dp $dx sub 1$ $dy sub 1$ $dx sub 2$ $dy sub 2$ $...$ $dx sub n$ $dy sub
               n$\n
              Draw a polygon with, for $i = 1 ,..., n+1$, the i-th vertex at
              the current position $+ sum from j=1 to i-1 ( dx sub j , dy sub
              j )$.  At the moment, GNU pic only uses this command to generate
              triangles and rectangles.

       DP $dx sub 1$ $dy sub 1$ $dx sub 2$ $dy sub 2$ $...$ $dx sub n$ $dy sub
               n$\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 $x sub 1$ $y sub 1$ $x sub 2$ $y sub 2$ $...$ $x sub n$ $y
              sub n$'

       where c is not one of c, e, l, a or ~, Unix troff will treat each of
       the $x sub i$ as a horizontal quantity, and each of the $y sub i$ as a
       vertical quantity and will assume that the width of the drawn object is
       $sum from i=1 to n x sub i$, and that the height is $sum from i=1 to n
       y sub i$.  (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


              Dc $x sub 1$ $y sub 1$ $x sub 2$ $y sub 2$ $...$ $x sub n$ $y
              sub n$\n

       the current position should be increased by $( sum from i=1 to n x sub
       i , sum from i=1 to n y sub i )$.

       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)



Groff Version 1.15                                                9 April 2000
