1'\" e
2.\" The above line should force the use of eqn as a preprocessor
3.ig
4groff_out.5
5
6Last update: 2 Jul 2005
7
8This file is part of groff, the GNU roff type-setting system.
9
10Copyright (C) 1989, 2001, 2002, 2003, 2004, 2005
11Free Software Foundation, Inc.
12rewritten from scrach 2001 by Bernd Warken <bwarken@mayn.de>
13
14Permission is granted to copy, distribute and/or modify this document
15under the terms of the GNU Free Documentation License, Version 1.1 or
16any later version published by the Free Software Foundation; with the
17Invariant Sections being this .ig-section and AUTHORS, with no
18Front-Cover Texts, and with no Back-Cover Texts.
19
20A copy of the Free Documentation License is included as a file called
21FDL in the main directory of the groff source package.
22..
23.
24.\" --------------------------------------------------------------------
25.\" Setup
26.\" --------------------------------------------------------------------
27.
28.do nr groff_out_C \n[.C]
29.cp 0
30.
31.mso www.tmac
32.
33.if n \{\
34. mso tty-char.tmac
35. ftr CR R
36. ftr CI I
37. ftr CB B
38.\}
--- 212 unchanged lines hidden (view full) ---
251.SH NAME
252groff_out \- groff intermediate output format
253.
254.
255.\" --------------------------------------------------------------------
256.SH DESCRIPTION
257.\" --------------------------------------------------------------------
258.
259This manual page describes the
260.I intermediate output
261format of the GNU
262.BR roff (@MAN7EXT@)
263text processing system
264.BR groff (@MAN1EXT@).
265.
266This output is produced by a run of the GNU
267.BR @g@troff (@MAN1EXT@)
268program.
269.
270It contains already all device-specific information, but it is not yet
271fed into a device postprocessor program.
272.
273.
274.P
275As the GNU
276.I roff
277processor
278.BR groff (@MAN1EXT@)
279is a wrapper program around
280.B @g@troff
281that automatically calls a
282postprocessor, this output does not show up normally.
283.
284This is why it is called
285.I intermediate
286within the
287.I groff
288.IR system .
289.
290The
291.B groff
292program provides the option
293.B -Z
294to inhibit postprocessing, such that the produced
295.I intermediate output
296is sent to standard output just like calling
297.B @g@troff
298manually.
299.
300.
301.P
302In this document, the term
303.I @g@troff output
304describes what is output by the GNU
305.B @g@troff
306program, while
307.I intermediate output
308refers to the language that is accepted by the parser that prepares
309this output for the postprocessors.
310.
311This parser is smarter on whitespace and implements obsolete elements
312for compatibility, otherwise both formats are the same.
313.
314Both formats can be viewed directly with
315.BR \%gxditview (@MAN1EXT@).
316.
317.
318.P
319The main purpose of the
320.I intermediate output
321concept is to facilitate the development of postprocessors by
322providing a common programming interface for all devices.
323.
324It has a language of its own that is completely different from the
325.BR groff (@MAN7EXT@)
326language.
327.
328While the
329.I groff
330language is a high-level programming language for text processing, the
331.I intermediate output
332language is a kind of low-level assembler language by specifying all
333positions on the page for writing and drawing.
334.
335.
336.P
337The
338.RI pre- groff
339.I roff
340versions are denoted as
341.I classical
342.IR troff .
343The
344.I intermediate output
345produced by
346.B groff
347is fairly readable, while
348.I classical troff
349output was hard to understand because of strange habits that are
350still supported, but not used any longer by
351.I GNU
352.IR @g@troff .
353.
354.
355.\" --------------------------------------------------------------------
356.SH "LANGUAGE CONCEPTS"
357.\" --------------------------------------------------------------------
358.
359During the run of
360.BR @g@troff ,
361the
362.I roff
363input is cracked down to the information on what has to be printed at
364what position on the intended device.
365.
366So the language of the
367.I intermediate output
368format can be quite small.
369.
370Its only elements are commands with or without arguments.
371.
372In this document, the term "command" always refers to the
373.I intermediate output
374language, never to the
375.I roff
376language used for document formatting.
377.
378There are commands for positioning and text writing, for drawing, and
379for device controlling.
380.
381.
382.\" --------------------------------------------------------------------
383.SS "Separation"
384.\" --------------------------------------------------------------------
385.
386.I Classical troff output
387had strange requirements on whitespace.
388.
389The
390.B groff
391output parser, however, is smart about whitespace by making it
392maximally optional.
393.
394The whitespace characters, i.e., the
395.IR tab ,
396.IR space ,
397and
398.I newline
399characters, always have a syntactical meaning.
400.
401They are never printable because spacing within the output is always
402done by positioning commands.
403.
404.
405.P
406Any sequence of
407.I space
408or
409.I tab
410characters is treated as a single
411.I syntactical
412.IR space .
413.
414It separates commands and arguments, but is only required when there
415would occur a clashing between the command code and the arguments
416without the space.
417.
418Most often, this happens when variable length command names,
419arguments, argument lists, or command clusters meet.
420.
421Commands and arguments with a known, fixed length need not be
422separated by
423.I syntactical
424.IR space .
425.
426.
427.P
428A line break is a syntactical element, too.
429.
430Every command argument can be followed by whitespace, a comment, or a
431newline character.
432.
433Thus a
434.I syntactical line break
435is defined to consist of optional
436.I syntactical space
437that is optionally followed by a comment, and a newline character.
438.
439.
440.P
441The normal commands, those for positioning and text, consist of a
442single letter taking a fixed number of arguments.
443.
444For historical reasons, the parser allows to stack such commands on
445the same line, but fortunately, in
446.I groff intermediate
447.IR output ,
448every command with at least one argument is followed by a line break,
449thus providing excellent readability.
450.
451.P
452The other commands \[em] those for drawing and device controlling \[em]
453have a more complicated structure; some recognize long command names,
454and some take a variable number of arguments.
455.
456So all
457.B D
458and
459.B x
460commands were designed to request a
461.I syntactical line break
462after their last argument.
463.
464Only one command,
465.RB ` x\ X '
466has an argument that can stretch over several lines, all other
467commands must have all of their arguments on the same line as the
468command, i.e., the arguments may not be splitted by a line break.
469.
470.P
471Empty lines, i.e., lines containing only space and/or a comment, can
472occur everywhere.
473.
474They are just ignored.
475.
476.
477.\" --------------------------------------------------------------------
478.SS "Argument Units"
479.\" --------------------------------------------------------------------
480.
481Some commands take integer arguments that are assumed to represent
482values in a measurement unit, but the letter for the corresponding
483.I scale indicator
484is not written with the output command arguments; see
485.BR groff (@MAN7EXT@)
486and the
487.I groff info file
488for more on this topic.
489.
490Most commands assume the scale indicator\~\c
491.unit u ,
492the basic unit of the device, some use\~\c
493.unit z ,
494the
495.I scaled point unit
496of the device, while others, such as the color commands expect plain
497integers.
498.
499Note that these scale indicators are relative to the chosen device.
500.
501They are defined by the parameters specified in the device's
502.I DESC
503file; see
504.BR groff_font (@MAN5EXT@).
505.
506.
507.P
508Note that single characters can have the eighth bit set, as can the
509names of fonts and special characters.
510.
511The names of characters and fonts can be of arbitrary length.
512.
513A character that is to be printed will always be in the current font.
514.
515.
516.P
517A string argument is always terminated by the next whitespace
518character (space, tab, or newline); an embedded
519.B #
520character is regarded as part of the argument, not as the beginning of
521a comment command.
522.
523An integer argument is already terminated by the next non-digit
524character, which then is regarded as the first character of the next
525argument or command.
526.
527.
528.\" --------------------------------------------------------------------
529.SS "Document Parts"
530.\" --------------------------------------------------------------------
531A correct
532.I intermediate output
533document consists of two parts, the
534.I prologue
535and the
536.IR body .
537.
538.P
539The task of the
540.I prologue
541is to set the general device parameters using three exactly specified
542commands.
543.
544The
--- 8 unchanged lines hidden (view full) ---
553.I n\ h\ v
554.br
555.B x init
556.RE
557.P
558with the arguments set as outlined in the section
559.BR "Device Control Commands" .
560.
561But the parser for the
562.I intermediate output
563format is able to swallow additional whitespace and comments as well.
564.
565.
566.P
567The
568.I body
569is the main section for processing the document data.
570.
571Syntactically, it is a sequence of any commands different from the
572ones used in the
573.IR prologue .
574.
575Processing is terminated as soon as the first
576.B x\ stop
577command is encountered; the last line of any
578.I groff intermediate output
579always contains such a command.
580.
581.
582.P
583Semantically, the
584.I body
585is page oriented.
586.
587A new page is started by a
588.BR p \~command.
589.
590Positioning, writing, and drawing commands are always done within the
591current page, so they cannot occur before the first
592.BR p \~command.
593.
--- 4 unchanged lines hidden (view full) ---
598is done relative to the current page, all other positioning
599is done relative to the current location within this page.
600.
601.
602.\" --------------------------------------------------------------------
603.SH "COMMAND REFERENCE"
604.\" --------------------------------------------------------------------
605.
606This section describes all
607.I intermediate output
608commands, the classical commands as well as the
609.I groff
610extensions.
611.
612.
613.\" --------------------------------------------------------------------
614.SS "Comment Command"
615.\" --------------------------------------------------------------------
616.
617.TP
618.BI # anything \[la]end_of_line\[ra]
619A comment.
620.
621Ignore any characters from the
622.BR # \~\c
623character up to the next newline character.
624.
625.P
626This command is the only possibility for commenting in the
627.I intermediate
628.IR output .
629.
630Each comment can be preceded by arbitrary
631.I syntactical
632.IR space ;
633every command can be terminated by a comment.
634.
635.
636.\" --------------------------------------------------------------------
--- 11 unchanged lines hidden (view full) ---
648.I syntactical space
649can be inserted before, after, and between the command letter and its
650arguments.
651.
652All of these commands are stackable, i.e., they can be preceded by
653other simple commands or followed by arbitrary other commands on the
654same line.
655.
656A separating
657.I syntactical space
658is only necessary when two integer arguments would clash or if the
659preceding argument ends with a string argument.
660.
661.
662.if (\n[@USE_ENV_STACK] == 1) \{\
663.command {
664Open a new environment by copying the actual device configuration data
665to the environment stack.
666.
667The current environment is setup by the device specification and
--- 8 unchanged lines hidden (view full) ---
676.
677\} \" endif @USE_ENV_STACK
678.
679.
680.command C xxx \[la]white_space\[ra]
681Print a special groff character named
682.argument xxx .
683.
684The trailing
685.I syntactical space
686or
687.I line break
688is necessary to allow character names of arbitrary length.
689.
690The character is printed at the current print position; the
691character's size is read from the font file.
692.
693The print position is not changed.
694.
695.
696.command c c
697Print character\~\c
698.argument c
699at the current print position;
--- 18 unchanged lines hidden (view full) ---
718.
719.command h n
720Move
721.argument n
722(a non-negative integer) basic units\~\c
723.unit u
724horizontally to the right.
725.
726.I [CSTR\~#54]
727allows negative values for
728.I n
729also, but
730.I groff
731doesn't use this.
732.
733.
734.command m "color_scheme \f[R][\f[]component .\|.\|.\f[R]]\f[]"
735Set the color for text (glyphs), line drawing, and the outline of
736graphic objects using different color schemes; the analoguous command
737for the filling color of graphic objects is
738.BR DF .
739.
740The color components are specified as integer arguments between 0 and
741\n[@maxcolor].
742.
743The number of color components and their meaning vary for the
744different color schemes.
745.
746These commands are generated by the
747.I groff
748escape sequence
749.BR \*[@backslash]m .
750.
751No position changing.
752.
753These commands are a
754.I groff
755extension.
756.
757.
758.RS
759.
760.command mc "cyan magenta yellow"
761Set color using the CMY color scheme, having the 3\~color components
762cyan, magenta, and yellow.
763.
--- 32 unchanged lines hidden (view full) ---
796.B \-T\~html
797is used, negative values are emitted also to indicate an unbreakable space
798with given width.
799.
800For example,
801.B N\~-193
802represents an unbreakable space which has a width of 193u.
803.
804This command is a
805.I groff
806extension.
807.
808.
809.command n b\ a
810Inform the device about a line break, but no positioning is done by
811this command.
812.
813In
814.I classical
815.IR troff ,
816the integer arguments
817.argument b
818and\~\c
819.argument a
820informed about the space before and after the current line to
821make the
822.I intermediate output
823more human readable without performing any action.
824.
825In
826.IR groff ,
827they are just ignored, but they must be provided for compatibility
828reasons.
829.
830.
831.command p n
832Begin a new page in the outprint.
833.
834The page number is set to\~\c
835.argument n .
836.
--- 10 unchanged lines hidden (view full) ---
847.
848.command s n
849Set point size to
850.argument n
851scaled points
852(this is unit\~\c
853.unit z
854in GNU
855.BR @g@troff ).
856.
857.I Classical troff
858used the unit
859.I points
860(\c
861.unit p )
862instead; see section
863.BR COMPATIBILITY .
864.
865.
866.command t xxx \[la]white_space\[ra]
867.command+ t "xxx dummy_arg" \[la]white_space\[ra]
868Print a word, i.e., a sequence of characters
869.argument xxx
870terminated by a space character or a line break; an optional second
871integer argument is ignored (this allows the formatter to generate
872an even number of arguments).
873.
874The first character should be printed at the current position, the
875current horizontal position should then be increased by the width of
876the first character, and so on for each character.
877.
878The widths of the characters are read from the font file, scaled for the
879current point size, and rounded to a multiple of the horizontal
880resolution.
881.
882Special characters cannot be printed using this command (use the
883.B C
884command for named characters).
885.
886This command is a
887.I groff
888extension; it is only used for devices whose
889.I DESC
890file contains the
891.B tcommand
892keyword; see
893.BR groff_font (@MAN5EXT@).
894.
895.
896.command u "n xxx" \[la]white_space\[ra]
897Print word with track kerning.
898.
899This is the same as the
900.B t
901command except that after printing each character, the current
902horizontal position is increased by the sum of the width of that
903character and\~\c
904.argument n
905(an integer in
906basic units\~\c
907.unit u ).
908This command is a
909.I groff
910extension; it is only used for devices whose
911.I DESC
912file contains the
913.B tcommand
914keyword; see
915.BR groff_font (@MAN5EXT@).
916.
917.
918.command V n
--- 8 unchanged lines hidden (view full) ---
927Move
928.argument n
929basic units\~\c
930.unit u
931down
932.RI ( n
933is a non-negative integer).
934.
935.I [CSTR\~#54]
936allows negative values for
937.I n
938also, but
939.I groff
940doesn't use this.
941.
942.
943.command w
944Informs about a paddable whitespace to increase readability.
945.
946The spacing itself must be performed explicitly by a move command.
947.
948.
949.\" --------------------------------------------------------------------
950.SS "Graphics Commands"
951.\" --------------------------------------------------------------------
952.
953Each graphics or drawing command in the
954.I intermediate output
955starts with the letter\~\c
956.B D
957followed by one or two characters that specify a subcommand; this
958is followed by a fixed or variable number of integer arguments that
959are separated by a single space character.
960.
961A
962.B D\c
963\~command
964may not be followed by another command on the same line (apart from a
965comment), so each
966.B D\c
967\~command
968is terminated by a
969.I syntactical line
970.IR break .
971.
972.
973.P
974.B @g@troff
975output follows the classical spacing rules (no space between command
976and subcommand, all arguments are preceded by a single space
977character), but the parser allows optional space between the command
978letters and makes the space before the first argument optional.
979.
980As usual, each space can be any sequence of tab and space characters.
981.
982.
983.P
984Some graphics commands can take a variable number of arguments.
985.
986In this case, they are integers representing a size measured in basic
987units\~\c
988.unit u .
989.
990The arguments called
991.list1..n h
992stand for horizontal distances where positive means right, negative
993left.
994.
995The arguments called
996.list1..n v
997stand for vertical distances where positive means down, negative up.
998.
999All these distances are offsets relative to the current location.
1000.
1001.
1002.P
1003Unless indicated otherwise, each graphics command directly corresponds
1004to a similar
1005.I groff
1006.B \*[@backslash]D
1007escape sequence; see
1008.BR groff (@MAN7EXT@).
1009.
1010.
1011.P
1012Unknown
1013.B D\c
1014\~commands are assumed to be device-specific.
1015.
1016Its arguments are parsed as strings; the whole information is then
1017sent to the postprocessor.
1018.
1019.
1020.P
1021In the following command reference, the syntax element
1022.I \[la]line_break\[ra]
1023means a
1024.I syntactical line break
1025as defined in section
1026.BR Separation .
1027.
1028.
1029.D-multiarg ~
1030Draw B-spline from current position to offset
1031.indexed_offset h 1 v 1 ,
1032then to offset
1033.indexed_offset h 2 v 2
1034if given, etc.\& up to
1035.indexed_offset h n v n .
1036This command takes a variable number of argument pairs; the current
1037position is moved to the terminal point of the drawn curve.
1038.
1039.
1040.Da-command
1041Draw arc from current position to
1042.indexed_offset h 1 v 1 \|+\|\c
1043.indexed_offset h 2 v 2
1044with center at
1045.indexed_offset h 1 v 1 ;
--- 7 unchanged lines hidden (view full) ---
1053(integer in basic units\~\c
1054.unit u )
1055with leftmost point at the current position; then move the current
1056position to the rightmost point of the circle.
1057.
1058An optional second integer argument is ignored (this allows to the
1059formatter to generate an even number of arguments).
1060.
1061This command is a
1062.I groff
1063extension.
1064.
1065.
1066.D-command c d
1067Draw circle line with diameter\~\c
1068.argument d
1069(integer in basic units\~\c
1070.unit u )
1071with leftmost point at the current position; then move the current
--- 6 unchanged lines hidden (view full) ---
1078.argument h
1079and a vertical diameter of\~\c
1080.argument v
1081(both integers in basic units\~\c
1082.unit u )
1083with the leftmost point at the current position; then move to the
1084rightmost point of the ellipse.
1085.
1086This command is a
1087.I groff
1088extension.
1089.
1090.
1091.D-command e "h v"
1092Draw an outlined ellipse with a horizontal diameter of\~\c
1093.argument h
1094and a vertical diameter of\~\c
1095.argument v
1096(both integers in basic units\~\c
--- 9 unchanged lines hidden (view full) ---
1106.BR m .
1107.
1108The color components are specified as integer arguments between 0 and
1109\n[@maxcolor].
1110.
1111The number of color components and their meaning vary for the
1112different color schemes.
1113.
1114These commands are generated by the
1115.I groff
1116escape sequences
1117.B \*[@backslash]D'F\ .\|.\|.'
1118and
1119.B \*[@backslash]M
1120(with no other corresponding graphics commands).
1121.
1122No position changing.
1123.
1124This command is a
1125.I groff
1126extension.
1127.
1128.
1129.RS
1130.
1131.D-command Fc "cyan magenta yellow"
1132Set fill color for solid drawing objects using the CMY color scheme,
1133having the 3\~color components cyan, magenta, and yellow.
1134.
--- 50 unchanged lines hidden (view full) ---
1185Df -1
1186.RE
1187.ft
1188.fi
1189.
1190sets all colors to blue.
1191.RE
1192.
1193.
1194.P
1195No position changing.
1196.
1197This command is a
1198.I groff
1199extension.
1200.
1201.RE
1202.
1203.
1204.D-command l "h v"
1205Draw line from current position to offset
1206.offset h v
1207(integers in basic units\~\c
--- 18 unchanged lines hidden (view full) ---
1226Although this doesn't make sense it is kept for compatibility.
1227.
1228\}
1229.el \{\
1230As the polygon is closed, the end of drawing is the starting point, so
1231the position doesn't change.
1232\}
1233.
1234This command is a
1235.I groff
1236extension.
1237.
1238.
1239.D-multiarg P
1240The same macro as the corresponding
1241.B Dp
1242command with the same arguments, but draws a solid polygon in the
1243current fill color rather than an outlined polygon.
1244.
1245.ie (\n[@STUPID_DRAWING_POSITIONING] == 1) \{\
1246The position is changed in the same way as with
1247.BR Dp .
1248\}
1249.el \
1250No position changing.
1251.
1252This command is a
1253.I groff
1254extension.
1255.
1256.
1257.D-command t n
1258Set the current line thickness to\~\c
1259.argument n
1260(an integer in basic units\~\c
1261.unit u )
1262if
--- 13 unchanged lines hidden (view full) ---
1276position is not changed.
1277.
1278Although this doesn't make sense it is kept for compatibility.
1279.
1280\}
1281.el \
1282No position changing.
1283.
1284This command is a
1285.I groff
1286extension.
1287.
1288.
1289.\" --------------------------------------------------------------------
1290.SS "Device Control Commands"
1291.\" --------------------------------------------------------------------
1292.
1293Each device control command starts with the letter
1294.B x
1295followed by a space character (optional or arbitrary space/\:tab in
1296.IR groff )
1297and a subcommand letter or word; each argument (if any) must be
1298preceded by a
1299.I syntactical
1300.IR space .
1301.
1302All
1303.B x
1304commands are terminated by a
1305.IR "syntactical line break" ;
1306no device control command can be followed by another command on the same
1307line (except a comment).
1308.
1309.P
1310The subcommand is basically a single letter, but to increase
1311readability, it can be written as a word, i.e., an arbitrary sequence
1312of characters terminated by the next tab, space, or newline character.
1313.
1314All characters of the subcommand word but the first are simply ignored.
1315.
1316For example,
1317.B @g@troff
1318outputs the initialization command
1319.B x\ i
1320as
1321.B x\ init
1322and the resolution command
1323.B x\ r
1324as
1325.BR "x\ res" .
--- 13 unchanged lines hidden (view full) ---
1339.BR Separation .
1340.
1341.x-command F name
1342.xsub Filename
1343Use
1344.argument name
1345as the intended name for the current file in error reports.
1346.
1347This is useful for remembering the original file name when
1348.B groff
1349uses an internal piping mechanism.
1350.
1351The input file is not changed by this command.
1352.
1353This command is a
1354.I groff
1355extension.
1356.
1357.
1358.x-command f "n\ s"
1359.xsub font
1360Mount font position\~\c
1361.argument n
1362(a non-negative integer) with font named\~\c
1363.argument s
--- 4 unchanged lines hidden (view full) ---
1368.
1369.x-command H n
1370.xsub Height
1371Set character height to\~\c
1372.argument n
1373(a positive integer in scaled points\~\c
1374.unit z ).
1375.
1376.I Classical troff
1377used the unit points (\c
1378.unit p )
1379instead; see section
1380.BR COMPATIBILITY .
1381.
1382.
1383.x-command i
1384.xsub init
1385Initialize device.
1386.
1387This is the third command of the
1388.IR prologue .
1389.
1390.
1391.x-command p
1392.xsub pause
1393Parsed but ignored.
1394.
1395The classical documentation reads
1396.I pause device, can be
--- 8 unchanged lines hidden (view full) ---
1405.argument h
1406is the minimal horizontal motion, and
1407.argument v
1408the minimal vertical motion possible with this device; all arguments
1409are positive integers in basic units\~\c
1410.unit u
1411per inch.
1412.
1413This is the second command of the
1414.IR prologue .
1415.
1416.
1417.x-command S n
1418.xsub Slant
1419Set slant to\~\c
1420.argument n
1421degrees (an integer in basic units\~\c
1422.unit u ).
1423.
1424.
1425.x-command s
1426.xsub stop
1427Terminates the processing of the current file; issued as the last
1428command of any
1429.I intermediate @g@troff
1430.IR output .
1431.
1432.
1433.x-command t
1434.xsub trailer
1435Generate trailer information, if any.
1436.
1437In
1438.BR groff ,
1439this is actually just ignored.
1440.
1441.
1442.x-command T xxx
1443.xsub Typesetter
1444Set name of device to word
1445.argument xxx ,
1446a sequence of characters ended by the next whitespace character.
1447.
1448The possible device names coincide with those from the groff
1449.B -T
1450option.
1451.
1452This is the first command of the
1453.IR prologue .
1454.
1455.
1456.x-command u n
1457.xsub underline
1458Configure underlining of spaces.
1459.
1460If
1461.argument n
1462is\~1, start underlining of spaces;
1463if
1464.argument n
1465is\~0, stop underlining of spaces.
1466.
1467This is needed for the
1468.B cu
1469request in
1470.B @g@nroff
1471mode and is ignored otherwise.
1472.
1473This command is a
1474.I groff
1475extension.
1476.
1477.
1478.x-command X anything
1479.xsub X-escape
1480Send string
1481.argument anything
1482uninterpreted to the device.
1483.
--- 12 unchanged lines hidden (view full) ---
1496.B +
1497character.
1498.
1499This command is generated by the
1500.I groff
1501escape sequence
1502.BR \*[@backslash]X .
1503.
1504The line-continuing feature is a
1505.I groff
1506extension.
1507.
1508.
1509.\" --------------------------------------------------------------------
1510.SS "Obsolete Command"
1511.\" --------------------------------------------------------------------
1512.
1513In
1514.I classical troff
--- 8 unchanged lines hidden (view full) ---
1523.argument ddc
1524Move right
1525.argument dd
1526(exactly two decimal digits) basic units\~\c
1527.unit u ,
1528then print character\~\c
1529.argument c .
1530.
1531.
1532.RS
1533.P
1534In
1535.IR groff ,
1536arbitrary
1537.I syntactical space
1538around and within this command is allowed to be added.
1539.
1540Only when a preceding command on the same line ends with an argument
1541of variable length a separating space is obligatory.
1542.
1543In
1544.I classical
1545.IR troff ,
1546large clusters of these and other commands were used, mostly without
1547spaces; this made such output almost unreadable.
1548.
1549.RE
1550.
1551.
1552.P
1553For modern high-resolution devices, this command does not make sense
1554because the width of the characters can become much larger than two
1555decimal digits.
1556.
1557In
1558.BR groff ,
1559this is only used for the devices
1560.BR X75 ,
1561.BR X75-12 ,
1562.BR X100 ,
1563and
1564.BR X100-12 .
1565.
1566For other devices,
1567the commands
--- 5 unchanged lines hidden (view full) ---
1573.
1574.\" --------------------------------------------------------------------
1575.SH "POSTPROCESSING"
1576.\" --------------------------------------------------------------------
1577.
1578The
1579.I roff
1580postprocessors are programs that have the task to translate the
1581.I intermediate output
1582into actions that are sent to a device.
1583.
1584A device can be some piece of hardware such as a printer, or a software
1585file format suitable for graphical or text processing.
1586.
1587The
1588.I groff
1589system provides powerful means that make the programming of such
1590postprocessors an easy task.
1591.P
1592There is a library function that parses the
1593.I intermediate output
1594and sends the information obtained to the device via methods of a
1595class with a common interface for each device.
1596.
1597So a
1598.I groff
1599postprocessor must only redefine the methods of this class.
1600.
1601For details, see the reference in section
1602.BR FILES .
1603.
1604.
1605.\" --------------------------------------------------------------------
1606.SH "EXAMPLES"
1607.\" --------------------------------------------------------------------
1608.
1609This section presents the
1610.I intermediate output
1611generated from the same input for three different devices.
1612.
1613The input is the sentence
1614.I hell world
1615fed into
1616.B groff
1617on the command line.
1618.
1619.
1620.Topic
1621High-resolution device
1622.I ps
1623.
1624.
1625.RS
1626.P
1627.ShellCommand echo "hell world" | groff -Z -T ps
1628.
1629.
1630.P
1631.nf
1632.ft CB
1633x T ps
1634x res 72000 1 1
1635x init
1636p1
1637x font 5 TR
--- 9 unchanged lines hidden (view full) ---
1647n12000 0
1648x trailer
1649V792000
1650x stop
1651.ft P
1652.fi
1653.RE
1654.
1655.
1656.P
1657This output can be fed into the postprocessor
1658.BR grops (@MAN1EXT@)
1659to get its representation as a PostScript file.
1660.
1661.
1662.Topic
1663Low-resolution device
1664.I latin1
1665.
1666.
1667.RS
1668.P
1669This is similar to the high-resolution device except that the
1670positioning is done at a minor scale.
1671.
1672Some comments (lines starting with
1673.IR # )
1674were added for clarification; they were not generated by the
1675formatter.
1676.
1677.
1678.P
1679.ShellCommand echo "hell world" | groff -Z -T latin1
1680.
1681.
1682.P
1683.nf
1684.I "# prologue"
1685.ft CB
1686x T latin1
1687x res 240 24 40
1688x init
1689.I "# begin a new page"
1690.ft CB
1691p1
1692.I "# font setup"
1693.ft CB
1694x font 1 R
1695f1
1696s10
1697.I "# initial positioning on the page"
1698.ft CB
1699V40
1700H0
1701.I "# write text `hell'"
1702.ft CB
1703thell
1704.I "# inform about a space, and do it by a horizontal jump"
1705.ft CB
1706wh24
1707.I "# write text `world'"
1708.ft CB
1709tworld
1710.I "# announce line break, but do nothing because ..."
1711.ft CB
1712n40 0
1713.I "# ... the end of the document has been reached"
1714.ft CB
1715x trailer
1716V2640
1717x stop
1718.ft P
1719.fi
1720.RE
1721.
1722.
1723.P
1724This output can be fed into the postprocessor
1725.BR grotty (@MAN1EXT@)
1726to get a formatted text document.
1727.
1728.
1729.Topic
1730Classical style output
1731.
1732.
1733.RS
1734.P
1735As a computer monitor has a very low resolution compared to modern
1736printers the
1737.I intermediate output
1738for the X\~devices can use the jump-and-write command with its 2-digit
1739displacements.
1740.
1741.
1742.P
1743.ShellCommand echo "hell world" | groff -Z -T X100
1744.
1745.
1746.P
1747.nf
1748.ft CB
1749x T X100
1750x res 100 1 1
1751x init
1752p1
1753x font 5 TR
1754f5
1755s10
1756V16
1757H100
1758.I "# write text with old-style jump-and-write command"
1759.ft CB
1760ch07e07l03lw06w11o07r05l03dh7
1761n16 0
1762x trailer
1763V1100
1764x stop
1765.ft P
1766.fi
1767.RE
1768.
1769.
1770.P
1771This output can be fed into the postprocessor
1772.BR \%xditview (1x)
1773or
1774.BR \%gxditview (@MAN1EXT@)
1775for displaying in\~X.
1776.
1777.
1778.P
1779Due to the obsolete jump-and-write command, the text clusters in the
1780classical output are almost unreadable.
1781.
1782.
1783.\" --------------------------------------------------------------------
1784.SH "COMPATIBILITY"
1785.\" --------------------------------------------------------------------
1786.
1787The
1788.I intermediate output
1789language of the
1790.I classical troff
1791was first documented in
1792.IR [CSTR\~#97] .
1793.
1794The
1795.I groff intermediate output
1796format is compatible with this specification except for the following
1797features.
1798.
1799.
1800.Topic
1801The classical quasi device independence is not yet implemented.
1802.
1803.
1804.Topic
1805The old hardware was very different from what we use today.
1806.
1807So the
1808.I groff
1809devices are also fundamentally different from the ones in
1810.I classical
1811.IR troff .
1812.
1813For example, the classical PostScript device was called
1814.I post
1815and had a resolution of 720 units per inch,
1816while
1817.IR groff 's
1818.I ps
1819device has a resolution of 72000 units per inch.
1820.
1821Maybe, by implementing some rescaling mechanism similar to the
1822classical quasi device independence, these could be integrated into
1823modern
1824.IR groff .
1825.
1826.
1827.Topic
1828The B-spline command
1829.B D~
1830is correctly handled by the
1831.I intermediate output
1832parser, but the drawing routines aren't implemented in some of the
1833postprocessor programs.
1834.
1835.
1836.Topic
1837The argument of the commands
1838.B s
1839and
1840.B x H
1841has the implicit unit scaled point\~\c
1842.unit z
1843in
1844.IR groff ,
1845while
1846.I classical troff
1847had point (\c
1848.unit p ).
1849.
1850This isn't an incompatibility, but a compatible extension, for both
1851units coincide for all devices without a
1852.I sizescale
1853parameter, including all classical and the
1854.I groff
1855text devices.
1856.
1857The few
1858.I groff
1859devices with a sizescale parameter either did not exist, had a
1860different name, or seem to have had a different resolution.
1861.
1862So conflicts with classical devices are very unlikely.
1863.
1864.
1865.ie (\n[@STUPID_DRAWING_POSITIONING] == 1) \{\
1866.Topic
1867The position changing after the commands
1868.BR Dp ,
1869.BR DP ,
1870and
1871.B Dt
1872is illogical, but as old versions of groff used this feature it is
1873kept for compatibility reasons.
1874.\} \" @STUPID_DRAWING_POSITIONING
1875.el \{\
1876.Topic
1877Temporarily, there existed some confusion on the positioning after the
1878.B D
1879commands that are
1880.I groff
1881extensions.
1882.
1883This has been clarified by establishing the classical rule for all
1884groff drawing commands:
1885.
1886.
1887.RS
1888.P
1889.ft I
1890The position after a graphic object has been drawn is at its end;
1891for circles and ellipses, the "end" is at the right side.
1892.ft
1893.RE
1894.
1895.
1896.P
1897From this, the positionings specified for the drawing commands above
1898follow quite naturally.
1899.\} \" @STUPID_DRAWING_POSITIONING
1900.
1901.P
1902The differences between
1903.I groff
1904and
1905.I classical troff
1906are documented in
1907.BR groff_diff (@MAN7EXT@).
1908.
1909.
1910.\" --------------------------------------------------------------------
1911.SH "FILES"
1912.\" --------------------------------------------------------------------
1913.
1914.TP
1915.BI @FONTDIR@/dev name /DESC
1916Device description file for device
1917.IR name .
1918.
1919.TP
1920.IB \[la]groff_source_dir\[ra] /src/libs/libdriver/input.cpp
1921Defines the parser and postprocessor for the
1922.I intermediate
1923.IR output .
1924.
1925It is located relative to the top directory of the
1926.I groff
1927source tree, e.g.
1928.IR @GROFFSRCDIR@ .
1929.
1930This parser is the definitive specification of the
1931.I groff intermediate output
1932format.
1933.
1934.
1935.\" --------------------------------------------------------------------
1936.SH "SEE ALSO"
1937.\" --------------------------------------------------------------------
1938.
1939A reference like
1940.BR groff (@MAN7EXT@)
1941refers to a manual page; here
1942.B groff
1943in section\~\c
1944.I @MAN7EXT@
1945of the man-page documentation system.
1946.
1947To read the example, look up section\~@MAN7EXT@ in your desktop help
1948system or call from the shell prompt
1949.
1950.
1951.RS
1952.P
1953.ShellCommand man @MAN7EXT@ groff
1954.RE
1955.
1956.
1957.P
1958For more details, see
1959.BR man (1).
1960.
1961.
1962.TP
1963.BR groff (@MAN1EXT@)
1964option
1965.B -Z
1966and further readings on groff.
1967.
1968.
1969.TP
1970.BR groff (@MAN7EXT@)
1971for details of the
1972.I groff
1973language such as numerical units and escape sequences.
1974.
1975.
1976.TP
1977.BR groff_font (@MAN5EXT@)
1978for details on the device scaling parameters of the
1979.B DESC
1980file.
1981.
1982.
1983.TP
1984.BR @g@troff (@MAN1EXT@)
1985generates the device-independent intermediate output.
1986.
1987.
1988.TP
1989.BR roff (@MAN7EXT@)
1990for historical aspects and the general structure of roff systems.
1991.
1992.
1993.TP
1994.BR groff_diff (@MAN7EXT@)
1995The differences between the intermediate output in groff and classical
1996troff.
1997.
1998.
1999.TP
2000.BR gxditview (@MAN1EXT@)
2001Viewer for the
2002.I intermediate
2003.IR output .
2004.
2005.
2006.P
2007.BR \%grodvi (@MAN1EXT@),
2008.BR \%grohtml (@MAN1EXT@),
2009.BR \%grolbp (@MAN1EXT@),
2010.BR \%grolj4 (@MAN1EXT@),
2011.BR \%grops (@MAN1EXT@),
2012.BR \%grotty (@MAN1EXT@)
2013.br
2014.RS
2015the groff postprocessor programs.
2016.RE
2017.
2018.
2019.P
2020For a treatment of all aspects of the groff system within a single
2021document, see the
2022.I groff info
2023.IR file .
2024.
2025It can be read within the integrated help systems, within
2026.BR emacs (1)
2027or from the shell prompt by
2028.
2029.RS
2030.ShellCommand info groff
2031.RE
2032.
2033.
2034.P
2035The
2036.I classical troff output language
2037is described in two AT&T Bell Labs CSTR documents available on-line at
2038.URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr.html \
2039 "Bell Labs CSTR site" .
2040.
2041.
2042.TP
2043.I [CSTR #97]
2044.I A Typesetter-independent TROFF
2045by
2046.I Brian Kernighan
2047is the original and most concise documentation on the output language;
2048see
2049.URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr/\:97.ps.gz CSTR\~#97 .
2050.
2051.
2052.TP
2053.I [CSTR\~#54]
2054The 1992 revision of the
2055.I Nroff/\:Troff User's Manual
2056by
2057.I J.\& F.\& Osanna
2058and
2059.I Brian Kernighan
2060isn't as concise as
2061.I [CSTR\~#97]
2062regarding the output language; see
2063.URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr/\:54.ps.gz CSTR\~#54 .
2064.
2065.
2066.\" --------------------------------------------------------------------
2067.SH "AUTHORS"
2068.\" --------------------------------------------------------------------
2069.
2070Copyright (C) 1989, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
2071.
2072.
2073.P
2074This document is distributed under the terms of the FDL (GNU Free
2075Documentation License) version 1.1 or later.
2076.
2077You should have received a copy of the FDL with this package; it is also
2078available on-line at the
2079.URL http://\:www.gnu.org/\:copyleft/\:fdl.html "GNU copyleft site" .
2080.
2081.
2082.P
2083This document is part of
2084.IR groff ,
2085the GNU
2086.I roff
2087distribution.
2088.
2089It is based on a former version \- published under the GPL \- that
2090described only parts of the
2091.I groff
2092extensions of the output language.
2093.
2094It has been rewritten 2002 by \m[blue]Bernd Warken\m[] and is
2095maintained by
2096.MTO wl@gnu.org "Werner Lemberg" .
2097.
2098.cp \n[groff_out_C]
2099.
2100.\" --------------------------------------------------------------------
2101.\" Emacs settings
2102.\" --------------------------------------------------------------------
2103.\"
2104.\" Local Variables:
2105.\" mode: nroff
2106.\" End:
2.\" The above line should force the use of eqn as a preprocessor
3.ig
4groff_out.5
5
6Last update: 2 Jul 2005
7
8This file is part of groff, the GNU roff type-setting system.
9
10Copyright (C) 1989, 2001, 2002, 2003, 2004, 2005
11Free Software Foundation, Inc.
12rewritten from scrach 2001 by Bernd Warken <bwarken@mayn.de>
13
14Permission is granted to copy, distribute and/or modify this document
15under the terms of the GNU Free Documentation License, Version 1.1 or
16any later version published by the Free Software Foundation; with the
17Invariant Sections being this .ig-section and AUTHORS, with no
18Front-Cover Texts, and with no Back-Cover Texts.
19
20A copy of the Free Documentation License is included as a file called
21FDL in the main directory of the groff source package.
22..
23.
24.\" --------------------------------------------------------------------
25.\" Setup
26.\" --------------------------------------------------------------------
27.
28.do nr groff_out_C \n[.C]
29.cp 0
30.
31.mso www.tmac
32.
33.if n \{\
34. mso tty-char.tmac
35. ftr CR R
36. ftr CI I
37. ftr CB B
38.\}
--- 212 unchanged lines hidden (view full) ---
251.SH NAME
252groff_out \- groff intermediate output format
253.
254.
255.\" --------------------------------------------------------------------
256.SH DESCRIPTION
257.\" --------------------------------------------------------------------
258.
259This manual page describes the
260.I intermediate output
261format of the GNU
262.BR roff (@MAN7EXT@)
263text processing system
264.BR groff (@MAN1EXT@).
265.
266This output is produced by a run of the GNU
267.BR @g@troff (@MAN1EXT@)
268program.
269.
270It contains already all device-specific information, but it is not yet
271fed into a device postprocessor program.
272.
273.
274.P
275As the GNU
276.I roff
277processor
278.BR groff (@MAN1EXT@)
279is a wrapper program around
280.B @g@troff
281that automatically calls a
282postprocessor, this output does not show up normally.
283.
284This is why it is called
285.I intermediate
286within the
287.I groff
288.IR system .
289.
290The
291.B groff
292program provides the option
293.B -Z
294to inhibit postprocessing, such that the produced
295.I intermediate output
296is sent to standard output just like calling
297.B @g@troff
298manually.
299.
300.
301.P
302In this document, the term
303.I @g@troff output
304describes what is output by the GNU
305.B @g@troff
306program, while
307.I intermediate output
308refers to the language that is accepted by the parser that prepares
309this output for the postprocessors.
310.
311This parser is smarter on whitespace and implements obsolete elements
312for compatibility, otherwise both formats are the same.
313.
314Both formats can be viewed directly with
315.BR \%gxditview (@MAN1EXT@).
316.
317.
318.P
319The main purpose of the
320.I intermediate output
321concept is to facilitate the development of postprocessors by
322providing a common programming interface for all devices.
323.
324It has a language of its own that is completely different from the
325.BR groff (@MAN7EXT@)
326language.
327.
328While the
329.I groff
330language is a high-level programming language for text processing, the
331.I intermediate output
332language is a kind of low-level assembler language by specifying all
333positions on the page for writing and drawing.
334.
335.
336.P
337The
338.RI pre- groff
339.I roff
340versions are denoted as
341.I classical
342.IR troff .
343The
344.I intermediate output
345produced by
346.B groff
347is fairly readable, while
348.I classical troff
349output was hard to understand because of strange habits that are
350still supported, but not used any longer by
351.I GNU
352.IR @g@troff .
353.
354.
355.\" --------------------------------------------------------------------
356.SH "LANGUAGE CONCEPTS"
357.\" --------------------------------------------------------------------
358.
359During the run of
360.BR @g@troff ,
361the
362.I roff
363input is cracked down to the information on what has to be printed at
364what position on the intended device.
365.
366So the language of the
367.I intermediate output
368format can be quite small.
369.
370Its only elements are commands with or without arguments.
371.
372In this document, the term "command" always refers to the
373.I intermediate output
374language, never to the
375.I roff
376language used for document formatting.
377.
378There are commands for positioning and text writing, for drawing, and
379for device controlling.
380.
381.
382.\" --------------------------------------------------------------------
383.SS "Separation"
384.\" --------------------------------------------------------------------
385.
386.I Classical troff output
387had strange requirements on whitespace.
388.
389The
390.B groff
391output parser, however, is smart about whitespace by making it
392maximally optional.
393.
394The whitespace characters, i.e., the
395.IR tab ,
396.IR space ,
397and
398.I newline
399characters, always have a syntactical meaning.
400.
401They are never printable because spacing within the output is always
402done by positioning commands.
403.
404.
405.P
406Any sequence of
407.I space
408or
409.I tab
410characters is treated as a single
411.I syntactical
412.IR space .
413.
414It separates commands and arguments, but is only required when there
415would occur a clashing between the command code and the arguments
416without the space.
417.
418Most often, this happens when variable length command names,
419arguments, argument lists, or command clusters meet.
420.
421Commands and arguments with a known, fixed length need not be
422separated by
423.I syntactical
424.IR space .
425.
426.
427.P
428A line break is a syntactical element, too.
429.
430Every command argument can be followed by whitespace, a comment, or a
431newline character.
432.
433Thus a
434.I syntactical line break
435is defined to consist of optional
436.I syntactical space
437that is optionally followed by a comment, and a newline character.
438.
439.
440.P
441The normal commands, those for positioning and text, consist of a
442single letter taking a fixed number of arguments.
443.
444For historical reasons, the parser allows to stack such commands on
445the same line, but fortunately, in
446.I groff intermediate
447.IR output ,
448every command with at least one argument is followed by a line break,
449thus providing excellent readability.
450.
451.P
452The other commands \[em] those for drawing and device controlling \[em]
453have a more complicated structure; some recognize long command names,
454and some take a variable number of arguments.
455.
456So all
457.B D
458and
459.B x
460commands were designed to request a
461.I syntactical line break
462after their last argument.
463.
464Only one command,
465.RB ` x\ X '
466has an argument that can stretch over several lines, all other
467commands must have all of their arguments on the same line as the
468command, i.e., the arguments may not be splitted by a line break.
469.
470.P
471Empty lines, i.e., lines containing only space and/or a comment, can
472occur everywhere.
473.
474They are just ignored.
475.
476.
477.\" --------------------------------------------------------------------
478.SS "Argument Units"
479.\" --------------------------------------------------------------------
480.
481Some commands take integer arguments that are assumed to represent
482values in a measurement unit, but the letter for the corresponding
483.I scale indicator
484is not written with the output command arguments; see
485.BR groff (@MAN7EXT@)
486and the
487.I groff info file
488for more on this topic.
489.
490Most commands assume the scale indicator\~\c
491.unit u ,
492the basic unit of the device, some use\~\c
493.unit z ,
494the
495.I scaled point unit
496of the device, while others, such as the color commands expect plain
497integers.
498.
499Note that these scale indicators are relative to the chosen device.
500.
501They are defined by the parameters specified in the device's
502.I DESC
503file; see
504.BR groff_font (@MAN5EXT@).
505.
506.
507.P
508Note that single characters can have the eighth bit set, as can the
509names of fonts and special characters.
510.
511The names of characters and fonts can be of arbitrary length.
512.
513A character that is to be printed will always be in the current font.
514.
515.
516.P
517A string argument is always terminated by the next whitespace
518character (space, tab, or newline); an embedded
519.B #
520character is regarded as part of the argument, not as the beginning of
521a comment command.
522.
523An integer argument is already terminated by the next non-digit
524character, which then is regarded as the first character of the next
525argument or command.
526.
527.
528.\" --------------------------------------------------------------------
529.SS "Document Parts"
530.\" --------------------------------------------------------------------
531A correct
532.I intermediate output
533document consists of two parts, the
534.I prologue
535and the
536.IR body .
537.
538.P
539The task of the
540.I prologue
541is to set the general device parameters using three exactly specified
542commands.
543.
544The
--- 8 unchanged lines hidden (view full) ---
553.I n\ h\ v
554.br
555.B x init
556.RE
557.P
558with the arguments set as outlined in the section
559.BR "Device Control Commands" .
560.
561But the parser for the
562.I intermediate output
563format is able to swallow additional whitespace and comments as well.
564.
565.
566.P
567The
568.I body
569is the main section for processing the document data.
570.
571Syntactically, it is a sequence of any commands different from the
572ones used in the
573.IR prologue .
574.
575Processing is terminated as soon as the first
576.B x\ stop
577command is encountered; the last line of any
578.I groff intermediate output
579always contains such a command.
580.
581.
582.P
583Semantically, the
584.I body
585is page oriented.
586.
587A new page is started by a
588.BR p \~command.
589.
590Positioning, writing, and drawing commands are always done within the
591current page, so they cannot occur before the first
592.BR p \~command.
593.
--- 4 unchanged lines hidden (view full) ---
598is done relative to the current page, all other positioning
599is done relative to the current location within this page.
600.
601.
602.\" --------------------------------------------------------------------
603.SH "COMMAND REFERENCE"
604.\" --------------------------------------------------------------------
605.
606This section describes all
607.I intermediate output
608commands, the classical commands as well as the
609.I groff
610extensions.
611.
612.
613.\" --------------------------------------------------------------------
614.SS "Comment Command"
615.\" --------------------------------------------------------------------
616.
617.TP
618.BI # anything \[la]end_of_line\[ra]
619A comment.
620.
621Ignore any characters from the
622.BR # \~\c
623character up to the next newline character.
624.
625.P
626This command is the only possibility for commenting in the
627.I intermediate
628.IR output .
629.
630Each comment can be preceded by arbitrary
631.I syntactical
632.IR space ;
633every command can be terminated by a comment.
634.
635.
636.\" --------------------------------------------------------------------
--- 11 unchanged lines hidden (view full) ---
648.I syntactical space
649can be inserted before, after, and between the command letter and its
650arguments.
651.
652All of these commands are stackable, i.e., they can be preceded by
653other simple commands or followed by arbitrary other commands on the
654same line.
655.
656A separating
657.I syntactical space
658is only necessary when two integer arguments would clash or if the
659preceding argument ends with a string argument.
660.
661.
662.if (\n[@USE_ENV_STACK] == 1) \{\
663.command {
664Open a new environment by copying the actual device configuration data
665to the environment stack.
666.
667The current environment is setup by the device specification and
--- 8 unchanged lines hidden (view full) ---
676.
677\} \" endif @USE_ENV_STACK
678.
679.
680.command C xxx \[la]white_space\[ra]
681Print a special groff character named
682.argument xxx .
683.
684The trailing
685.I syntactical space
686or
687.I line break
688is necessary to allow character names of arbitrary length.
689.
690The character is printed at the current print position; the
691character's size is read from the font file.
692.
693The print position is not changed.
694.
695.
696.command c c
697Print character\~\c
698.argument c
699at the current print position;
--- 18 unchanged lines hidden (view full) ---
718.
719.command h n
720Move
721.argument n
722(a non-negative integer) basic units\~\c
723.unit u
724horizontally to the right.
725.
726.I [CSTR\~#54]
727allows negative values for
728.I n
729also, but
730.I groff
731doesn't use this.
732.
733.
734.command m "color_scheme \f[R][\f[]component .\|.\|.\f[R]]\f[]"
735Set the color for text (glyphs), line drawing, and the outline of
736graphic objects using different color schemes; the analoguous command
737for the filling color of graphic objects is
738.BR DF .
739.
740The color components are specified as integer arguments between 0 and
741\n[@maxcolor].
742.
743The number of color components and their meaning vary for the
744different color schemes.
745.
746These commands are generated by the
747.I groff
748escape sequence
749.BR \*[@backslash]m .
750.
751No position changing.
752.
753These commands are a
754.I groff
755extension.
756.
757.
758.RS
759.
760.command mc "cyan magenta yellow"
761Set color using the CMY color scheme, having the 3\~color components
762cyan, magenta, and yellow.
763.
--- 32 unchanged lines hidden (view full) ---
796.B \-T\~html
797is used, negative values are emitted also to indicate an unbreakable space
798with given width.
799.
800For example,
801.B N\~-193
802represents an unbreakable space which has a width of 193u.
803.
804This command is a
805.I groff
806extension.
807.
808.
809.command n b\ a
810Inform the device about a line break, but no positioning is done by
811this command.
812.
813In
814.I classical
815.IR troff ,
816the integer arguments
817.argument b
818and\~\c
819.argument a
820informed about the space before and after the current line to
821make the
822.I intermediate output
823more human readable without performing any action.
824.
825In
826.IR groff ,
827they are just ignored, but they must be provided for compatibility
828reasons.
829.
830.
831.command p n
832Begin a new page in the outprint.
833.
834The page number is set to\~\c
835.argument n .
836.
--- 10 unchanged lines hidden (view full) ---
847.
848.command s n
849Set point size to
850.argument n
851scaled points
852(this is unit\~\c
853.unit z
854in GNU
855.BR @g@troff ).
856.
857.I Classical troff
858used the unit
859.I points
860(\c
861.unit p )
862instead; see section
863.BR COMPATIBILITY .
864.
865.
866.command t xxx \[la]white_space\[ra]
867.command+ t "xxx dummy_arg" \[la]white_space\[ra]
868Print a word, i.e., a sequence of characters
869.argument xxx
870terminated by a space character or a line break; an optional second
871integer argument is ignored (this allows the formatter to generate
872an even number of arguments).
873.
874The first character should be printed at the current position, the
875current horizontal position should then be increased by the width of
876the first character, and so on for each character.
877.
878The widths of the characters are read from the font file, scaled for the
879current point size, and rounded to a multiple of the horizontal
880resolution.
881.
882Special characters cannot be printed using this command (use the
883.B C
884command for named characters).
885.
886This command is a
887.I groff
888extension; it is only used for devices whose
889.I DESC
890file contains the
891.B tcommand
892keyword; see
893.BR groff_font (@MAN5EXT@).
894.
895.
896.command u "n xxx" \[la]white_space\[ra]
897Print word with track kerning.
898.
899This is the same as the
900.B t
901command except that after printing each character, the current
902horizontal position is increased by the sum of the width of that
903character and\~\c
904.argument n
905(an integer in
906basic units\~\c
907.unit u ).
908This command is a
909.I groff
910extension; it is only used for devices whose
911.I DESC
912file contains the
913.B tcommand
914keyword; see
915.BR groff_font (@MAN5EXT@).
916.
917.
918.command V n
--- 8 unchanged lines hidden (view full) ---
927Move
928.argument n
929basic units\~\c
930.unit u
931down
932.RI ( n
933is a non-negative integer).
934.
935.I [CSTR\~#54]
936allows negative values for
937.I n
938also, but
939.I groff
940doesn't use this.
941.
942.
943.command w
944Informs about a paddable whitespace to increase readability.
945.
946The spacing itself must be performed explicitly by a move command.
947.
948.
949.\" --------------------------------------------------------------------
950.SS "Graphics Commands"
951.\" --------------------------------------------------------------------
952.
953Each graphics or drawing command in the
954.I intermediate output
955starts with the letter\~\c
956.B D
957followed by one or two characters that specify a subcommand; this
958is followed by a fixed or variable number of integer arguments that
959are separated by a single space character.
960.
961A
962.B D\c
963\~command
964may not be followed by another command on the same line (apart from a
965comment), so each
966.B D\c
967\~command
968is terminated by a
969.I syntactical line
970.IR break .
971.
972.
973.P
974.B @g@troff
975output follows the classical spacing rules (no space between command
976and subcommand, all arguments are preceded by a single space
977character), but the parser allows optional space between the command
978letters and makes the space before the first argument optional.
979.
980As usual, each space can be any sequence of tab and space characters.
981.
982.
983.P
984Some graphics commands can take a variable number of arguments.
985.
986In this case, they are integers representing a size measured in basic
987units\~\c
988.unit u .
989.
990The arguments called
991.list1..n h
992stand for horizontal distances where positive means right, negative
993left.
994.
995The arguments called
996.list1..n v
997stand for vertical distances where positive means down, negative up.
998.
999All these distances are offsets relative to the current location.
1000.
1001.
1002.P
1003Unless indicated otherwise, each graphics command directly corresponds
1004to a similar
1005.I groff
1006.B \*[@backslash]D
1007escape sequence; see
1008.BR groff (@MAN7EXT@).
1009.
1010.
1011.P
1012Unknown
1013.B D\c
1014\~commands are assumed to be device-specific.
1015.
1016Its arguments are parsed as strings; the whole information is then
1017sent to the postprocessor.
1018.
1019.
1020.P
1021In the following command reference, the syntax element
1022.I \[la]line_break\[ra]
1023means a
1024.I syntactical line break
1025as defined in section
1026.BR Separation .
1027.
1028.
1029.D-multiarg ~
1030Draw B-spline from current position to offset
1031.indexed_offset h 1 v 1 ,
1032then to offset
1033.indexed_offset h 2 v 2
1034if given, etc.\& up to
1035.indexed_offset h n v n .
1036This command takes a variable number of argument pairs; the current
1037position is moved to the terminal point of the drawn curve.
1038.
1039.
1040.Da-command
1041Draw arc from current position to
1042.indexed_offset h 1 v 1 \|+\|\c
1043.indexed_offset h 2 v 2
1044with center at
1045.indexed_offset h 1 v 1 ;
--- 7 unchanged lines hidden (view full) ---
1053(integer in basic units\~\c
1054.unit u )
1055with leftmost point at the current position; then move the current
1056position to the rightmost point of the circle.
1057.
1058An optional second integer argument is ignored (this allows to the
1059formatter to generate an even number of arguments).
1060.
1061This command is a
1062.I groff
1063extension.
1064.
1065.
1066.D-command c d
1067Draw circle line with diameter\~\c
1068.argument d
1069(integer in basic units\~\c
1070.unit u )
1071with leftmost point at the current position; then move the current
--- 6 unchanged lines hidden (view full) ---
1078.argument h
1079and a vertical diameter of\~\c
1080.argument v
1081(both integers in basic units\~\c
1082.unit u )
1083with the leftmost point at the current position; then move to the
1084rightmost point of the ellipse.
1085.
1086This command is a
1087.I groff
1088extension.
1089.
1090.
1091.D-command e "h v"
1092Draw an outlined ellipse with a horizontal diameter of\~\c
1093.argument h
1094and a vertical diameter of\~\c
1095.argument v
1096(both integers in basic units\~\c
--- 9 unchanged lines hidden (view full) ---
1106.BR m .
1107.
1108The color components are specified as integer arguments between 0 and
1109\n[@maxcolor].
1110.
1111The number of color components and their meaning vary for the
1112different color schemes.
1113.
1114These commands are generated by the
1115.I groff
1116escape sequences
1117.B \*[@backslash]D'F\ .\|.\|.'
1118and
1119.B \*[@backslash]M
1120(with no other corresponding graphics commands).
1121.
1122No position changing.
1123.
1124This command is a
1125.I groff
1126extension.
1127.
1128.
1129.RS
1130.
1131.D-command Fc "cyan magenta yellow"
1132Set fill color for solid drawing objects using the CMY color scheme,
1133having the 3\~color components cyan, magenta, and yellow.
1134.
--- 50 unchanged lines hidden (view full) ---
1185Df -1
1186.RE
1187.ft
1188.fi
1189.
1190sets all colors to blue.
1191.RE
1192.
1193.
1194.P
1195No position changing.
1196.
1197This command is a
1198.I groff
1199extension.
1200.
1201.RE
1202.
1203.
1204.D-command l "h v"
1205Draw line from current position to offset
1206.offset h v
1207(integers in basic units\~\c
--- 18 unchanged lines hidden (view full) ---
1226Although this doesn't make sense it is kept for compatibility.
1227.
1228\}
1229.el \{\
1230As the polygon is closed, the end of drawing is the starting point, so
1231the position doesn't change.
1232\}
1233.
1234This command is a
1235.I groff
1236extension.
1237.
1238.
1239.D-multiarg P
1240The same macro as the corresponding
1241.B Dp
1242command with the same arguments, but draws a solid polygon in the
1243current fill color rather than an outlined polygon.
1244.
1245.ie (\n[@STUPID_DRAWING_POSITIONING] == 1) \{\
1246The position is changed in the same way as with
1247.BR Dp .
1248\}
1249.el \
1250No position changing.
1251.
1252This command is a
1253.I groff
1254extension.
1255.
1256.
1257.D-command t n
1258Set the current line thickness to\~\c
1259.argument n
1260(an integer in basic units\~\c
1261.unit u )
1262if
--- 13 unchanged lines hidden (view full) ---
1276position is not changed.
1277.
1278Although this doesn't make sense it is kept for compatibility.
1279.
1280\}
1281.el \
1282No position changing.
1283.
1284This command is a
1285.I groff
1286extension.
1287.
1288.
1289.\" --------------------------------------------------------------------
1290.SS "Device Control Commands"
1291.\" --------------------------------------------------------------------
1292.
1293Each device control command starts with the letter
1294.B x
1295followed by a space character (optional or arbitrary space/\:tab in
1296.IR groff )
1297and a subcommand letter or word; each argument (if any) must be
1298preceded by a
1299.I syntactical
1300.IR space .
1301.
1302All
1303.B x
1304commands are terminated by a
1305.IR "syntactical line break" ;
1306no device control command can be followed by another command on the same
1307line (except a comment).
1308.
1309.P
1310The subcommand is basically a single letter, but to increase
1311readability, it can be written as a word, i.e., an arbitrary sequence
1312of characters terminated by the next tab, space, or newline character.
1313.
1314All characters of the subcommand word but the first are simply ignored.
1315.
1316For example,
1317.B @g@troff
1318outputs the initialization command
1319.B x\ i
1320as
1321.B x\ init
1322and the resolution command
1323.B x\ r
1324as
1325.BR "x\ res" .
--- 13 unchanged lines hidden (view full) ---
1339.BR Separation .
1340.
1341.x-command F name
1342.xsub Filename
1343Use
1344.argument name
1345as the intended name for the current file in error reports.
1346.
1347This is useful for remembering the original file name when
1348.B groff
1349uses an internal piping mechanism.
1350.
1351The input file is not changed by this command.
1352.
1353This command is a
1354.I groff
1355extension.
1356.
1357.
1358.x-command f "n\ s"
1359.xsub font
1360Mount font position\~\c
1361.argument n
1362(a non-negative integer) with font named\~\c
1363.argument s
--- 4 unchanged lines hidden (view full) ---
1368.
1369.x-command H n
1370.xsub Height
1371Set character height to\~\c
1372.argument n
1373(a positive integer in scaled points\~\c
1374.unit z ).
1375.
1376.I Classical troff
1377used the unit points (\c
1378.unit p )
1379instead; see section
1380.BR COMPATIBILITY .
1381.
1382.
1383.x-command i
1384.xsub init
1385Initialize device.
1386.
1387This is the third command of the
1388.IR prologue .
1389.
1390.
1391.x-command p
1392.xsub pause
1393Parsed but ignored.
1394.
1395The classical documentation reads
1396.I pause device, can be
--- 8 unchanged lines hidden (view full) ---
1405.argument h
1406is the minimal horizontal motion, and
1407.argument v
1408the minimal vertical motion possible with this device; all arguments
1409are positive integers in basic units\~\c
1410.unit u
1411per inch.
1412.
1413This is the second command of the
1414.IR prologue .
1415.
1416.
1417.x-command S n
1418.xsub Slant
1419Set slant to\~\c
1420.argument n
1421degrees (an integer in basic units\~\c
1422.unit u ).
1423.
1424.
1425.x-command s
1426.xsub stop
1427Terminates the processing of the current file; issued as the last
1428command of any
1429.I intermediate @g@troff
1430.IR output .
1431.
1432.
1433.x-command t
1434.xsub trailer
1435Generate trailer information, if any.
1436.
1437In
1438.BR groff ,
1439this is actually just ignored.
1440.
1441.
1442.x-command T xxx
1443.xsub Typesetter
1444Set name of device to word
1445.argument xxx ,
1446a sequence of characters ended by the next whitespace character.
1447.
1448The possible device names coincide with those from the groff
1449.B -T
1450option.
1451.
1452This is the first command of the
1453.IR prologue .
1454.
1455.
1456.x-command u n
1457.xsub underline
1458Configure underlining of spaces.
1459.
1460If
1461.argument n
1462is\~1, start underlining of spaces;
1463if
1464.argument n
1465is\~0, stop underlining of spaces.
1466.
1467This is needed for the
1468.B cu
1469request in
1470.B @g@nroff
1471mode and is ignored otherwise.
1472.
1473This command is a
1474.I groff
1475extension.
1476.
1477.
1478.x-command X anything
1479.xsub X-escape
1480Send string
1481.argument anything
1482uninterpreted to the device.
1483.
--- 12 unchanged lines hidden (view full) ---
1496.B +
1497character.
1498.
1499This command is generated by the
1500.I groff
1501escape sequence
1502.BR \*[@backslash]X .
1503.
1504The line-continuing feature is a
1505.I groff
1506extension.
1507.
1508.
1509.\" --------------------------------------------------------------------
1510.SS "Obsolete Command"
1511.\" --------------------------------------------------------------------
1512.
1513In
1514.I classical troff
--- 8 unchanged lines hidden (view full) ---
1523.argument ddc
1524Move right
1525.argument dd
1526(exactly two decimal digits) basic units\~\c
1527.unit u ,
1528then print character\~\c
1529.argument c .
1530.
1531.
1532.RS
1533.P
1534In
1535.IR groff ,
1536arbitrary
1537.I syntactical space
1538around and within this command is allowed to be added.
1539.
1540Only when a preceding command on the same line ends with an argument
1541of variable length a separating space is obligatory.
1542.
1543In
1544.I classical
1545.IR troff ,
1546large clusters of these and other commands were used, mostly without
1547spaces; this made such output almost unreadable.
1548.
1549.RE
1550.
1551.
1552.P
1553For modern high-resolution devices, this command does not make sense
1554because the width of the characters can become much larger than two
1555decimal digits.
1556.
1557In
1558.BR groff ,
1559this is only used for the devices
1560.BR X75 ,
1561.BR X75-12 ,
1562.BR X100 ,
1563and
1564.BR X100-12 .
1565.
1566For other devices,
1567the commands
--- 5 unchanged lines hidden (view full) ---
1573.
1574.\" --------------------------------------------------------------------
1575.SH "POSTPROCESSING"
1576.\" --------------------------------------------------------------------
1577.
1578The
1579.I roff
1580postprocessors are programs that have the task to translate the
1581.I intermediate output
1582into actions that are sent to a device.
1583.
1584A device can be some piece of hardware such as a printer, or a software
1585file format suitable for graphical or text processing.
1586.
1587The
1588.I groff
1589system provides powerful means that make the programming of such
1590postprocessors an easy task.
1591.P
1592There is a library function that parses the
1593.I intermediate output
1594and sends the information obtained to the device via methods of a
1595class with a common interface for each device.
1596.
1597So a
1598.I groff
1599postprocessor must only redefine the methods of this class.
1600.
1601For details, see the reference in section
1602.BR FILES .
1603.
1604.
1605.\" --------------------------------------------------------------------
1606.SH "EXAMPLES"
1607.\" --------------------------------------------------------------------
1608.
1609This section presents the
1610.I intermediate output
1611generated from the same input for three different devices.
1612.
1613The input is the sentence
1614.I hell world
1615fed into
1616.B groff
1617on the command line.
1618.
1619.
1620.Topic
1621High-resolution device
1622.I ps
1623.
1624.
1625.RS
1626.P
1627.ShellCommand echo "hell world" | groff -Z -T ps
1628.
1629.
1630.P
1631.nf
1632.ft CB
1633x T ps
1634x res 72000 1 1
1635x init
1636p1
1637x font 5 TR
--- 9 unchanged lines hidden (view full) ---
1647n12000 0
1648x trailer
1649V792000
1650x stop
1651.ft P
1652.fi
1653.RE
1654.
1655.
1656.P
1657This output can be fed into the postprocessor
1658.BR grops (@MAN1EXT@)
1659to get its representation as a PostScript file.
1660.
1661.
1662.Topic
1663Low-resolution device
1664.I latin1
1665.
1666.
1667.RS
1668.P
1669This is similar to the high-resolution device except that the
1670positioning is done at a minor scale.
1671.
1672Some comments (lines starting with
1673.IR # )
1674were added for clarification; they were not generated by the
1675formatter.
1676.
1677.
1678.P
1679.ShellCommand echo "hell world" | groff -Z -T latin1
1680.
1681.
1682.P
1683.nf
1684.I "# prologue"
1685.ft CB
1686x T latin1
1687x res 240 24 40
1688x init
1689.I "# begin a new page"
1690.ft CB
1691p1
1692.I "# font setup"
1693.ft CB
1694x font 1 R
1695f1
1696s10
1697.I "# initial positioning on the page"
1698.ft CB
1699V40
1700H0
1701.I "# write text `hell'"
1702.ft CB
1703thell
1704.I "# inform about a space, and do it by a horizontal jump"
1705.ft CB
1706wh24
1707.I "# write text `world'"
1708.ft CB
1709tworld
1710.I "# announce line break, but do nothing because ..."
1711.ft CB
1712n40 0
1713.I "# ... the end of the document has been reached"
1714.ft CB
1715x trailer
1716V2640
1717x stop
1718.ft P
1719.fi
1720.RE
1721.
1722.
1723.P
1724This output can be fed into the postprocessor
1725.BR grotty (@MAN1EXT@)
1726to get a formatted text document.
1727.
1728.
1729.Topic
1730Classical style output
1731.
1732.
1733.RS
1734.P
1735As a computer monitor has a very low resolution compared to modern
1736printers the
1737.I intermediate output
1738for the X\~devices can use the jump-and-write command with its 2-digit
1739displacements.
1740.
1741.
1742.P
1743.ShellCommand echo "hell world" | groff -Z -T X100
1744.
1745.
1746.P
1747.nf
1748.ft CB
1749x T X100
1750x res 100 1 1
1751x init
1752p1
1753x font 5 TR
1754f5
1755s10
1756V16
1757H100
1758.I "# write text with old-style jump-and-write command"
1759.ft CB
1760ch07e07l03lw06w11o07r05l03dh7
1761n16 0
1762x trailer
1763V1100
1764x stop
1765.ft P
1766.fi
1767.RE
1768.
1769.
1770.P
1771This output can be fed into the postprocessor
1772.BR \%xditview (1x)
1773or
1774.BR \%gxditview (@MAN1EXT@)
1775for displaying in\~X.
1776.
1777.
1778.P
1779Due to the obsolete jump-and-write command, the text clusters in the
1780classical output are almost unreadable.
1781.
1782.
1783.\" --------------------------------------------------------------------
1784.SH "COMPATIBILITY"
1785.\" --------------------------------------------------------------------
1786.
1787The
1788.I intermediate output
1789language of the
1790.I classical troff
1791was first documented in
1792.IR [CSTR\~#97] .
1793.
1794The
1795.I groff intermediate output
1796format is compatible with this specification except for the following
1797features.
1798.
1799.
1800.Topic
1801The classical quasi device independence is not yet implemented.
1802.
1803.
1804.Topic
1805The old hardware was very different from what we use today.
1806.
1807So the
1808.I groff
1809devices are also fundamentally different from the ones in
1810.I classical
1811.IR troff .
1812.
1813For example, the classical PostScript device was called
1814.I post
1815and had a resolution of 720 units per inch,
1816while
1817.IR groff 's
1818.I ps
1819device has a resolution of 72000 units per inch.
1820.
1821Maybe, by implementing some rescaling mechanism similar to the
1822classical quasi device independence, these could be integrated into
1823modern
1824.IR groff .
1825.
1826.
1827.Topic
1828The B-spline command
1829.B D~
1830is correctly handled by the
1831.I intermediate output
1832parser, but the drawing routines aren't implemented in some of the
1833postprocessor programs.
1834.
1835.
1836.Topic
1837The argument of the commands
1838.B s
1839and
1840.B x H
1841has the implicit unit scaled point\~\c
1842.unit z
1843in
1844.IR groff ,
1845while
1846.I classical troff
1847had point (\c
1848.unit p ).
1849.
1850This isn't an incompatibility, but a compatible extension, for both
1851units coincide for all devices without a
1852.I sizescale
1853parameter, including all classical and the
1854.I groff
1855text devices.
1856.
1857The few
1858.I groff
1859devices with a sizescale parameter either did not exist, had a
1860different name, or seem to have had a different resolution.
1861.
1862So conflicts with classical devices are very unlikely.
1863.
1864.
1865.ie (\n[@STUPID_DRAWING_POSITIONING] == 1) \{\
1866.Topic
1867The position changing after the commands
1868.BR Dp ,
1869.BR DP ,
1870and
1871.B Dt
1872is illogical, but as old versions of groff used this feature it is
1873kept for compatibility reasons.
1874.\} \" @STUPID_DRAWING_POSITIONING
1875.el \{\
1876.Topic
1877Temporarily, there existed some confusion on the positioning after the
1878.B D
1879commands that are
1880.I groff
1881extensions.
1882.
1883This has been clarified by establishing the classical rule for all
1884groff drawing commands:
1885.
1886.
1887.RS
1888.P
1889.ft I
1890The position after a graphic object has been drawn is at its end;
1891for circles and ellipses, the "end" is at the right side.
1892.ft
1893.RE
1894.
1895.
1896.P
1897From this, the positionings specified for the drawing commands above
1898follow quite naturally.
1899.\} \" @STUPID_DRAWING_POSITIONING
1900.
1901.P
1902The differences between
1903.I groff
1904and
1905.I classical troff
1906are documented in
1907.BR groff_diff (@MAN7EXT@).
1908.
1909.
1910.\" --------------------------------------------------------------------
1911.SH "FILES"
1912.\" --------------------------------------------------------------------
1913.
1914.TP
1915.BI @FONTDIR@/dev name /DESC
1916Device description file for device
1917.IR name .
1918.
1919.TP
1920.IB \[la]groff_source_dir\[ra] /src/libs/libdriver/input.cpp
1921Defines the parser and postprocessor for the
1922.I intermediate
1923.IR output .
1924.
1925It is located relative to the top directory of the
1926.I groff
1927source tree, e.g.
1928.IR @GROFFSRCDIR@ .
1929.
1930This parser is the definitive specification of the
1931.I groff intermediate output
1932format.
1933.
1934.
1935.\" --------------------------------------------------------------------
1936.SH "SEE ALSO"
1937.\" --------------------------------------------------------------------
1938.
1939A reference like
1940.BR groff (@MAN7EXT@)
1941refers to a manual page; here
1942.B groff
1943in section\~\c
1944.I @MAN7EXT@
1945of the man-page documentation system.
1946.
1947To read the example, look up section\~@MAN7EXT@ in your desktop help
1948system or call from the shell prompt
1949.
1950.
1951.RS
1952.P
1953.ShellCommand man @MAN7EXT@ groff
1954.RE
1955.
1956.
1957.P
1958For more details, see
1959.BR man (1).
1960.
1961.
1962.TP
1963.BR groff (@MAN1EXT@)
1964option
1965.B -Z
1966and further readings on groff.
1967.
1968.
1969.TP
1970.BR groff (@MAN7EXT@)
1971for details of the
1972.I groff
1973language such as numerical units and escape sequences.
1974.
1975.
1976.TP
1977.BR groff_font (@MAN5EXT@)
1978for details on the device scaling parameters of the
1979.B DESC
1980file.
1981.
1982.
1983.TP
1984.BR @g@troff (@MAN1EXT@)
1985generates the device-independent intermediate output.
1986.
1987.
1988.TP
1989.BR roff (@MAN7EXT@)
1990for historical aspects and the general structure of roff systems.
1991.
1992.
1993.TP
1994.BR groff_diff (@MAN7EXT@)
1995The differences between the intermediate output in groff and classical
1996troff.
1997.
1998.
1999.TP
2000.BR gxditview (@MAN1EXT@)
2001Viewer for the
2002.I intermediate
2003.IR output .
2004.
2005.
2006.P
2007.BR \%grodvi (@MAN1EXT@),
2008.BR \%grohtml (@MAN1EXT@),
2009.BR \%grolbp (@MAN1EXT@),
2010.BR \%grolj4 (@MAN1EXT@),
2011.BR \%grops (@MAN1EXT@),
2012.BR \%grotty (@MAN1EXT@)
2013.br
2014.RS
2015the groff postprocessor programs.
2016.RE
2017.
2018.
2019.P
2020For a treatment of all aspects of the groff system within a single
2021document, see the
2022.I groff info
2023.IR file .
2024.
2025It can be read within the integrated help systems, within
2026.BR emacs (1)
2027or from the shell prompt by
2028.
2029.RS
2030.ShellCommand info groff
2031.RE
2032.
2033.
2034.P
2035The
2036.I classical troff output language
2037is described in two AT&T Bell Labs CSTR documents available on-line at
2038.URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr.html \
2039 "Bell Labs CSTR site" .
2040.
2041.
2042.TP
2043.I [CSTR #97]
2044.I A Typesetter-independent TROFF
2045by
2046.I Brian Kernighan
2047is the original and most concise documentation on the output language;
2048see
2049.URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr/\:97.ps.gz CSTR\~#97 .
2050.
2051.
2052.TP
2053.I [CSTR\~#54]
2054The 1992 revision of the
2055.I Nroff/\:Troff User's Manual
2056by
2057.I J.\& F.\& Osanna
2058and
2059.I Brian Kernighan
2060isn't as concise as
2061.I [CSTR\~#97]
2062regarding the output language; see
2063.URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr/\:54.ps.gz CSTR\~#54 .
2064.
2065.
2066.\" --------------------------------------------------------------------
2067.SH "AUTHORS"
2068.\" --------------------------------------------------------------------
2069.
2070Copyright (C) 1989, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
2071.
2072.
2073.P
2074This document is distributed under the terms of the FDL (GNU Free
2075Documentation License) version 1.1 or later.
2076.
2077You should have received a copy of the FDL with this package; it is also
2078available on-line at the
2079.URL http://\:www.gnu.org/\:copyleft/\:fdl.html "GNU copyleft site" .
2080.
2081.
2082.P
2083This document is part of
2084.IR groff ,
2085the GNU
2086.I roff
2087distribution.
2088.
2089It is based on a former version \- published under the GPL \- that
2090described only parts of the
2091.I groff
2092extensions of the output language.
2093.
2094It has been rewritten 2002 by \m[blue]Bernd Warken\m[] and is
2095maintained by
2096.MTO wl@gnu.org "Werner Lemberg" .
2097.
2098.cp \n[groff_out_C]
2099.
2100.\" --------------------------------------------------------------------
2101.\" Emacs settings
2102.\" --------------------------------------------------------------------
2103.\"
2104.\" Local Variables:
2105.\" mode: nroff
2106.\" End: