| 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: |