plot.1 21 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708
  1. .TH PLOT 1 "Jun 2000" "FSF" "GNU Plotting Utilities"
  2. .SH NAME
  3. plot \- translate GNU metafiles to other graphics formats
  4. .\" Not all man macros define SB
  5. .de SB
  6. \&\fB\s-1\&\\$1 \\$2\s0\fR
  7. ..
  8. .SH SYNOPSIS
  9. .B plot
  10. [
  11. .I options
  12. ] [
  13. .I files
  14. ]
  15. .SH DESCRIPTION
  16. .LP
  17. .B plot
  18. translates files in GNU metafile format to other graphics formats, or
  19. displays them on an X Window System display.
  20. GNU metafile format is a device-independent format for the storage of
  21. graphic data.
  22. It is the default output format of the programs
  23. .BR graph (1),
  24. .BR pic2plot (1),
  25. .BR tek2plot (1),
  26. and
  27. .BR plotfont (1),
  28. and is further documented in
  29. .BR plot (5),
  30. since it is an enhanced version of the traditional
  31. .BR plot (5)
  32. format found on non-GNU systems.
  33. It can also be produced by the GNU libplot 2-D graphics export library (see
  34. .BR plot (3)).
  35. .LP
  36. The output format is specified with the
  37. .BR \-T " option."
  38. The possible output formats and display types are the same as those
  39. supported by
  40. .BR graph (1),
  41. .BR plotfont (1),
  42. .BR pic2plot (1),
  43. and
  44. .BR tek2plot (1).
  45. If an output file is produced, it is written to standard output.
  46. .LP
  47. Options and file names may be interspersed on the command line, but
  48. the options are processed before the file names are read.
  49. If
  50. .B \-\-
  51. is seen, it is interpreted as the end of the options.
  52. If no file names are specified, or the file name
  53. .B \-
  54. is encountered, the standard input is read.
  55. .SH OPTIONS
  56. .SS General Options
  57. .TP
  58. .BI \-T " type"
  59. .br
  60. .ns
  61. .TP
  62. .BI \-\-output\-format " type"
  63. Select
  64. .I type
  65. as the output format.
  66. It may be "X", "png", "pnm", "gif", "svg", "ai", "ps", "cgm", "fig",
  67. "pcl", "hpgl", "regis", "tek", or "meta" (the default).
  68. These refer respectively
  69. to the X Window System,
  70. PNG (Portable Network Graphics) format,
  71. portable anymap format (PBM/PGM/PPM),
  72. a pseudo-GIF format that
  73. does not use LZW encoding,
  74. the new XML-based Scalable Vector Graphics format,
  75. the format used by Adobe Illustrator, Postscript or
  76. Encapsulated Postscript (EPS) that can be edited with
  77. .BR idraw (1),
  78. CGM format (by default, confirming to the WebCGM profile),
  79. the format used by the
  80. .BR xfig (1)
  81. drawing editor, the Hewlett\-Packard PCL 5 printer
  82. language, the Hewlett\-Packard Graphics Language,
  83. ReGIS graphics format (which can be displayed
  84. by the
  85. .BR dxterm (1)
  86. terminal emulator or by a VT330 or VT340 terminal),
  87. Tektronix format (which can be displayed by the
  88. .BR xterm (1)
  89. terminal emulator),
  90. and device-independent GNU metafile format itself.
  91. Unless \fItype\fP\^ is "X", an output file is produced and written
  92. to standard output.
  93. .IP ""
  94. Omitting the
  95. .B \-T
  96. option is equivalent to specifying
  97. .BR "\-T meta" .
  98. Translating from metafile format to itself is occasionally useful, since
  99. there are two versions of metafile format (see the
  100. .B \-O
  101. option below).
  102. .IP ""
  103. A listing of the fonts available in any specified output format may be
  104. obtained with the
  105. .B \-\-help\-fonts
  106. option (see below).
  107. If a requested font is unavailable, a default font will be substituted.
  108. The default font
  109. is "Helvetica" for "X", "svg", "ai", "ps", "cgm", and "fig",
  110. "Univers" for "pcl",
  111. and "HersheySerif" for "png", "pnm", "gif", "hpgl", "regis", "tek", and "meta".
  112. .TP
  113. .BI \-p " n"
  114. .br
  115. .ns
  116. .TP
  117. .BI \-\-page\-number " n"
  118. Output only page number
  119. .IR n ,
  120. within the metafile or sequence of metafiles that is being translated.
  121. .IP ""
  122. Metafiles may consist of one or more pages, numbered beginning with 1.
  123. Also, each page may contain multiple `frames'.
  124. .BR "plot \-T X" ,
  125. .BR "plot \-T regis" ,
  126. and
  127. .BR "plot \-T tek" ,
  128. which plot in real time, will separate
  129. successive frames by screen erasures.
  130. .BR "plot \-T png" ,
  131. .BR "plot \-T pnm" ,
  132. .BR "plot \-T gif" ,
  133. .BR "plot \-T svg" ,
  134. .BR "plot \-T ai" ,
  135. .BR "plot \-T ps" ,
  136. .BR "plot \-T cgm" ,
  137. .BR "plot \-T fig" ,
  138. .BR "plot \-T pcl" ,
  139. and
  140. .BR "plot \-T hpgl" ,
  141. which do not plot in real time, will output only the last frame of any
  142. multi-frame page.
  143. .IP ""
  144. The default behavior, if \fB\-p\fP is not used, is to output all pages.
  145. For example, \fBplot \-T X\fP displays each page in its own X window.
  146. If the
  147. .BR "\-T png" ,
  148. .BR "\-T pnm" ,
  149. .BR "\-T gif" ,
  150. .BR "\-T ai" ,
  151. or
  152. .B \-T fig
  153. option is used, the default behavior is to output only the first nonempty
  154. page, since files in those output formats contain only a single page of
  155. graphics.
  156. .IP ""
  157. Metafiles produced by
  158. .BR graph (1)
  159. and
  160. .BR plotfont (1)
  161. contain only a single page (page #1), which consists of two frames: an
  162. empty frame to clear the display, and a second frame that contains the
  163. graphics.
  164. .TP
  165. .B \-s
  166. .br
  167. .ns
  168. .TP
  169. .B \-\-merge\-pages
  170. Merge all displayed pages into a single page, and also merge all `frames'.
  171. .IP ""
  172. This option is useful when merging together single-page plots from
  173. different sources.
  174. For example, it can be used to merge together plots obtained from separate
  175. invocations of
  176. .BR graph (1).
  177. .TP
  178. .BI \-\-bitmap\-size " bitmap_size"
  179. Set the size of the graphics display in which the plot will be drawn,
  180. in terms of pixels, to be
  181. .IR bitmap_size .
  182. The default is "570x570".
  183. This is relevant only to
  184. .BR "plot \-T X" ,
  185. .BR "plot \-T png" ,
  186. .BR "plot \-T pnm" ,
  187. and
  188. .BR "plot \-T gif" ,
  189. all of which produce bitmaps.
  190. If you choose a rectangular (non-square) window size, the fonts in the
  191. plot will be scaled anisotropically, i.e., by different factors in the
  192. horizontal and vertical directions.
  193. For
  194. .BR "plot \-T X" ,
  195. this requires an X11R6 display.
  196. Any font that cannot be scaled in this way will be replaced by a default
  197. scalable font, such as the vector font "HersheySerif".
  198. .IP ""
  199. The environment variable
  200. .SB BITMAPSIZE
  201. can equally well be used to specify the window size.
  202. For backward compatibility, the X resource
  203. .B Xplot.geometry
  204. may be used instead.
  205. .TP
  206. .BI \-\-emulate\-color " option"
  207. If
  208. .I option
  209. is
  210. .IR yes ,
  211. replace each color in the output by an appropriate shade of gray. This is
  212. seldom useful, except when using
  213. .B plot \-T pcl
  214. to prepare output for a PCL 5 device.
  215. (Many monochrome PCL 5 devices, such as monochrome LaserJets, do a poor job
  216. of emulating color on their own.)
  217. You may equally well request color emulation by setting the environment
  218. variable
  219. .SB EMULATE_COLOR
  220. to "yes".
  221. .TP
  222. .BI \-\-max\-line\-length " max_line_length"
  223. Set the maximum number of points that a
  224. polygonal line may contain, before it is flushed out, to be
  225. .IR max_line_length .
  226. If this flushing occurs, the polygonal line will be split into two or more
  227. sub-lines, though the splitting should not be noticeable.
  228. The default value of \fImax_line_length\fP\^ is 500.
  229. .IP ""
  230. The reason for splitting long polygonal lines is that some display devices
  231. (e.g., old Postscript printers and pen HP-GL plotters) have limited buffer
  232. sizes.
  233. The environment variable
  234. .SB MAX_LINE_LENGTH
  235. can also be used to specify the maximum line length.
  236. .TP
  237. .BI \-\-page\-size " pagesize"
  238. Set the size of the page on which the plot will be positioned.
  239. This is relevant only to
  240. .BR "plot \-T svg" ,
  241. .BR "plot \-T ai" ,
  242. .BR "plot \-T ps" ,
  243. .BR "plot \-T cgm" ,
  244. .BR "plot \-T fig" ,
  245. .BR "plot \-T pcl" ,
  246. and
  247. .BR "plot \-T hpgl" .
  248. The default is "letter", which means an 8.5 inch by 11 inch page.
  249. Any ISO page size in the range "a0".\|.\|."a4" or ANSI page size in the
  250. range "a".\|.\|."e" may be specified ("letter" is an alias for "a" and
  251. "tabloid" is an alias for "b").
  252. "legal" and "ledger" are recognized page sizes also.
  253. The environment variable
  254. .SB PAGESIZE
  255. can equally well be used to specify the page size.
  256. .IP ""
  257. The graphics display in which the plot is drawn will, by default, be a square
  258. region that occupies nearly the full width of the specified page.
  259. An alternative size for the graphics display can be specified.
  260. For example, the page size could be specified as
  261. "letter,xsize=4in,ysize=6in", or "a4,xsize=5.0cm,ysize=100mm".
  262. For all of the above except
  263. .BR "plot \-T hpgl" ,
  264. the graphics display will, by default, be centered on the page.
  265. For all of the above except
  266. .B "plot \-T svg"
  267. and
  268. .BR "plot \-T cgm" ,
  269. the graphics display may be repositioned manually, by specifying the
  270. location of its lower left corner, relative to the lower left corner of the
  271. page.
  272. For example, the page size could be specified as
  273. "letter,xorigin=2in,yorigin=3in", or "a4,xorigin=0.5cm,yorigin=0.5cm".
  274. It is also possible to specify an offset vector.
  275. For example, the page size could be specified as "letter,xoffset=1in",
  276. or "letter,xoffset=1in,yoffset=1.2in", or "a4,yoffset=\-1cm".
  277. In SVG format and WebCGM format it is possible to specify the size
  278. of the graphics display, but not its position.
  279. .TP
  280. .BI \-\-rotation " angle"
  281. Rotate the graphics display by
  282. .IR angle " degrees."
  283. Recognized values are "0", "90", "180", and "270".
  284. "no" and "yes" are equivalent to "0" and "90", respectively.
  285. The environment variable
  286. .SB ROTATION
  287. can also be used to specify a rotation angle.
  288. .SS "Parameter Initialization Options"
  289. The following options set the initial values of drawing parameters.
  290. However, all of these may be overridden by directives in a metafile.
  291. In fact, these options are useful primarily when plotting old metafiles in
  292. the traditional (pre-GNU)
  293. .BR plot (5)
  294. format, which did not support such directives.
  295. .TP
  296. .BI \-\-bg\-color " name"
  297. Set the color initially used for the background to be
  298. .IR name .
  299. This is relevant only to
  300. .BR "plot \-T X" ,
  301. .BR "plot \-T png" ,
  302. .BR "plot \-T pnm" ,
  303. .BR "plot \-T gif" ,
  304. .BR "plot \-T svg" ,
  305. .BR "plot \-T cgm" ,
  306. and
  307. .BR "plot \-T regis" .
  308. An unrecognized name sets the color to the default, which is "white".
  309. The environment variable
  310. .SB BG_COLOR
  311. can equally well be used to specify the background color.
  312. .IP ""
  313. If the
  314. .B \-T png
  315. or
  316. .B \-T gif
  317. option is used, a transparent PNG file
  318. or a transparent pseudo-GIF, respectively, may be produced by
  319. setting the
  320. .SB TRANSPARENT_COLOR
  321. environment variable to the name of the background color.
  322. If the
  323. .B \-T svg
  324. or
  325. .B \-T cgm
  326. option is used, an output file without a background may be produced
  327. by setting the background color to "none".
  328. .TP
  329. .BI \-f " size"
  330. .br
  331. .ns
  332. .TP
  333. .BI \-\-font\-size " size"
  334. Set the size of the font initially used for rendering text, as a fraction
  335. of the width of the graphics display, to be
  336. .IR size .
  337. The default is 0.0525.
  338. .TP
  339. .BI \-F " name"
  340. .br
  341. .ns
  342. .TP
  343. .BI \-\-font\-name " name"
  344. Set the font initially used for text to be
  345. .IR name .
  346. Font names are case-insensitive.
  347. If the specified font is not available, the default font will be used.
  348. Which fonts are available, and the default font, depend on which \fB\-T\fP
  349. option is specified (see above).
  350. A list of available fonts can be obtained with the
  351. .B \-\-help\-fonts
  352. option (see below).
  353. .TP
  354. .BI \-W " line_width"
  355. .br
  356. .ns
  357. .TP
  358. .BI \-\-line\-width " line_width"
  359. Set the initial width of lines, as a fraction of the width of the display,
  360. to be
  361. .IR line_width .
  362. A negative value means that a default value should be used.
  363. This value is format-dependent.
  364. The interpretation of zero line width is also format-dependent (in some
  365. output formats, a zero-width line is the thinnest line that can be drawn;
  366. in others, a zero-width line is invisible).
  367. .TP
  368. .BI \-\-pen\-color " name"
  369. Set the initial pen color to be
  370. .IR name .
  371. An unrecognized name sets the pen color to the default, which is "black".
  372. .SS Options for Metafile Output
  373. .LP
  374. The following option is relevant only if the
  375. .B \-T
  376. option is omitted or if
  377. .B "\-T meta"
  378. is used.
  379. In this case the output of
  380. .BR plot ,
  381. like the input, will be in GNU graphics metafile format.
  382. .TP
  383. .B \-O
  384. .br
  385. .ns
  386. .TP
  387. .B \-\-portable\-output
  388. Output the portable (human-readable) version of GNU metafile
  389. format, rather than the binary version (the default).
  390. The format of the binary version is machine-dependent.
  391. .SS Options for Backward Compatibility
  392. By default, \fBplot\fP assumes that its input file(s) are in
  393. either the binary version or the portable version of GNU metafile format.
  394. You may specify that the input is, instead, in the traditional Unix (pre-GNU)
  395. graphics metafile format, which is documented in
  396. .BR plot (5).
  397. The traditional graphics metafile format was produced by
  398. pre-GNU versions of
  399. .BR graph (1).
  400. .TP
  401. .B \-h
  402. .br
  403. .ns
  404. .TP
  405. .B \-\-high\-byte\-first\-input
  406. Input file(s) are assumed to be in the binary, `high byte first' version
  407. of traditional metafile format.
  408. This variant is uncommon.
  409. .TP
  410. .B \-l
  411. .br
  412. .ns
  413. .TP
  414. .B \-\-low\-byte\-first\-input
  415. Input file(s) are assumed to be in the binary, `low byte first' version
  416. of traditional metafile format.
  417. This variant is the most common.
  418. .TP
  419. .B \-A
  420. .br
  421. .ns
  422. .TP
  423. .B \-\-ascii\-input
  424. Input file(s) are assumed to be in the
  425. .SM ASCII
  426. (human-readable) variant of traditional metafile format.
  427. On some older Unix systems, this variant was produced by
  428. .BR plottoa (1).
  429. .SS Informational Options
  430. .TP
  431. .B \-\-help
  432. Print a list of command-line options, and exit.
  433. .TP
  434. .B \-\-help\-fonts
  435. Print a table of available fonts, and exit.
  436. The table will depend on which output format
  437. is specified with the
  438. .B \-T
  439. option.
  440. .BR "plot \-T X" ,
  441. .BR "plot \-T svg" ,
  442. .BR "plot \-T ai" ,
  443. .BR "plot \-T ps" ,
  444. .BR "plot \-T cgm" ,
  445. and
  446. .B plot \-T fig
  447. each support the 35 standard Postscript fonts.
  448. .BR "plot \-T svg" ,
  449. .BR "plot \-T pcl" ,
  450. and
  451. .B plot \-T hpgl
  452. support the 45 standard PCL 5 fonts,
  453. and the latter two support a number of Hewlett\-Packard vector fonts.
  454. All seven support a set of 22 Hershey vector fonts, as do
  455. .BR "plot \-T png" ,
  456. .BR "plot \-T pnm" ,
  457. .BR "plot \-T gif" ,
  458. .BR "plot \-T regis" ,
  459. and
  460. .BR "plot \-T tek" .
  461. .B plot
  462. without a
  463. .B \-T
  464. option in principle
  465. supports any of these fonts, since its output must be translated
  466. to other formats by a further invocation of
  467. .BR plot .
  468. .IP ""
  469. The
  470. .BR plotfont (1)
  471. utility may be used to obtain a character map of any supported font.
  472. .TP
  473. .B \-\-list\-fonts
  474. Like
  475. .BR \-\-help\-fonts ,
  476. but lists the fonts in a single column to facilitate piping to other
  477. programs.
  478. If no output format is specified with the
  479. .B \-T
  480. option, the full set of supported fonts is listed.
  481. .TP
  482. .B \-\-version
  483. Print the version number of
  484. .B plot
  485. and the plotting utilities package, and exit.
  486. .SH "ENVIRONMENT"
  487. The environment variables
  488. .SB BITMAPSIZE,
  489. .SB PAGESIZE,
  490. .SB BG_COLOR,
  491. .SB EMULATE_COLOR,
  492. .SB MAX_LINE_LENGTH
  493. and
  494. .SB ROTATION
  495. serve as backups for the options
  496. .BR \-\-bitmap\-size ,
  497. .BR \-\-page\-size ,
  498. .BR \-\-bg\-color ,
  499. .BR \-\-emulate\-color ,
  500. .BR \-\-max\-line\-length ,
  501. and
  502. .BR \-\-rotation ,
  503. respectively.
  504. The remaining environment variables are specific to individual output formats.
  505. .LP
  506. .BR "plot \-T X" ,
  507. which pops up a window on an X Window System
  508. display and draws graphics in it, checks the
  509. .SB DISPLAY
  510. environment variable.
  511. Its value determines the display that will be used.
  512. .LP
  513. .BR "plot \-T png"
  514. and
  515. .BR "plot \-T gif" ,
  516. which produce output in PNG format and pseudo-GIF format respectively,
  517. are affected by the
  518. .SB INTERLACE
  519. environment variable.
  520. If its value is "yes", the output will be interlaced.
  521. Also, if the
  522. .SB TRANSPARENT_COLOR
  523. environment variable is set to the name of a color, that color will
  524. be treated as transparent in the output.
  525. .LP
  526. .BR "plot \-T pnm" ,
  527. which produces output in portable anymap (PBM/PGM/PPM) format,
  528. is affected by the
  529. .SB PNM_PORTABLE
  530. environment variable.
  531. If its value is "yes", the output will be in a human-readable format
  532. rather than binary (the default).
  533. .LP
  534. .BR "plot \-T cgm" ,
  535. which produces output in CGM (Computer Graphics Metafile) format,
  536. is affected by the
  537. .SB CGM_MAX_VERSION
  538. and
  539. .SB CGM_ENCODING
  540. environment variables.
  541. By default, it produces a binary-encoded version of CGM version 3 format.
  542. For backward compatibility, the version number may be reduced by setting
  543. .SB CGM_MAX_VERSION
  544. to "2" or "1".
  545. Irrespective of version, the output CGM file will use the human-readable
  546. clear text encoding if
  547. .SB CGM_ENCODING
  548. is set to "clear_text".
  549. However, only binary-encoded CGM files conform to the WebCGM profile.
  550. .LP
  551. .BR "plot \-T pcl" ,
  552. which produces PCL 5 output for Hewlett\-Packard
  553. printers and plotters, is affected by the environment variable
  554. .SB PCL_ASSIGN_COLORS.
  555. It should be set to "yes" when producing PCL 5 output for a color printer
  556. or other color device.
  557. This will ensure accurate color reproduction by giving the output device
  558. complete freedom in assigning colors, internally, to its "logical pens".
  559. If it is "no" then the device will use a fixed set
  560. of colored pens, and will emulate other colors by shading.
  561. The default is "no" because monochrome PCL 5 devices, which are much more
  562. common than colored ones, must use shading to emulate color.
  563. .LP
  564. .BR "plot \-T hpgl" ,
  565. which produces Hewlett\-Packard Graphics Language
  566. output, is affected by several environment variables.
  567. The most important is
  568. .SB HPGL_VERSION,
  569. which may be set to "1", "1.5", or "2" (the default).
  570. "1" means that the output should be generic HP-GL, "1.5" means that the
  571. output should be suitable for the HP7550A graphics plotter and the HP758x,
  572. HP7595A and HP7596A drafting plotters (HP-GL with some HP-GL/2 extensions),
  573. and "2" means that the output should be modern HP-GL/2.
  574. If the version is "1" or "1.5" then the only available fonts will be vector
  575. fonts, and all lines will be drawn with a default width (the
  576. .B \-W
  577. option will not work).
  578. Additionally, if the version is "1" then the filling of arbitrary curves
  579. with solid color will not be supported (circles and rectangles aligned with
  580. the coordinate axes may be filled, though).
  581. .LP
  582. The position of the
  583. .B plot \-T hpgl
  584. graphics display on the page
  585. can be rotated 90 degrees counterclockwise by setting the
  586. .SB HPGL_ROTATE
  587. environment variable to "yes".
  588. This is not the same as the rotation obtained with the
  589. .B \-\-rotation
  590. option, since it both rotates the graphics display and repositions its
  591. lower left corner toward another corner of the page. Besides "no" and
  592. "yes", recognized values for
  593. .SB HPGL_ROTATE
  594. are "0", "90", "180", and "270".
  595. "no" and "yes" are equivalent to "0" and
  596. "90", respectively.
  597. "180" and "270" are supported only if
  598. .SB HPGL_VERSION
  599. is "2" (the default).
  600. .LP
  601. By default,
  602. .B plot \-T hpgl
  603. will draw with a fixed set of pens.
  604. Which pens are present may be specified by setting the
  605. .SB HPGL_PENS
  606. environment variable.
  607. If
  608. .SB HPGL_VERSION
  609. is "1", the default value of
  610. .SB HPGL_PENS
  611. is "1=black"; if
  612. .SB HPGL_VERSION
  613. is "1.5" or "2", the default value of
  614. .SB HPGL_PENS
  615. is "1=black:2=red:3=green:4=yellow:5=blue:6=magenta:7=cyan".
  616. The format should be self-explanatory.
  617. By setting
  618. .SB HPGL_PENS
  619. you may specify a color for any pen in the range #1.\|.\|.#31.
  620. All color names recognized by the X Window System may be used.
  621. Pen #1 must always be present, though it need not be black.
  622. Any other pen in the range #1.\|.\|.#31 may be omitted.
  623. .LP
  624. If
  625. .SB HPGL_VERSION
  626. is "2" then
  627. .B plot \-T hpgl
  628. will also be
  629. affected by the environment variable
  630. .SB HPGL_ASSIGN_COLORS.
  631. If its value is "yes", then
  632. .B plot \-T hpgl
  633. will not be restricted to the palette specified in
  634. .SB HPGL_PENS:
  635. it will assign colors to "logical pens" in the range #1.\|.\|.#31, as needed.
  636. The default value is "no" because other than color LaserJet printers and
  637. DesignJet plotters, not many HP-GL/2 devices allow the assignment of colors
  638. to logical pens.
  639. .LP
  640. Opaque filling and the drawing of visible white lines are supported
  641. only if
  642. .SB HPGL_VERSION
  643. is "2" and the environment variable
  644. .SB HPGL_OPAQUE_MODE
  645. is "yes" (the default).
  646. If its value is "no" then white lines (if any), which are normally drawn
  647. with pen #0, will not be drawn.
  648. This feature is to accommodate older HP-GL/2 devices.
  649. HP-GL/2 pen plotters, for example, do not support opacity or the use
  650. of pen #0 to draw visible white lines.
  651. Some older HP-GL/2 devices may, in fact, malfunction if asked to draw
  652. opaque objects.
  653. .LP
  654. .BR "plot \-T tek" ,
  655. which produces output for a Tektronix terminal or emulator, checks the
  656. .SB TERM
  657. environment variable.
  658. If the value of
  659. .SB TERM
  660. is a string beginning with "xterm", "nxterm", or "kterm", it is taken as a
  661. sign that
  662. .B plot
  663. is running in an X Window System VT100 terminal emulator: a copy of
  664. .BR xterm (1),
  665. .BR nxterm (1),
  666. or
  667. .BR kterm (1).
  668. Before drawing graphics,
  669. .B plot \-T tek
  670. will emit an escape sequence that causes the terminal emulator's auxiliary
  671. Tektronix window, which is normally hidden, to pop up.
  672. After the graphics are drawn, an escape sequence that returns control to
  673. the original VT100 window will be emitted.
  674. The Tektronix window will remain on the screen.
  675. .LP
  676. If the value of
  677. .SB TERM
  678. is a string beginning with
  679. "kermit", "ansi.sys", or "nansi.sys", it is
  680. taken as a sign that
  681. .B plot
  682. is running in the VT100 terminal emulator provided by the MS-DOS version of
  683. .BR kermit (1).
  684. Before drawing graphics, \fBplot \-T tek\fP will emit an escape sequence
  685. that switches the terminal emulator to Tektronix mode.
  686. Also, some of the Tektronix control codes emitted by
  687. \fBplot \-T tek\fP will be \fBkermit\fP-specific.
  688. There will be a limited amount of color support, which is not normally the
  689. case (the 16 `ansi.sys' colors will be supported).
  690. After drawing graphics, \fBplot \-T tek\fP will emit an escape sequence
  691. that returns the emulator to VT100 mode.
  692. The key sequence `ALT minus' can be employed manually within \fBkermit\fP
  693. to switch between the two modes.
  694. .SH "SEE ALSO"
  695. .BR graph (1),
  696. .BR pic2plot (1),
  697. .BR tek2plot (1),
  698. .BR plotfont (1),
  699. .BR plot (3),
  700. .BR plot (5),
  701. and "The GNU Plotting Utilities Manual".
  702. .SH AUTHORS
  703. .B plot
  704. was written by Robert S. Maier (\fBrsm@math.arizona.edu\fP).
  705. .SH BUGS
  706. Email bug reports to
  707. .BR bug\-gnu\-utils@gnu.org .