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pic 8.0 KB

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  1. .TH PIC 1
  2. .de PS \" start picture
  3. . \" $1 is height, $2 is width, both in inches
  4. .if \\$1>0 .sp .35
  5. .ie \\$1>0 .nr $1 \\$1
  6. .el .nr $1 0
  7. .in (\\n(.lu-\\$2)/2u
  8. .ne \\$1
  9. ..
  10. .de PE \" end of picture
  11. .in
  12. .if \\n($1>0 .sp .65
  13. ..
  14. .SH NAME
  15. pic, tpic \- troff and tex preprocessors for drawing pictures
  16. .SH SYNOPSIS
  17. .B pic
  18. [
  19. .I files
  20. ]
  21. .PP
  22. .B tpic
  23. [
  24. .I files
  25. ]
  26. .SH DESCRIPTION
  27. .I Pic
  28. is a
  29. .IR troff (1)
  30. preprocessor for drawing figures on a typesetter.
  31. .I Pic
  32. code is contained between
  33. .B .PS
  34. and
  35. .B .PE
  36. lines:
  37. .IP
  38. .EX
  39. \&.PS \f2optional-width\fP \f2optional-height\fP
  40. \f2element-list\fP
  41. \&.PE
  42. .EE
  43. .LP
  44. or in a file mentioned in a
  45. .B .PS
  46. line:
  47. .IP
  48. .BI .PS " " < file
  49. .LP
  50. If
  51. .IR optional-width
  52. is present, the picture is made that many inches wide,
  53. regardless of any dimensions used internally.
  54. The height is scaled in the same proportion unless
  55. .IR optional-height
  56. is present.
  57. If
  58. .B .PF
  59. is used instead of
  60. .BR .PE ,
  61. the typesetting position after printing is restored to what it was
  62. upon entry.
  63. .PP
  64. An
  65. .IR element-list
  66. is a list of elements:
  67. .EX
  68. \f2primitive attribute-list\fP
  69. \f2placename\fP : \f2element\fP
  70. \f2placename\fP : \f2position\fP
  71. \f2var\fP = \f2expr\fP
  72. \f2direction\fP
  73. { \f2element-list\fP }
  74. [ \f2element-list\fP ]
  75. for \f2var\fP = \f2expr\fP to \f2expr\fP by \f2expr\fP do { \f2anything\fP }
  76. if \f2expr\fP then { \f2anything\fP } else { \f2anything\fP }
  77. copy \f2file,\fP copy thru \f2macro,\fP copy \f2file\fP thru \fPmacro\fP
  78. sh { \f2commandline\fP }
  79. print \f2expr\fP
  80. reset \f2optional var-list\fP
  81. \f2troff-command\fP
  82. .EE
  83. .PP
  84. Elements are separated by newlines or semicolons;
  85. a long element may be continued by ending the line with a backslash.
  86. Comments are introduced by a
  87. .BI #
  88. and terminated by a newline.
  89. Variable names begin with a lower case letter;
  90. place names begin with upper case.
  91. Place and variable names retain their values
  92. from one picture to the next.
  93. .PP
  94. After each primitive
  95. the current position moves in the current direction
  96. .RB ( up , down ,
  97. .BR left , right
  98. (default)) by the size of the primitive.
  99. The current position and direction are saved upon entry
  100. to a
  101. .BR { ... }
  102. block and restored upon exit.
  103. Elements within a block enclosed in
  104. .BR [ ... ]
  105. are treated as a unit;
  106. the dimensions are determined by the extreme points
  107. of the contained objects.
  108. Names, variables, and direction of motion within a block are local to that block.
  109. .PP
  110. .IR Troff-command
  111. is any line that begins with a period.
  112. Such a line is assumed to make sense in the context where it appears;
  113. generally, this means only size and font changes.
  114. .PP
  115. The
  116. .I primitive
  117. objects are:
  118. .br
  119. .EX
  120. box circle ellipse arc line arrow spline move \f2text-list\fP
  121. .EE
  122. .L arrow
  123. is a synonym for
  124. .LR "line ->" .
  125. .PP
  126. An
  127. .IR attribute-list
  128. is a sequence of zero or more attributes;
  129. each attribute consists of a keyword, perhaps followed by a value.
  130. .EX
  131. .ta .5i 2.5i
  132. h(eigh)t \f2expr\fP wid(th) \f2expr\fP
  133. rad(ius) \f2expr\fP diam(eter) \f2expr\fP
  134. up \f2opt-expr\fP down \f2opt-expr\fP
  135. right \f2opt-expr\fP left \f2opt-expr\fP
  136. from \f2position\fP to \f2position\fP
  137. at \f2position\fP with \f2corner\fP
  138. by \f2expr, expr\fP then
  139. dotted \f2opt-expr\fP dashed \f2opt-expr\fP
  140. chop \f2opt-expr\fP -> <- <->
  141. invis same
  142. fill \f2opt-expr\fP
  143. \f2text-list\fP \f2expr\fP
  144. .EE
  145. Missing attributes and values are filled in from defaults.
  146. Not all attributes make sense for all primitives;
  147. irrelevant ones are silently ignored.
  148. The attribute
  149. .L at
  150. causes the geometrical center to be put at the specified place;
  151. .L with
  152. causes the position on the object to be put at the specified place.
  153. For lines, splines and arcs,
  154. .L height
  155. and
  156. .L width
  157. refer to arrowhead size.
  158. A bare
  159. .I expr
  160. implies motion in the current direction.
  161. .PP
  162. Text is normally an attribute of some primitive;
  163. by default it is placed at the geometrical center of the object.
  164. Stand-alone text is also permitted.
  165. A text list
  166. is a list of text items:
  167. .EX
  168. \f2 text-item\fP:
  169. "..." \f2positioning ...\fP
  170. sprintf("\f2format\fP", \f2expr\fP, \f2...\fP) \f2positioning ...\fP
  171. \f2 positioning\fP:
  172. center ljust rjust above below
  173. .EE
  174. If there are multiple text items for some primitive,
  175. they are arranged vertically and centered except as qualified.
  176. Positioning requests apply to each item independently.
  177. Text items may contain
  178. .I troff
  179. commands for size and font changes, local motions, etc.,
  180. but make sure that these are balanced
  181. so that the entering state is restored before exiting.
  182. .PP
  183. A position is ultimately an
  184. .I x,y
  185. coordinate pair, but it may be specified in other ways.
  186. .EX
  187. \f2 position\fP:
  188. \f2expr, expr\fP
  189. \f2place\fP ± \f2expr, expr\fP
  190. \f2place\fP ± ( \f2expr, expr\fP )
  191. ( \f2position\fP,\f2 position\fP ) \f2x\fP\fR from one, \f2y\fP\fR the other\fP
  192. \f2expr\fP [\fLof the way\fP] between \f2position\fP and \f2position\fP
  193. \f2expr\fP < \f2position\fP , \f2position\fP >
  194. ( \f2position\fP )
  195. .EE
  196. .PP
  197. .EX
  198. \f2 place\fP:
  199. \f2placename\fP \f2optional-corner\fP
  200. \f2corner\fP of \f2placename\fP
  201. \f2nth\fP \f2primitive\fP \f2optional-corner\fP
  202. \f2corner\fP of \f2nth\fP \f2primitive\fP
  203. Here
  204. .EE
  205. An
  206. .IR optional-corner
  207. is one of the eight compass points
  208. or the center or the start or end of a primitive.
  209. .EX
  210. \f2 optional-corner\fP:
  211. .n .e .w .s .ne .se .nw .sw .c .start .end
  212. \f2 corner\fP:
  213. top bot left right start end
  214. .EE
  215. Each object in a picture has an ordinal number;
  216. .IR nth
  217. refers to this.
  218. .EX
  219. \f2 nth\fP:
  220. \f2n\fPth\f2, n\fPth last
  221. .EE
  222. .PP
  223. The built-in variables and their default values are:
  224. .EX
  225. .ta .5i 2.5i
  226. boxwid 0.75 boxht 0.5
  227. circlerad 0.25 arcrad 0.25
  228. ellipsewid 0.75 ellipseht 0.5
  229. linewid 0.5 lineht 0.5
  230. movewid 0.5 moveht 0.5
  231. textwid 0 textht 0
  232. arrowwid 0.05 arrowht 0.1
  233. dashwid 0.1 arrowhead 2
  234. scale 1
  235. .EE
  236. These may be changed at any time,
  237. and the new values remain in force from picture to picture until changed again
  238. or reset by a
  239. .L reset
  240. statement.
  241. Variables changed within
  242. .B [
  243. and
  244. .B ]
  245. revert to their previous value upon exit from the block.
  246. Dimensions are divided by
  247. .B scale
  248. during output.
  249. .PP
  250. Expressions in
  251. .I pic
  252. are evaluated in floating point.
  253. All numbers representing dimensions are taken to be in inches.
  254. .EX
  255. \f2 expr\fP:
  256. \f2expr\fP \f2op\fP \f2expr\fP
  257. - \f2expr\fP
  258. ! \f2expr\fP
  259. ( \f2expr\fP )
  260. variable
  261. number
  262. \f2place\fP .x \f2place\fP .y \f2place\fP .ht \f2place\fP .wid \f2place\fP .rad
  263. sin(\f2expr\fP) cos(\f2expr\fP) atan2(\f2expr,expr\fP) log(\f2expr\fP) exp(\f2expr\fP)
  264. sqrt(\f2expr\fP) max(\f2expr,expr\fP) min(\f2expr,expr\fP) int(\f2expr\fP) rand()
  265. \f2 op\fP:
  266. + - * / % < <= > >= == != && ||
  267. .EE
  268. .PP
  269. The
  270. .B define
  271. and
  272. .B undef
  273. statements are not part of the grammar.
  274. .EX
  275. define \f2name\fP { \f2replacement text\fP }
  276. undef \f2name\fP
  277. .EE
  278. Occurrences of
  279. .BR $1 ,
  280. .BR $2 ,
  281. etc.,
  282. in the replacement text
  283. will be replaced by the corresponding arguments if
  284. .I name
  285. is invoked as
  286. .EX
  287. \f2name\fP(\f2arg1\fP, \f2arg2\fP, ...)
  288. .EE
  289. Non-existent arguments are replaced by null strings.
  290. Replacement text
  291. may contain newlines.
  292. The
  293. .B undef
  294. statement removes the definition of a macro.
  295. .PP
  296. .I Tpic
  297. is a
  298. .IR tex (1)
  299. preprocessor that accepts
  300. .IR pic
  301. language.
  302. It produces Tex commands that define a box called
  303. .BR \egraph ,
  304. which contains the picture.
  305. The box may be output this way:
  306. .IP
  307. .L
  308. \ecenterline{\ebox\egraph}
  309. .SH EXAMPLES
  310. .EX
  311. arrow "input" above; box "process"; arrow "output" above
  312. move
  313. A: ellipse
  314. circle rad .1 with .w at A.e
  315. circle rad .05 at 0.5 <A.c, A.ne>
  316. circle rad .065 at 0.5 <A.c, A.ne>
  317. spline from last circle.nw left .25 then left .05 down .05
  318. arc from A.c to A.se rad 0.5
  319. for i = 1 to 10 do { line from A.s+.025*i,.01*i down i/50 }
  320. .EE
  321. .PP
  322. .PS
  323. arrow "input" above; box "process"; arrow "output" above
  324. move
  325. A: ellipse
  326. circle rad .1 with .w at A.e
  327. circle rad .05 at 0.5 <A.c, A.ne>
  328. circle rad .065 at 0.5 <A.c, A.ne>
  329. spline from last circle.nw left .25 then left .05 down .05
  330. arc from A.c to A.se rad 0.5
  331. for i = 1 to 10 do { line from A.s+.025*i,.01*i down i/50 }
  332. .PE
  333. .SH SOURCE
  334. .B /sys/src/cmd/pic
  335. .SH "SEE ALSO"
  336. .IR grap (1),
  337. .IR doctype (1),
  338. .IR troff (1)
  339. .br
  340. B. W. Kernighan,
  341. ``PIC\(ema Graphics Language for Typesetting'',
  342. .I
  343. Unix Research System Programmer's Manual,
  344. Tenth Edition, Volume 2