1PIC(1)                      General Commands Manual                     PIC(1)
2
3
4

NAME

6       pic - compile pictures for troff or TeX
7

SYNOPSIS

9       pic [ -nvCSU ] [ filename ... ]
10       pic -t [ -cvzCSU ] [ filename ... ]
11

DESCRIPTION

13       This manual page describes the GNU version of pic, which is part of the
14       groff document formatting system.  pic compiles  descriptions  of  pic‐
15       tures  embedded  within troff or TeX input files into commands that are
16       understood by TeX or troff.  Each picture starts with a line  beginning
17       with  .PS and ends with a line beginning with .PE.  Anything outside of
18       .PS and .PE is passed through without change.
19
20       It is the user's responsibility to provide appropriate  definitions  of
21       the  PS and PE macros.  When the macro package being used does not sup‐
22       ply such definitions (for example, old versions  of  -ms),  appropriate
23       definitions can be obtained with -mpic: these will center each picture.
24

OPTIONS

26       Options  that  do  not take arguments may be grouped behind a single -.
27       The special option -- can be used to mark the end of  the  options.   A
28       filename of - refers to the standard input.
29
30       -C     Recognize  .PS  and  .PE even when followed by a character other
31              than space or newline.
32
33       -S     Safer mode; do not execute sh commands.  This can be useful when
34              operating on untrustworthy input.  (enabled by default)
35
36       -U     Unsafe mode; revert the default option -S.
37
38       -n     Don't  use  the  groff extensions to the troff drawing commands.
39              You should use this  if  you  are  using  a  postprocessor  that
40              doesn't  support these extensions.  The extensions are described
41              in groff_out(5).  The -n option also causes pic not to use zero-
42              length lines to draw dots in troff mode.
43
44       -t     TeX mode.
45
46       -c     Be more compatible with tpic.  Implies -t.  Lines beginning with
47              \ are not passed through transparently.  Lines beginning with  .
48              are  passed  through  with  the initial .  changed to \.  A line
49              beginning with .ps is  given  special  treatment:  it  takes  an
50              optional  integer  argument  specifying  the line thickness (pen
51              size) in milliinches; a missing argument restores  the  previous
52              line  thickness;  the  default  line thickness is 8 milliinches.
53              The line thickness thus specified takes effect only when a  non-
54              negative  line  thickness  has  not been specified by use of the
55              thickness attribute or by setting the linethick variable.
56
57       -v     Print the version number.
58
59       -z     In TeX mode draw dots using zero-length lines.
60
61       The following options supported by other versions of pic are ignored:
62
63       -D     Draw all lines using the \D escape sequence.   pic  always  does
64              this.
65
66       -T dev Generate  output  for the troff device dev.  This is unnecessary
67              because the troff output generated by pic is device-independent.
68

USAGE

70       This section describes only the differences between  GNU  pic  and  the
71       original version of pic.  Many of these differences also apply to newer
72       versions of Unix pic.  A complete documentation  is  available  in  the
73       file
74
75              /usr/share/doc/groff/1.18.1.4/pic.ms
76
77   TeX mode
78       TeX  mode  is enabled by the -t option.  In TeX mode, pic will define a
79       vbox called \graph for each picture.  You must yourself print that vbox
80       using, for example, the command
81
82              \centerline{\box\graph}
83
84       Actually,  since  the  vbox  has  a  height  of  zero this will produce
85       slightly more vertical space above the picture than below it;
86
87              \centerline{\raise 1em\box\graph}
88
89       would avoid this.
90
91       You must use a TeX driver that supports the tpic specials, version 2.
92
93       Lines beginning with \ are passed through transparently; a %  is  added
94       to  the  end  of the line to avoid unwanted spaces.  You can safely use
95       this feature to change fonts or to change the value  of  \baselineskip.
96       Anything  else  may  well  produce undesirable results; use at your own
97       risk.  Lines beginning with a period are not given any  special  treat‐
98       ment.
99
100   Commands
101       for variable = expr1 to expr2 [by [*]expr3] do X body X
102              Set variable to expr1.  While the value of variable is less than
103              or equal to expr2, do body and increment variable by  expr3;  if
104              by  is not given, increment variable by 1.  If expr3 is prefixed
105              by * then variable will instead be multiplied by expr3.   X  can
106              be any character not occurring in body.
107
108       if expr then X if-true X [else Y if-false Y]
109              Evaluate  expr;  if it is non-zero then do if-true, otherwise do
110              if-false.  X can be any character not occurring in  if-true.   Y
111              can be any character not occurring in if-false.
112
113       print arg...
114              Concatenate  the  arguments and print as a line on stderr.  Each
115              arg must be an expression, a position, or text.  This is  useful
116              for debugging.
117
118       command arg...
119              Concatenate  the  arguments  and  pass them through as a line to
120              troff or TeX.  Each arg must be an expression,  a  position,  or
121              text.   This  has a similar effect to a line beginning with . or
122              \, but allows the values of variables to be passed through.
123
124       sh X command X
125              Pass command to a shell.  X can be any character  not  occurring
126              in command.
127
128       copy "filename"
129              Include filename at this point in the file.
130
131       copy ["filename"] thru X body X [until "word"]
132       copy ["filename"] thru macro [until "word"]
133              This  construct  does  body  once for each line of filename; the
134              line is split into blank-delimited words, and occurrences of  $i
135              in body, for i between 1 and 9, are replaced by the i-th word of
136              the line.  If filename is not given, lines are  taken  from  the
137              current input up to .PE.  If an until clause is specified, lines
138              will be read only until a line the first word of which is  word;
139              that  line  will  then be discarded.  X can be any character not
140              occurring in body.  For example,
141
142                     .PS
143                     copy thru % circle at ($1,$2) % until "END"
144                     1 2
145                     3 4
146                     5 6
147                     END
148                     box
149                     .PE
150
151              is equivalent to
152
153                     .PS
154                     circle at (1,2)
155                     circle at (3,4)
156                     circle at (5,6)
157                     box
158                     .PE
159
160              The commands to be performed for each line  can  also  be  taken
161              from  a macro defined earlier by giving the name of the macro as
162              the argument to thru.
163
164       reset
165       reset variable1[,] variable2 ...
166              Reset pre-defined variables variable1, variable2  ...  to  their
167              default  values.   If  no  arguments  are  given, reset all pre-
168              defined variables to their default values.  Note that  assigning
169              a value to scale also causes all pre-defined variables that con‐
170              trol dimensions to be reset to their default  values  times  the
171              new value of scale.
172
173       plot expr ["text"]
174              This  is  a  text object which is constructed by using text as a
175              format string for sprintf with an argument of expr.  If text  is
176              omitted  a  format  string  of  "%g" is used.  Attributes can be
177              specified in the same way as for a normal text object.  Be  very
178              careful  that you specify an appropriate format string; pic does
179              only very limited checking of the string.  This is deprecated in
180              favour of sprintf.
181
182       variable := expr
183              This  is  similar  to = except variable must already be defined,
184              and expr will be assigned to variable without creating  a  vari‐
185              able  local  to  the current block.  (By contrast, = defines the
186              variable in the current block  if  it  is  not  already  defined
187              there,  and  then  changes the value in the current block only.)
188              For example, the following:
189
190                     .PS
191                     x = 3
192                     y = 3
193                     [
194                       x := 5
195                       y = 5
196                     ]
197                     print x " " y
198                     .PE
199
200              prints 5 3.
201
202       Arguments of the form
203
204              X anything X
205
206       are also allowed to be of the form
207
208              { anything }
209
210       In this case anything can contain balanced  occurrences  of  {  and  }.
211       Strings may contain X or imbalanced occurrences of { and }.
212
213   Expressions
214       The syntax for expressions has been significantly extended:
215
216       x ^ y (exponentiation)
217       sin(x)
218       cos(x)
219       atan2(y, x)
220       log(x) (base 10)
221       exp(x) (base 10, ie 10^x)
222       sqrt(x)
223       int(x)
224       rand() (return a random number between 0 and 1)
225       rand(x) (return a random number between 1 and x; deprecated)
226       srand(x) (set the random number seed)
227       max(e1, e2)
228       min(e1, e2)
229       !e
230       e1 && e2
231       e1 || e2
232       e1 == e2
233       e1 != e2
234       e1 >= e2
235       e1 > e2
236       e1 <= e2
237       e1 < e2
238       "str1" == "str2"
239       "str1" != "str2"
240
241       String comparison expressions must be parenthesised in some contexts to
242       avoid ambiguity.
243
244   Other Changes
245       A bare expression, expr, is acceptable as an attribute; it  is  equiva‐
246       lent to dir expr, where dir is the current direction.  For example
247
248              line 2i
249
250       means  draw a line 2 inches long in the current direction.  The `i' (or
251       `I') character is ignored; to use another  measurement  unit,  set  the
252       scale variable to an appropriate value.
253
254       The  maximum  width  and height of the picture are taken from the vari‐
255       ables maxpswid and maxpsht.  Initially these have values 8.5 and 11.
256
257       Scientific notation is allowed for numbers.  For example
258              x = 5e-2
259
260       Text attributes can be compounded.  For example,
261              "foo" above ljust
262       is legal.
263
264       There is no limit to the depth to which blocks can  be  examined.   For
265       example,
266              [A: [B: [C: box ]]] with .A.B.C.sw at 1,2
267              circle at last [].A.B.C
268       is acceptable.
269
270       Arcs  now have compass points determined by the circle of which the arc
271       is a part.
272
273       Circles and arcs can be dotted or dashed.  In TeX mode splines  can  be
274       dotted or dashed.
275
276       Boxes can have rounded corners.  The rad attribute specifies the radius
277       of the quarter-circles at each corner.  If no rad or diam attribute  is
278       given, a radius of boxrad is used.  Initially, boxrad has a value of 0.
279       A box with rounded corners can be dotted or dashed.
280
281       The .PS line can have a second argument specifying a maximum height for
282       the  picture.   If  the  width  of  zero is specified the width will be
283       ignored in computing the scaling factor for the picture.  Note that GNU
284       pic  will  always scale a picture by the same amount vertically as well
285       as horizontally.  This is different from the  DWB  2.0  pic  which  may
286       scale a picture by a different amount vertically than horizontally if a
287       height is specified.
288
289       Each text object has an invisible box associated with it.  The  compass
290       points  of  a  text  object  are  determined by this box.  The implicit
291       motion associated with the object is also determined by this box.   The
292       dimensions  of this box are taken from the width and height attributes;
293       if the width attribute is not supplied then the width will be taken  to
294       be  textwid;  if  the  height attribute is not supplied then the height
295       will be taken to be the number of  text  strings  associated  with  the
296       object times textht.  Initially textwid and textht have a value of 0.
297
298       In  (almost  all)  places  where  a  quoted text string can be used, an
299       expression of the form
300
301              sprintf("format", arg,...)
302
303       can also be used; this will produce the arguments  formatted  according
304       to format, which should be a string as described in printf(3) appropri‐
305       ate for the number of arguments supplied.
306
307       The thickness of the lines used to draw objects is  controlled  by  the
308       linethick  variable.   This  gives the thickness of lines in points.  A
309       negative value means use the default thickness:  in  TeX  output  mode,
310       this  means  use  a thickness of 8 milliinches; in TeX output mode with
311       the -c option, this means use  the  line  thickness  specified  by  .ps
312       lines; in troff output mode, this means use a thickness proportional to
313       the pointsize.  A zero value means draw the thinnest possible line sup‐
314       ported by the output device.  Initially it has a value of -1.  There is
315       also a thick[ness] attribute.  For example,
316
317              circle thickness 1.5
318
319       would draw a circle using a line with a thickness of 1.5  points.   The
320       thickness  of lines is not affected by the value of the scale variable,
321       nor by the width or height given in the .PS line.
322
323       Boxes (including boxes with rounded corners), circles and ellipses  can
324       be  filled  by  giving  them  an  attribute of fill[ed].  This takes an
325       optional argument of an expression with a value between 0 and 1; 0 will
326       fill  it with white, 1 with black, values in between with a proportion‐
327       ally gray shade.  A value greater than 1 can also be used:  this  means
328       fill  with  the shade of gray that is currently being used for text and
329       lines.  Normally this will be black, but output devices may  provide  a
330       mechanism  for  changing  this.  Without an argument, then the value of
331       the variable fillval will be used.  Initially this has a value of  0.5.
332       The  invisible  attribute  does not affect the filling of objects.  Any
333       text associated with a filled object will be added after the object has
334       been filled, so that the text will not be obscured by the filling.
335
336       Three  additional  modifiers  are available to specify colored objects:
337       outline[d] sets the color of the outline, shaded the  fill  color,  and
338       colo[u]r[ed]  sets both.  All three keywords expect a suffix specifying
339       the color, for example
340
341              circle shaded "green" outline "black"
342
343       Currently, color support isn't available in TeX mode.  Predefined color
344       names  for  groff  are  in the device macro files, for example ps.tmac;
345       additional colors can be defined with the .defcolor  request  (see  the
346       manual page of troff(1) for more details).
347
348       pic  assumes  that  at  the  beginning of a picture both glyph and fill
349       color are set to the default value.
350
351       Arrow heads will be drawn as solid triangles if the variable  arrowhead
352       is  non-zero  and  either  TeX mode is enabled or the -n option has not
353       been given.  Initially arrowhead has a value  of 1.   Note  that  solid
354       arrow heads are always filled with the current outline color.
355
356       The troff output of pic is device-independent.  The -T option is there‐
357       fore redundant.  All numbers are taken to be  in  inches;  numbers  are
358       never interpreted to be in troff machine units.
359
360       Objects  can  have  an  aligned  attribute.  This will only work if the
361       postprocessor is grops.  Any text associated with an object having  the
362       aligned  attribute  will  be  rotated about the center of the object so
363       that it is aligned in the direction from the start  point  to  the  end
364       point  of the object.  Note that this attribute will have no effect for
365       objects whose start and end points are coincident.
366
367       In places where nth is allowed `expr'th is also allowed.  Note that 'th
368       is  a  single token: no space is allowed between the ' and the th.  For
369       example,
370
371              for i = 1 to 4 do {
372                 line from `i'th box.nw to `i+1'th box.se
373              }
374

CONVERSION

376       To obtain a stand-alone picture from a pic file, enclose your pic  code
377       with  .PS and .PE requests; roff configuration commands may be added at
378       the beginning of the file, but no roff text.
379
380       It is necessary to feed this file into groff without  adding  any  page
381       information,  so you must check which .PS and .PE requests are actually
382       called.  For example, the mm macro package adds a page number, which is
383       very annoying.  At the moment, calling standard groff without any macro
384       package works.  Alternatively, you can define your own  requests,  e.g.
385       to do nothing:
386
387              .de PS
388              ..
389              .de PE
390              ..
391
392       groff  itself  does  not  provide direct conversion into other graphics
393       file formats.  But there are lots of possibilities if you first  trans‐
394       form  your picture into PostScript® format using the groff option -Tps.
395       Since this ps-file lacks BoundingBox information it is not very  useful
396       by  itself,  but  it may be fed into other conversion programs, usually
397       named ps2other or pstoother or  the  like.   Moreover,  the  PostScript
398       interpreter  ghostscript  (gs) has built-in graphics conversion devices
399       that are called with the option
400
401              gs -sDEVICE=<devname>
402
403       Call
404              gs --help
405
406       for a list of the available devices.
407
408       As the Encapsulated PostScript File Format EPS is getting more and more
409       important,  and  the conversion wasn't regarded trivial in the past you
410       might be interested to know that  there  is  a  conversion  tool  named
411       ps2eps  which  does  the  right  job.   It is much better than the tool
412       ps2epsi packaged with gs.
413
414       For bitmapped graphic formats, you should use  pstopnm;  the  resulting
415       (intermediate) PNM file can be then converted to virtually any graphics
416       format using the tools of the netpbm package .
417

FILES

419       /usr/share/groff/1.18.1.4/tmac/pic.tmac
420              Example definitions of the PS and PE macros.
421

SEE ALSO

423       troff(1),   groff_out(5),   tex(1),   gs(1),   ps2eps(1),   pstopnm(1),
424       ps2epsi(1), pnm(5)
425
426       Tpic: Pic for TeX
427
428       Brian  W.  Kernighan,  PIC  — A Graphics Language for Typesetting (User
429       Manual).  AT&T Bell Laboratories, Computing  Science  Technical  Report
430       No. 116  <http://cm.bell-labs.com/cm/cs/cstr/116.ps.gz>  (revised  May,
431       1991).
432
433       ps2eps is available from CTAN mirrors, e.g.
434       <ftp://ftp.dante.de/tex-archive/support/ps2eps/>
435
436       W. Richard Stevens - Turning PIC Into HTML
437       <http://www.kohala.com/start/troff/pic2html.html>
438
439       W. Richard Stevens - Examples of picMacros
440       <http://www.kohala.com/start/troff/pic.examples.ps>
441

BUGS

443       Input characters that are invalid for groff (ie those with  ASCII  code
444       0, or 013 octal, or between 015 and 037 octal, or between 0200 and 0237
445       octal) are rejected even in TeX mode.
446
447       The interpretation of fillval is incompatible with the pic in 10th edi‐
448       tion Unix, which interprets 0 as black and 1 as white.
449
450       PostScript® is a registered trademark of Adobe Systems Incorporation.
451
452
453
454Groff Version 1.18.1.4         20 September 2002                        PIC(1)
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