Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
PIC(1)			    General Commands Manual			PIC(1)

       pic - compile pictures for troff	or TeX

       pic [ -nvCSU ] [	filename ... ]
       pic -t [	-cvzCSU	] [ filename ... ]

       This manual page	describes the GNU version of pic, which	is part	of the
       groff document formatting system.  pic compiles	descriptions  of  pic-
       tures  embedded	within troff or	TeX input files	into commands that are
       understood by TeX or troff.  Each picture starts	with a line  beginning
       with  .PS and ends with a line beginning	with .PE.  Anything outside of
       .PS and .PE is passed through without change.

       It is the user's	responsibility to provide appropriate  definitions  of
       the  PS and PE macros.  When the	macro package being used does not sup-
       ply such	definitions (for example, old versions	of  -ms),  appropriate
       definitions can be obtained with	-mpic: These will center each picture.

       Options	that  do  not take arguments may be grouped behind a single -.
       The special option -- can be used to mark the end of  the  options.   A
       filename	of - refers to the standard input.

       -C     Recognize	 .PS  and  .PE even when followed by a character other
	      than space or newline.

       -S     Safer mode; do not execute sh commands.  This can	be useful when
	      operating	on untrustworthy input.	 (enabled by default)

       -U     Unsafe mode; revert the default option -S.

       -n     Don't  use  the  groff extensions	to the troff drawing commands.
	      You should use this  if  you  are	 using	a  postprocessor  that
	      doesn't  support these extensions.  The extensions are described
	      in groff_out(5).	The -n option also causes pic not to use zero-
	      length lines to draw dots	in troff mode.

       -t     TeX mode.

       -c     Be more compatible with tpic.  Implies -t.  Lines	beginning with
	      \	are not	passed through transparently.  Lines beginning with  .
	      are passed through with the initial .  changed to	\.  A line be-
	      ginning with .ps is given	special	treatment:  it	takes  an  op-
	      tional integer argument specifying the line thickness (pen size)
	      in milliinches; a	missing	argument restores  the	previous  line
	      thickness;  the  default	line  thickness	is 8 milliinches.  The
	      line thickness thus specified takes effect only when a non-nega-
	      tive  line thickness has not been	specified by use of the	thick-
	      ness attribute or	by setting the linethick variable.

       -v     Print the	version	number.

       -z     In TeX mode draw dots using zero-length lines.

       The following options supported by other	versions of pic	are ignored:

       -D     Draw all lines using the \D escape sequence.   pic  always  does

       -T dev Generate	output	for the	troff device dev.  This	is unnecessary
	      because the troff	output generated by pic	is device-independent.

       This section describes only the differences between  GNU	 pic  and  the
       original	version	of pic.	 Many of these differences also	apply to newer
       versions	of Unix	pic.  A	complete documentation	is  available  in  the


   TeX mode
       TeX  mode  is enabled by	the -t option.	In TeX mode, pic will define a
       vbox called \graph for each picture.  Use the figname command to	change
       the name	of the vbox.  You must yourself	print that vbox	using, for ex-
       ample, the command


       Actually, since the vbox	has a height  of  zero	(it  is	 defined  with
       \vtop) this will	produce	slightly more vertical space above the picture
       than below it;

	      \centerline{\raise 1em\box\graph}

       would avoid this.

       To make the vbox	having a positive height and a depth of	zero (as  used
       e.g. by LaTeX's graphics.sty), define the following macro in your docu-

		 \vbox{\unvbox\csname #1\endcsname\kern	0pt}}

       Now you can simply say \gpicbox{graph} instead of \box\graph.

       You must	use a TeX driver that supports the tpic	specials, version 2.

       Lines beginning with \ are passed through transparently;	a %  is	 added
       to  the	end  of	the line to avoid unwanted spaces.  You	can safely use
       this feature to change fonts or to change the value  of	\baselineskip.
       Anything	 else  may  well  produce undesirable results; use at your own
       risk.  Lines beginning with a period are	not given any  special	treat-

       for variable = expr1 to expr2 [by [*]expr3] do X	body X
	      Set variable to expr1.  While the	value of variable is less than
	      or equal to expr2, do body and increment variable	by  expr3;  if
	      by  is not given,	increment variable by 1.  If expr3 is prefixed
	      by * then	variable will instead be  multiplied  by  expr3.   The
	      value  of	 expr3 can be negative for the additive	case; variable
	      is then tested whether it	is greater than	 or  equal  to	expr2.
	      For  the	multiplicative	case, expr3 must be greater than zero.
	      If the constraints aren't	met, the loop isn't executed.	X  can
	      be any character not occurring in	body.

       if expr then X if-true X	[else Y	if-false Y]
	      Evaluate	expr;  if it is	non-zero then do if-true, otherwise do
	      if-false.	 X can be any character	not occurring in  if-true.   Y
	      can be any character not occurring in if-false.

       print arg...
	      Concatenate  the	arguments and print as a line on stderr.  Each
	      arg must be an expression, a position, or	text.  This is	useful
	      for debugging.

       command arg...
	      Concatenate  the	arguments  and	pass them through as a line to
	      troff or TeX.  Each arg must be an expression,  a	 position,  or
	      text.   This  has	a similar effect to a line beginning with . or
	      \, but allows the	values of variables to be passed through.  For

		     x = 14
		     command ".ds string x is "	x "."


		     x is 14.

       sh X command X
	      Pass  command  to	a shell.  X can	be any character not occurring
	      in command.

       copy "filename"
	      Include filename at this point in	the file.

       copy ["filename"] thru X	body X [until "word"]
       copy ["filename"] thru macro [until "word"]
	      This construct does body once for	each  line  of	filename;  the
	      line  is split into blank-delimited words, and occurrences of $i
	      in body, for i between 1 and 9, are replaced by the i-th word of
	      the  line.   If  filename	is not given, lines are	taken from the
	      current input up to .PE.	If an until clause is specified, lines
	      will  be read only until a line the first	word of	which is word;
	      that line	will then be discarded.	 X can be  any	character  not
	      occurring	in body.  For example,

		     copy thru % circle	at ($1,$2) % until "END"
		     1 2
		     3 4
		     5 6

	      is equivalent to

		     circle at (1,2)
		     circle at (3,4)
		     circle at (5,6)

	      The  commands  to	 be  performed for each	line can also be taken
	      from a macro defined earlier by giving the name of the macro  as
	      the argument to thru.

       reset variable1[,] variable2 ...
	      Reset  pre-defined  variables  variable1,	variable2 ... to their
	      default values.  If no arguments are given,  reset  all  pre-de-
	      fined  variables to their	default	values.	 Note that assigning a
	      value to scale also causes all pre-defined variables  that  con-
	      trol  dimensions	to  be reset to	their default values times the
	      new value	of scale.

       plot expr ["text"]
	      This is a	text object which is constructed by using  text	 as  a
	      format  string for sprintf with an argument of expr.  If text is
	      omitted a	format string of "%g"  is  used.   Attributes  can  be
	      specified	 in the	same way as for	a normal text object.  Be very
	      careful that you specify an appropriate format string; pic  does
	      only very	limited	checking of the	string.	 This is deprecated in
	      favour of	sprintf.

       variable	:= expr
	      This is similar to = except variable must	 already  be  defined,
	      and  expr	 will be assigned to variable without creating a vari-
	      able local to the	current	block.	(By contrast,  =  defines  the
	      variable	in  the	 current  block	 if  it	is not already defined
	      there, and then changes the value	in the	current	 block	only.)
	      For example, the following:

		     x = 3
		     y = 3
		       x := 5
		       y = 5
		     print x " " y


		     5 3

       Arguments of the	form

	      X	anything X

       are also	allowed	to be of the form

	      {	anything }

       In  this	 case  anything	 can  contain balanced occurrences of {	and }.
       Strings may contain X or	imbalanced occurrences of { and	}.

       The syntax for expressions has been significantly extended:

       x ^ y (exponentiation)
       atan2(y,	x)
       log(x) (base 10)
       exp(x) (base 10,	ie 10^x)
       rand() (return a	random number between 0	and 1)
       rand(x) (return a random	number between 1 and x;	deprecated)
       srand(x)	(set the random	number seed)
       max(e1, e2)
       min(e1, e2)
       e1 && e2
       e1 || e2
       e1 == e2
       e1 != e2
       e1 >= e2
       e1 > e2
       e1 <= e2
       e1 < e2
       "str1" == "str2"
       "str1" != "str2"

       String comparison expressions must be parenthesised in some contexts to
       avoid ambiguity.

   Other Changes
       A  bare	expression, expr, is acceptable	as an attribute; it is equiva-
       lent to dir expr, where dir is the current direction.  For example

	      line 2i

       means draw a line 2 inches long in the current direction.  The `i'  (or
       `I')  character	is  ignored;  to use another measurement unit, set the
       scale variable to an appropriate	value.

       The maximum width and height of the picture are taken  from  the	 vari-
       ables maxpswid and maxpsht.  Initially these have values	8.5 and	11.

       Scientific notation is allowed for numbers.  For	example

	      x	= 5e-2

       Text attributes can be compounded.  For example,

	      "foo" above ljust

       is valid.

       There  is  no  limit to the depth to which blocks can be	examined.  For

	      [A: [B: [C: box ]]] with .A.B.C.sw at 1,2
	      circle at	last [].A.B.C

       is acceptable.

       Arcs now	have compass points determined by the circle of	which the  arc
       is a part.

       Circles,	 ellipses,  and	 arcs  can  be	dotted or dashed.  In TeX mode
       splines can be dotted or	dashed also.

       Boxes can have rounded corners.	The rad	attribute specifies the	radius
       of  the quarter-circles at each corner.	If no rad or diam attribute is
       given, a	radius of boxrad is used.  Initially, boxrad has a value of 0.
       A box with rounded corners can be dotted	or dashed.

       The .PS line can	have a second argument specifying a maximum height for
       the picture.  If	the width of zero is specified the width will  be  ig-
       nored  in  computing the	scaling	factor for the picture.	 Note that GNU
       pic will	always scale a picture by the same amount vertically  as  well
       as  horizontally.   This	 is  different	from the DWB 2.0 pic which may
       scale a picture by a different amount vertically	than horizontally if a
       height is specified.

       Each  text object has an	invisible box associated with it.  The compass
       points of a text	object are determined by this box.  The	 implicit  mo-
       tion  associated	 with  the object is also determined by	this box.  The
       dimensions of this box are taken	from the width and height  attributes;
       if  the width attribute is not supplied then the	width will be taken to
       be textwid; if the height attribute is not  supplied  then  the	height
       will  be	taken to be the	number of text strings associated with the ob-
       ject times textht.  Initially textwid and textht	have a value of	0.

       In (almost all) places where a quoted text string can be	used,  an  ex-
       pression	of the form

	      sprintf("format",	arg,...)

       can  also  be used; this	will produce the arguments formatted according
       to format, which	should be a string as described	in printf(3) appropri-
       ate for the number of arguments supplied.

       The  thickness  of  the lines used to draw objects is controlled	by the
       linethick variable.  This gives the thickness of	lines  in  points.   A
       negative	 value	means  use  the	default	thickness: in TeX output mode,
       this means use a	thickness of 8 milliinches; in TeX  output  mode  with
       the  -c	option,	 this  means  use  the line thickness specified	by .ps
       lines; in troff output mode, this means use a thickness proportional to
       the pointsize.  A zero value means draw the thinnest possible line sup-
       ported by the output device.  Initially it has a	value of -1.  There is
       also a thick[ness] attribute.  For example,

	      circle thickness 1.5

       would  draw  a circle using a line with a thickness of 1.5 points.  The
       thickness of lines is not affected by the value of the scale  variable,
       nor by the width	or height given	in the .PS line.

       Boxes  (including boxes with rounded corners), circles and ellipses can
       be filled by giving them	an attribute of	fill[ed].  This	takes  an  op-
       tional  argument	 of an expression with a value between 0 and 1;	0 will
       fill it with white, 1 with black, values	in between with	a  proportion-
       ally  gray  shade.  A value greater than	1 can also be used: this means
       fill with the shade of gray that	is currently being used	for  text  and
       lines.	Normally  this will be black, but output devices may provide a
       mechanism for changing this.  Without an	argument, then	the  value  of
       the  variable fillval will be used.  Initially this has a value of 0.5.
       The invisible attribute does not	affect the filling  of	objects.   Any
       text associated with a filled object will be added after	the object has
       been filled, so that the	text will not be obscured by the filling.

       Three additional	modifiers are available	to  specify  colored  objects:
       outline[d]  sets	 the  color of the outline, shaded the fill color, and
       colo[u]r[ed] sets both.	All three keywords expect a suffix  specifying
       the color, for example

	      circle shaded "green" outline "black"

       Currently, color	support	isn't available	in TeX mode.  Predefined color
       names for groff are in the device macro files, for example ps.tmac; ad-
       ditional	colors can be defined with the .defcolor request (see the man-
       ual page	of troff(1) for	more details).

       To change the name of the vbox in TeX  mode,  set  the  pseudo-variable
       figname	(which	is  actually a specially parsed	command) within	a pic-
       ture.  Example:

	      figname =	foobar;

       The picture is then available in	the box	\foobar.

       pic assumes that	at the beginning of a  picture	both  glyph  and  fill
       color are set to	the default value.

       Arrow  heads will be drawn as solid triangles if	the variable arrowhead
       is non-zero and either TeX mode is enabled or the  -n  option  has  not
       been given.  Initially arrowhead	has a value of 1.  Note	that solid ar-
       row heads are always filled with	the current outline color.

       The troff output	of pic is device-independent.  The -T option is	there-
       fore  redundant.	  All  numbers	are taken to be	in inches; numbers are
       never interpreted to be in troff	machine	units.

       Objects can have	an aligned attribute.  This  will  only	 work  if  the
       postprocessor  is grops.	 Any text associated with an object having the
       aligned attribute will be rotated about the center  of  the  object  so
       that  it	 is  aligned  in the direction from the	start point to the end
       point of	the object.  Note that this attribute will have	no effect  for
       objects whose start and end points are coincident.

       In places where nth is allowed `expr'th is also allowed.	 Note that 'th
       is a single token: no space is allowed between the ' and	the  th.   For

	      for i = 1	to 4 do	{
		 line from `i'th box.nw	to `i+1'th

       To  obtain a stand-alone	picture	from a pic file, enclose your pic code
       with .PS	and .PE	requests; roff configuration commands may be added  at
       the beginning of	the file, but no roff text.

       It  is  necessary  to feed this file into groff without adding any page
       information, so you must	check which .PS	and .PE	requests are  actually
       called.	For example, the mm macro package adds a page number, which is
       very annoying.  At the moment, calling standard groff without any macro
       package	works.	 Alternatively,	you can	define your own	requests, e.g.
       to do nothing:

	      .de PS
	      .de PE

       groff itself does not provide direct  conversion	 into  other  graphics
       file  formats.  But there are lots of possibilities if you first	trans-
       form your picture into PostScript(R)  format  using  the	 groff	option
       -Tps.   Since this ps-file lacks	BoundingBox information	it is not very
       useful by itself, but it	may be fed  into  other	 conversion  programs,
       usually	named  ps2other	or pstoother or	the like.  Moreover, the Post-
       Script interpreter ghostscript (gs) has	built-in  graphics  conversion
       devices that are	called with the	option

	      gs -sDEVICE=_devname_


	      gs --help

       for a list of the available devices.

       As the Encapsulated PostScript File Format EPS is getting more and more
       important, and the conversion wasn't regarded trivial in	the  past  you
       might  be  interested  to  know	that  there is a conversion tool named
       ps2eps which does the right job.	 It  is	 much  better  than  the  tool
       ps2epsi packaged	with gs.

       For  bitmapped  graphic	formats, you should use	pstopnm; the resulting
       (intermediate) PNM file can be then converted to	virtually any graphics
       format using the	tools of the netpbm package .

       /usr/share/tmac/pic.tmac	  Example definitions of the PS	and PE macros.

       troff(1),   groff_out(5),   tex(1),   gs(1),   ps2eps(1),   pstopnm(1),
       ps2epsi(1), pnm(5)

       Tpic: Pic for TeX

       Brian W.	Kernighan, PIC -- A Graphics Language  for  Typesetting	 (User
       Manual).	  AT&T	Bell  Laboratories, Computing Science Technical	Report
       No. 116	<>	(revised  May,

       ps2eps is available from	CTAN mirrors, e.g.

       W. Richard Stevens - Turning PIC	Into HTML

       W. Richard Stevens - Examples of	picMacros

       Input  characters  that	are  invalid for groff (i.e., those with ASCII
       code 0, or 013 octal, or	between	015 and	037 octal, or between 0200 and
       0237 octal) are rejected	even in	TeX mode.

       The interpretation of fillval is	incompatible with the pic in 10th edi-
       tion Unix, which	interprets 0 as	black and 1 as white.

       PostScript(R) is	a registered trademark of Adobe	Systems	Incorporation.

Groff Version 1.19.2		 23 July 2015				PIC(1)


Want to link to this manual page? Use this URL:

home | help