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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
	      beginning with .ps is  given  special  treatment:	 it  takes  an
	      optional	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-
	      negative	line  thickness	 has  not been specified by use of the
	      thickness 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
       example, 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-
	      defined  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.

       Boxes  can have slanted sides.  This effectively changes the shape of a
       box from a rectangle to an arbitrary parallelogram.  The	 xslanted  and
       yslanted attributes specify the x and y offset of the box's upper right
       corner from its default position.

       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
       ignored 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
       motion 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
       object times textht.  Initially textwid and textht have a value of 0.

       In  (almost  all)  places  where	 a  quoted text string can be used, an
       expression 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 or slanted sides),  circles
       and  ellipses  can  be  filled by giving them an attribute of fill[ed].
       This takes an optional 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 proportionally 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;
       additional  colors  can	be defined with the .defcolor request (see the
       manual 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
       arrow 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, or gropdf.  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 box.se

       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.

       An  alternative	may be to use the -Tpdf option to convert your picture
       directly into PDF format.  The MediaBox of the  file  produced  can  be
       controlled by passing a -P-p papersize to groff.

       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 .

	      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)

       Eric S. Raymond, Making Pictures With GNU PIC.
       /usr/share/doc/groff-1.22.2/pic.ps (this file, together with its source
       file, pic.ms, is part of the groff documentation)

       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
       <http://cm.bell-labs.com/cm/cs/cstr/116.ps.gz> (revised May, 1991).

       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 1.22.2		7 February 2013				PIC(1)