# pic(1) - man - phpMan [PIC(1)](https://www.chedong.com/phpMan.php/man/PIC/1/markdown) General Commands Manual [PIC(1)](https://www.chedong.com/phpMan.php/man/PIC/1/markdown) ## NAME pic - compile pictures for troff or TeX ## SYNOPSIS **pic** [**-nvCSU**] [_file_ ...] **pic** **-t** [**-cvzCSU**] [_file_ ...] ## DESCRIPTION This manual page describes the GNU version of **pic**, which is part of the groff document for‐ matting system. **pic** compiles descriptions of pictures embedded within **troff** or TeX input files into commands that are understood by TeX or **troff**. Each picture starts with a line be‐ ginning 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 supply such definitions (for example, old versions of -ms), appropriate definitions can be obtained with **-mpic**: These will center each picture. ## OPTIONS 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 ### -S worthy input (enabled by default). ### -U -S ### -n you are using a postprocessor that doesn't support these extensions. The extensions are described in **groff**___**[out**(5)](https://www.chedong.com/phpMan.php/man/out/5/markdown). The **-n** option also causes **pic** not to use zero-length lines to draw dots in troff mode. ### -t ### -c -t 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 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-negative line thickness has not been specified by use of the **thickness** attribute or by setting the **linethick** variable. ### -v ### -z The following options supported by other versions of **pic** are ignored: ### -D ### -T put generated by **pic** is device-independent. ## USAGE 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 file _/usr/share/doc/groff-base/pic.ms.gz_ ### 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 **\centerline{\box\graph}** 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 document: **\def\gpicbox#1{%** **\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 treatment. ### Commands **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 expres‐ sion, 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 be‐ ginning with **.** or **\**, but allows the values of variables to be passed through. For ex‐ ample, **.PS** **x** **=** **14** **command** **".ds** **string** **x** **is** **"** **x** **"."** **.PE** **\*[string]** prints **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, **.PS** **copy** **thru** **%** **circle** **at** **($1,$2)** **%** **until** **"END"** **1** **2** **3** **4** **5** **6** **END** **box** **.PE** is equivalent to **.PS** **circle** **at** **(1,2)** **circle** **at** **(3,4)** **circle** **at** **(5,6)** **box** **.PE** The commands to be performed for each line can also be taken from a macro defined ear‐ lier by giving the name of the macro as the argument to **thru**. ### reset **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 control di‐ mensions 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 as‐ signed to _variable_ without creating a variable local to the current block. (By con‐ trast, **=** 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: **.PS** **x** **=** **3** **y** **=** **3** **[** **x** **:=** **5** **y** **=** **5** **]** **print** **x** **"** **"** **y** **.PE** prints **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 **}**. ### Expressions The syntax for expressions has been significantly extended: _x_ **^** _y_ (exponentiation) **sin(**_x_**)** **cos(**_x_**)** **atan2(**_y_**,** _x_**)** **log(**_x_**)** (base 10) **exp(**_x_**)** (base 10, i.e. 10^_x_) **sqrt(**_x_**)** **int(**_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_**)** **!**_e_ _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 equivalent 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 ig‐ nored; 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 variables **maxpswid** and **maxp**‐‐ **sht**. 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 example, **[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-cir‐ cles at each corner. If no **rad** or **diam** attribute is given, a radius of **boxrad** is used. Ini‐ tially, **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 off‐ set 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 dif‐ ferent 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 ob‐ ject are determined by this box. The implicit motion associated with the object is also de‐ termined by this box. The dimensions of this box are taken from the width and height at‐ tributes; 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)](https://www.chedong.com/phpMan.php/man/printf/3/markdown) appropriate 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 thick‐ ness: 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 supported 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 ex‐ pression with a value between 0 and 1; 0 will fill it with white, 1 with black, values in be‐ tween 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 ar‐ gument, 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)](https://www.chedong.com/phpMan.php/man/troff/1/markdown) for more details). To change the name of the vbox in TeX mode, set the pseudo-variable **figname** (which is actu‐ ally a specially parsed command) within a picture. Example: **.PS** **figname** **=** **foobar;** **...** **.PE** 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 de‐ fault 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 therefore 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 _n_**th** is allowed ‘‘_expr_’’**th** is also allowed. Note that ’’**th** is a single token: no space is allowed between the ’’ and the **th**. For example, **for** **i** **=** **1** **to** **4** **do** **{** **line** **from** ‘‘**i**’’**th** **box.nw** **to** ‘‘**i+1**’’**th** **box.se** **}** ## CONVERSION To obtain a stand-alone picture from a **pic** file, enclose your **pic** code with **.PS** and **.PE** re‐ quests; **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 transform your picture into PostScript® format using the **groff** option **-Tps**. Since this _ps_-file lacks BoundingBox information it is not very use‐ ful by itself, but it may be fed into other conversion programs, usually named **ps2**_other_ or **psto**_other_ or the like. Moreover, the PostScript interpreter **ghostscript** (**gs**) has built-in graphics conversion devices that are called with the option **gs** **-sDEVICE=**__ Call **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** for‐ mat. 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. ## FILES _/usr/share/groff/1.22.4/tmac/pic.tmac_ Example definitions of the **PS** and **PE** macros. ## SEE ALSO [**troff**(1)](https://www.chedong.com/phpMan.php/man/troff/1/markdown), **groff**___**[out**(5)](https://www.chedong.com/phpMan.php/man/out/5/markdown), [**tex**(1)](https://www.chedong.com/phpMan.php/man/tex/1/markdown), [**gs**(1)](https://www.chedong.com/phpMan.php/man/gs/1/markdown), [**ps2eps**(1)](https://www.chedong.com/phpMan.php/man/ps2eps/1/markdown), [**pstopnm**(1)](https://www.chedong.com/phpMan.php/man/pstopnm/1/markdown), [**ps2epsi**(1)](https://www.chedong.com/phpMan.php/man/ps2epsi/1/markdown), [**pnm**(5)](https://www.chedong.com/phpMan.php/man/pnm/5/markdown) Eric S. Raymond, _Making_ _Pictures_ _With_ _GNU_ _PIC._ _/usr/share/doc/groff-base/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)_ ⟨http:// cm.bell-labs.com/cm/cs/cstr/116.ps.gz⟩. AT&T Bell Laboratories, Computing Science Technical Report No. 116 (revised May, 1991). **ps2eps** is available from CTAN mirrors, e.g. ⟨ftp://ftp.dante.de/tex-archive/support/ps2eps/⟩ W. Richard Stevens, _Turning_ _PIC_ _into_ _HTML_ ⟨⟩ W. Richard Stevens, _Examples_ _of_ pic _Macros_ ⟨ pic.examples.ps⟩ ## BUGS 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 edition Unix, which inter‐ prets 0 as black and 1 as white. PostScript® is a registered trademark of Adobe Systems Incorporation. groff 1.22.4 23 March 2022 [PIC(1)](https://www.chedong.com/phpMan.php/man/PIC/1/markdown)