# grn(1) - man - phpMan [GRN(1)](https://www.chedong.com/phpMan.php/man/GRN/1/markdown) General Commands Manual [GRN(1)](https://www.chedong.com/phpMan.php/man/GRN/1/markdown) ## NAME grn - groff preprocessor for gremlin files ## SYNOPSIS **grn** [**-Cv**] [**-T** _dev_] [**-M** _dir_] [**-F** _dir_] [_file_ ...] ## DESCRIPTION _grn_ is a preprocessor for including _gremlin_ pictures in _groff_ input. _grn_ writes to standard output, processing only input lines between two that start with **.GS** and **.GE**. Those lines must contain _grn_ commands (see below). These commands request a _gremlin_ file, and the pic‐ ture in that file is converted and placed in the _troff_ input stream. The **.GS** request may be followed by a C, L, or R to center, left, or right justify the whole _gremlin_ picture (default justification is center). If no _file_ is mentioned, the standard input is read. At the end of the picture, the position on the page is the bottom of the _gremlin_ picture. If the _grn_ entry is ended with **.GF** instead of **.GE**, the position is left at the top of the picture. Please note that currently only the -me macro package has support for **.GS**, **.GE**, and **.GF**. ## OPTIONS Whitespace is permitted between a command-line option and its argument. ### -T able devices. ### -M that order) the current directory, the home directory, _/usr/lib/groff/site-tmac_, _/usr/_ _share/groff/site-tmac_, and _/usr/share/groff/1.22.4/tmac_. ### -F file before the default font directories _/usr/share/groff/site-font_, _/usr/share/groff/_ _1.22.4/font_, and _/usr/lib/font_. ### -C newline. ### -v ## GRN COMMANDS Each input line between **.GS** and **.GE** may have one _grn_ command. Commands consist of one or two strings separated by white space, the first string being the command and the second its oper‐ and. Commands may be upper or lower case and abbreviated down to one character. Commands that affect a picture's environment (those listed before **default**, see below) are only in effect for the current picture: The environment is reinitialized to the defaults at the start of the next picture. The commands are as follows: **1** _N_ **2** _N_ **3** _N_ **4** _N_ Set _gremlin_'s text size number 1 (2, 3, or 4) to _N_ points. The default is 12 (16, 24, and 36, respectively). **roman** _f_ **italics** _f_ **bold** _f_ **special** _f_ Set the roman (italics, bold, or special) font to _troff_'s font _f_ (either a name or number). The default is R (I, B, and S, respectively). **l** _f_ **stipple** _f_ Set the stipple font to _troff_'s stipple font _f_ (name or number). The command **stipple** may be abbreviated down as far as ‘st’ (to avoid confusion with **special**). There is _no_ default for stipples (unless one is set by the default command), and it is invalid to include a _gremlin_ picture with polygons without specifying a stipple font. **x** _N_ **scale** _N_ Magnify the picture (in addition to any default magnification) by _N_, a floating point number larger than zero. The command **scale** may be abbreviated down to ‘sc’. **narrow** _N_ **medium** _N_ **thick** _N_ Set the thickness of _gremlin_'s narrow (medium and thick, respectively) lines to _N_ times 0.15pt (this value can be changed at compile time). The default is 1.0 (3.0 and 5.0, respectively), which corresponds to 0.15pt (0.45pt and 0.75pt, respectively). A thickness value of zero selects the smallest available line thickness. Negative val‐ ues cause the line thickness to be proportional to the current point size. **pointscale** __ Scale text to match the picture. Gremlin text is usually printed in the point size specified with the commands **1**, **2**, **3**, or **4**, regardless of any scaling factors in the picture. Setting **pointscale** will cause the point sizes to scale with the picture (within _troff_'s limitations, of course). An operand of anything but _off_ will turn text scaling on. ### default Reset the picture environment defaults to the settings in the current picture. This is meant to be used as a global parameter setting mechanism at the beginning of the _troff_ input file, but can be used at any time to reset the default settings. **width** _N_ Forces the picture to be _N_ inches wide. This overrides any scaling factors present in the same picture. ‘**width** _0_’ is ignored. **height** _N_ Forces picture to be _N_ inches high, overriding other scaling factors. If both ‘width’ and ‘height’ are specified the tighter constraint will determine the scale of the pic‐ ture. **Height** and **width** commands are not saved with a **default** command. They will, however, affect point size scaling if that option is set. **file** _name_ Get picture from _gremlin_ file _name_ located the current directory (or in the library directory; see the **-M** option above). If two **file** commands are given, the second one overrides the first. If _name_ doesn't exist, an error message is reported and process‐ ing continues from the **.GE** line. ## NOTES ABOUT GROFF Since _grn_ is a preprocessor, it doesn't know about current indents, point sizes, margins, number registers, etc. Consequently, no _troff_ input can be placed between the **.GS** and **.GE** requests. However, _gremlin_ text is now processed by _troff_, so anything valid in a single line of _troff_ input is valid in a line of _gremlin_ text (barring ‘.’ directives at the begin‐ ning of a line). Thus, it is possible to have equations within a _gremlin_ figure by including in the _gremlin_ file _eqn_ expressions enclosed by previously defined delimiters (e.g. _$$_). When using _grn_ along with other preprocessors, it is best to run _tbl_ before _grn_, _pic_, and/or _ideal_ to avoid overworking _tbl_. _Eqn_ should always be run last. A picture is considered an entity, but that doesn't stop _troff_ from trying to break it up if it falls off the end of a page. Placing the picture between ‘keeps’ in -me macros will en‐ sure proper placement. _grn_ uses _troff_'s number registers **g1** through **g9** and sets registers **g1** and **g2** to the width and height of the _gremlin_ figure (in device units) before entering the **.GS** request (this is for those who want to rewrite these macros). ## GREMLIN FILE FORMAT There exist two distinct _gremlin_ file formats, the original format from the _AED_ graphic ter‐ minal version, and the _SUN_ or _X11_ version. An extension to the _SUN_/_X11_ version allowing ref‐ erence points with negative coordinates is **not** compatible with the _AED_ version. As long as a _gremlin_ file does not contain negative coordinates, either format will be read correctly by either version of _gremlin_ or _grn_. The other difference from _SUN_/_X11_ format is the use of names for picture objects (e.g., POLYGON, CURVE) instead of numbers. Files representing the same picture are shown in Table 1 in each format. sungremlinfile gremlinfile 0 240.00 128.00 0 240.00 128.00 CENTCENT 2 240.00 128.00 240.00 128.00 185.00 120.00 185.00 120.00 240.00 120.00 240.00 120.00 296.00 120.00 296.00 120.00 * -1.00 -1.00 2 3 2 3 10 A Triangle 10 A Triangle POLYGON 6 224.00 416.00 224.00 416.00 96.00 160.00 96.00 160.00 384.00 160.00 384.00 160.00 * -1.00 -1.00 5 1 5 1 0 0 -1 -1 Table 1. File examples • The first line of each _gremlin_ file contains either the string **gremlinfile** (_AED_ ver‐ sion) or **sungremlinfile** (_SUN_/_X11_) • The second line of the file contains an orientation, and **x** and **y** values for a posi‐ tioning point, separated by spaces. The orientation, either **0** or **1**, is ignored by the _SUN_/_X11_ version. **0** means that _gremlin_ will display things in horizontal format (draw‐ ing area wider than it is tall, with menu across top). **1** means that _gremlin_ will dis‐ play things in vertical format (drawing area taller than it is wide, with menu on left side). **x** and **y** are floating point values giving a positioning point to be used when this file is read into another file. The stuff on this line really isn't all that im‐ portant; a value of “1 0.00 0.00” is suggested. • The rest of the file consists of zero or more element specifications. After the last element specification is a line containing the string “-1”. • Lines longer than 127 characters are chopped to this limit. ## ELEMENT SPECIFICATIONS • The first line of each element contains a single decimal number giving the type of the element (_AED_ version) or its ASCII name (_SUN_/_X11_ version). See Table 2. _gremlin_ File Format − Object Type Specification _AED_ Number _SUN_/_X11_ Name Description 0 BOTLEFT bottom-left-justified text 1 BOTRIGHT bottom-right-justified text 2 CENTCENT center-justified text 3 VECTOR vector 4 ARC arc 5 CURVE curve 6 POLYGON polygon 7 BSPLINE b-spline 8 BEZIER Bézier 10 TOPLEFT top-left-justified text 11 TOPCENT top-center-justified text 12 TOPRIGHT top-right-justified text 13 CENTLEFT left-center-justified text 14 CENTRIGHT right-center-justified text 15 BOTCENT bottom-center-justified text Table 2. Type Specifications in _gremlin_ Files • After the object type comes a variable number of lines, each specifying a point used to display the element. Each line contains an x-coordinate and a y-coordinate in floating point format, separated by spaces. The list of points is terminated by a line containing the string “-1.0 -1.0” (_AED_ version) or a single asterisk, “*” (_SUN_/_X11_ version). • After the points comes a line containing two decimal values, giving the brush and size for the element. The brush determines the style in which things are drawn. For vec‐ tors, arcs, and curves there are six valid brush values: 1 − thin dotted lines 2 − thin dot-dashed lines 3 − thick solid lines 4 − thin dashed lines 5 − thin solid lines 6 − medium solid lines For polygons, one more value, 0, is valid. It specifies a polygon with an invisible border. For text, the brush selects a font as follows: 1 − roman (R font in groff) 2 − italics (I font in groff) 3 − bold (B font in groff) 4 − special (S font in groff) If you're using _grn_ to run your pictures through _groff_, the font is really just a starting font: The text string can contain formatting sequences like “\fI” or “\d” which may change the font (as well as do many other things). For text, the size field is a decimal value between 1 and 4. It selects the size of the font in which the text will be drawn. For polygons, this size field is interpreted as a stipple number to fill the polygon with. The number is used to index into a stipple font at print time. • The last line of each element contains a decimal number and a string of characters, separated by a single space. The number is a count of the number of characters in the string. This information is only used for text elements, and contains the text string. There can be spaces inside the text. For arcs, curves, and vectors, this line of the element contains the string “0”. ## NOTES ON COORDINATES _gremlin_ was designed for _AED_s, and its coordinates reflect the _AED_ coordinate space. For vertical pictures, x-values range 116 to 511, and y-values from 0 to 483. For horizontal pictures, x-values range from 0 to 511 and y-values range from 0 to 367. Although you needn't absolutely stick to this range, you'll get best results if you at least stay in this vicinity. Also, point lists are terminated by a point of (-1, -1), so you shouldn't ever use negative coordinates. _gremlin_ writes out coordinates using format “%f1.2”; it's probably a good idea to use the same format if you want to modify the _grn_ code. ## NOTES ON SUN/X11 COORDINATES There is no longer a restriction on the range of coordinates used to create objects in the _SUN_/_X11_ version of _gremlin_. However, files with negative coordinates **will** cause problems if displayed on the _AED_. ## FILES _/usr/share/groff/1.22.4/font/dev_name_/DESC_ Device description file for device _name_. ## AUTHORS David Slattengren and Barry Roitblat wrote the original Berkeley _grn_. Daniel Senderowicz and Werner Lemberg modified it for _groff_. ## SEE ALSO [**gremlin**(1)](https://www.chedong.com/phpMan.php/man/gremlin/1/markdown), [**groff**(1)](https://www.chedong.com/phpMan.php/man/groff/1/markdown), [**pic**(1)](https://www.chedong.com/phpMan.php/man/pic/1/markdown), [**ideal**(1)](https://www.chedong.com/phpMan.php/man/ideal/1/markdown) groff 1.22.4 23 March 2022 [GRN(1)](https://www.chedong.com/phpMan.php/man/GRN/1/markdown)