It is possible to have whitespace between the -F option and its parameter.
By default, grotty emits SGR escape sequences (from ISO 6429, also called ANSI color escapes) to change text attributes (bold, italic, colors). This makes it possible to have eight different [green]background and [red]foreground colors; additionally, bold and italic attributes can be used BI]at the same time] (by using the BI font).
The following colors are defined in tty.tmac: black, white, red, green, blue, yellow, magenta, cyan. Unknown colors are mapped to the default color (which is dependent on the settings of the terminal; in most cases, this is black for the foreground and white for the background).
Use the -c switch to revert to the old behaviour, printing a bold character c with the sequence c BACKSPACE c and an italic character c by the sequence _ BACKSPACE c. At the same time, color output is disabled. The same effect can be achieved by setting either the GROFF_NO_SGR environment variable or using the sgr X command (see below).
For SGR support, it is necessary to use the -R option of less(1) to disable the interpretation of grottys old output format. Consequently, all programs which use less as the pager program have to pass this option to it. For man(1) in particular, either add -R to the $PAGER environment variable, e.g.
PAGER= /usr/bin/less -R
or use the -P option of man to set the pager executable and its options, or modify the configuration file of man in a similar fashion.
grottys old output format can be displayed on a terminal by piping through ul(1). Pagers such as more(1) or less(1) are also able to display these sequences. Use either -B or -U when piping into less(1); use -b when piping into more(1). There is no need to filter the output through col(1) since grotty never outputs reverse line feeds.
The font description file may contain a command
|-b||Suppress the use of overstriking for bold characters. Ignored if -c isnt used.|
|-B||Use only overstriking for bold-italic characters. Ignored if -c isnt used.|
|-c||Use grottys old output format (see above). This also disables color output.|
|-d||Ignore all [rs]D commands. Without this grotty will render [rs]Dl... commands that have at least one zero argument (and so are either horizontal or vertical) using -, |, and + characters.|
|-f||Use form feeds in the output. A form feed will be output at the end of each page that has no output on its last line.|
|-Fdir||Prepend directory dir/devname to the search path for font and device description files; name is the name of the device, usually ascii, ascii8, latin1, utf8, nippon or cp1047.|
|-h||Use horizontal tabs in the output. Tabs are assumed to be set every 8 columns.|
|-i||Use escape sequences to set the italic text attribute instead of the underline attribute for italic fonts (I and BI). Note that most terminals (including xterm) dont support this. Ignored if -c is active.|
|-o||Suppress overstriking (other than for bold or underlined characters in case the old output format has been activated with -c).|
|-u||Suppress the use of underlining for italic characters. Ignored if -c isnt used.|
|-U||Use only underlining for bold-italic characters. Ignored if -c isnt used.|
|-v||Print the version number.|
|[rs]Xtty: sgr n|
|If n is non-zero or missing, enable SGR output (this is the default), otherwise use the old drawing scheme for bold and underline.|
|If set, the old drawing scheme for bold and underline (using the backspace character) is active. Colors are disabled.|
|Device description file for ascii device.|
|Font description file for font F of ascii device.|
|Device description file for ascii8 device.|
|Device description file for latin1 device.|
|Device description file for nippon device.|
|Font description file for font F of latin1 device.|
|Device description file for utf8 device.|
|Font description file for font F of utf8 device.|
|Device description file for cp1047 device.|
|Font description file for font F of cp1047 device.|
|Macros for use with grotty.|
|Additional klugdey character definitions for use with grotty.|
grotty is intended only for simple documents.
There is no support for fractional horizontal or vertical motions.
There is no support for [rs]D commands other than horizontal and vertical lines.
Characters above the first line (ie with a vertical position of~0) cannot be printed.
Color handling is different compared to grops(1). [rs]M doesnt set the fill color for closed graphic objects (which grotty doesnt support anyway) but changes the background color of the character cell, affecting all subsequent operations.