# man > post-grohtml(1)

[_grohtml_(1)](https://www.chedong.com/phpMan.php/man/grohtml/1/markdown)                             General Commands Manual                            [_grohtml_(1)](https://www.chedong.com/phpMan.php/man/grohtml/1/markdown)

## Name
       grohtml, post-grohtml, pre-grohtml - _groff_ output driver for HTML

## Synopsis
       **pre-grohtml **[**-epV**] [**-a _**anti-aliasing-text-bits_] [**-D _**image-directory_] [**-F _**font-directory_] [**-g**
                   _anti-aliasing-graphic-bits_] [**-i _**resolution_] [**-I _**image-stem_] [**-o _**image-vertical-_
                   _offset_] [**-x _**html-dialect_] _troff-command_ _troff-argument_ ...

### pre-grohtml --help

### pre-grohtml -v
### pre-grohtml --version

       **post-grohtml **[**-bCGhlnrVy**] [**-F _**font-directory_] [**-j _**output-stem_] [**-s _**base-point-size_] [**-S**
                    _heading-level_] [**-x _**html-dialect_] [_file_ ...]

### post-grohtml --help

### post-grohtml -v
### post-grohtml --version

## Description
       The  GNU  _roff_  system's  HTML support consists of a preprocessor, _pre-grohtml_, and an output
       driver, _post-grohtml_; together, they translate ]8;;man:[roff(7)](https://www.chedong.com/phpMan.php/man/roff/7/markdown)\[_roff_(7)](https://www.chedong.com/phpMan.php/man/roff/7/markdown)]8;;\ documents to  HTML.   Because  a  pre‐
       processor  is (uniquely) required for this output driver, users should invoke _grohtml_ via the
       ]8;;man:[groff(1)](https://www.chedong.com/phpMan.php/man/groff/1/markdown)\[_groff_(1)](https://www.chedong.com/phpMan.php/man/groff/1/markdown)]8;;\ command with the **-Thtml **or **-Txhtml **options.  (In this installation, **ps  **is  the  de‐
       fault  output device.)  Use _groff_'s **-P **option to pass any options shown above to _grohtml_.  If
       no operands are given, or if _file_ is “**-**”, _grohtml_ reads the standard input stream.  Output is
       written to the standard output stream.

       _grohtml_ invokes _groff_ twice.  In the first pass, the preprocessor  _pre-grohtml_  renders  pic‐
       tures,  equations,  and tables as images in PostScript format using the **ps **output device.  In
       the second pass, the output driver _post-grohtml_ translates the output of ]8;;man:[troff(1)](https://www.chedong.com/phpMan.php/man/troff/1/markdown)\[_troff_(1)](https://www.chedong.com/phpMan.php/man/troff/1/markdown)]8;;\ to HTML.

       _grohtml_ writes output encoded in UTF-8 and has built-in HTML entities for  all  non-composite
       Unicode characters.  In spite of this, _groff_ may issue warnings about unknown special charac‐
       ters  if  they can't be found during the first pass.  Such warnings can be safely ignored un‐
       less the special characters appear inside a table or equation.

### Typefaces
       _grohtml_ supports the standard four styles: **R **(roman), **I **(_italic_), **B  **(**bold**),  and  **BI  **(**bold-**
       _**italic_**).  Fonts are grouped into families **T **and **C **having members in each style.

              **TR     **Times roman
              **TI     **Times italic
              **TB     **Times bold
              **TBI    **Times bold-italic
              **CR     **Courier roman
              **CI     **Courier italic
              **CB     **Courier bold
              **CBI    **Courier bold-italic

       A special font, **S**, is also provided to accommodate _roff_ documents that expect it to always be
       available.

### Font description files
       The  font  description  files  used  with  _grohtml_  expose the same glyph repertoire in their
       **charset **sections.  See ]8;;man:[groff_font(5)](https://www.chedong.com/phpMan.php/man/grofffont/5/markdown)\[_groff_font_(5)](https://www.chedong.com/phpMan.php/man/grofffont/5/markdown)]8;;\.

### Dependencies
       _pre-grohtml_ generates an image whenever an _eqn_ equation, _tbl_ table, or _pic_ picture is encoun‐
       tered in the input.  _grohtml_ therefore may run several commands as  part  of  its  operation.
       These  include  the  Netpbm  tools  _pnmcrop_,  _pnmcut_, and _pnmtopng_; Ghostscript (_gs_); and the
       PSUtils tool _psselect_.

## Options
       **--help **displays a usage message, while **-v **and **--version **show version  information;  all  exit
       afterward.

### -a _
              Number  of bits of antialiasing information to be used by text when generating PNG im‐
              ages.  The default is **4 **but **0**, **1**, and **2 **are also valid.  Your system's version  of  _gs_
              must  support  the  **-dTextAlphaBits  **option in order to exploit antialiasing.  A value
              of **0 **stops _grohtml_ from issuing antialiasing commands to _gs_.

### -b     

### -C     

### -D _
              Instruct _grohtml_ to place all image files into directory _image-directory_.

### -e     

              This option should not be manually specified; it is synthesized by _groff_ depending  on
              whether it was given the **-Thtml **or **-Txhtml **option.

### -F _
              Prepend  directory  font-directory_/dev_name  to the search path for font and device de‐
              scription files; _name_ is the name of the device, usually **html**.

### -g _
              Number of bits of antialiasing information to be used by graphics when generating  PNG
              images.  The default is **4 **but **0**, **1**, and **2 **are also valid.  Your system's version of _gs_
              must  support the **-dGraphicAlphaBits **option in order to exploit antialiasing.  A value
              of **0 **stops _grohtml_ from issuing antialiasing commands to _gs_.

### -G     

### -h     
              rather than HTML **H **elements.

### -i _
              Set the image resolution in pixels per inch; the default is **100**.

### -I _
              Determine  the  image  file  name stem.  If omitted, _grohtml_ uses _grohtml-_XXXXX (where
              _XXXXX_ is the process ID).  A dash is appended to the stem to separate it from the fol‐
              lowing image number.

### -j _
              Instruct _grohtml_ to split the HTML output into multiple files.  Output is written to a
              new file at each section heading (but see option **-S **below) named _output-stem-_n_.html_.

### -l     

### -n     
              the  option  the  anchor value is the textual heading.  This can cause problems when a
              heading contains a “?” on older versions of some browsers.  This feature is  automati‐
              cally enabled if a heading contains an image.

### -o _
              Specify the vertical offset of images in points.

### -p     
              number only when an image is required.

### -r     

### -s _
              Set the document's base type size in points.  When this size is used in the source, it
              corresponds  to  the  HTML base type size.  Every increase of two points in the source
              will produce a “**big**” element, and conversely when a decrease of two points is seen,  a
              “**small**” element is emitted.

### -S _
              When  splitting  HTML output (see option **-j **above), split at each nested heading level
              defined by _heading-level_, or higher).  The default is **1**.

### -V     

### -x _
              Select HTML dialect.  Currently, _html-dialect_ should be either the digit **4 **or the let‐
              ter **x**, which indicates whether _grohtml_ should generate HTML 4 or XHTML, respectively.

              This option should not be manually specified; it is synthesized by _groff_ depending  on
              whether it was given the **-Thtml **or **-Txhtml **option.

### -y      -V 
              specified).

## Environment
       _GROFF_FONT_PATH_
              lists  directories  in  which to search for _devhtml_, _grohtml_'s directory of device and
              font description files.  See ]8;;man:[troff(1)](https://www.chedong.com/phpMan.php/man/troff/1/markdown)\[_troff_(1)](https://www.chedong.com/phpMan.php/man/troff/1/markdown)]8;;\ and ]8;;man:[groff_font(5)](https://www.chedong.com/phpMan.php/man/grofffont/5/markdown)\[_groff_font_(5)](https://www.chedong.com/phpMan.php/man/grofffont/5/markdown)]8;;\.

       _SOURCE_DATE_EPOCH_
              A timestamp (expressed as seconds since the Unix epoch) to use as the output  creation
              timestamp  in place of the current time.  The time is converted to human-readable form
              using ]8;;man:[gmtime(3)](https://www.chedong.com/phpMan.php/man/gmtime/3/markdown)\[_gmtime_(3)](https://www.chedong.com/phpMan.php/man/gmtime/3/markdown)]8;;\ and ]8;;man:[asctime(3)](https://www.chedong.com/phpMan.php/man/asctime/3/markdown)\[_asctime_(3)](https://www.chedong.com/phpMan.php/man/asctime/3/markdown)]8;;\, and recorded in an HTML comment.

       _TZ_     The time zone to use when converting the current  time  to  human-readable  form;  see
              ]8;;man:[tzset(3)](https://www.chedong.com/phpMan.php/man/tzset/3/markdown)\[_tzset_(3)](https://www.chedong.com/phpMan.php/man/tzset/3/markdown)]8;;\.  If _SOURCE_DATE_EPOCH_ is used, it is always converted to human-readable form
              using UTC.

## Files
       _/usr/share/groff/1.23.0/font/devhtml/DESC_
              describes the **html **output device.

       _/usr/share/groff/1.23.0/font/devhtml/_F
              describes the font known as _F_ on device **html**.

       _/usr/share/groff/1.23.0/tmac/html.tmac_
              defines font mappings, special characters, and colors for use with the **html **output de‐
              vice.   It  is automatically loaded by _troffrc_ when either of the **html **or **xhtml **output
              devices is selected.

       _/usr/share/groff/1.23.0/tmac/html-end.tmac_
              finalizes setup of the **html **output device.  It is automatically loaded by  _troffrc-end_
              when either of the **html **or **xhtml **output devices is selected.

       _grohtml_ uses temporary files.  See ]8;;man:[groff(1)](https://www.chedong.com/phpMan.php/man/groff/1/markdown)\[_groff_(1)](https://www.chedong.com/phpMan.php/man/groff/1/markdown)]8;;\ for details about where such files are created.

## Bugs
       _grohtml_ is still beta code.

       _grohtml_  does  not truly support hyphenation, but you can fool it into hyphenating long input
       lines, which can appear in HTML output with a hyphenated word followed by a space but no line
       break.

**See also**
       ]8;;man:[groff(1)](https://www.chedong.com/phpMan.php/man/groff/1/markdown)\[_groff_(1)](https://www.chedong.com/phpMan.php/man/groff/1/markdown)]8;;\, ]8;;man:[troff(1)](https://www.chedong.com/phpMan.php/man/troff/1/markdown)\[_troff_(1)](https://www.chedong.com/phpMan.php/man/troff/1/markdown)]8;;\, ]8;;man:[groff_font(5)](https://www.chedong.com/phpMan.php/man/grofffont/5/markdown)\[_groff_font_(5)](https://www.chedong.com/phpMan.php/man/grofffont/5/markdown)]8;;\

groff 1.23.0                                31 March 2024                                 [_grohtml_(1)](https://www.chedong.com/phpMan.php/man/grohtml/1/markdown)