/*	dvipost manpage

$Copyright (C) 2002 Erich Fruehstueck

Dvipost is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

Dvipost is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty
of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.

You should have received a copy of the GNU General Public
License along with dvipost; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*/

\mpage[1] dvipost
\Name
dvipost, pptex, pplatex - post processing of dvi files

\Synopsis
|dvipost| [|-debug|] [|-version|] [|-help|] <in> <out>

|pplatex| [|-debug|] [|-version|] [|-help|] [LaTeX-Arguments]

|pptex| [|-debug|] [|-version|] [|-help|] [TeX-Arguments]

\Description
The command |dvipost| is a post procesor for dvi files, created by
|latex| or |tex|. It is used for special modes, which normally needs
the support of dvi drivers (such as |dvips|). With |dvipost|, this
features could be implemented independent of the prefered driver.
Currently, the post processor supports layout raster, change bars and
overstrike mode.

This version of |dvipost| does not seek the dvi file, so it could be
used as a filter. If |-| is given as file name, the command uses
standard input or standard output respective. The command does not
substitute a missing |.dvi| extension to the filename.

Because the command works with a temporary file and
creates the ouput file only after successfull processing the input file,
it is possible to use the same name for input and output.

If the command is renamed or linked to |pplatex|/|pptex|, it
runs |latex|/|tex| and post processes the createt output.
If the name of the dvi file could not be determined by the arguments
to |latex|/|tex| (e.g. on an interactive run),
the command processes all dvi files in the current directory with
a modification time later than the run of |latex|/|tex|.

\shead	Basics
If the filter is used in context of \LaTeX;, the style file
|dvipost.sty| should be included in the \LaTeX; source.

The filter interpretes dvi extensions in the form of
	|dvipost:| <name> [<arg>]
where <arg> depends on the command <name> and may be separated from
<name> by |=|  or space.
All other extensions are not interpreted by |dvipost| and
remain in the dvi file.

Such a dvipost command could be placed with the \TeX; primitive
	|\special{dvipost:| <cmd>|}|
or the \LaTeX; macro (provided by |dvipost.sty|)
	|\dvipost{|<cmd>|}|
in the dvi file.

Depending on the type of |dvipost| commands,
the following kinds of arguments may be used:
\ititem	length
	is a floating point number followed by a
	unit specification.
	The following units are supportet by |divipost|:
	|pt|, |in|, |cm| and |mm|.
	If no argument is given or the unit specification is missing,
	the corresponding <length> is set to 0.
\ititem	string
	is an arbitrary string argument.
\ititem	flag
	is an integer argument, where a value
	different from 0 (usually 1) means true and a missing value or 0
	means false.
\ititem	depth
	is an integer argument, where a value
	different from 0 (usually 1) increments a depth counter
	and a missing value or 0 decrements it.

\shead	Change bars

All text printed with change mode level higher than 0 is
marked with a change bar.

The following \LaTeX; macros modifies the change mode level:

\ttitem	|\changestart|
	increments the change mode level.
\ttitem	|\changeend|
	decrements the change mode level.
\ttitem	|\textchanged|{<text>}
	increments the change mode level for <text> only.

The following |dvipost| commands are used in context of change bars:
\ttitem cbmode <depth>
	increments/decrements the change mode level.
	This command is used by the \LaTeX; macros.
\ttitem cbrule <length>
	determines the thickness of the change bar. The default value
	is 2pt.
\ttitem cbsep <length>
	sets the distance beetween page margin and change bar.
	The default value is 2pt.
\ttitem cbexp <length>
	sets the additional height and depth of a character in
	calculating the change bar positions.
	The default value is 6pt.
\ttitem cbstart <string>
	places the dvi extension <string> before printing
	characters in change mode.
\ttitem cbend <string>
	places the dvi extension <string> after printing
	characters in change mode.

The use of |cbstart| and |cbend| allows to set additional attributes
to the marked text, depending on the dvi driver.

If |dvips| is used as dvi driver and the preamble of the \LaTeX;
source contains
	|\usepackage{dvipost}|\br
	|\dvipost{cbstart color push Blue}|\br
	|\dvipost{cbend color pop}|
the marked text is colored blue.

\shead	Overstrike mode

All text printed with overstrike level higher than 0 is
overstriked with a horizontal line.

The overstrike line is positioned at the mean height
of every block of text not broken by vertical movements and font
changes.

The following \LaTeX; macros modifies the overstrike level:

\ttitem	|\overstrikeon|
	increments the overstrike level.
\ttitem	|\overstrikeoff|
	decrements the overstrike level.
\ttitem	|\overstrike|{<text>}
	increments the overstrike level for <text> only.

The following |dvipost| commands are used in context of overstrike mode:
\ttitem osmode <depth>
	increments/decrements the overstrike level.
	This command is used by the \LaTeX; macros.
\ttitem osrule <length>
	sets the thickness of the overstrike line to <length>.
	The default value is |\fboxrule|.
\ttitem osstart <string>
	places the dvi extension <string> before change
	of overstrike mode.
\ttitem osend <string>
	places the dvi extension <string> after change
	of overstrike mode.

The use of |osstart| and |osend| is similar to |cbstart| and |cbend|.

\shead	Layout parameters

Layout parameters are transfered to the dvi file on loading the
style file. If any changes are made to layout parameters, like
|\evensidemargin|, the macro |\dvipostlayout| must be called
to get the correct placement of change bars. Additional calls
to |\dvipostlayout| are harmeless.

\latex{\begin{sloppypar}}
The following layout parameters are transfered to the dvi file:
|\hoffset|,
|\voffset|,
|\textwidth|,
|\textheight|,
|\oddsidemargin|,
|\evensidemargin|,
|\topmargin|,
|\headheight|,
|\headsep|,
|\footskip|,
|\marginparsep| and
|\marginparwidth|.
Additional the flag |twoside| is set to 0 or 1, depending on
the document style option |twoside|.
\latex{\end{sloppypar}}

Instead of calling |\dvipostlayout|, partciucular values could be set.
The command
	|\dvipost{evensidemargin=\the\evensidemargin}|
transfers the actual setting of |\evensidemargin| to the
dvi file.

The |dvipost| command allows the printing of the layout raster
by setting |layout| to a length different to 0. The value of
|layout| is used as the thickness of the raster lines.

For example: The command
	|\dvipost{layout=\the\fboxrule}|
activates the layout raster and uses the same line thicknes as frame boxes.

/*
top
footnote
bottom
float <depth>
*/

\Notes
The filter is primarly written for \LaTeX;.
It could be used for plain \TeX;, but currently there is no
assistance style file included in the distribution.
Maybe somone would write one, I am not a plain \TeX; user.

The current state of change bar mode and overstrike mode
must be committed do environments, which are placed on different
locations than the current text. This is done in |dvipost.sty|
by redefining |\color@begingroup| and |\color@endgroup|.
This may conflict with other packages.

If the macro |\footnoterule| is redefined, it should start with
the command |\dvipost{footnote}| for a correct handling of
overstrike mode and change bars.

\Copyright
Copyright \latex[(C)]{\copyright{}} 2002 Erich Fruehstueck