Frequently Asked Questions about preview-latex
**********************************************

Table of Contents
*****************

Frequently Asked Questions about preview-latex
1 Introduction
  1.1 How can I contribute to the FAQ?
2 Requirements
  2.1 Which version of (X)Emacs is needed?
  2.2 Which versions of GhostScript and AUCTeX are needed?
  2.3 I have trouble with the display format...
  2.4 For which OS does preview work?
3 Installation Trouble
  3.1 I could not install the precompiled RPM binaries
  3.2 I just get `LaTeX found no preview images'.
  3.3 I have problems with the XEmacs installation
  3.4 After installation of the XEmacs RPM package, AUCTeX does not work
4 Customization
  4.1 Why don't I get balloon help like in the screen shots?
  4.2 How to include additional environments like `enumerate'
  4.3 What if I don't want to change the document?
  4.4 Suddenly I get gazillions of ridiculous pages?!?
  4.5 Does preview-latex work with presentation classes?
5 Troubleshooting
  5.1 Preview causes all sort of strange error messages
6 preview-latex when not using LaTeX
  6.1 Does preview-latex work with  PDFLaTeX?
  6.2 Does preview-latex work with `elatex'?
  6.3 Does preview-latex work with ConTeXt?
  6.4 Does preview-latex work with plain TeX?


1 Introduction
**************

1.1 How can I contribute to the FAQ?
====================================

Send an email with the subject:
     Preview FAQ
   to <auctex-devel@gnu.org>.

2 Requirements
**************

2.1 Which version of (X)Emacs is needed?
========================================

See also the table at the end of the section.

   preview-latex nominally requires GNU Emacs with a version of at
least 21.1.  However, Emacs 22 (currently under development) offers
superior performance and wider platform support, and is even now the
recommended platform to use.  While XEmacs is still basically supported
by the AUCTeX team in spite of having almost no XEmacs users among
them, preview-latex and AUCTeX support is not a priority for XEmacs
developers.  This makes getting XEmacs bugs and shortcomings fixed such
an inefficient and unpleasant task that we can't in good conscience
recommend XEmacs to users that rely on continued support of AUCTeX.

2.2 Which versions of GhostScript and AUCTeX are needed?
========================================================

We recommend to use GNU or AFPL GhostScript with a version of at least
7.07.

   Proper PDFLaTeX support will require AUCTeX version 11.50 or later.
Versions before that are not supported.

2.3 I have trouble with the display format...
=============================================

We recommend keeping the variable `preview-image-type' set to `dvipng'
(if you have it installed) or `png'.  This is the default and can be
set via the Preview/Customize menu.

   All other formats are known to have inconveniences, either in file
size or quality.  There are some Emacs versions around not supporting
PNG, the proper idea to deal with that is to complain to your Emacs
providers.  Short of that, checking out PNM or JPEG formats might be a
good way to find out whether the lack of PNG format support might be
the only problem with your Emacs.

2.4 For which OS does preview work?
===================================

It is known to work under the X Window System for Linux and for several
flavors of Unix: we have reports for HP and Solaris.

   Under Windows, you should try the most recent versions of
preview-latex since a lot of typical Windows problems have been ironed
out lately.  Under XEmacs, both Cygwin and native ports should work.
Image support for GNU Emacs under Windows is expected with Emacs 22
which has not yet been released at the time of this writing.  CVS
versions of it already work, however.

   The entry "X11/Unix" currently means Linux, Solaris or HP/UX, as well
as the X-specific version for Mac/OSX.

OS             Emacs version   XEmacs version
X11/Unix       21.1            21.4.9
Win9x cygwin   21.4?           21.4.8
Win9x native   21.4?           21.4.8

   With display errors, XEmacs versions as early as 21.1.14 might also
work.

3 Installation Trouble
**********************

3.1 I could not install the precompiled RPM binaries
====================================================

Note that the binaries require RPM version 3.

3.2 I just get `LaTeX found no preview images'.
===============================================

The reason for this is that LaTeX found no preview images in the
document in question.

   One reason might be that there are no previews to be seen.  If you
have not used preview-latex before, you might not know its manner of
operation.  One sure-fire way to test if you just have a document where
no previews are to be found is to use the provided example document
`circ.tex' (you will have to copy it to some directory where you have
write permissions).  If the symptom persists, you have a problem, and
the problem is most likely a LaTeX problem.  Here are possible reasons:

Incompatible RPM installation
     The RPM packages are intended to run on a Redhat system. So the
     TeX files, provided by package `preview-latex-common' go into
     `/usr/share/texmf/tex/latex/preview' and
     `/usr/share/texmf/doc/latex/styles/preview'. If for your system the
     TeX files are in different places you have to set appropriate
     links.

     Another possibility is to get the tar archive, edit the
     `preview-latex.spec' accordingly, repack and then use the
     appropriate `rpm' command for building RPMs from a tar archive.
     If this works, please don't forget to send us the spec file, so
     that we may be able to help others with your platform.

Filename database not updated
     Various TeX distributions have their own ways of knowing where the
     files are without actually searching directories.  The normal
     preview-latex installation should detect common tools for that
     purpose and use them.  If this goes wrong, or if the files get
     installed into a place where they are not looked for, the LaTeX
     run will fail.

An incomplete manual installation
     This should not happen if you followed installation instructions.
     Unfortunately, people know better all the time.  If only
     `preview.sty' gets installed without a set of supplementary files
     also in the `latex' subdirectory, preview-latex runs will not
     generate any errors, but they will not produce any previews,
     either.

An outdated `preview' installation
     The `preview.sty' package is useful for more than just
     preview-latex.  For example, it is part of TeXlive.  So you have
     to make sure that preview-latex does not get to work with outdated
     style and configuration files: some newer features will not work
     with older TeX style files, and really old files will make
     preview-latex fail completely.  There usual is a local `texmf'
     tree, or even a user-specific tree that are searched before the
     default tree.  Make sure that the first version of those files
     that gets found is the correct one.

3.3 I have problems with the XEmacs installation
================================================

Please note that the XEmacs installation is different, since XEmacs has
a package system that gets used here.  Please make sure that you read
and follow the installation instructions for XEmacs.

   The XEmacs Lisp files provided by the `preview-latex-xemacs' RPM
package are in XEmacs package format and will be installed right into
the XEmacs package tree.  The location is detected when the RPM file is
built.  If it is wrong for your system, doing an
       rpmbuild --rebuild preview-latex-0.9.1-1.fedora.src.rpm
   should do the trick and should generate RPMs for your system (even if
that System happens to be SuSE rather than Fedora).

   Alternatively you could install preview-latex manually in your home
directory either in `~/.xemacs' (for XEmacs version below 21.4.x) or in
`~/.xemacs/xemacs-packages' (for versions starting with 21.4).

3.4 After installation of the XEmacs RPM package, AUCTeX does not work
======================================================================

Most likely you installed the RPM files and you have an XEmacs version
which uses a different architecture of directories, (SuSE is known to
have a no standard architecture, besides it changes it from SuSE
version to SuSE version).  Your init file will contain an invocation of
preview-latex according to the installation instructions in `INSTALL'.

   In consequence, the attempt to load preview-latex when entering
AUCTeX mode fails because of preview-latex being in a different
directory, and this AUCTeX's actication is aborted.  Please notice that
the installation instructions for Emacs and XEmacs differ.

4 Customization
***************

4.1 Why don't I get balloon help like in the screen shots?
==========================================================

Some users have reported problems with their XEmacs version, so balloon
help is no longer switched on by default.  Use the Preview/Customize
menu or `<M-x> customize-variable' in order to customize
`preview-use-balloon-help' to `On'.  This only concerns XEmacs:
tooltips under GNU Emacs are enabled by default and unproblematic.

4.2 How to include additional environments like `enumerate'
===========================================================

By default, preview-latex is intended mainly for displaying
mathematical formulas, so environments like `enumerate' or `tabular'
(except where contained in a float) are not included.  You can include
them however manually by adding the lines:

     \usepackage[displaymath,textmath,sections,graphics,floats]{preview}
     \PreviewEnvironment{enumerate}

   in your document header, that is before

     \begin{document}
   In general, `preview' should be loaded as the last thing before the
start of document.

   Be aware that

     \PreviewEnvironment{...}

   does not accept a comma separated list!  Also note that by putting
more and more

     \PreviewEnvironment{...}

   in your document, it will look more and more like a DVI file preview
when running preview-latex.  Since each preview is treated as one large
monolithic block by Emacs, one should really restrict previews to those
elements where the improvement in visual representation more than makes
up for the decreased editability.

4.3 What if I don't want to change the document?
================================================

The easiest way is to generate a configuration file in the current
directory.  You can basically either create `prdefault.cfg' which is
used for any use of the `preview' package, or you can use
`prauctex.cfg' which only applies to the use from with Emacs.  Let us
assume you use the latter.  In that case you should write something like

     \InputIfFileExists{preview/prauctex.cfg}{}{}
     \PreviewEnvironment{enumerate}

   in it.  The first line inputs the system-wide default configuration
(the file name should match that, but not your own `prauctex.cfg'),
then you add your own stuff.

4.4 Suddenly I get gazillions of ridiculous pages?!?
====================================================

When preview-latex works on extracting its stuff, it typesets each
single preview on a page of its own.  This only happens when actual
previews get generated.  Now if you want to configure preview-latex in
your document, you need to add your own `\usepackage' call to `preview'
so that it will be able to interpret its various definition commands.
It is an error to add the `active' option to this invocation: you don't
want the package to be active unless preview-latex itself enables the
previewing operation (which it will).

4.5 Does preview-latex work with presentation classes?
======================================================

preview-latex should work with most presentation classes.  However,
since those classes often have macros or pseudo environments
encompassing a complete slide, you will need to use the customization
facilities of `preview.sty' to tell it how to resolve this, whether you
want no previews, previews of whole slides or previews of inner
material.

5 Troubleshooting
*****************

5.1 Preview causes all sort of strange error messages
=====================================================

When running preview-latex and taking a look at either log file or
terminal output, lots of messages like

     ! Preview: Snippet 3 started.
     <-><->

     l.52 \item Sie lassen sich als Funktion $
                                              y = f(x)$ darstellen.
     ! Preview: Snippet 3 ended.(491520+163840x2494310).
     <-><->

     l.52 \item Sie lassen sich als Funktion $y = f(x)$
                                                        darstellen.

   appear (previous versions generated messages looking even more like
errors).  Those are not real errors (as will be noted in the log file).
Or rather, while they *are* really TeX error messages, they are
intentional.  This currently is the only reliable way to pass the
information from the LaTeX run of preview-latex to its Emacs part about
where the previews originated in the source text.  Since they are
actual errors, you will also get AUCTeX to state
     Preview-LaTeX exited as expected with code 1 at Wed Sep  4 17:03:30
   after the LaTeX run in the run buffer.  This merely indicates that
errors were present, and errors will always be present when
preview-latex is operating.  There might be also real errors, so in
case of doubt, look for them explicitly in either run buffer or the
resulting `.log' file.

6 preview-latex when not using LaTeX
************************************

6.1 Does preview-latex work with  PDFLaTeX?
===========================================

Yes, but the foreground color appears fixed to black.  Competent
volunteers to fix this welcome.  PDFLaTeX works fine with AUCTeX
version 11.50 or later.  For earlier versions, you need to have
LATEX-COMMAND-STYLE configured manually to call PDFLaTeX.

6.2 Does preview-latex work with `elatex'?
==========================================

No problem here.  If you configure your AUCTeX to use `elatex', or
simply have `latex' point to `elatex', this will work fine.

6.3 Does preview-latex work with ConTeXt?
=========================================

In short, no.  The `preview' package is LaTeX-dependent.  Adding
support for other formats requires volunteers.

6.4 Does preview-latex work with plain TeX?
===========================================

Again, no.  Restructuring the `preview' package for `plain' operation
would be required.  Volunteers welcome.

   In some cases you might get around by making a wrapper pseudo-Master
file looking like the following:

     \documentclass{article}
     \usepackage{plain}
     \begin{document}
     \begin{plain}
     \input myplainfile
     \end{plain}
     \end{document}