source: rtems-source-builder/source-builder/sb/asciidoc/doc/latex-bugs.txt @ 0464153

Bugs in asciidoc latex backend
==============================
Geoff Eddy

Benjamin Klum was unable to maintain the LaTeX backend beyond version
8.2.7, and as a consequence the `latex.conf` file ceased to work with
`asciidoc` sometime after this. For version 8.4.3 I made some changes
to the file to get it working again. This document summarises the
remaining issues which I have found with generating LaTeX and thence
PDF output with `asciidoc`, which is done as follows:

- `asciidoc --backend=latex --unsafe FILE.txt`
- `latex FILE.tex`
- `kpdf FILE.pdf`

Many of these were found by processing the `asciidoc.txt` file and
comparing the HTML output with the PDF.

== Footnotes

Priority:: Low.

Problem:: References to footnotes, and a sensible value for the
`[footnoteref-inlinemacro]` section, don't seem to be possible.

Cause:: LaTeX doesn't support footnoting much beyond creating a
footnote at a certain point in text and displaying the footnote
itself.

Solution:: Unclear. How important or necessary is this, anyway?

== Spurious text at starts of paragraphs

Priority:: Medium

Problem:: It is necessary to insert spurious text in paragraphs.

Cause:: This `asciidoc` input:
+
  -------------------------------------------------------------------
  Text
  -------------------------------------------------------------------
+
generates this LaTeX code:
+
  \begin{lstlisting}
  SPURIOUS TEXTText\end{lstlisting}
+
which should be:
+
  \begin{lstlisting}[]
  Text\end{lstlisting}

Solution:: Find out a way to generate the correct LaTeX output as
above. The obvious solution, as explained in `latet.conf`, doesn't
work.

== Tables

Priority:: Rather high.

Problem:: Not all of the table configuration options can be passed
through to the LaTeX backend. In particular, I've had to assume that
all tables will be fifteen or fewer left-justified columns wide.

Cause:: The table models in LaTeX and HTML are too dissimilar for one
`asciidoc` specification to generate valid output in both formats by
simple regexp replacement. Related to this is the unfortunate fact
that `<COLGROUP>` and related tags aren't a required part of HTML4,
and some broswers (at least Firefox and Konqueror) don't implement
them.

Solution:: Perhaps table processing could be handled by a Python
plugin, which would read in a table spec and generate the appropriate
text?

== Unicode escaping

Priority:: Rather high, to me at least.

Problem:: The commented-out section in `latex.conf`, if uncommented,
converts `&#960;` to `\unichar{960}`, which then causes LaTeX to
complain that the resulting command is unavailable in encoding T1. The
more common non-ASCII characters, such as those in `félicité` and
`świeca`, are handled properly, but some - such as the IPA characters
in the `tipa` package - are not.

Cause:: The encodings in the LaTeX output are wrong.

Solution:: Correct the encodings.

== Text colours

Priority:: Probably low

Problem:: The text colour options are not processed by LaTeX; for
example `[#ff0000]#Red text#` is not rendered in red.

Cause:: LaTeX and HTML represent RGB triads differently: HTML is happy
with `#ff8000`, but LaTeX needs `[rgb]{1,0.5,0}`.

Solution:: Provide some sort of internal RGB conversion mechanism
which can convert RGB triads to different representations.

== Text sizes

Priority:: Probably low

Problem:: The text size options are not processed by LaTeX:
`[,,1]#text#` is rendered in the same size as normal text.

Cause:: HTML size tags - `h1` through `h7` - are directly derivable
from the size number, whereas LaTeX has a series of descriptive words
(`HUGE` through `normalsize` to `scriptsize`).

Solution:: Provide a way to treat the number as an index into an
array.

== Background colour in paragraphs

Priority:: Medium

Problem:: If the `backgroundcolor` attribute is specified in the
`lstset` command, all paragraphs are displayed as black rectangles by
`kpdf`, `xpdf`, and `evince`, although `kdvi` has no problems. I've
had to remove the attribute, and so paragraphs all appear on white
backgrounds. The PDF viewers also complain:

  Error (NNNN): Unknown operator 'rgb'

Cause:: Apparently a known bug in the output of `pdflatex`. Not a bug
in `asciidoc`.

Solution:: Wait until this bug is fixed?