Re: [docbook-apps] Quality of encoded charts . . .

[Vincent Hennebert <vhennebert@gmail.com>]

Hi,

My experience with LaTeX is getting old, so I may have missed the latest
news. Anyway...

Albretch Mueller wrote:
> ~
>  Say you have a body of texts about engineering or Sciences including
> lots of drawings (colours are not important) with basically lines,
> planes, ... how well can you encode and ultimately render/print such
> charts using latex?

AFAIK you’ll have very low accuracy with plain, portable LaTeX. However,
in this case almost everyone uses an extension like pstricks or
pdftricks. By outputting PostScript or PDF commands they bring the full
power of the underlying format; with the obvious limitation that the
resulting file will be compatible only with that format. It all depends
on your needs: if you need only PDF output you can use pdftricks and
pdflatex to create PDF; if you need both PostScript and PDF you’ll have
to use pstricks and a tool like ps2pdf to get the PDF version.

Search the web for pstricks/pdftricks or graphics with LaTeX. You might
find the syntax of the commands provided by those extensions quite scary.


>  If you want to specify, say, a circumference a la (X - X0)^2 + (Y -
> Y0)^2 = 25 and then specify a line going right through its center Y =
> P*(X - X0) + Y0, which what precision could you specify P?

With the tools above, a virtually perfect precision (i.e., error on the
printed output not noticeable by human eye).


>  Could you specify any of these formulas of analytic Geometry?
> ~
>  Is this a problem relating to DocBook or it is just related to the
> resolution of the printer you use?

Printers have a resolution of at least 300dpi nowadays, so it’s
certainly not a printer issue. This may be, however, a DocBook issue,
and again it depends on the output format(s) you need. If you only need
a printed output then the LaTeX route might suit your needs; see
dblatex [1] for converting DocBook into LaTeX. However, in that case you
might want to skip the DocBook step and directly author the document in
LaTeX.

If you also need a decent HTML output then it suddenly becomes more
complicated. Basically you need to find the right format to create your
drawings; ideally you would have only one source format that you would
convert into PNG (or any bitmap format) for web output, and SVG,
PostScript or PDF (or any vectorial format) for printed output.

You can use any graphics editor (like inkscape [2]) to create your
drawings, but they may not be suitable for producing mathematical
figures like this. You may have to go for more specialized tools
(gnuplot [3], maybe).

In short, the possible lack of precision (and convenience) will not be
due to the printer resolution, but to the chain tool you will be using
to produce your documents. Be it based on DocBook or any other format,
BTW.


>  Once I have a DocBook document I don't need a LaTeX one in order to
> convert if to ps and pdf formats right?

Right. You can also go the XSL-FO (+ SVG and possibly MathML) route. The
official DocBook stylesheets have an XSL-FO output option, that you can
then render into PDF (or PostScript) using an XSL-FO processor. See
FOP [4] for an open-source one, Xep [5] or XSL Formatter [6] for
commercial ones.

At the risk of overly simplifying, LaTeX is old, complicated to setup
and use, not very flexible, but produces high quality,
professional-looking output (especially formulas). XSL-FO tools
represent the future, are modern and easy, but may still lack of
functionalities and especially typographical quality. In the end you
have to choose the tool that best meets the trade-offs you are ready to
make.


Hope this clarifies the whole thing a bit,
Vincent


[1] http://dblatex.sourceforge.net/
[2] http://www.inkscape.org/
[3] http://www.gnuplot.info/
[4] http://xmlgraphics.apache.org/fop/
[5] http://www.renderx.com/tools/xep.html
[6] http://www.antennahouse.com/