November 28, 2006

ProWikiCenter
Cdml Te X

The element CdmlTeX is used for writing mathematical formulas primarily. This feature uses TeX as a subsystem called from ProWiki to render the formulas.

The text:

 [[Tex]
x_{1,2} = - { b \over 2 } \pm \sqrt { { b^2 \over 4 } - c }
]

produces:

You can test this on http://www.schoolwiki.org/wiki.cgi?TestPageForFormulas.

### Parameters

• scale: influences the size of the graphic produced (default: 0.5); e.g. [scale=0.8] which produces a picture 60% larger.

### Installation of the TeX subsystem

To use this feature you should follow these instructions:

• install TeX (the tetex package, you need tex, gs, dvips)
• install the graphics package netpbm (you need pnmcrop, pbmtopgm,pnmcrop, pnmscale, ppmtogif)
• create seven corresponding symbolic links in the ExecutablesDir, so that the ProWiki script can call these programs.
• install the following Perl script tex2gif in the ExecutablesDir, which is called by the ProWiki script and actually does most of interfacing.
 cd $2 tex$1.tex dvips $1.dvi time gs -r300 -dNOPAUSE -dBATCH -sDEVICE=pbmraw -sPAPERSIZE=a3 -sOutputFile=$1.pbm $1.ps pnmcrop$1.pbm >$1.pnm pbmtopgm 3 3$1.pnm >$1.pgm pnmscale$3 $1.pgm >$1-ss.pgm ppmtogif $1-ss.pgm >$1.gif rm $1*.p*$1.dvi \$1.log

• check all permissions to make sure that the ProWiki script is allowed to call the tex2gif script and the other executables.
Note: If you want to use very special symbols, fonts or font sizes then you must install these according to instructions of the TeX system. ProWiki can only pass commands to TeX, and TeX can only act with what it has available.

Note: If you have LaTeX installed, then you also have TeX installed. LaTeX is a macro package that makes TeX easier to use. It has no effect on the ProWiki => TeX interface.

Note: TeX produces BlackAndWhite pixel graphics which is not very beautiful on screen. So we use the trick to produce the formula in triple resolution of what we need on screen (300 dpi instead of 100dpi) and then scale this down by this factor 3 going to gray scale, which produces nicer, smooth antialiased pictures.

### Implementation notes

The TeX subsystem uses SubSystemPictureCaching.

FolderWikiFeatures FolderCdml