math/README

   1 == About texvc ==
   2
   3 texvc takes LaTeX-compatible equations and produces formatted output in
   4 HTML, MathML, and (via LaTeX/dvipng) rasterized PNG images.
   5 Input data is parsed and scrutinized for safety, and the output includes
   6 an estimate of whether the code is simple enough that HTML rendering will
   7 look acceptable.
   8
   9 The program was written by Tomasz Wegrzanowski for use with MediaWiki;
  10 it's included as part of the MediaWiki package (http://wikipedia.sf.net)
  11 and is under the GPL license.
  12
  13 Please report bugs at: http://bugzilla.wikimedia.org/ (under "MediaWiki")
  14
  15 == Setup ==
  16
  17 === Requirements ===
  18
  19 OCaml 3.06 or later is required to compile texvc; this can be acquired
  20 from http://caml.inria.fr/ if your system doesn't have it available.
  21
  22 The makefile requires GNU make.
  23
  24 Rasterization is done via LaTeX, dvipng. These need
  25 to be installed and in the PATH: latex, dvipng
  26
  27 AMS* packages for LaTeX also need to be installed. Without AMS* some
  28 equations will render correctly while others won't render.
  29 Most distributions of TeX already contain AMS*.
  30 In Debian/Ubuntu you need to install tetex-extra.
  31
  32 To work properly with rendering non-ASCII Unicode characters, a
  33 supplemental TeX package is needed (cjk-latex in Debian)
  34
  35 === Installation ===
  36
  37 Run 'make' (or 'gmake' if GNU make is not your default make). This should
  38 produce the texvc executable.
  39
  40 If you're using MediaWiki's install.php and have enabled $wgUseTeX in your
  41 LocalSettings.php, the installer will try to copy texvc into place, in the
  42 'math' subdirectory under where wiki.phtml is installed.
  43
  44
  45 == Usage ==
  46
  47 Normally texvc is called from MediaWiki's Math.php modules and everything
  48 Just Works. It can be run manually for testing or for use in another app.
  49
  50 === Command-line parameters ===
  51
  52     texvc <temp directory> <output directory> <TeX code> <encoding>
  53
  54 Be sure to properly quote the TeX code!
  55
  56 Example:
  57
  58     texvc /home/wiki/tmp /home/wiki/math "y=x+2" iso-8859-1
  59
  60 === Output format ===
  61
  62 Status codes and HTML/MathML transformations are returned on stdout.
  63 A rasterized PNG file will be written to the output directory, named
  64 for the MD5 hash code.
  65
  66 texvc output format is like this:
  67     +%5         ok, but not html or mathml
  68     c%5%h       ok, conservative html, no mathml
  69     m%5%h       ok, moderate html, no mathml
  70     l%5%h       ok, liberal html, no mathml
  71     C%5%h\0%m   ok, conservative html, with mathml
  72     M%5%h\0%m   ok, moderate html, with mathml
  73     L%5%h\0%m   ok, liberal html, with mathml
  74     X%5%m       ok, no html, with mathml
  75     S           syntax error
  76     E           lexing error
  77     F%s         unknown function %s
  78     -           other error
  79
  80  \0 - null character
  81  %5 - md5, 32 hex characters
  82  %h - html code, without \0 characters
  83  %m - mathml code, without \0 characters
  84
  85
  86 == Troubleshooting ==
  87
  88 Unforunately, many error conditions with rasterization are not well reported.
  89 texvc will return as though everything is successful, and the only obvious
  90 sign of problems for the user is a big X on a wiki page where an equation
  91 should be.
  92
  93 Try running texvc from the command line to ensure that the software it relies
  94 upon is all set up.
  95
  96 Ensure that the temporary and math directories exist and can be written to by
  97 the user account the web server runs under; if you don't control the server,
  98 you may have to make them world-writable.
  99
 100 If some equations render correctly while others don't, you probably don't have
 101 AMS* packages for LaTeX installed. Most distributions of TeX come with AMS*.
 102 In Debian/Ubuntu AMS* is in tetex-extra package.
 103 To check if that is the problem you can try those two equations:
 104     x + y
 105     x \implies y
 106 The first uses only standard LaTeX, while the second uses symbol \implies from AMS*.
 107 If the first renders, but the second doesn't, you need to install AMS*.
 108
 109 == Hacking ==
 110
 111 Before you start hacking on the math package its good to know the workflow,
 112 which is basically:
 113
 114 1. texvc gets called by includes/Math.php (check out the line begining with "$cmd")
 115 2. texvc does its magic, which is basically to check for invalid latex code.
 116 3. texvc takes the user input if valid and creates a latex file containing it, see
 117    get_preface in texutil.ml
 118 4. dvipng(1) gets called to create a .png file
 119    See render.ml for this process (commenting out the removal of
 120    the temporary file is useful for debugging).