# Filters Administration

The Filters administration page allows you to specify which filters are applied to displayed text and in what order. It also provides access to the settings page provided by some filters. Filters are applied to most user-text in moodle just before it is displayed. They permit 'last minute' modification of the text.

Filters are a 'pluggable' resource. More may be available at http://download.moodle.org/modules/filters.php.

Select the filters you wish to use by 'unhiding' them, with the eye icon. If you have more that one unhidden you can change the order in which they are applied with the up and down arrows.

## TeX notation

TeX notation is primarily used to generate inline mathematical formulae within Moodle resources. For example $$ sqrt(a+b) $$ (the $$ is the 'tag' for the start and end of this format).

Moodle uses external binaries to render the images which may need setting up for your system. The filter will first check for a LaTeX renderer (Ghostscript is also required for this method) and failing that will use the simpler mimetex binary included in the Moodle distribution. LaTex permits the whole range of syntax, whereas mimetex only supports a mathematical subset.

Ghostscript is available for Windows and there is a LaTeX implementation called MikTeX available also.

The settings page allows the LaTeX and Ghostscript binary paths to be configured, along with the LaTeX preamble.

### More info

MiKTeX
MimeTeX
LaTeX
ghostscript

## Word Censorship

Word Censorship scans text for 'bad words' from a pre-defined list. Each language pack has its own default list, but you can define your own. To define your own list enter the settings page and specify your list of words. The user will see the words obscured with a black block, although mousing over will pop up the original word.

## Resource Names Auto-Linking

Resource Name Auto-linking scans text for resource titles that exist in the same course. Where found they will be highlighted and a link created. Note that to use this effectively you should use descriptive titles. For example a title of 'Introduction' is poor because any use of the word 'Introduction' in the text will be linked regardless of what it refers to.

## Activity Names Auto-Linking

Activity Name Auto-linking scans text for activity titles that exist in the same course. Where found they will be highlighted and a link created. Note that to use this effectively you should use descriptive titles. For example a title of 'Quiz' is poor because any use of the word 'Quiz' in the text will be linked regardless of what it refers to.

## Glossary Auto-Linking

This filter scans the text for keywords used in any glossary in the course. Note, however, that each glossary entry must have linking enabled. Where found they will be highlighted and a link created.

## Email Protection

The Email Protection filter scans the text for any email addresses. Where found they are 'obfusticated' to help prevent automatic email collection systems from harvesting emails. This can reduce the risk of spam if parts of your Moodle site are open.

## Tidy

Tidy scans text for HTML constructs. Where found it applies rules that attempt to make the HTML valid. Note that the tidy functionality must be built in to your PHP installation for this to work.

## Multi-Language Content

This filter enables resources to be created in multiple languages. The resource language will then change when the user changes their selected Moodle language. To use this feature first create your contents in multiple languages (in the same resource). Then enclose each language block in the following tags:

          <span lang="XX" class="multilang">your_content_here</span>

You can still use the old (deprecated) span tags instead, for example:

          <lang lang="XX" >your_content_here</lang>