The document category filter controls normally appear at the top of the recoll GUI, either as checkboxes just above the result list, or as a dropbox in the tool area.

By default, they are labeled Media, Message, Spreadsheet, Text, etc. and each map to a document category.

The mapping used to be fixed. You could change the number and composition of categories by redefining them inside the {{{mimeconf}}} configuration file (you still can), but the filters always used document categories.

Categories can also be selected from the query language by using an rclcat: selector. E.g.: rclcat:message.

As of Recoll release 1.17, the filters are not hard-wired any more. They map to query language fragments. This means that you can freely redefine what they do.

The associations are configured inside the 'mimeconf' file, in the [guifilters] section. Most GUI parameters are stored in the Qt configuration file, so this is not entirely consistent, and you will have to bear with my lazyness here.

A simple exemple will hopefuly make things clearer. If you add the following to your '~/.recoll/mimeconf' file:

You will have four filter checkboxes, labelled Big Books, My Docs, etc.

The text after the equal sign must be a valid query language fragment, and will be translated to a Recoll query and combined with the rest of the query with an AND conjunction.

Any name text before a colon character will be erased in the display, but used for sorting. You can use this to display the checkboxes in any order you like. For exemple, the following would do exactly the same as above, but ordering the checkboxes in the reverse order.