## 4. The Filters Window

The filters window

This window displays all filters currently installed in the system. It provides simple descriptions of each filter, and allows you to drag and drop filters into pipelines. Access this window by selecting Windows -> Filters from a song window or a track window.

The window consists of a single list view, which behaves similarly to the Tracker list view. The columns are:

- Name. The name of the filter.
- Type. Certain filters only work in certain positions in the pipeline. The most common type of filter is through, which can be placed anywhere in the edit pipeline, anywhere but the head of the input pipeline, and anywhere but the tail of the output pipeline. Input filters can be placed only at the head of the input pipeline, and output filters can be placed only at the tail of the output pipeline.
- Description. A short description of the filter.
- Info. (by default this column is hidden; select Attributes -> Info to make it visible) Miscellaneous information about the filter: Its unique name, version number, and author.

4.1. Installing New Filters
Filter add-ons for Sequitur can be placed in the following folder:

- add-ons/Filters/ (from the folder in which Sequitur was launched)

True to the live nature of BeOS, it's not necessary to exit Sequitur before installing new add-ons. Simply drop them in a valid directory and watch them appear in the filter window.

4.2. Writing New Filters
Sequitur includes a development kit and the source code for nearly all of its filters (not included are the input and output filters) in the DevKit/ExampleFilters/ folder. The Example filter is a simple filter to get started if you simply want a template. The Dan filter is another simple example, and is also heavily commented.

Neither of these filters provide examples of writing user interfaces to change your filter's attributes. Please direct any questions to Eric Hackborn.

PLEASE NOTE: The filter API included with this release will change for Sequitur 2.0. While rewriting filters will hopefully be nothing more than a recompilation, the changes might be more drastic. Be aware of this as you're developing your own filters.

4.3. Menu Bar
Attributes

- Toggles the Name, Type, Description and Info columns.