filter (combination)

Description

In Regina 6.0.1 and earlier, the filter element was used to store different types of normal surface filters, and was held within an enclosing packet (surface filter) element.. This page describes how the filter element was structured when storing a combination filter. Since Regina 7.0, each filter type now has its own XML element, which also serves as the XML element for the filter packet. In particular, combination filters are now stored using the filtercomb element.

A combination filter uses a logical operation to combine other normal surface filters into a single more complex surface filter.

The filters being combined must be immediate children of the packet representing this combination filter. The logical operation used to combine these child filters is described by the child op element.

More information about surface filters can be found in the general filter element documentation.