MetaDataHandlers are used to keep a state of the metaData rendered by a layer,
analyzing that data, and then performing some function based on that overall analysis.
As a subclass of MetaDataHandler, PolygonLabelMetaDataHandler is registered to a
PolygonLayer and is responsible for properly the labeling polygons of that layer
It does so by averaging the midpoint of each polygon evaluated that has the same
metadata, thus finding the centeral common points among the related polygons.
The sort function processes the element from a writable layer, sorting them
into a BSP tree with a depth no greater than maxDepth, and no more than
maxWeight elements per node.
The sort function processes the point elements from a writable layer, sorting them
into a BSP tree with a depth no greater than maxDepth, and no more than
maxWeight elements per node.
The sort function processes the polyline elements from a writable layer, sorting them
into a BSP tree with a depth no greater than maxDepth, and no more than
maxWeight elements per node.
The sort function processes the polygon elements from a writable layer, sorting them
into a BSP tree with a depth no greater than maxDepth, and no more than
maxWeight elements per node.