registerFilter:
Create the definition a filter effect.
Description
A feature of SVG is that elements can be filtered using filter effects
defined somewhere in the document. The purpose of this function is to
create the definition of a filter effect so that it can be referred to
by grobs drawn by gridSVG.
Usage
registerFilter(label, filter)
Arguments
label
A character identifier for the definition.
filter
A filter object, produced by the filterEffect
function.
Value
None.
Details
When registering a filter, all locations and dimensions that filter
effects refer to become fixed.