filter editor 4

For the very first filter, let's try out the flood fill, 

by selecting it from the list.
Click the add effect button right after.

”The feFlood filter primitive fills the region
with a given color and opacity.
It is usually used as an input
to other filters to apply color to a graphic.”




That equals as a base for bucket filling,
with the difference you have to define

the filled region's boundaries.

svg source