ImageProcedure

A [class@Procedure] subclass that makes it easier to write standard plug-in procedures that operate on drawables.

It automatically adds the standard

( [enum@RunMode], [class@Image], [class@Drawable] )

arguments of an image procedure. It is possible to add additional arguments.

When invoked via [method@Procedure.run], it unpacks these standard arguments and calls run_func which is a [ callback@RunImageFunc]. The "args" [struct@ValueArray] of [callback@RunImageFunc] only contains additionally added arguments.