The step's parameters by name, in a natural order for controls.
The parameter a single number sets in pipeline.set(op, value) (the
amount, EV or gamma), or null when the step only takes an object.
True when the step only changes colors, so it does nothing to a monochrome image.
True when the step reads neighbouring pixels (it needs pipeline.margin around tiles).
True when the step is computed from the image's own statistics.
Description of one correction step, for building controls such as sliders.