Added perimeters to the Scala implementation, both PerimeterPoints (which is just a list of perimeter
points), and PixelWalk (which traces the outline of the animal in a compressed 4-connected contour).
Simultaneously dropped double-origin scheme where either origin or centroid could serve; now everything is relative to origin only. (Writing the perimeter code highlighted that the double-origin scheme was a significant hassle.)
Original origin scheme could be reinstated now that it's working in the simpler way.
Added perimeters to the Scala implementation, both PerimeterPoints (which is just a list of perimeter points), and PixelWalk (which traces the outline of the animal in a compressed 4-connected contour).
Simultaneously dropped double-origin scheme where either origin or centroid could serve; now everything is relative to origin only. (Writing the perimeter code highlighted that the double-origin scheme was a significant hassle.)
Original origin scheme could be reinstated now that it's working in the simpler way.