/*
 * #%L
 * Image processing operations for SciJava Ops.
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 * Copyright (C) 2014 - 2024 SciJava developers.
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package org.scijava.ops.image.geom.geom2d;

import java.util.List;

import org.scijava.ops.image.geom.GeomUtils;
import net.imglib2.RealLocalizable;
import net.imglib2.roi.geom.real.Polygon2D;
import net.imglib2.type.numeric.real.DoubleType;

import org.scijava.function.Computers;

/**
 * Generic implementation of {@code geom.boundarySize}.
 *
 * @author Daniel Seebacher (University of Konstanz)
 * @implNote op names='geom.boundarySize', label='Geometric (2D): Perimeter'
 */
public class DefaultPerimeterLength implements
	Computers.Arity1<Polygon2D, DoubleType>
{

	/**
	 * TODO
	 *
	 * @param input
	 * @param boundarySize
	 */
	@Override
	public void compute(final Polygon2D input, final DoubleType boundarySize) {
		double perimeter = 0;
		final List<? extends RealLocalizable> vertices = GeomUtils.vertices(input);
		final var size = vertices.size();
		for (var i = 0; i < size; i++) {
			final var nexti = (i + 1) % size;

			final var dx2 = vertices.get(nexti).getDoublePosition(0) - vertices
				.get(i).getDoublePosition(0);
			final var dy2 = vertices.get(nexti).getDoublePosition(1) - vertices
				.get(i).getDoublePosition(1);

			perimeter += Math.sqrt(dx2 * dx2 + dy2 * dy2);
		}

		boundarySize.set(perimeter);
	}

}
