/*
 * Copyright (C) 2008-2015 by Holger Arndt
 *
 * This file is part of the Universal Java Matrix Package (UJMP).
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership and licensing.
 *
 * UJMP is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * UJMP is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with UJMP; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301  USA
 */

package org.ujmp.core.doublematrix.calculation.entrywise.misc;

import org.ujmp.core.Matrix;
import org.ujmp.core.doublematrix.calculation.AbstractDoubleCalculation;

public class GrayScale extends AbstractDoubleCalculation {
	private static final long serialVersionUID = -4082255477140195806L;

	public enum ColorChannel {
		Red, Green, Blue
	}

	private final ColorChannel colorChannel;;

	public GrayScale(Matrix matrix, ColorChannel colorChannel) {
		super(matrix);
		this.colorChannel = colorChannel;
	}

	public double getDouble(long... coordinates) {
		final int value = getSource().getAsInt(coordinates);
		switch (colorChannel) {
		case Red:
			return ((value >> 16) & 0xFF) / 255.0;
		case Green:
			return ((value >> 8) & 0xFF) / 255.0;
		default:
			return (value & 0xFF) / 255.0;
		}
	}
}