    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.imaging.color;
    018
    019/**
    020 * Represents a color in the CIELAB color space, also known as LAB color space.
    021 *
    022 * <p>
    023 * Contains the constant values for black, white, red, green, and blue.
    024 * </p>
    025 *
    026 * @see <a href="https://en.wikipedia.org/wiki/CIELAB_color_space#CIELAB">https://en.wikipedia.org/wiki/CIELAB_color_space#CIELAB</a>
    027 * @since 1.0-alpha1
    028 */
    029public final class ColorCieLab {
    030
    031    /**
    032     * A constant for color black. Color components are:
    033     *
    034     * <pre>
    035     *     L*: 0
    036     *     a*: 0
    037     *     b*: 0
    038     * </pre>
    039     */
    040    public static final ColorCieLab BLACK = new ColorCieLab(0, 0, 0);
    041
    042    /**
    043     * A constant for color white. Color components are:
    044     *
    045     * <pre>
    046     *     L*: 100
    047     *     a*: 0
    048     *     b*: 0
    049     * </pre>
    050     */
    051    public static final ColorCieLab WHITE = new ColorCieLab(100, 0, 0);
    052
    053    /**
    054     * A constant for color red. Color components are:
    055     *
    056     * <pre>
    057     *     L*: 53
    058     *     a*: 80
    059     *     b*: 67
    060     * </pre>
    061     */
    062    public static final ColorCieLab RED = new ColorCieLab(53, 80, 67);
    063
    064    /**
    065     * A constant for color green. Color components are:
    066     *
    067     * <pre>
    068     *     L*:  88
    069     *     a*: -86
    070     *     b*:  83
    071     * </pre>
    072     */
    073    public static final ColorCieLab GREEN = new ColorCieLab(88, -86, 83);
    074
    075    /**
    076     * A constant for color blue. Color components are:
    077     *
    078     * <pre>
    079     *     L*:   32
    080     *     a*:   79
    081     *     b*: -108
    082     * </pre>
    083     */
    084    public static final ColorCieLab BLUE = new ColorCieLab(32, 79, -108);
    085
    086    /** Lightness L*. */
    087    public final double l;
    088
    089    /** a* value. */
    090    public final double a;
    091
    092    /** b* value. */
    093    public final double b;
    094
    095    /**
    096     * Constructs a new instance.
    097     *
    098     * @param l perceptual lightness L*.
    099     * @param a a* value.
    100     * @param b b* value.
    101     */
    102    public ColorCieLab(final double l, final double a, final double b) {
    103        this.l = l;
    104        this.a = a;
    105        this.b = b;
    106    }
    107
    108    @Override
    109    public boolean equals(final Object o) {
    110        if (this == o) {
    111            return true;
    112        }
    113        if (o == null || getClass() != o.getClass()) {
    114            return false;
    115        }
    116
    117        final ColorCieLab that = (ColorCieLab) o;
    118        if (Double.compare(that.l, l) != 0) {
    119            return false;
    120        }
    121        if (Double.compare(that.a, a) != 0) {
    122            return false;
    123        }
    124        if (Double.compare(that.b, b) != 0) {
    125            return false;
    126        }
    127
    128        return true;
    129    }
    130
    131    @Override
    132    public int hashCode() {
    133        int result;
    134        long temp;
    135        temp = Double.doubleToLongBits(l);
    136        result = (int) (temp ^ temp >>> 32);
    137        temp = Double.doubleToLongBits(a);
    138        result = 31 * result + (int) (temp ^ temp >>> 32);
    139        temp = Double.doubleToLongBits(b);
    140        return 31 * result + (int) (temp ^ temp >>> 32);
    141    }
    142
    143    @Override
    144    public String toString() {
    145        return "{L: " + l + ", a: " + a + ", b: " + b + "}";
    146    }
    147}