Returns the HSL (Hue/Saturation/Luminance) equivalent of a given RGB color. - Java 2D Graphics

Java examples for 2D Graphics:Color RGB

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Description

Returns the HSL (Hue/Saturation/Luminance) equivalent of a given RGB color.

Demo Code

/*//from   w w w .java  2  s  . co  m
 * This is a fork of GHEAT_JAVA https://github.com/varunpant/GHEAT-JAVA
 * <p>
 * The MIT License
 * <p>
 * Copyright (c) 2014 Varun Pant
 * <p>
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 * <p>
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 * <p>
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * <p>
 */
//package com.java2s;
import java.awt.*;

public class Main {
    /**
     * <p>Returns the HSL (Hue/Saturation/Luminance) equivalent of a given
     * RGB color. All three HSL components are between 0.0 and 1.0.</p>
     *
     * @param color the RGB color to convert
     * @return a new array of 3 floats corresponding to the HSL components
     */
    public static float[] RGBtoHSL(Color color) {
        return RGBtoHSL(color.getRed(), color.getGreen(), color.getBlue(),
                null);
    }

    /**
     * <p>Returns the HSL (Hue/Saturation/Luminance) equivalent of a given
     * RGB color. All three HSL components are between 0.0 and 1.0.</p>
     *
     * @param color the RGB color to convert
     * @param hsl   a pre-allocated array of floats; can be null
     * @return <code>hsl</code> if non-null, a new array of 3 floats otherwise
     * @throws IllegalArgumentException if <code>hsl</code> has a length lower
     *                                  than 3
     */
    public static float[] RGBtoHSL(Color color, float[] hsl) {
        return RGBtoHSL(color.getRed(), color.getGreen(), color.getBlue(),
                hsl);
    }

    /**
     * <p>Returns the HSL (Hue/Saturation/Luminance) equivalent of a given
     * RGB color. All three HSL components are between 0.0 and 1.0.</p>
     *
     * @param r the red component, between 0 and 255
     * @param g the green component, between 0 and 255
     * @param b the blue component, between 0 and 255
     * @return a new array of 3 floats corresponding to the HSL components
     */
    public static float[] RGBtoHSL(int r, int g, int b) {
        return RGBtoHSL(r, g, b, null);
    }

    /**
     * <p>Returns the HSL (Hue/Saturation/Luminance) equivalent of a given
     * RGB color. All three HSL components are floats between 0.0 and 1.0.</p>
     *
     * @param r   the red component, between 0 and 255
     * @param g   the green component, between 0 and 255
     * @param b   the blue component, between 0 and 255
     * @param hsl a pre-allocated array of floats; can be null
     * @return <code>hsl</code> if non-null, a new array of 3 floats otherwise
     * @throws IllegalArgumentException if <code>hsl</code> has a length lower
     *                                  than 3
     */
    public static float[] RGBtoHSL(int r, int g, int b, float[] hsl) {
        if (hsl == null) {
            hsl = new float[3];
        } else if (hsl.length < 3) {
            throw new IllegalArgumentException(
                    "hsl array must have a length of" + " at least 3");
        }

        if (r < 0)
            r = 0;
        else if (r > 255)
            r = 255;
        if (g < 0)
            g = 0;
        else if (g > 255)
            g = 255;
        if (b < 0)
            b = 0;
        else if (b > 255)
            b = 255;

        float var_R = (r / 255f);
        float var_G = (g / 255f);
        float var_B = (b / 255f);

        float var_Min;
        float var_Max;
        float del_Max;

        if (var_R > var_G) {
            var_Min = var_G;
            var_Max = var_R;
        } else {
            var_Min = var_R;
            var_Max = var_G;
        }
        if (var_B > var_Max) {
            var_Max = var_B;
        }
        if (var_B < var_Min) {
            var_Min = var_B;
        }

        del_Max = var_Max - var_Min;

        float H, S, L;
        L = (var_Max + var_Min) / 2f;

        if (del_Max - 0.01f <= 0.0f) {
            H = 0;
            S = 0;
        } else {
            if (L < 0.5f) {
                S = del_Max / (var_Max + var_Min);
            } else {
                S = del_Max / (2 - var_Max - var_Min);
            }

            float del_R = (((var_Max - var_R) / 6f) + (del_Max / 2f))
                    / del_Max;
            float del_G = (((var_Max - var_G) / 6f) + (del_Max / 2f))
                    / del_Max;
            float del_B = (((var_Max - var_B) / 6f) + (del_Max / 2f))
                    / del_Max;

            if (var_R == var_Max) {
                H = del_B - del_G;
            } else if (var_G == var_Max) {
                H = (1 / 3f) + del_R - del_B;
            } else {
                H = (2 / 3f) + del_G - del_R;
            }
            if (H < 0) {
                H += 1;
            }
            if (H > 1) {
                H -= 1;
            }
        }

        hsl[0] = H;
        hsl[1] = S;
        hsl[2] = L;

        return hsl;
    }
}

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