Main.java Source code

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Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright (C) 2014 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.graphics.Color;

public class Main {
    /**
     * Calculates the luminance value of a given {@code int} representation of {@link Color}.
     * <p>
     * Derived from formula at http://gmazzocato.altervista.org/colorwheel/algo.php
     *
     * @param color The {@link Color} to evaluate
     * @return the luminance value of the given color
     */
    public static double calculateLuminance(int color) {
        final double[] sRGB = new double[3];
        sRGB[0] = Color.red(color) / 255.0d;
        sRGB[1] = Color.green(color) / 255.0d;
        sRGB[2] = Color.blue(color) / 255.0d;

        final double[] lumRGB = new double[3];
        for (int i = 0; i < sRGB.length; ++i) {
            lumRGB[i] = (sRGB[i] <= 0.03928d) ? sRGB[i] / 12.92d : Math.pow(((sRGB[i] + 0.055d) / 1.055d), 2.4d);
        }

        return 0.2126d * lumRGB[0] + 0.7152d * lumRGB[1] + 0.0722d * lumRGB[2];
    }
}