Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright 2015 The Android Open Source Project
 *
 * 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 {
    /**
     * Composite two potentially translucent colors over each other and returns the result.
     */
    public static int compositeColors(int foreground, int background) {
        int bgAlpha = Color.alpha(background);
        int fgAlpha = Color.alpha(foreground);
        int a = compositeAlpha(fgAlpha, bgAlpha);

        int r = compositeComponent(Color.red(foreground), fgAlpha, Color.red(background), bgAlpha, a);
        int g = compositeComponent(Color.green(foreground), fgAlpha, Color.green(background), bgAlpha, a);
        int b = compositeComponent(Color.blue(foreground), fgAlpha, Color.blue(background), bgAlpha, a);

        return Color.argb(a, r, g, b);
    }

    private static int compositeAlpha(int foregroundAlpha, int backgroundAlpha) {
        return 0xFF - (((0xFF - backgroundAlpha) * (0xFF - foregroundAlpha)) / 0xFF);
    }

    private static int compositeComponent(int fgC, int fgA, int bgC, int bgA, int a) {
        if (a == 0)
            return 0;
        return ((0xFF * fgC * fgA) + (bgC * bgA * (0xFF - fgA))) / (a * 0xFF);
    }
}