ColorUtils.java

package net.frakbot.util.color;

import android.graphics.Color;

/**
 * The MIT License (MIT)
 * 
 * Copyright (c) 2014 Sebastiano Poggi
 * 
 * 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:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * 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.
 */
public class ColorUtils {

    public static final int MASK_ALPHA = 0xFF000000;
    public static final int MASK_RGB = 0x00FFFFFF;

    private static final int COMPONENT_MIN = 0;
    private static final int COMPONENT_MAX = 255;
    private static final float COMPONENT_MIN_FLOAT = 0f;
    private static final float COMPONENT_MAX_FLOAT = 1f;

    private static final int HSV_HUE = 0;
    private static final int HSV_SATURATION = 1;
    private static final int HSV_VALUE = 2;

    public static int getOpaqueVersionOf(int color) {
        return MASK_ALPHA | extractRGB(color);
    }

    public static int setAlphaOf(int color, int alpha) {
        alpha = clipComponent(alpha);
        return (MASK_ALPHA * alpha) | extractRGB(color);
    }

    private static int extractRGB(int color) {
        return color & MASK_RGB;
    }

    private static int clipComponent(int value) {
        if (value < COMPONENT_MIN) {
            return COMPONENT_MIN;
        } else if (value > COMPONENT_MAX) {
            return COMPONENT_MAX;
        }
        return value;
    }

    public static int changeHueOf(int originalColor, float factor) {
        float[] hsv = new float[3];
        int alpha = Color.alpha(originalColor);
        Color.colorToHSV(originalColor, hsv);

        hsv[HSV_HUE] = multiplyComponent(hsv[HSV_HUE], factor);

        return Color.HSVToColor(alpha, hsv);
    }

    public static int changeSaturationOf(int originalColor, float factor) {
        float[] hsv = new float[3];
        int alpha = Color.alpha(originalColor);
        Color.colorToHSV(originalColor, hsv);

        hsv[HSV_SATURATION] = multiplyComponent(hsv[HSV_SATURATION], factor);

        return Color.HSVToColor(alpha, hsv);
    }

    public static int changeValueOf(int originalColor, float factor) {
        float[] hsv = new float[3];
        int alpha = Color.alpha(originalColor);
        Color.colorToHSV(originalColor, hsv);

        hsv[HSV_VALUE] = multiplyComponent(hsv[HSV_VALUE], factor);

        return Color.HSVToColor(alpha, hsv);
    }

    private static float multiplyComponent(float component, float factor) {
        return Math.min(component * factor, COMPONENT_MAX_FLOAT);
    }

    public static int setHueOf(int originalColor, float hue) {
        float[] hsv = new float[3];
        int alpha = Color.alpha(originalColor);
        Color.colorToHSV(originalColor, hsv);

        hue = clipComponent(hue);
        hsv[HSV_HUE] = hue;

        return Color.HSVToColor(alpha, hsv);
    }

    public static int setSaturationOf(int originalColor, float saturation) {
        float[] hsv = new float[3];
        int alpha = Color.alpha(originalColor);
        Color.colorToHSV(originalColor, hsv);

        saturation = clipComponent(saturation);
        hsv[HSV_SATURATION] = saturation;

        return Color.HSVToColor(alpha, hsv);
    }

    public static int setValueOf(int originalColor, float value) {
        float[] hsv = new float[3];
        int alpha = Color.alpha(originalColor);
        Color.colorToHSV(originalColor, hsv);

        value = clipComponent(value);
        hsv[HSV_VALUE] = value;

        return Color.HSVToColor(alpha, hsv);
    }

    private static float clipComponent(float value) {
        if (value < COMPONENT_MIN_FLOAT) {
            return COMPONENT_MIN_FLOAT;
        } else if (value > COMPONENT_MAX_FLOAT) {
            return COMPONENT_MAX_FLOAT;
        }
        return value;
    }

}