Lightens or darkens a color

ColorUtils.java

package com.desk.android.util;

import android.graphics.Color;

/**
 * Lightens or darkens a color
 */
public final class ColorUtils {

    private ColorUtils() {
        // prevent instantiation
    }

    public static int lighten(int color, float amount) {
        String hex = Integer.toHexString(color);
        if (hex.length() == 8) {
            hex = hex.substring(2, 8);
        }
        if (hex.length() < 6) {
            return color;
        }
        int r = Integer.parseInt(hex.substring(0, 2), 16);
        int g = Integer.parseInt(hex.substring(2, 4), 16);
        int b = Integer.parseInt(hex.substring(4, 6), 16);

        int nR = (int) ((r * (1 - amount) / 255 + amount) * 255);
        int nG = (int) ((g * (1 - amount) / 255 + amount) * 255);
        int nB = (int) ((b * (1 - amount) / 255 + amount) * 255);

        return Color.rgb(nR, nG, nB);
    }

    public static int darken(int color, float amount) {
        String hex = Integer.toHexString(color);
        if (hex.length() == 8) {
            hex = hex.substring(2, 8);
        }
        if (hex.length() < 6) {
            return color;
        }
        int r = Integer.parseInt(hex.substring(0, 2), 16);
        int g = Integer.parseInt(hex.substring(2, 4), 16);
        int b = Integer.parseInt(hex.substring(4, 6), 16);

        int nR = (int) ((r * (1 - amount) / 255) * 255);
        int nG = (int) ((g * (1 - amount) / 255) * 255);
        int nB = (int) ((b * (1 - amount) / 255) * 255);

        return Color.rgb(nR, nG, nB);
    }

}