Color alpha

ColorAlpha.java

 /** 
 * @param originalColor color, without alpha 
 * @param alpha         from 0.0 to 1.0 
 * @return 
 */ 
public static String addAlpha(String originalColor, double alpha) {
    long alphaFixed = Math.round(alpha * 255);
    String alphaHex = Long.toHexString(alphaFixed);
    if (alphaHex.length() == 1) {
        alphaHex = "0" + alphaHex;
    } 
    originalColor = originalColor.replace("#", "#" + alphaHex);
 
 
    return originalColor;
}