* @param   magenta the intensity of magenta. A value between 0 and 1
     * @param   yellow  the intensity of yellow. A value between 0 and 1
     * @param   black   the intensity of black. A value between 0 and 1
     */
    private void HelperCMYK(float cyan, float magenta, float yellow, float black) {
        if (cyan < 0)
            cyan = 0.0f;
        else if (cyan > 1.0f)
            cyan = 1.0f;
        if (magenta < 0)
            magenta = 0.0f;
        else if (magenta > 1.0f)
            magenta = 1.0f;
        if (yellow < 0)
            yellow = 0.0f;
        else if (yellow > 1.0f)
            yellow = 1.0f;
        if (black < 0)
            black = 0.0f;
        else if (black > 1.0f)
            black = 1.0f;
        content.append(cyan).append(' ').append(magenta).append(' ').append(yellow).append(' ').append(black);
    }