titanscssc::lib_opacify PHP Method

    protected function lib_opacify($args)
    {
        $color = $this->assertColor($args[0]);
        $amount = $this->coercePercent($args[1]);
        $color[4] = (isset($color[4]) ? $color[4] : 1) + $amount;
        $color[4] = min(1, max(0, $color[4]));
        return $color;
    }