<layers>
    <visual>
        <param name="opacity" type="anim">
            <style>outquad</style>
            <duration>0.4</duration>
            <keyframe at="0.0">1.0</keyframe>
            <keyframe at="0.5">0.0</keyframe>
            <keyframe at="1.0">1.0</keyframe>
        </param>
    </visual>
</layers>