1 <layers>

     2 <visual>

     3 

     4 <param name="opacity" type="anim">

     5 <duration>2.0</duration>

     6 <style>linear</style>

     7 <keyframe at="0.0">0</keyframe>

     8 <keyframe at="0.5">0.75</keyframe>

     9 <keyframe at="1.0">1.0</keyframe>

    10 </param>

    11 

    12 </visual>

    13 </layers>

    14