Compass layer

<!-- compass background layer -->
<layer name="compass1" 
url="compass_bg.png" align="rightbottom" x="10" y="10" keep="true" 
children="false" scalechildren="true" destscale="1.0" 
onclick="switch(destscale,1.0,0.5);tween(scale,get(destscale));">


<!-- compass plate -->
<layer name="compass1_plate" url="buscard.png" align="center" zorder="1" /> 


<!-- compass pointer -->
<layer name="compass1_pointer" url="agocor.png" align="center" zorder="2" />


	</layer>
	
	<!-- view changing event -->
	<events name="compass_events" onviewchange="compass_update_rotate();" />


	<!-- update the rotation values -->
	
<action name="compass_update_rotate">
set(global_heading, 180);
calc(layer[compass1_pointer].rotate, view.hlookat - global_heading);
</action>