OsmAnd/OsmAnd/res/drawable/btn_circle_n.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >

    <item>
        <bitmap
            android:gravity="fill"
            android:src="@drawable/map_bt_round_1_shadow" />
    </item>
    <item>
        
        <inset
            android:insetBottom="@dimen/map_button_inset_shadow"
            android:insetLeft="@dimen/map_button_inset_shadow"
            android:insetRight="@dimen/map_button_inset_shadow"
            android:insetTop="@dimen/map_button_inset_shadow" >
            <shape android:shape="oval" >
                <solid android:color="@color/map_widget_light" />
            </shape>
        </inset>
    </item>

</layer-list>