Mobile Device Features 2

Compass

• Certain devices have a built in compass sensor.

• If they do, they call the ondeviceorientation() function when the compass reading changes.

• An event object is passed to the function with the compass reading in evt.webkitCompassHeading.

function window_ondeviceorientation(evt)
  TextBox1.value=evt.webkitCompassHeading
End function

• The Compass sample uses this information to rotate an image of a compass.

• The webKitTransform function rotates an image efficiently.

pos="0"

function window_ondeviceorientation(e)
  imgCompass.style.webkitTransform="rotate(" & pos & "deg)"
  pos = e.webkitCompassHeading
  imgCompass.style.webkitTransform="rotate(-" & pos & "deg)"
End function