How does the Maps app on the iPhone 3Gs rotate as you turn the phone?

Question

On an iPhone 3Gs, if you click the little "show my location" symbol on the lower left of the window twice, it switches to a mode that causes the map to rotate so that north on the map faces towards north according to the compass. I don't have a 3Gs, so I just found out about this from a buddy who does have one.

I tried applying a rotation transformation to a MKMapView's layer, like this:

CATransform3D rotationTransform = CATransform3DIdentity;  
rotationTransform = CATransform3DRotate(rotationTransform, degreesToRadians(-20), 0.0, 0.0, 1.0);  
theMapView.layer.transform = rotationTransform;

That sort of works, but not really. The contents of the map do rotate, but the frame rotates and stretches. The map view ends up in a strip that stretches diagonally across the screen, and it ends up under the buttons in my view.

I tried enclosing the map in another view to isolate it, but that doesn't work either. Next I'll try rotating the enclosing view, but I'm hoping somebody else has figured this out. Getting it to work by trial and error is likely to be difficult at best.

Regards,

Duncan C

Answer 1

Would you be able to provide some sample code on how you did this. I seem to be muddling through xcode and getting errors with trying to implement this.

Appreciate you sharing your knowledge