How to resize MKAnnotationView on iOS6? - mkmapview

Question

Resize MKAnnotationView Image When map zooms in and out? This methord are successful on iOS5, but failed on iOS6.
I change the MKAnnotationView's transform directly, and no luck. The MKAnnotationView only resize in a flash(When touch up inside the MKMapView, after the touch up finish, the MKAnnotationView will restore the original size).
My code are below:
- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated {
for (id <MKAnnotation>annotation in _mapView.annotations) {
// if it's the user location, just return nil.
if ([annotation isKindOfClass:[MKUserLocation class]])
continue;
// handle our custom annotations
//
if ([annotation isKindOfClass:[XPMKAnnotation class]])
{
// try to retrieve an existing pin view first
MKAnnotationView *pinView = [_mapView viewForAnnotation:annotation];
//resize the pin view
double zoomLevel = [_mapView getZoomLevel];
double scale = (1.0 * zoomLevel / 16) + 0.5;
pinView.transform = CGAffineTransformMakeScale(scale, scale);
}
}
}
Can we resize the MKAnnotationView on iOS6? Anybody know any way?

Answer 1

Apple suggests resizing the .image property of an annotation view. In my case shown below, I looked at the UIImage that was set in the viewforAnnotation and re-scaled it to the zoom level in a UIPinchGestureRecognizer
UIImage *orangeImage = [UIImage imageNamed:#"Orange210.PNG"];
CGRect resizeRect;
//rescale image based on zoom level
resizeRect.size.height = orangeImage.size.height * scale;
resizeRect.size.width = orangeImage.size.width * scale ;
NSLog(#"height = %f, width = %f, zoomLevel = %f", resizeRect.size.height, resizeRect.size.width,zoomLevel );
resizeRect.origin = (CGPoint){0,0};
UIGraphicsBeginImageContext(resizeRect.size);
[orangeImage drawInRect:resizeRect];
UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
pinView.image = resizedImage;