Restrict MKMapView scrolling

Question

I\'m trying to add a custom image to an MKMapView as an MKOverlayView - I need to restrict users from being able to scroll outside the bounds of th

Answer 1

In my case, I needed to restrict bounds to tiled overlay which has an upperleft / lowerRight coordinates. Code above still works well, but substituted theOverlay.boundingMapRect for MKMapRect paddedBoundingMapRect

- (void)mapView:(MKMapView *)_mapView regionDidChangeAnimated:(BOOL)animated
{
if (manuallyChangingMapRect) //prevents possible infinite recursion when we call setVisibleMapRect below
    return;     

[self updateDynamicPaddedBounds];

MKMapPoint pt =  MKMapPointForCoordinate( mapView.centerCoordinate);

BOOL mapInsidePaddedBoundingRect = MKMapRectContainsPoint(paddedBoundingMapRect,pt );

if (!mapInsidePaddedBoundingRect)
{
    // Overlay is no longer visible in the map view.
    // Reset to last "good" map rect...

    manuallyChangingMapRect = YES;
    [mapView setVisibleMapRect:lastGoodMapRect animated:YES];
    manuallyChangingMapRect = NO;


}


-(void)updateDynamicPaddedBounds{

ENTER_METHOD;

CLLocationCoordinate2D  northWestPoint= CLLocationCoordinate2DMake(-33.841171,151.237318 );
CLLocationCoordinate2D  southEastPoint= CLLocationCoordinate2DMake(-33.846127, 151.245058);



MKMapPoint upperLeft = MKMapPointForCoordinate(northWestPoint);
MKMapPoint lowerRight = MKMapPointForCoordinate(southEastPoint);
double width = lowerRight.x - upperLeft.x;
double height = lowerRight.y - upperLeft.y;


MKMapRect mRect = mapView.visibleMapRect;
MKMapPoint eastMapPoint = MKMapPointMake(MKMapRectGetMinX(mRect), MKMapRectGetMidY(mRect));
MKMapPoint westMapPoint = MKMapPointMake(MKMapRectGetMaxX(mRect), MKMapRectGetMidY(mRect));
MKMapPoint northMapPoint = MKMapPointMake(MKMapRectGetMidX(mRect), MKMapRectGetMaxY(mRect));
MKMapPoint southMapPoint = MKMapPointMake(MKMapRectGetMidX(mRect), MKMapRectGetMinY(mRect));

double xMidDist = abs(eastMapPoint.x -  westMapPoint.x)/2;
double yMidDist = abs(northMapPoint.y -  southMapPoint.y)/2;


upperLeft.x = upperLeft.x + xMidDist;
upperLeft.y = upperLeft.y + yMidDist;


double paddedWidth =  width - (xMidDist*2); 
double paddedHeight = height - (yMidDist*2);

paddedBoundingMapRect= MKMapRectMake(upperLeft.x, upperLeft.y, paddedWidth, paddedHeight);

}