Aquí es una mejora que tiene en cuenta la altura de las vistas de anotación que se está superponiendo en el mapa (de tal manera que la parte superior de la anotación no recibe corten durante su cota de desplazamiento es en la parte inferior de ejemplo). O para generalizar aún más, le permite especificar el relleno en píxeles en lugar de un porcentaje. Requiere un pase de dos etapas mediante el cual descubres los límites de las anotaciones, luego aumentas los límites para tener en cuenta el relleno del mapa.
- (void) zoomToAnnotationsBounds:(NSArray *)annotations {
CLLocationDegrees minLatitude = DBL_MAX;
CLLocationDegrees maxLatitude = -DBL_MAX;
CLLocationDegrees minLongitude = DBL_MAX;
CLLocationDegrees maxLongitude = -DBL_MAX;
for (MyAnnotation *annotation in annotations) {
double annotationLat = annotation.coordinate.latitude;
double annotationLong = annotation.coordinate.longitude;
minLatitude = fmin(annotationLat, minLatitude);
maxLatitude = fmax(annotationLat, maxLatitude);
minLongitude = fmin(annotationLong, minLongitude);
maxLongitude = fmax(annotationLong, maxLongitude);
}
// See function below
[self setMapRegionForMinLat:minLatitude minLong:minLongitude maxLat:maxLatitude maxLong:maxLongitude];
// If your markers were 40 in height and 20 in width, this would zoom the map to fit them perfectly. Note that there is a bug in mkmapview's set region which means it will snap the map to the nearest whole zoom level, so you will rarely get a perfect fit. But this will ensure a minimum padding.
UIEdgeInsets mapPadding = UIEdgeInsetsMake(40.0, 10.0, 0.0, 10.0);
CLLocationCoordinate2D relativeFromCoord = [self.mapView convertPoint:CGPointMake(0, 0) toCoordinateFromView:self.mapView];
// Calculate the additional lat/long required at the current zoom level to add the padding
CLLocationCoordinate2D topCoord = [self.mapView convertPoint:CGPointMake(0, mapPadding.top) toCoordinateFromView:self.mapView];
CLLocationCoordinate2D rightCoord = [self.mapView convertPoint:CGPointMake(0, mapPadding.right) toCoordinateFromView:self.mapView];
CLLocationCoordinate2D bottomCoord = [self.mapView convertPoint:CGPointMake(0, mapPadding.bottom) toCoordinateFromView:self.mapView];
CLLocationCoordinate2D leftCoord = [self.mapView convertPoint:CGPointMake(0, mapPadding.left) toCoordinateFromView:self.mapView];
double latitudeSpanToBeAddedToTop = relativeFromCoord.latitude - topCoord.latitude;
double longitudeSpanToBeAddedToRight = relativeFromCoord.latitude - rightCoord.latitude;
double latitudeSpanToBeAddedToBottom = relativeFromCoord.latitude - bottomCoord.latitude;
double longitudeSpanToBeAddedToLeft = relativeFromCoord.latitude - leftCoord.latitude;
maxLatitude = maxLatitude + latitudeSpanToBeAddedToTop;
minLatitude = minLatitude - latitudeSpanToBeAddedToBottom;
maxLongitude = maxLongitude + longitudeSpanToBeAddedToRight;
minLongitude = minLongitude - longitudeSpanToBeAddedToLeft;
[self setMapRegionForMinLat:minLatitude minLong:minLongitude maxLat:maxLatitude maxLong:maxLongitude];
}
-(void) setMapRegionForMinLat:(double)minLatitude minLong:(double)minLongitude maxLat:(double)maxLatitude maxLong:(double)maxLongitude {
MKCoordinateRegion region;
region.center.latitude = (minLatitude + maxLatitude)/2;
region.center.longitude = (minLongitude + maxLongitude)/2;
region.span.latitudeDelta = (maxLatitude - minLatitude);
region.span.longitudeDelta = (maxLongitude - minLongitude);
// MKMapView BUG: this snaps to the nearest whole zoom level, which is wrong- it doesn't respect the exact region you asked for. See http://stackoverflow.com/questions/1383296/why-mkmapview-region-is-different-than-requested
[self.mapView setRegion:region animated:YES];
}