MKSnapshotter Implementation

MKSnapshotter

#import "MyViewController.h"
#import <MapKit/MapKit.h>

@interface MyViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *mapImageView;
@end

//helper method to get the rect in the map for an array of points
MKMapRect MapRectBoundingMapPoints(MKMapPoint points[], NSUInteger pointCount){
    double minX = INFINITY, maxX = -INFINITY, minY = INFINITY, maxY = -INFINITY;
    NSInteger i;
    for (i = 0; i < pointCount; i++) {
        MKMapPoint p = points[i];
        minX = MIN(p.x, minX);
        minY = MIN(p.y, minY);
        maxX = MAX(p.x, maxX);
        maxY = MAX(p.y, maxY);
    }
    return MKMapRectMake(minX, minY, maxX - minX,  maxY - minY);
    
}
@implementation MyViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self prepareSnapshot];
	// Do any additional setup after loading the view, typically from a nib.
}

#pragma mark map snapshooting

-(MKMapSnapshotOptions *)snapshotOptionsWithRegion:(MKCoordinateRegion)coordinateRegion
{
    //create the optionn for the snapshotter
    MKMapSnapshotOptions *options = [[MKMapSnapshotOptions alloc]init];
    //we passed the region previously created
    options.region = coordinateRegion;
    options.scale = [[UIScreen mainScreen] scale]; // get the scale depending on the device resolution
    options.size = self.mapImageView.frame.size;//this is the image view that is going to display the snapshot
    //you can also define a camera for the options, to rotate heading pitch and other variables, but we won't do this here.
    
    return options;
}

-(void)createSnapshotWithOptions:(MKMapSnapshotOptions *)options fristCoords:(CLLocationCoordinate2D)firstCoords secondCoords:(CLLocationCoordinate2D)secondCoords
{
    
    //create the snapshotter
    MKMapSnapshotter *snapshotter = [[MKMapSnapshotter alloc]initWithOptions:options];
    [snapshotter startWithCompletionHandler:^(MKMapSnapshot *snapshot, NSError *error) {
        if (error) {
            NSLog(@"error %@",error);
            return ;
        }
        
        UIImage *image = snapshot.image;
        
        //create a pin to get the pin image
        MKPinAnnotationView *pin = [[MKPinAnnotationView alloc]initWithAnnotation:nil reuseIdentifier:@""];
        pin.pinColor = MKPinAnnotationColorPurple;
        UIImage *firstPointPinImage = pin.image;
        pin.pinColor = MKPinAnnotationColorGreen;
        UIImage *secondPointPinImage = pin.image;
        
        CGPoint firstPoint = [snapshot pointForCoordinate:firstCoords];
        CGPoint secondPoint = [snapshot pointForCoordinate:secondCoords];
        
        //move the pin so that the "base" of the pin points to the right spot
        CGPoint pinCenterOffset = pin.centerOffset;
        firstPoint.x -= pin.bounds.size.width / 2.0;
        firstPoint.y -= pin.bounds.size.height / 2.0;
        firstPoint.x += pinCenterOffset.x;
        firstPoint.y += pinCenterOffset.y;
        
        secondPoint.x -= pin.bounds.size.width / 2.0;
        secondPoint.y -= pin.bounds.size.height / 2.0;
        secondPoint.x += pinCenterOffset.x;
        secondPoint.y += pinCenterOffset.y;
        
        
        UIGraphicsBeginImageContextWithOptions(image.size, YES, image.scale);
        
        //draw the pins on the image
        [image drawAtPoint:CGPointMake(0, 0)];
        [firstPointPinImage drawAtPoint:firstPoint];
        [secondPointPinImage drawAtPoint:secondPoint];
        
        //get the final image with the pins on top
        UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
        
        UIGraphicsEndImageContext();
        
        [self.mapImageView setImage:finalImage];
        
        
    }];
    
}
-(void)prepareSnapshot
{
    
    //get the coordinates to show
    CLLocationCoordinate2D firstPoint = CLLocationCoordinate2DMake(37.425105, -122.126424);
    CLLocationCoordinate2D secondPoint = CLLocationCoordinate2DMake(37.430285, -122.168309);
    
    MKMapPoint points[] = {
        MKMapPointForCoordinate(firstPoint),
        MKMapPointForCoordinate(secondPoint)
    };
    
    //create the region with the helper method previously declared
    MKMapRect rect = MapRectBoundingMapPoints(points, 2);
    
    //create the region with padding
    rect = MKMapRectInset(rect,
                          -rect.size.width * 0.05,
                          -rect.size.height * 0.05);
    MKCoordinateRegion coordinateRegion = MKCoordinateRegionForMapRect(rect);
    
    //create the options for the snapshotter
    //a snapshot requires some options to be defined, more on that on the next method
    MKMapSnapshotOptions *options = [self snapshotOptionsWithRegion:coordinateRegion];
    
    //create snapshotter and execute the snapshot
    [self createSnapshotWithOptions:options
                        fristCoords:firstPoint
                       secondCoords:secondPoint];
    
    
}