如何在MKMapSnapshotter上绘制CLLocationCoordinate2Ds (在mapView打印图像上绘制)

MKMapSnapshotter *snapshotter = [[MKMapSnapshotter alloc] initWithOptions:options];

[snapshotter startWithQueue:dispatch_get_main_queue() completionHandler:^(MKMapSnapshot *snapshot, NSError *error) {
    if (error) {
        NSLog(@"Snapshot error: %@", error);
    } else {
        // 在快照上绘制CLLocationCoordinate2Ds
        UIImage *image = snapshot.image;
        UIGraphicsBeginImageContextWithOptions(image.size, YES, image.scale);
        [image drawAtPoint:CGPointZero];
        
        CGContextRef context = UIGraphicsGetCurrentContext();
        
        // 绘制CLLocationCoordinate2Ds
        for (int i = 0; i < count; i++) {
            CLLocationCoordinate2D coordinate = coordinates[i];
            CGPoint point = [snapshot pointForCoordinate:coordinate];
            CGContextAddEllipseInRect(context, CGRectMake(point.x - 5, point.y - 5, 10, 10));
        }
        
        CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);
        CGContextFillPath(context);
        
        UIImage *annotatedImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        
        // 在mapView上显示annotatedImage
        ...
    }
}];

UIImageView *imageView = [[UIImageView alloc] initWithFrame:mapView.bounds];
imageView.image = annotatedImage;
[mapView addSubview:imageView];