I am trying to make a custom annotation view by subclassing MKAnnotationView and overriding the drawRect method. I want the view to be drawn offset from the annotation's position, somewhat like MKPinAnnotationView does it, so that the point of the pin is at the specified coordinates, rather than the middle of the pin. So I set the frame position and size as shown below. However, it doesn't look like I can affect the position of the frame at all, only the size. The image ends up being drawn centered over the annotation position. Any tips on how to achieve what I want?

MyAnnotationView.h:

@interface MyAnnotationView : MKAnnotationView {

}

MyAnnotationView.m:

- (id)initWithAnnotation:(id <MKAnnotation>)annotation reuseIdentifier:(NSString *)reuseIdentifier {
    if (self = [super initWithAnnotation:annotation reuseIdentifier:reuseIdentifier]) {
        self.canShowCallout = YES;
        self.backgroundColor = [UIColor clearColor];
        // Position the frame so that the bottom of it touches the annotation position 
        self.frame = CGRectMake(0, -16, 32, 32);
    }
    return self;
}

- (void)drawRect:(CGRect)rect {
    [[UIImage imageNamed:@"blue-dot.png"] drawInRect:rect];
}