Subclassing UIView in a map to draw lines

I have an app that displays custom maps. I use a CATiledView to display the maps.

I would like to be able to draw a route over the top of the maps. To do this, I am creating a UIView then adding it to the scrollView after I add the tiling layer like this:

- (void)displayTiledImageNamed:(NSString *)imageName size:(CGSize)imageSize
{
    // clear the previous imageView
    [imageView removeFromSuperview];
    [imageView release];
    imageView = nil;
    [linesView removeFromSuperview];
    [linesView release];
    linesView = nil;

    // reset our zoomScale to 1.0 before doing any further calculations
    self.zoomScale = 1.0;

    // make a new TilingView for the new image
    imageView = [[TilingView alloc] initWithImageName:imageName size:imageSize];
    linesView = [[LinesView alloc]initWithImageName:imageName size:imageSize];

    linesView.backgroundColor = [UIColor clearColor];
    [self addSubview:imageView];
    [self addSubview:linesView];
    [self configureForImageSize:imageSize];


}

The problem, is the line that I create in linesView is not scaling correctly.

It's hard to describe, but the line that is being created is scaled as 开发者_如何学Goif it were drawn on the device itself, rather than drawn on the map. See the following code:

#import "LinesView.h"


@implementation LinesView
@synthesize imageName;


- (id)initWithImageName:(NSString *)name size:(CGSize)size
{
    if ((self = [super initWithFrame:CGRectMake(0, 0, size.width, size.height)])) {
        self.imageName = name;

    }

    return self;
}
- (void)dealloc
{
    [super dealloc];
}

- (void)drawRect:(CGRect)rect {
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetRGBStrokeColor(context, 1, 0, 0, 1);
    CGContextSetLineWidth(context, 20.0);
    CGContextMoveToPoint(context, 1.0f, 220.0f);
    CGContextAddLineToPoint(context, 340.0f, 80);
    CGContextStrokePath(context);
}

@end

I have tried putting the code to draw the line in the drawRect method of the tilingView and it works perfectly. The line width is 20px relative to the map. In the linesView the line appears to be 20px wide relative to the device and positioned relative to the scrollview.

Sorry I'm trying my best to describe the problem...

Figured this out - I added the linesView to the tilingView instead of the scrollView like this:

- (void)displayTiledImageNamed:(NSString *)imageName size:(CGSize)imageSize
{
    // clear the previous imageView
    [imageView removeFromSuperview];
    [imageView release];
    imageView = nil;
    [linesView removeFromSuperview];
    [linesView release];
    linesView = nil;

    // reset our zoomScale to 1.0 before doing any further calculations
    self.zoomScale = 1.0;

    // make a new TilingView for the new image
    imageView = [[TilingView alloc] initWithImageName:imageName size:imageSize];
    linesView = [[LinesView alloc]initWithImageName:imageName size:imageSize];

    linesView.backgroundColor = [UIColor clearColor];
    [self addSubview:imageView];
    [imageView addSubview:linesView];
    [self configureForImageSize:imageSize];


}