PDF and zoom - CATiledLayer - iphone

Question

I have a problem, I'm not a programmer but I try to do some app for fun.
I try to create a pdf viewer, I create a UIView class like this:
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:(CGRect)frame];
if (self) {
self.backgroundColor = [UIColor clearColor];
NSString *pathToPdfDoc = [[NSBundle mainBundle] pathForResource:#"myPDF" ofType:#"pdf"];
NSURL *pdfUrl = [NSURL fileURLWithPath:pathToPdfDoc];
document = CGPDFDocumentCreateWithURL((CFURLRef)pdfUrl);
currentPage = 1;
}
return self;
}
-(void)drawRect:(CGRect)inRect{
if(document) {
CGPDFPageRef page = CGPDFDocumentGetPage(document, currentPage);
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSaveGState(ctx);
CGContextTranslateCTM(ctx, 0.0, [self bounds].size.height);
CGContextScaleCTM(ctx, 1.0, -1.0);
CGContextConcatCTM(ctx, CGPDFPageGetDrawingTransform(page, kCGPDFCropBox, [self bounds], 0, true));
CGContextDrawPDFPage(ctx, page);
CGContextRestoreGState(ctx);
}
}
-(void)increasePageNumber {
size_t pageCount = CGPDFDocumentGetNumberOfPages(document);
if (currentPage == pageCount) {
// do nothing
}
else {
currentPage++;
[self setNeedsDisplay];
}
}
-(void)decreasePageNumber {
if (currentPage == 1) {
// do nothing
}
else {
currentPage--;
[self setNeedsDisplay];
}
}
now I try to add zoom but without luck, fro zoom I create a layer:
-(void)viewDidLoad {
CGRect frame;
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
frame = CGRectMake(0, 0, 960, 1024);
}
else{
frame = CGRectMake(0, 0, 320, 460);
}
tiledLayer = [CATiledLayer layer];
tiledLayer.delegate = self;
tiledLayer.tileSize = CGSizeMake(1024, 1024);
tiledLayer.levelsOfDetail = 200;
tiledLayer.levelsOfDetailBias = 200;
tiledLayer.frame = frame;
myPDFView = [[viewPDF alloc] initWithFrame:frame];
//[self.view addSubview:myPDFView];
[myPDFView.layer addSublayer:tiledLayer];
CGRect viewFrame = self.view.frame;
viewFrame.origin = CGPointZero;
scrollView = [[UIScrollView alloc] initWithFrame:viewFrame];
scrollView.delegate = self;
scrollView.contentSize = frame.size;
scrollView.maximumZoomScale = 5;
[scrollView addSubview:myPDFView];
[self.view addSubview:scrollView];
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return myPDFView;
}
EDIT: the zoom work, I use shouldAutorotateToInterfaceOrientation that was the problem (I need to rewrite some code), now it work BUT when I zoom quality worsens. :(