为什么我的CATiledLayer在缩放后不能在UIScrollView中滚动？

Question

我目前对CATiledLayer有以下问题：当视图第一次加载时，滚动完美地工作，但是当你缩放一次时，视图捕捉到锚点（左上角），并且它不能滚动到所有。缩放的作用在于可以放大和缩小，但只能缩放到左上角。

我的代码如下：

#import <QuartzCore/QuartzCore.h> 
#import "PracticeViewController.h" 

@implementation practiceViewController 
//@synthesize image; 

- (void)viewDidLoad 
{ 


    NSString *path = [[NSBundle mainBundle] pathForResource:@"H-5" ofType:@"jpg"]; 
    NSData *data = [NSData dataWithContentsOfFile:path]; 
    image = [UIImage imageWithData:data]; 

    CGRect pageRect = CGRectMake(0, 0, image.size.width, image.size.height); 


    CATiledLayer *tiledLayer = [CATiledLayer layer]; 
    tiledLayer.anchorPoint = CGPointMake(0.0f, 1.0f); 
    tiledLayer.delegate = self; 
    tiledLayer.tileSize = CGSizeMake(1000, 1000); 
    tiledLayer.levelsOfDetail = 6; 
    tiledLayer.levelsOfDetailBias = 0; 
    tiledLayer.bounds = pageRect; 
    tiledLayer.transform = CATransform3DMakeScale(1.0f, -1.0f, 0.3f); 

    myContentView = [[UIView alloc] initWithFrame:self.view.bounds]; 
    [myContentView.layer addSublayer:tiledLayer]; 

    UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds]; 
    scrollView.delegate = self; 
    scrollView.contentSize = pageRect.size; 
    scrollView.minimumZoomScale = .2; 
    scrollView.maximumZoomScale = 1; 
    [scrollView addSubview:myContentView]; 
    [self.view addSubview:scrollView]; 


} 

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView 
{ 
    return myContentView; 
} 

- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx 
{ 
    NSString *path = [[NSBundle mainBundle] pathForResource:@"H-5" ofType:@"jpg"]; 
    NSData *data = [NSData dataWithContentsOfFile:path]; 
    image = [UIImage imageWithData:data]; 

    CGRect imageRect = CGRectMake (0.0, 0.0, image.size.width, image.size.height); 
    CGContextDrawImage (ctx, imageRect, [image CGImage]); 
} 

@end 

Answer 1

这是我在固定明显错误第一遍：

#import <QuartzCore/QuartzCore.h> 
#import "PracticeViewController.h" 

@implementation PracticeViewController 
@synthesize image; 

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 

    // You do not need to and must not autorelease [NSBundle mainBundle] 
    NSString *path = [[NSBundle mainBundle] pathForResource:@"H-5" ofType:@"jpg"]; 
    NSData *data = [NSData dataWithContentsOfFile:path]; 
    image = [UIImage imageWithData:data]; 

    CGRect pageRect = CGRectMake(0, 0, 1600, 2400); 

    CATiledLayer *tiledLayer = [CATiledLayer layer]; 
    tiledLayer.delegate = self; 
    tiledLayer.tileSize = CGSizeMake(1024.0, 1024.0); 
    tiledLayer.levelsOfDetail = 5; // was 1000, which makes no sense. Each level of detail is a power of 2. 
    tiledLayer.levelsOfDetailBias = 0; // was 1000, which also makes no sense. 
    // Do not change the tiledLayer.frame. 
    tiledLayer.bounds = pageRect; // I think you meant bounds instead of frame. 
    // Flip the image vertically. 
    tiledLayer.transform = CATransform3DMakeScale(zoom, -zoom, 1.0f); 

    myContentView = [[UIView alloc] initWithFrame:self.view.bounds]; 
    [myContentView.layer addSublayer:tiledLayer]; 

    UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds]; 
    scrollView.delegate = self; 
    scrollView.contentSize = pageRect.size; 
    scrollView.maximumZoomScale = 32; // = 2^5 
    [scrollView addSubview:myContentView]; 

    [self.view addSubview:scrollView]; 
} 

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView 
{ 
    return myContentView; 
} 

- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx 
{ 
    NSString *path = [[NSBundle mainBundle] pathForResource:@"H-5" ofType:@"jpg"]; 
    NSData *data = [NSData dataWithContentsOfFile:path]; 
    image = [UIImage imageWithData:data]; 
    CGRect imageRect = CGRectMake (0.0, 0.0, image.size.width, image.size.height); 
    CGContextDrawImage (context, imageRect, [image CGImage]); 
} 

@end