Ios obj-c中的静态背景图像位置（类似于背景附件：固定）

我正在尝试创建一个视图，无论它如何移动，都会将其背景图像保持在同一位置。因此，如果拖动视图，背景将保持不变，类似于css3中的

background attachment:fixed

我的问题是

clipstobunds=YES

似乎不起作用。图像仍然占据整个屏幕，不会被剪裁到父帧。有什么想法吗

@implementation StaticBackgroundView {
    UIImageView *imageView;
}

// Must be init'd from code or won't work
- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"myImage.png"]];
        imageView.clipsToBounds = YES;
        self.clipsToBounds = YES;

        [self addSubview:imageView];
        [self sendSubviewToBack:imageView];
    }
    return self;
}

- (void) setFrame:(CGRect)frame
{
    // Call the parent class to move the view
    [super setFrame:frame];

    // Do your custom code here.
    NSLog(@"Setframe");
    imageView.frame = CGRectMake(-1*frame.origin.x, frame.origin.y, imageView.frame.size.width, imageView.frame.size.height);
}

---

每当StaticBackgroundView移动时，也必须调整背景图像中心

在下面给出的示例中，每当StaticBackgroundView在PanGesture更新期间移动时，都会调用updateBackgroundImage

-(void)updateBackgroundImage
{
    imageView.center = CGPointMake(( (imageView.image.size.width*0.5) - self.center.x) + (self.bounds.size.width*0.5)
                               ,     ((imageView.image.size.height*0.5) - self.center.y) + (self.bounds.size.height*0.5));
}

如果向右移动StaticBackgroundView，则图像将向左移动，并且在StaticBackgroundView下保持静态

下面的示例代码允许您使用手指移动StaticBackgroundView并在下面显示静态图像：

静态背景视图

#import <UIKit/UIKit.h>
@interface StaticBackgroundView : UIView
-(void)updateBackgroundImage;
@end

ViewController.m

#import "ViewController.h"
#import "StaticBackgroundView.h"

@interface ViewController ()

@property (strong, nonatomic)  StaticBackgroundView *outletStaticView;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    self.outletStaticView = [[StaticBackgroundView alloc] initWithFrame:CGRectMake(100, 100, 120, 150)];
    [self.view addSubview:self.outletStaticView];

    UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];

    [self.outletStaticView addGestureRecognizer:panGestureRecognizer];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


-(void)handlePan:(UIPanGestureRecognizer *)gestureRecognizer
{

    if([gestureRecognizer state] == UIGestureRecognizerStateChanged)
    {

        CGPoint translation = [gestureRecognizer translationInView:self.view];

        gestureRecognizer.view.center = CGPointMake(gestureRecognizer.view.center.x + translation.x, gestureRecognizer.view.center.y + translation.y);

        [gestureRecognizer setTranslation:CGPointMake(0, 0) inView:self.view];

        StaticBackgroundView * theView = (StaticBackgroundView*)gestureRecognizer.view;
        [theView updateBackgroundImage];

    }

}
@end

---

如果我关心的视图是平移的目标，这没关系，但是如果另一个视图完全是位置变化的原因呢？或者如果视图正在设置动画，你在吗？有什么办法可以解决这个问题吗？如果视图是动画，那么你就不走运了。您只能获取开始和结束动画转换数据，而不能在动画制作时获取。如果另一个视图导致更改，则相应地调整handlePan。其他视图的平移值将调整静态背景视图。

#import "ViewController.h"
#import "StaticBackgroundView.h"

@interface ViewController ()

@property (strong, nonatomic)  StaticBackgroundView *outletStaticView;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    self.outletStaticView = [[StaticBackgroundView alloc] initWithFrame:CGRectMake(100, 100, 120, 150)];
    [self.view addSubview:self.outletStaticView];

    UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];

    [self.outletStaticView addGestureRecognizer:panGestureRecognizer];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


-(void)handlePan:(UIPanGestureRecognizer *)gestureRecognizer
{

    if([gestureRecognizer state] == UIGestureRecognizerStateChanged)
    {

        CGPoint translation = [gestureRecognizer translationInView:self.view];

        gestureRecognizer.view.center = CGPointMake(gestureRecognizer.view.center.x + translation.x, gestureRecognizer.view.center.y + translation.y);

        [gestureRecognizer setTranslation:CGPointMake(0, 0) inView:self.view];

        StaticBackgroundView * theView = (StaticBackgroundView*)gestureRecognizer.view;
        [theView updateBackgroundImage];

    }

}
@end