CALayer层的属性(转)

 

 

 

 

 

 

 

 

一.position和anchorPoint 
1.简单介绍 
CALayer有2个非常重要的属性：position和anchorPoint 
　　position： 
　　(1)用来设置CALayer在父层中的位置 
　　(2)以父层的左上角为原点(0,0) 
anchorPoint： 
　　(1)称为”定位点”，”锚点” 
　　(2)决定着CALayer身上的哪个点会在position属性所指的位置 
　　(3)以自己的左上角为原点(0,0) 
　　(4)它的x，y取值范围都是0~1，默认值为(0.5,0.5)

 

2.图示 
　　anchorPoint 它的取值为0～1 

红色图层的anchorPoint为(0,0) 

红色图层的anchorPoint为(0.5,0.5) 

红色图层的anchorPoint为(1,1) 

红色图层的anchorPoint为(0.5,0) 

position和anchorPoint 
添加一个红色图层到绿色图层上，红色图层显示到什么位置，由position属性决定 
假设红色图层的position是(100,100) 
到底把红色图层的哪个点移动到(100,100)的坐标位置，锚点。 
红色图层的锚点是(0,0) 

红色图层的锚点是(0.5,0.5)

红色图层的锚点是(1,1) 

红色图层的锚点是(0.5,0) 

3.代码示例 
(1)没有设置锚点。默认的锚点位置为(0.5,0.5)

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //创建图层
    CALayer *layer = [CALayer layer];
    //设置图层的属性
    layer.backgroundColor = [UIColor redColor].CGColor;
    layer.bounds = CGRectMake(0, 0, 100, 100);
    //添加图层
    [self.view.layer addSublayer:layer];
}

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

@end

(2)设置锚点为(0,0)

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //创建图层
    CALayer *layer = [CALayer layer];
    //设置图层的属性
    layer.backgroundColor = [UIColor redColor].CGColor;
    layer.bounds = CGRectMake(0, 0, 100, 100);
    //设置锚点为（0，0）
    layer.anchorPoint = CGPointZero;
    //添加图层
    [self.view.layer addSublayer:layer];
}

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

@end

二.隐式动画 

 

 
2.代码示例

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //创建图层
    CALayer *layer = [CALayer layer];
    //设置图层属性
    layer.backgroundColor = [UIColor brownColor].CGColor;
    layer.bounds = CGRectMake(0, 0, 150, 100);
    //显示位置
    layer.position = CGPointMake(100, 100);
    layer.anchorPoint = CGPointZero;
    layer.cornerRadius = 20;
    //添加图层
    [self.view.layer addSublayer:layer];
    _myLayer = layer;
}

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

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    //隐式动画
    _myLayer.bounds = CGRectMake(0, 0, 200, 60);
    _myLayer.backgroundColor = [UIColor yellowColor].CGColor;
}

@end

关闭隐式动画

 //关闭隐式动画
    [CATransaction begin];
    [CATransaction setDisableActions:YES];
    //隐式动画
    _myLayer.bounds = CGRectMake(0, 0, 200, 60);
    _myLayer.backgroundColor = [UIColor yellowColor].CGColor;
    [CATransaction commit];