CALayer

Posted 2020-06-08

CALayer是UIView可以响应事件。一般来说，layer可以有两种用途：一是对view相关属性的设置，包括圆角、阴影、边框等参数；二是实现对view的动画操控。

因此对一个view进行core animation动画，本质上是对该view的.layer进行动画操纵。

1.CALayer常见属性

新建图层

    CALayer * layer = [CALayer layer];

图层颜色

    layer.backgroundColor = [UIColor redColor].CGColor;

图层大小

    layer.bounds = CGRectMake(0, 0, 100, 100);

图层锚点

    layer.anchorPoint = CGPointMake(0, 0);

图层位置

    layer.position = self.view.center;

圆角半径

    layer.cornerRadius = 50; 

边框宽度

    layer.borderWidth = 2;

边框颜色

    layer.borderColor = [UIColor blackColor].CGColor;

添加图层

    [self.view.layer addSublayer:layer];

2.CALayer有2个非常重要的属性：position和anchorPoint

@property CGPoint position;

用来设置CALayer在父层中的位置

以父层的左上角为原点(0, 0)

@property CGPoint anchorPoint;

称为“定位点”、“锚点”

决定着CALayer身上的哪个点会在position属性所指的位置

以自己的左上角为原点(0, 0)

它的x、y取值范围都是0~1，默认值为（0.5, 0.5）

layer.anchorPoint = CGPointMake(0, 0); 

layer.anchorPoint = CGPointMake(0.5, 0.5);

layer.anchorPoint = CGPointMake(1, 1);

3.改变transform的动画

    旋转

    layer.transform = CATransform3DRotate(_layer.transform, 10/180.0*M_PI, 1, 1, 1);

    放大缩小

    layer.transform = CATransform3DScale(_layer.transform, 2, 2, 2);

    平移

    layer.transform = CATransform3DTranslate(_layer.transform, 10, 10, 0);

4.CABasicAnimation

     CALayer *Layer = [[CALayer alloc] init];

    Layer.backgroundColor = [UIColor blueColor].CGColor;

    Layer.frame = CGRectMake(100, 100, 50, 50);

    Layer.cornerRadius = 10;

    [self.view.layer addSublayer:scaleLayer];

     

    CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];

    scaleAnimation.fromValue = [NSNumber numberWithFloat:1.0];

    scaleAnimation.toValue = [NSNumber numberWithFloat:1.5];

    scaleAnimation.fillMode = kCAFillModeForwards;最后以什么填充

    scaleAnimation.repeatCount = MAXFLOAT;重复次数

    scaleAnimation.duration = 1;

 

    [Layer addAnimation:scaleAnimation forKey:nil];

5.CAAnimationGroup

    CALayer *Layer = [[CALayer alloc] init];

    Layer.backgroundColor = [UIColor blueColor].CGColor;

    Layer.frame = CGRectMake(100, 100, 50, 50);

    Layer.cornerRadius = 10;

    [self.view.layer addSublayer:Layer];

    放大

    CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];

    scaleAnimation.fromValue = [NSNumber numberWithFloat:1.0];

    scaleAnimation.toValue = [NSNumber numberWithFloat:1.5];

    渐变

    CABasicAnimation * opacityAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];

    opacityAnimation.fromValue = @1;

    opacityAnimation.toValue = @0;

    移动

    CABasicAnimation *moveAnimation = [CABasicAnimation animationWithKeyPath:@"position"];

    moveAnimation.toValue = [NSValue valueWithCGPoint:CGPointMake(200, 200)];

    旋转

    CABasicAnimation *rotateANimation = [CABasicAnimation animationWithKeyPath:@"transform"];

    rotateANimation.fromValue = [NSValue valueWithCATransform3D:CATransform3DIdentity];

    rotateANimation.toValue = [NSValue valueWithCATransform3D:CATransform3DRotate(Layer.transform, M_PI, 0, 0, 1)];

    

    CAAnimationGroup * group = [CAAnimationGroup animation];

    group.removedOnCompletion = NO;

    group.fillMode = kCAFillModeForwards;

    group.repeatCount = MAXFLOAT;

    group.duration = 1;

 

    group.animations [email protected][scaleAnimation,opacityAnimation,moveAnimation,rotateANimation];

    [Layer addAnimation:group forKey:nil];

6.补充

再旋转中，上边的写法转换成弧度之后不能转多圈，下面实现转多圈

    CABasicAnimation *zrotateANimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];

    zrotateANimation.fromValue = [NSNumber numberWithFloat:0];

    zrotateANimation.toValue = [NSNumber numberWithFloat:M_PI * 4.0];