《iOS核心动画高级技巧》part1-CALayer

UIView和CALayer的选择

可以发现，前面的2个效果不仅可以通过添加层来实现，还可以通过添加UIView来实现。如显示图片的层可以用一个UIImageView来实现。 既然CALayer和UIView都能实现相同的显示效果，那究竟该选择谁好呢？

其实，对比CALayer，UIView多了一个事件处理的功能。也就是说，CALayer不能处理用户的触摸事件，而UIView可以。

所以，在选择的过程中，需要考虑到实际的情况，如果显示出来的东西需要跟用户进行交互的话，用UIView；如果不需要跟用户进行交互，用UIView或者CALayer都可以

当然，CALayer的性能会高一些，因为它少了事件处理的功能，更加轻量级 。

特别注意：如果一个控件是另外一个控件的子控件，那么这个控件的layer也是另一个控件的子layer。

@interface ViewController ()

@end

@implementation ViewController

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

//part1
-(void)addLayerOne{
//添加图层
CALayer *blueLayer = [CALayer layer];
blueLayer.frame = CGRectMake(20.0,20.0,50.0, 50.0);
blueLayer.backgroundColor= [UIColor blueColor].CGColor;
[self.view.layer addSublayer:blueLayer];

//为图层添加内容（图片）
UIImage *image = [UIImage imageNamed:@"appResearch"];
self.myView.layer.contents = (__bridge id)image.CGImage;
//为图层设置图片的模式
self.myView.layer.contentsGravity = kCAGravityCenter;
//设置圆角半径为10
self.myView.layer.cornerRadius=10;
//如果设置了图片，那么需要设置这个属性为YES才能显示圆角效果
self.myView.layer.masksToBounds=YES;
//设置边框
self.myView.layer.borderWidth=3;
self.myView.layer.borderColor=[UIColor brownColor].CGColor;
}
//part2
-(void)addLayerTwo{
CALayer *layer = [[CALayer alloc]init];
layer.backgroundColor = [UIColor brownColor].CGColor;
layer.bounds = CGRectMake(0, 0, 50, 50);
layer.position = CGPointMake(100, 100);//锚点到父层（0，0）的坐标的距离，锚点默认为（0.5，0.5）居中
[self.myView.layer addSublayer:layer];
}

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

@end

layer的响应事件

-(void)part1EventResponse{
//响应测试
self.blueLayer = [CALayer layer];
self.blueLayer.frame = CGRectMake(50, 50, 100, 100);
self.blueLayer.backgroundColor = [UIColor blueColor].CGColor;
self.blueLayer.delegate = self;
[self.view.layer addSublayer:self.blueLayer];
}

-(void)touchesBegan:(NSSet *)touches
withEvent:(UIEvent *)event{
CGPoint point = [[touches anyObject]locationInView:self.view];
NSLog(@"point1=%@",NSStringFromCGPoint(point));
if ([self.view.layer containsPoint:point]) {
//判断点击区域方法1
//        point = [self.blueLayer convertPoint:point fromLayer:self.view.layer];
//        NSLog(@"point2=%@",NSStringFromCGPoint(point));
//        if ([self.blueLayer containsPoint:point]) {
//            [[[UIAlertView alloc]initWithTitle:@"layer" message:nil delegate:nil cancelButtonTitle:@"sure" otherButtonTitles:nil, nil] show];
//        }
//判断点击区域方法2
CALayer *layer = [self.view.layer hitTest:point];
if (layer==self.blueLayer) {
[[[UIAlertView alloc]initWithTitle:@"layer" message:nil delegate:nil cancelButtonTitle:@"sure" otherButtonTitles:nil, nil] show];
}
}
}

添加layer图层蒙版

//图层蒙板
CALayer *maskLayer = [CALayer layer];
UIImage *image = [UIImage imageNamed:@"tuxedomask"];
maskLayer.contents = (__bridge id)(image.CGImage);
maskLayer.frame = CGRectMake(0, 0, image.size.width, image.size.height);
self.imageView.layer.mask = maskLayer;

设置layer的矩阵变换

//********************************2d*****************************//
//简单操作
//    CGAffineTransform transform = CGAffineTransformMakeRotation(M_PI_4);

//组合操作
//    CGAffineTransform originTransform = CGAffineTransformIdentity;
//    originTransform = CGAffineTransformScale(originTransform, 0.5, 0.5);
//    originTransform = CGAffineTransformTranslate(originTransform, 200, 0);
//    originTransform = CGAffineTransformRotate(originTransform, M_PI_4);
//    self.imageView.layer.affineTransform = originTransform;
//********************************3d*****************************//
//没有设置m34透视投影的情况
//    CATransform3D transform = CATransform3DMakeRotation(M_PI_4, 0, 0, 1);
//    self.imageView.layer.transform = transform;
//设置m34透视投影.需要设置视觉相机和屏幕之间的距离，通常是500～1000
CATransform3D transform = CATransform3DIdentity;
transform.m34 = -1.0/500;//
transform = CATransform3DRotate(transform, M_PI_4, 0, 1, 0);
self.imageView.layer.transform = transform;

设置组合图层的矩阵变换

//sublayerTransform设置所有本图层及所有子图透视投影
CATransform3D perspective = CATransform3DIdentity;
perspective.m34 = -1.0/500;
self.backgroundView.layer.sublayerTransform = perspective;

CATransform3D transform1 = CATransform3DMakeRotation(M_PI_4, 0, 1, 0);
self.view1.layer.contents  = (__bridge id)([UIImage imageNamed:@"123.jpg"].CGImage);
self.view1.layer.transform = transform1;

CATransform3D transform2 = CATransform3DMakeRotation(-M_PI_4, 0, 1, 0);
self.view2.layer.contents = (__bridge id)([UIImage imageNamed:@"123.jpg"].CGImage);
self.view2.layer.transform = transform2;