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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;
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原文地址：http://www.cnblogs.com/huen/p/4286948.html
