CALayer遮罩效果

#import "ViewController.h"

@interface ViewController ()

@property (nonatomic,strong) CALayer *imageLayer;

@property (nonatomic,strong) CALayer *maskLayer;

@property (nonatomic,strong) UIImage *imageContents;

@property (nonatomic,strong) UIImage *maskImageContents;

@end

@implementation ViewController

- (void)viewDidLoad {

    [superviewDidLoad];

    //获取图片

    _imageContents = [UIImageimageNamed:@"原始图片"];

    _maskImageContents = [UIImageimageNamed:@"遮罩图片"];

    //创建图片layer

    _imageLayer = [CALayerlayer];

    _imageLayer.frame =CGRectMake(50,50, 200,200);

    _imageLayer.contents = (__bridgeid _Nullable)(_imageContents.CGImage);

    [self.view.layeraddSublayer:_imageLayer];

    

    //创建遮罩layer

    _maskLayer = [CALayerlayer];

    _maskLayer.frame =_imageLayer.bounds;

    _maskLayer.contents =  (__bridgeid _Nullable)(_maskImageContents.CGImage);

    

    //给图片layer提供遮罩

    _imageLayer.mask =_maskLayer;

}

- (void)didReceiveMemoryWarning {

    [superdidReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}