iOS-CALayer图片淡入淡出动画

#import "ViewController.h"

@interface ViewController ()
@property (nonatomic,strong)CALayer *imageLayer;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    UIImage *image1 = [UIImage imageNamed:@"test1.jpg"];
   
    //可以显示图片类容,layer是view的载体
//    self.view.layer.contents = (__bridge id)(image.CGImage);
    
    //创建出图片layer
    self.imageLayer = [CALayer layer];
    self.imageLayer.frame = self.view.bounds;
    [self.view.layer addSublayer:self.imageLayer];
    
    self.imageLayer.contents = (__bridge id)(image1.CGImage);
    [self performSelector:@selector(imageAnimation) withObject:nil afterDelay:3];
}

- (void)imageAnimation {
    
    //隐式动画
     UIImage *image2 = [UIImage imageNamed:@"test2.jpg"];
    // self.imageLayer.contents = (__bridge id)(image2.CGImage);
    CABasicAnimation *contentsAnimation = [CABasicAnimation animationWithKeyPath:@"contens"];
    contentsAnimation.fromValue = self.imageLayer.contents;//原始图片
    contentsAnimation.toValue = (__bridge id)(image2.CGImage);//切换后图片
    contentsAnimation.duration = 3.f;
    
    CABasicAnimation *boundsAnimation = [CABasicAnimation animationWithKeyPath:@"bounds"];
    boundsAnimation.fromValue = [NSValue valueWithCGRect:self.imageLayer.bounds];
    boundsAnimation.toValue = [NSValue valueWithCGRect:CGRectMake(10, 100, 200, 200)];
    boundsAnimation.duration = 3.f;
    
    CAAnimationGroup *group = [CAAnimationGroup animation];
    group.animations = @[contentsAnimation,boundsAnimation];
    group.duration = 3.f;
    //设置layer动画结束后的值否则会回复东湖钱的状态
    self.imageLayer.contents = (__bridge id)(image2.CGImage);
    self.imageLayer.bounds = CGRectMake(10, 100, 200, 200);
    [self.imageLayer addAnimation:group forKey:nil];
    
}

来源：https://www.cnblogs.com/hxwj/p/4666036.html