利用CALayer的遮罩实现闪烁标题

想要的效果:

在cocos2dx中有一个遮罩类,ClippingNode.可以很容易的实现文字类遮罩效果,有兴趣的可以自行百度看一看.具体效果图如下.

闪烁的标题

但是cocos2dx中是用的是openGL实现的效果,直接使用openGL的话会比较难.所以就想着用CALayer的遮罩效果做一个闪烁的标题.

实现原理:

这里用两张一模一样的图片,一张渐变白色,一张是本来的图片,渐变白色是美工PS处理来的.将两张图重叠放在一起,白色在上面,将白色的图片进行遮罩剪切.见效果图.

遮罩加动画效果图

将原图片放入最底部实现的效果

实现代码:

- (void)viewDidLoad {
    [super viewDidLoad];
    //添加视图
    [self addView];
}
-(void)addView{
    //注意Z轴位置
    UIImageView *titleBack = [[UIImageView alloc]init];
    titleBack.image = [UIImage imageNamed:@"titleBack.png"];
    titleBack.frame = CGRectMake(0, 100, SCREEN_SIZE.width, 150);
    [self.view addSubview:titleBack];
    
    UIImageView *title = [[UIImageView alloc]init];
    title.image = [UIImage imageNamed:@"title.png"];
    title.frame = CGRectMake(0, 100, SCREEN_SIZE.width, 150);
    [self.view addSubview:title];
    
    //遮罩剪切
    title.layer.mask = [self titleMaskLayer:title];
    
}

-(CALayer*)titleMaskLayer:(UIImageView*)imageView{
    //通过图片剪切,也可以自己画一个路径来剪切
    CALayer *mask = [CALayer layer];
    UIImage *maskImage = [UIImage imageNamed:@"spark.png"];
    mask.contents = (__bridge id _Nullable)(maskImage.CGImage);
    mask.frame = CGRectMake(100.0f, 0, 50.0f, imageView.bounds.size.height);
    mask.bounds = CGRectMake(0, 0, 50.0f, imageView.bounds.size.height);
    
    //添加动画
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position"];
    animation.fromValue = [NSValue valueWithCGPoint:CGPointMake(-50.0f, imageView.bounds.size.height/2.0)];
    animation.toValue = [NSValue valueWithCGPoint:CGPointMake(imageView.bounds.size.width, imageView.bounds.size.height/2.0)];
    animation.duration = 3.0f;
    animation.repeatCount = HUGE_VALF;
    [mask addAnimation:animation forKey:@"animation"];

    return mask;
}