带辉光的文字和图片效果

效果如下：

本人已经将实现封装到一个分类里面，可以直接调用：

    // label
    UILabel *glowLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.view.width, 40)];
    glowLabel.center = self.view.center;
    glowLabel.text = @"LeiLuRong...";
    glowLabel.textAlignment = NSTextAlignmentCenter;
    glowLabel.textColor = [UIColor whiteColor];
    glowLabel.font = [UIFont systemFontOfSize:28];
    [self.view addSubview:glowLabel];
    
    glowLabel.glowRadius = @(2.f);
    glowLabel.glowOpacity = @(1.f);
    glowLabel.glowColor = [UIColor cyanColor];
    
    glowLabel.glowDuration = @(1.f);
    glowLabel.hideDuration = @(0.3);
    glowLabel.glowAnimationDuration = @(1.5f);
    
    [glowLabel createGlowLayer];
    [glowLabel insertGlowLayer];
    [glowLabel startGlowLoop];
    
    
    
    // imageView
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];
    imageView.center = CGPointMake(self.view.center.x, 400);
    imageView.image = [UIImage imageNamed:@"collection_new"];
    [self.view addSubview:imageView];
    
    imageView.glowRadius = @(2.f);
    imageView.glowOpacity = @(0.5f);
    imageView.glowColor = [UIColor whiteColor];
    
    imageView.glowDuration = @1.5;
    imageView.hideDuration = @0.5;
    imageView.glowAnimationDuration = @1.5;
    
    [imageView createGlowLayer];
    [imageView insertGlowLayer];
    [imageView startGlowLoop];
分类：
UIView+GlowView.h
/**
 *  辉光的颜色
 */
@property (nonatomic, strong) UIColor  *glowColor;
/**
 *  辉光的透明度
 */
@property (nonatomic, strong) NSNumber *glowOpacity;
/**
 *  辉光的阴影半径
 */
@property (nonatomic, strong) NSNumber *glowRadius;
#pragma mark - 设置辉光时间间隔
/**
 *  一次完整的辉光周期（从显示到透明或者从透明到显示），默认1s
 */
@property (nonatomic, strong) NSNumber *glowAnimationDuration;
/**
 *  保持辉光时间（不设置，默认为0.5s）
 */
@property (nonatomic, strong) NSNumber *glowDuration;
/**
 *  不显示辉光的周期（不设置默认为0.5s）
 */
@property (nonatomic, strong) NSNumber *hideDuration;
#pragma mark - 辉光相关操作
/**
 *  创建出辉光layer
 */
- (void)createGlowLayer;
/**
 *  插入辉光的layer
 */
- (void)insertGlowLayer;
/**
 *  移除辉光的layer
 */
- (void)removeGlowLayer;
/**
 *  显示辉光
 */
- (void)glowToshowAnimated:(BOOL)animated;
/**
 *  隐藏辉光
 */
- (void)glowToHideAnimated:(BOOL)animated;
/**
 *  开始循环辉光
 */
- (void)startGlowLoop;
UIView+GlowView.m
#import "UIView+GlowView.h"
#import @interface UIView ()
@property (nonatomic, strong) CALayer           *glowLayer;
@property (nonatomic, strong) dispatch_source_t  dispatchSource;
@end
@implementation UIView (GlowView)
- (void)createGlowLayer {
    
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, [UIScreen mainScreen].scale);
    [self.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIBezierPath* path = [UIBezierPath bezierPathWithRect:self.bounds];
    [[self accessGlowColor] setFill];
    [path fillWithBlendMode:kCGBlendModeSourceAtop alpha:1.0];
    
    self.glowLayer = [CALayer layer];
    self.glowLayer.frame = self.bounds;
    self.glowLayer.contents = (__bridge id)UIGraphicsGetImageFromCurrentImageContext().CGImage;
    self.glowLayer.opacity = 0.f;
    self.glowLayer.shadowOffset = CGSizeMake(0, 0);
    self.glowLayer.shadowOpacity = 1.f;
    
    UIGraphicsEndImageContext();
}
- (void)insertGlowLayer {
    
    if (self.glowLayer) {
        
        [self.layer addSublayer:self.glowLayer];
    }
}
- (void)removeGlowLayer {
    
    if (self.glowLayer) {
        
        [self.glowLayer removeFromSuperlayer];
    }
}
- (void)glowToshowAnimated:(BOOL)animated {
    
    self.glowLayer.shadowColor = [self accessGlowColor].CGColor;
    self.glowLayer.shadowRadius = [self accessGlowRadius].floatValue;
    
    if (animated) {
        
        CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"opacity"];
        animation.fromValue = @(0.f);
        animation.toValue = [self accessGlowOpacity];
        self.glowLayer.opacity = [self accessGlowOpacity].floatValue;
        animation.duration = [self accessAnimationDuration].floatValue;
        
        [self.glowLayer addAnimation:animation forKey:@"glowLayerOpacity"];
        
    } else {
        
        [self.glowLayer removeAnimationForKey:@"glowLayerOpacity"];
        self.glowLayer.opacity = [self accessGlowOpacity].floatValue;
    }
}
- (void)glowToHideAnimated:(BOOL)animated {
    
    self.glowLayer.shadowColor = [self accessGlowColor].CGColor;
    self.glowLayer.shadowRadius = [self accessGlowRadius].floatValue;
    
    if (animated) {
        
        CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"opacity"];
        animation.fromValue = [self accessGlowOpacity];
        animation.toValue = @(0.f);
        self.glowLayer.opacity = 0.f;
        animation.duration = [self accessAnimationDuration].floatValue;
        
        [self.glowLayer addAnimation:animation forKey:@"glowLayerOpacity"];
        
    } else {
        
        [self.glowLayer removeAnimationForKey:@"glowLayerOpacity"];
        self.glowLayer.opacity = 0.f;
    }
}
- (void)startGlowLoop {
    
    if (self.dispatchSource == nil) {
        
        CGFloat seconds = [self accessAnimationDuration].floatValue * 2 + [self accessGlowDuration].floatValue + [self accessHideDuration].floatValue;
        CGFloat delaySeconds = [self accessAnimationDuration].floatValue + [self accessGlowDuration].floatValue;
        
        self.dispatchSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_main_queue());
        
        __weak UIView *weakSelf = self;
        dispatch_source_set_timer(self.dispatchSource, dispatch_time(DISPATCH_TIME_NOW, 0), NSEC_PER_SEC * seconds, 0);
        dispatch_source_set_event_handler(self.dispatchSource, ^{
            
            [weakSelf glowToshowAnimated:YES];
            
            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_SEC * delaySeconds), dispatch_get_main_queue(), ^{
                
                [weakSelf glowToHideAnimated:YES];
            });
        });
        
        dispatch_resume(self.dispatchSource);
    }
}
#pragma mark - 处理数据越界问题
- (NSNumber *)accessGlowOpacity {
    
    if (self.glowOpacity) {
        
        if (self.glowOpacity.floatValue  1) {
            
            return @(0.8);
            
        } else {
            
            return self.glowOpacity;
        }
        
    } else {
        
        return @(0.8);
    }
}
- (NSNumber *)accessGlowDuration {
    
    if (self.glowDuration) {
        
        if (self.glowDuration.floatValue <= 0) {
            
            return @(0.5f);
            
        } else {
            
            return self.glowDuration;
        }
        
    } else {
        
        return @(0.5f);
    }
}
- (NSNumber *)accessHideDuration {
    
    if (self.hideDuration) {
        
        if (self.hideDuration.floatValue < 0) {
            
            return @(0.5);
            
        } else {
            
            return self.hideDuration;
        }
        
    } else {
        
        return @(0.5f);
    }
}
- (NSNumber *)accessAnimationDuration {
    
    if (self.glowAnimationDuration) {
        
        if (self.glowAnimationDuration.floatValue <= 0) {
            
            return @(1.f);
            
        } else {
            
            return self.glowAnimationDuration;
        }
        
    } else {
        
        return @(1.f);
    }
}
- (UIColor *)accessGlowColor {
    
    if (self.glowColor) {
        
        return self.glowColor;
        
    } else {
        
        return [UIColor redColor];
    }
}
- (NSNumber *)accessGlowRadius {
    
    if (self.glowRadius) {
        
        if (self.glowRadius.floatValue <= 0) {
            
            return @(2.f);
            
        } else {
            
            return self.glowRadius;
        }
        
    } else {
        
        return @(2.f);
    }
}
#pragma mark - runtime属性
- (void)setDispatchSource:(dispatch_source_t)dispatchSource {
    
    objc_setAssociatedObject(self, @selector(dispatchSource), dispatchSource, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (dispatch_source_t)dispatchSource {
    
    return objc_getAssociatedObject(self, _cmd);
}
- (void)setGlowColor:(UIColor *)glowColor {
    
    objc_setAssociatedObject(self, @selector(glowColor), glowColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (UIColor *)glowColor {
    
    return objc_getAssociatedObject(self, _cmd);
}
- (void)setGlowOpacity:(NSNumber *)glowOpacity {
    
    objc_setAssociatedObject(self, @selector(glowOpacity), glowOpacity, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSNumber *)glowOpacity {
    
    return objc_getAssociatedObject(self, _cmd);
}
- (void)setGlowRadius:(NSNumber *)glowRadius {
    
    objc_setAssociatedObject(self, @selector(glowRadius), glowRadius, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSNumber *)glowRadius {
    
    return objc_getAssociatedObject(self, _cmd);
}
- (void)setGlowAnimationDuration:(NSNumber *)glowAnimationDuration {
    
    objc_setAssociatedObject(self, @selector(glowAnimationDuration), glowAnimationDuration, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSNumber *)glowAnimationDuration {
    
    return objc_getAssociatedObject(self, _cmd);
}
- (void)setGlowDuration:(NSNumber *)glowDuration {
    
    objc_setAssociatedObject(self, @selector(glowDuration), glowDuration, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSNumber *)glowDuration {
    
    return objc_getAssociatedObject(self, _cmd);
}
- (void)setHideDuration:(NSNumber *)hideDuration {
    
    objc_setAssociatedObject(self, @selector(hideDuration), hideDuration, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSNumber *)hideDuration {
    
    return objc_getAssociatedObject(self, _cmd);
}
NSString * const _recognizerGlowLayer = @"_recognizerGlowLayer";
- (void)setGlowLayer:(CALayer *)glowLayer {
    
    objc_setAssociatedObject(self, @selector(glowLayer), glowLayer, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (CALayer *)glowLayer {
    
    return objc_getAssociatedObject(self, _cmd);
}
@end

源码已经放在GitHub：https://github.com/Fendouzhe/LRAnimations，有兴趣的欢迎下载查看，有帮助可以star，谢谢！