iOS开发UIMotionEffect运动视觉效果

1、UIMotionEffect简介

　　在iOS7.0推出了UIMotionEffect运动视觉效果，就是从屏幕偏移不同角度、看到的效果不同！

NS_CLASS_AVAILABLE_IOS(7_0)
@interface UIMotionEffect : NSObject <NSCopying, NSCoding>
- (instancetype)init NS_DESIGNATED_INITIALIZER;
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder NS_DESIGNATED_INITIALIZER;
//观察者的角度偏移viewerOffset，获取运动视觉效果的各项属性和值
- (nullable NSDictionary<NSString *, id> *)keyPathsAndRelativeValuesForViewerOffset:(UIOffset)viewerOffset;
@end

typedef NS_ENUM(NSInteger, UIInterpolatingMotionEffectType) {
    UIInterpolatingMotionEffectTypeTiltAlongHorizontalAxis,//X轴
    UIInterpolatingMotionEffectTypeTiltAlongVerticalAxis//Y轴
};

@interface UIInterpolatingMotionEffect : UIMotionEffect
- (instancetype)initWithKeyPath:(NSString *)keyPath type:(UIInterpolatingMotionEffectType)type NS_DESIGNATED_INITIALIZER;//初始化
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder NS_DESIGNATED_INITIALIZER;

@property (readonly, nonatomic) NSString *keyPath;//获取角度偏移
@property (readonly, nonatomic) UIInterpolatingMotionEffectType type;//获取类型
@property (nullable, strong, nonatomic) id minimumRelativeValue;//最小角度偏移
@property (nullable, strong, nonatomic) id maximumRelativeValue;//最大角度偏移
@end

@interface UIMotionEffectGroup : UIMotionEffect
@property (nullable, copy, nonatomic) NSArray<__kindof UIMotionEffect *> *motionEffects;//添加水平和垂直效果添加到对应UI上
@end

2、简单使用

- (void)addEffectWithOffset:(NSInteger)offset withView:(UIView *)view{
    UIInterpolatingMotionEffect *effectX = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:@"center.x" type:UIInterpolatingMotionEffectTypeTiltAlongHorizontalAxis];
    effectX.minimumRelativeValue = @(-offset);
    effectX.maximumRelativeValue = @(offset);
    
    UIInterpolatingMotionEffect *effectY = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:@"center.y" type:UIInterpolatingMotionEffectTypeTiltAlongVerticalAxis];
    effectY.minimumRelativeValue = @(-offset/2);
    effectY.maximumRelativeValue = @(offset/2);
    
//    UIMotionEffectGroup *group = [[UIMotionEffectGroup alloc] init];
//    group.motionEffects = @[effectX,effectY];
    view.motionEffects = @[effectX,effectY];
}