通过cagradientLayer类封装uiimageview动画色度差

#import <UIKit/UIKit.h>
typedef NS_ENUM(NSInteger, EcolorDirectionType)
{
    EcolorDirectionUp,    //上
    EcolorDirectionDown,  //下
    EcolorDirectionRight, //右
    EcolorDirectionLeft,  //左
};
@interface ColorImageView : UIImageView

/**
 *  @brief 确定方向
 */
@property(nonatomic,assign) EcolorDirectionType direction;

/**
 *  @brief  颜色
 */
@property(nonatomic,strong) UIColor *color;

/**
 *  @brief  百分比
 */
@property(nonatomic,assign) CGFloat percent;

@end
#import "ColorImageView.h"
@interface ColorImageView ()
{
    CAGradientLayer *_gradientLayer;
}
@end
@implementation ColorImageView
@synthesize color     = _color;
@synthesize percent   = _percent;
@synthesize direction = _direction;

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self)
    {
        _gradientLayer = [CAGradientLayer layer];
        _gradientLayer.frame = self.bounds;
        _gradientLayer.borderWidth = 1.0f;
        _gradientLayer.colors = @[ (__bridge id)[UIColor clearColor].CGColor,
                                   (__bridge id)[UIColor redColor].CGColor
                                  ];
        _gradientLayer.locations = @[@(0.1),@(1)];

        [self.layer addSublayer:_gradientLayer];
    }
    return self;
}
/**
 *  @brief  设置颜色
 *  @param color 重写setter方法
 */
- (void)setColor:(UIColor *)color
{
    _color = color;
    _gradientLayer.colors = @[ (__bridge id)[UIColor clearColor].CGColor,
                               (__bridge id)color.CGColor
                               ];
}
- (UIColor *)color
{
    return _color;
}
/**
 *  @brief  设置颜色分割点
 *  @param percent 重写setter方法
 */
- (void)setPercent:(CGFloat)percent
{
    _percent = percent;
    _gradientLayer.locations= @[@(percent),@(1)];
}

-(CGFloat)percent
{
    return _percent;
}

/**
 *  @brief  设置颜色渐变方向
 *  @param direction 重写setter方法
 */
-(void)setDirection:(EcolorDirectionType)direction
{
    _direction=direction;
    switch (direction) {
        case EcolorDirectionUp:
        {
            _gradientLayer.startPoint = CGPointMake(0, 0);
            _gradientLayer.endPoint   = CGPointMake(0, 1);
        }
            break;
        case EcolorDirectionDown:
        {
            _gradientLayer.startPoint = CGPointMake(0, 1);
            _gradientLayer.endPoint   = CGPointMake(0, 0);

        }
            break;
        case EcolorDirectionLeft:
        {
            _gradientLayer.startPoint = CGPointMake(0, 0);
            _gradientLayer.endPoint   = CGPointMake(1, 0);

        }
            break;
        case EcolorDirectionRight:
        {
            _gradientLayer.startPoint = CGPointMake(1, 0);
            _gradientLayer.endPoint   = CGPointMake(0, 0);
        }
            break;
        default:
        {
            _gradientLayer.startPoint = CGPointMake(0, 0);
            _gradientLayer.endPoint   = CGPointMake(0, 1);
        }
            break;
    }
}
-(EcolorDirectionType)direction
{
    return _direction;
}
@end
#import "ViewController.h"
#import "ColorImageView.h"
@interface ViewController ()
{

    ColorImageView *_imvColor;
}
@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    _imvColor=[[ColorImageView alloc]initWithFrame:CGRectMake(0, 0, 220, 185)];
    _imvColor.image = [UIImage imageNamed:@"1"];
    _imvColor.center = self.view.center;

    [self.view addSubview:_imvColor];
    [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(event) userInfo:nil repeats:YES];
   // [self performSelector:@selector(event) withObject:nil afterDelay:2.0f];

}
- (void)event
{
    _imvColor.direction=EcolorDirectionUp;
    _imvColor.color=[UIColor cyanColor];
    _imvColor.percent=arc4random()%100/100.f;
}
@end