UI基础--粒子动画

@interface RootViewController ()
@property (nonatomic, strong) CAEmitterLayer *emitterLayer;
@end

@implementation RootViewController


-(CAEmitterLayer *)emitterLayer{
    
    if (_emitterLayer) {
        return _emitterLayer;
    }
    _emitterLayer = [[CAEmitterLayer alloc]init];
    [self.view.layer addSublayer:_emitterLayer];
    return _emitterLayer;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.view.backgroundColor = [UIColor whiteColor];
    self.title = @"大头儿子";
    
    UIImageView *View = [[UIImageView alloc]initWithFrame:self.view.frame];
    //    View.center = CGPointMake(200,450);
    View.contentMode = UIViewContentModeScaleAspectFit;
    View.image = [UIImage imageNamed:@"1.jpg"];
    
    [self.view addSubview:View];
    
    self.emitterLayer.frame = CGRectMake(0, 0, self.view.frame.size.width, 600);
//    self.view.backgroundColor = [UIColor blackColor];
    //    设置粒子发送器 每秒钟发送的数量
    self.emitterLayer.birthRate = 1;
    //    self.emitterLayer.emitterPosition 中心点
    self.emitterLayer.position = CGPointMake(400,900);
    self.emitterLayer.emitterShape = kCAEmitterLayerCircle;
    //    设置粒子发送器的样式
    self.emitterLayer.renderMode = kCAEmitterLayerOldestLast;
    self.emitterLayer.emitterMode = kCAEmitterLayerVolume;
    NSMutableArray *array = [[NSMutableArray alloc]init];
    for (int i=0; i<5; i++) {
        CAEmitterCell *cell3 = [CAEmitterCell emitterCell];
        cell3.contents = (id)[UIImage imageNamed:[NSString stringWithFormat:@"桃心%d",i+1]].CGImage;
        //    粒子出生量
        cell3.birthRate = 1;
        //    存活时间->单位秒
        cell3.lifetime = 5;
        cell3.lifetimeRange = 2;
        //    发送速度
        cell3.velocity = 50;
        cell3.velocityRange = 100;
        // 粒子发送的方向
        cell3.emissionLatitude = 50*(i+1)*M_PI/180;
        //    发送的加速度
        cell3.yAcceleration = -50;
        //        散发粒子的范围 - 弧度
        cell3.emissionRange = 200;
        //    把粒子的cell 放到粒子发送器上
        [array addObject:cell3];
    }
    
    self.emitterLayer.emitterCells = array;
    
    
    //创建渐变图层对象
    CAGradientLayer *layer = [CAGradientLayer layer];
    layer.frame = self.view.frame;
    //图层的透明度
    layer.opacity = 0.2;
    //设置图层颜色渐变的开始点
    layer.startPoint = CGPointMake(0, 0);
    //设置图层颜色渐变的结束点
    layer.endPoint = CGPointMake(1,0.5);
    //颜色渐变的百分比 数组
    layer.locations = @[@0.2,@0.6];
    //渐变颜色的数组 数组不接受的CGColor类型 强转成id类型的
    layer.colors = @[(id)[UIColor redColor].CGColor,(id)[UIColor whiteColor].CGColor,(id)[UIColor cyanColor].CGColor,];
    [self.view.layer addSublayer:layer];
//
}