ios中天女散花效果

添加<QuartzCore/QuartzCore.h>库，一张背景图和花瓣图

#import "ViewController.h"

#import <QuartzCore/QuartzCore.h>

@interface ViewController ()

@property (nonatomic,weak) IBOutletUIView *containerView;

@end

@implementation ViewController

- (void)viewDidLoad

{

    [superviewDidLoad];

//    cell.contents = (__bridge id)[UIImage imageNamed:@"47b5e3384e311b4f.jpg"].CGImage;

    self.view.backgroundColor = [UIColorwhiteColor];

    

    

    

// =================== 背景图片 ===========================

    UIImageView * backgroundView = [[UIImageViewalloc] initWithFrame:CGRectMake(0,0, self.view.bounds.size.width,self.view.bounds.size.height)];

    backgroundView.image = [UIImageimageNamed:@"樱花树3iPhoneLandscapeiOS8_736x414pt@3x"];

    backgroundView.contentMode =UIViewContentModeScaleAspectFill;

    [self.viewaddSubview:backgroundView];

    

    

// =================== 樱花飘落 ====================

    CAEmitterLayer * snowEmitterLayer = [CAEmitterLayerlayer];

    snowEmitterLayer.emitterPosition =CGPointMake(100, -30);

    snowEmitterLayer.emitterSize =CGSizeMake(self.view.bounds.size.width , 0);

    snowEmitterLayer.emitterMode =kCAEmitterLayerOutline;

    snowEmitterLayer.emitterShape =kCAEmitterLayerLine;

//    snowEmitterLayer.renderMode = kCAEmitterLayerAdditive;

    

    CAEmitterCell * snowCell = [CAEmitterCellemitterCell];

    snowCell.contents = (__bridgeid)[UIImageimageNamed:@"樱花瓣2"].CGImage;

    

    // 花瓣缩放比例

    snowCell.scale =0.02;

    snowCell.scaleRange =0.5;

    

    // 每秒产生的花瓣数量

    snowCell.birthRate =7;

    snowCell.lifetime =80;

    

    // 每秒花瓣变透明的速度

    snowCell.alphaSpeed = -0.01;

    

    // 秒速“五”厘米～～

    snowCell.velocity =40;

    snowCell.velocityRange =60;

    

    // 花瓣掉落的角度范围

    snowCell.emissionRange =M_PI;

    

    // 花瓣旋转的速度

    snowCell.spin =M_PI_4;

    // 每个cell的颜色

//    snowCell.color = [[UIColor redColor] CGColor];

    

    // 阴影的不透明度

    snowEmitterLayer.shadowOpacity =1;

    // 阴影化开的程度（就像墨水滴在宣纸上化开那样）

    snowEmitterLayer.shadowRadius =8;

    // 阴影的偏移量

    snowEmitterLayer.shadowOffset =CGSizeMake(3,3);

    // 阴影的颜色

    snowEmitterLayer.shadowColor = [[UIColorwhiteColor] CGColor];

    

    

    snowEmitterLayer.emitterCells = [NSArrayarrayWithObject:snowCell];

    [backgroundView.layeraddSublayer:snowEmitterLayer];

    

                        

    

    

}