粒子雪花效果

粒子雪花效果

效果

源码

https://github.com/YouXianMing/Animations

//

// EmitterSnowController.m

// Animations

// Created by YouXianMing on 15/12/21.

// Copyright © 2015年 YouXianMing. All rights reserved.

#import "EmitterSnowController.h"

@interface EmitterSnowController ()

@property (nonatomic, strong) CALayer *movedMask;

@implementation EmitterSnowController

- (void)viewDidLoad {

 [super viewDidLoad];

- (void)setup {

 [super setup];

 self.backgroundView.backgroundColor = [UIColor blackColor];

 // 创建粒子Layer

 CAEmitterLayer *snowEmitter = [CAEmitterLayer layer];

 // 粒子发射位置

 snowEmitter.emitterPosition = CGPointMake(120,0);

 // 发射源的尺寸大小

 snowEmitter.emitterSize = self.contentView.bounds.size;

 // 发射模式

 snowEmitter.emitterMode = kCAEmitterLayerSurface;

 // 发射源的形状

 snowEmitter.emitterShape = kCAEmitterLayerLine;

 // 创建雪花类型的粒子

 CAEmitterCell *snowflake = [CAEmitterCell emitterCell];

 // 粒子的名字

 snowflake.name = @"snow";

 // 粒子参数的速度乘数因子

 snowflake.birthRate = 20.0;

 snowflake.lifetime = 120.0;

 // 粒子速度

 snowflake.velocity =10.0;

 // 粒子的速度范围

 snowflake.velocityRange = 10;

 // 粒子y方向的加速度分量

 snowflake.yAcceleration = 2;

 // 周围发射角度

 snowflake.emissionRange = 0.5 * M_PI;

 // 子旋转角度范围

 snowflake.spinRange = 0.25 * M_PI;

 snowflake.contents = (id)[[UIImage imageNamed:@"snow"] CGImage];

 // 设置雪花形状的粒子的颜色

 snowflake.color = [[UIColor whiteColor] CGColor];

 snowflake.redRange = 2.f;

 snowflake.greenRange = 2.f;

 snowflake.blueRange = 2.f;

 snowflake.scaleRange = 0.6f;

 snowflake.scale = 0.7f;

 snowEmitter.shadowOpacity = 1.0;

 snowEmitter.shadowRadius = 0.0;

 snowEmitter.shadowOffset = CGSizeMake(0.0, 0.0);

 // 粒子边缘的颜色

 snowEmitter.shadowColor = [[UIColor whiteColor] CGColor];

 // 添加粒子

 snowEmitter.emitterCells = @[snowflake];

 // 将粒子Layer添加进图层中

 [self.contentView.layer addSublayer:snowEmitter];

 // 形成遮罩

 UIImage *image = [UIImage imageNamed:@"alpha"];

 _movedMask = [CALayer layer];

 _movedMask.frame = (CGRect){CGPointZero, image.size};

 _movedMask.contents = (__bridge id)(image.CGImage);

 _movedMask.position = self.contentView.center;

 snowEmitter.mask = _movedMask;

 // 拖拽的View

 UIView *dragView = [[UIView alloc] initWithFrame:(CGRect){CGPointZero, image.size}];

 dragView.center = self.contentView.center;

 [self.contentView addSubview:dragView];

 // 给dragView添加拖拽手势

 UIPanGestureRecognizer *recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];

 [dragView addGestureRecognizer:recognizer];

- (void)handlePan:(UIPanGestureRecognizer *)recognizer {

 // 拖拽

 CGPoint translation = [recognizer translationInView:self.contentView];

 recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,

 recognizer.view.center.y + translation.y);

 [recognizer setTranslation:CGPointMake(0, 0) inView:self.contentView];

 // 关闭CoreAnimation实时动画绘制(核心)

 [CATransaction setDisableActions:YES];

 _movedMask.position = recognizer.view.center;

@end

细节