@property(copy) NSArray *colors 漸變顏色的數(shù)組 @property(copy) NSArray *locations 漸變顏色的區(qū)間分布，locations的數(shù)組長度和color一致，一般不用設(shè)置，默認是nil，會平均分布。//[NSArray arrayWithObjects:[NSNumber numberWithFloat:0.0],  //       [NSNumber numberWithFloat:0.3],  //       [NSNumber numberWithFloat:0.8],  //       [NSNumber numberWithFloat:1.0],  //      nil]; @property CGPoint startPoint 映射locations中第一個位置，用單位向量表示，比如（0，0）表示從左上角開始變化。默認值是(0.5,0.0)。@property CGPoint endPoint 映射locations中最后一個位置,用單位向量表示，比如（1，1）表示到右下角變化結(jié)束。默認值是(0.5,1.0)。

 //漸變色 CAGradientLayer *gradientLayer = [CAGradientLayer layer]; gradientLayer.frame = self.view.bounds; [self.view.layer addSublayer:gradientLayer]; UIColor *lightColor = [UIColor colorWithRed:40.0 / 255.0 green:150.0 / 255.0 blue:200.0 / 255.0 alpha:1.0]; UIColor *whiteColor = [UIColor colorWithRed:255.0 / 255.0 green:250.0 / 255.0 blue:250.0 / 255.0 alpha:1.0];//可以設(shè)置多個colors, gradientLayer.colors = @[(__bridge id)lightColor.CGColor,(__bridge id)whiteColor.CGColor]; //45度變色(由lightColor－>white) gradientLayer.startPoint = CGPointMake(0, 0); gradientLayer.endPoint = CGPointMake(1, 1);

 CAEmitterCell *cell = [[CAEmitterCell alloc] init]; //展示的圖片 cell.contents = (__bridge id _Nullable)([UIImage imageNamed:@"white"].CGImage); //每秒粒子產(chǎn)生個數(shù)的乘數(shù)因子，會和layer的birthRate相乘，然后確定每秒產(chǎn)生的粒子個數(shù) cell.birthRate = 2000; //每個粒子存活時長 cell.lifetime = 5.0; //粒子生命周期范圍 cell.lifetimeRange = 0.3; //粒子透明度變化，設(shè)置為－0.4，就是每過一秒透明度就減少0.4，這樣就有消失的效果,一般設(shè)置為負數(shù)。 cell.alphaSpeed = -0.2; cell.alphaRange = 0.5; //粒子的速度 cell.velocity = 40; //粒子的速度范圍 cell.velocityRange = 20; //周圍發(fā)射的角度，如果為M_PI*2 就可以從360度任意位置發(fā)射 //cell.emissionRange = M_PI*2; //粒子內(nèi)容的顏色 // cell.color = [[UIColor whiteColor] CGColor];//設(shè)置了顏色變化范圍后每次產(chǎn)生的粒子的顏色都是隨機的 cell.redRange = 0.5; cell.blueRange = 0.5; cell.greenRange = 0.5; //縮放比例 cell.scale = 0.2; //縮放比例范圍 cell.scaleRange = 0.02; //粒子的初始發(fā)射方向 cell.emissionLongitude = M_PI; //Y方向的加速度 cell.yAcceleration = 70.0; //X方向加速度 // cell.xAcceleration = 20.0; _emitterLayer = [CAEmitterLayer layer]; //發(fā)射位置 _emitterLayer.emitterPosition = CGPointMake(SCREEN_WIDTH/2.0, 0); //粒子產(chǎn)生系數(shù)，默認為1 _emitterLayer.birthRate = 1; //發(fā)射器的尺寸 _emitterLayer.emitterSize = CGSizeMake(SCREEN_WIDTH, 0); //發(fā)射的形狀 _emitterLayer.emitterShape = kCAEmitterLayerLine; //發(fā)射的模式 _emitterLayer.emitterMode = kCAEmitterLayerLine; //渲染模式 _emitterLayer.renderMode = kCAEmitterLayerOldestFirst; _emitterLayer.masksToBounds = NO; //_emitterLayer.zPosition = -1; _emitterLayer.emitterCells = @[cell];//emitterView是自己創(chuàng)建的一個View [self.emitterView.layer addSublayer:_emitterLayer];

CA_EXTERN NSString * const kCAEmitterLayerPoint//點 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerLine//線 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerRectangle//矩形 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerCuboid//立方體 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerCircle//圓形 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerSphere//球形 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);

CA_EXTERN NSString * const kCAEmitterLayerPoints//從發(fā)射器中 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerOutline//邊緣 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerSurface//表面 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerVolume//中點 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);

CA_EXTERN NSString * const kCAEmitterLayerUnordered//粒子是無序出現(xiàn)的，多個發(fā)射源將混合 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerOldestFirst//聲明久的粒子會被渲染在最上層 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerOldestLast//年輕的粒子會被渲染在最上層 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerBackToFront//粒子的渲染按照Z軸的前后順序進行 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);CA_EXTERN NSString * const kCAEmitterLayerAdditive//進行粒子混合 CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);