整体描述
CAEmitter相关的是粒子动画,可以实现很多酷炫的效果
源码
/* CoreAnimation - CAEmitterCell.h
Copyright (c) 2007-2016, Apple Inc.
All rights reserved. */
#import <QuartzCore/CALayer.h>
NS_ASSUME_NONNULL_BEGIN
CA_CLASS_AVAILABLE (10.6, 5.0, 9.0, 2.0)
@interface CAEmitterCell : NSObject <NSCoding, CAMediaTiming>
{
@private
void *_attr[2];
void *_state;
uint32_t _flags;
}
+ (instancetype)emitterCell;
/* Emitter cells implement the same property model as defined by CALayer.
* See CALayer.h for more details. */
+ (nullable id)defaultValueForKey:(NSString *)key;
- (BOOL)shouldArchiveValueForKey:(NSString *)key;
/* The name of the cell. Used to construct key paths. Defaults to nil. */
@property(nullable, copy) NSString *name;
/* Controls whether or not cells from this emitter are rendered. */
@property(getter=isEnabled) BOOL enabled;
/* The number of emitted objects created every second. Default value is
* zero. Animatable. */
@property float birthRate; // 每秒生成的粒子数量,默认值是1(支持隐式动画)
/* The lifetime of each emitted object in seconds, specified as a mean
* value and a range about the mean. Both values default to zero.
* Animatable. */
@property float lifetime; // 设置粒子的生存时间(支持隐式动画)默认是1.0
@property float lifetimeRange;
/* The orientation of the emission angle in radians, relative to the
* natural orientation angle of the emission shape. Note that latitude
* here is what is typically called colatitude, the zenith or phi, the
* angle from the z-axis. Similarly longitude is the angle in the
* xy-plane from the x-axis, often referred to as the azimuth or
* theta. Both values default to zero, which translates to no change
* relative to the emission shape's direction. Both values are
* animatable. */
@property CGFloat emissionLatitude;
@property CGFloat emissionLongitude;
/* An angle (in radians) defining a cone around the emission angle.
* Emitted objects are uniformly distributed across this cone. Defaults
* to zero. Animatable. */
@property CGFloat emissionRange;
/* The initial mean velocity of each emitted object, and its range. Both
* values default to zero. Animatable. */
@property CGFloat velocity; // 设置粒子的移动速度(支持隐式动画)默认值是1.0
@property CGFloat velocityRange;
/* The acceleration vector applied to emitted objects. Defaults to
* (0, 0, 0). Animatable. */
@property CGFloat xAcceleration;
@property CGFloat yAcceleration;
@property CGFloat zAcceleration;
/* The scale factor applied to each emitted object, defined as mean and
* range about the mean. Scale defaults to one, range to zero.
* Animatable. */
@property CGFloat scale; // 设置粒子发射器的生成粒子的初始缩放比例
@property CGFloat scaleRange;
@property CGFloat scaleSpeed;
/* The rotation speed applied to each emitted object, defined as mean
* and range about the mean. Defaults to zero. Animatable. */
@property CGFloat spin; // 设置粒子的自旋速度,数值越大旋转越快
@property CGFloat spinRange;
/* The mean color of each emitted object, and the range from that mean
* color. `color' defaults to opaque white, `colorRange' to (0, 0, 0,
* 0). Animatable. */
@property(nullable) CGColorRef color;
@property float redRange;
@property float greenRange;
@property float blueRange;
@property float alphaRange;
/* The speed at which color components of emitted objects change over
* their lifetime, defined as the rate of change per second. Defaults
* to (0, 0, 0, 0). Animatable. */
@property float redSpeed;
@property float greenSpeed;
@property float blueSpeed;
@property float alphaSpeed;
/* The cell contents, typically a CGImageRef. Defaults to nil.
* Animatable. */
@property(nullable, strong) id contents;
/* The sub-rectangle of the contents image that will be drawn. See
* CALayer.h for more details. Defaults to the unit rectangle [0 0 1 1].
* Animatable. */
@property CGRect contentsRect;
/* Defines the scale factor applied to the contents of the cell. See
* CALayer.h for more details. */
@property CGFloat contentsScale;
/* The filter parameters used when rendering the `contents' image. See
* CALayer.h for more details. */
@property(copy) NSString *minificationFilter;
@property(copy) NSString *magnificationFilter;
@property float minificationFilterBias;
/* An array containing the sub-cells of this cell, or nil (the default
* value). When non-nil each particle emitted by the cell will act as
* an emitter for each of the cell's sub-cells. The emission point is
* the current particle position and the emission angle is relative to
* the current direction of the particle. Animatable. */
@property(nullable, copy) NSArray<CAEmitterCell *> *emitterCells;
/* Inherited attributes similar to in layers. */
@property(nullable, copy) NSDictionary *style;
@end
NS_ASSUME_NONNULL_END