Class

CAEmitterCell

The definition of a particle emitted by a CAEmitterLayer.

Declaration

class CAEmitterCell : NSObject

Overview

The CAEmitterCell class represents one source of particles being emitted by a CAEmitterLayer object. An emitter cell defines the direction and properties of the emitted particles. Emitter cells can have an array of sub-cells, which lets the particles themselves emit particles.

Topics

Providing Emitter Cell Content

var contents: Any?

An object that provides the contents of the layer. Animatable.

var contentsRect: CGRect

A rectangle (in the unit coordinate space) that specifies the portion of contents that the receiver should draw. Animatable.

var emitterCells: [CAEmitterCell]?

An optional array containing the sub-cells of this cell.

Setting Emitter Cell Visual Attributes

var isEnabled: Bool

A Boolean value indicating whether or not cells from this emitter are rendered.

var color: CGColor?

The color of each emitted object. Animatable.

var redRange: Float

The amount by which the red color component of the cell can vary. Animatable.

var greenRange: Float

The amount by which the green color component of the cell can vary. Animatable.

var blueRange: Float

The amount by which the blue color component of the cell can vary. Animatable.

var alphaRange: Float

The amount by which the alpha component of the cell can vary. Animatable.

var redSpeed: Float

The speed, in seconds, at which the red color component changes over the lifetime of the cell. Animatable.

var greenSpeed: Float

The speed, in seconds, at which the green color component changes over the lifetime of the cell. Animatable.

var blueSpeed: Float

The speed, in seconds, at which the blue color component changes over the lifetime of the cell. Animatable.

var alphaSpeed: Float

The speed, in seconds, at which the alpha component changes over the lifetime of the cell. Animatable.

var magnificationFilter: String

The filter used when increasing the size of the content.

var minificationFilter: String

The filter used when reducing the size of the content.

var minificationFilterBias: Float

The bias factor used by the minification filter to determine the levels of detail.

var scale: CGFloat

Specifies the scale factor applied to the cell. Animatable.

var scaleRange: CGFloat

Specifies the range over which the scale value can vary. Animatable.

var contentsScale: CGFloat

The scale factor of the cell contents.

var name: String?

The name of the cell.

var style: [AnyHashable : Any]?

An optional dictionary containing additional style values that are not explicitly defined by the receiver.

Setting Emitter Cell Motion Attributes

var spin: CGFloat

The rotational velocity, measured in radians per second, to apply to the cell. Animatable.

var spinRange: CGFloat

The amount by which the spin of the cell can vary over its lifetime. Animatable.

var emissionLatitude: CGFloat

The latitudinal orientation of the emission angle. Animatable.

var emissionLongitude: CGFloat

The longitudinal orientation of the emission angle. Animatable.

var emissionRange: CGFloat

The angle, in radians, defining a cone around the emission angle. Animatable.

Setting Emitter Cell Temporal Attributes

var lifetime: Float

The lifetime of the cell, in seconds. Animatable.

var lifetimeRange: Float

The mean value by which the lifetime of the cell can vary. Animatable.

var birthRate: Float

The number of emitted objects created every second. Animatable.

var scaleSpeed: CGFloat

The speed at which the scale changes over the lifetime of the cell. Animatable.

var velocity: CGFloat

The initial velocity of the cell. Animatable.

var velocityRange: CGFloat

The amount by which the velocity of the cell can vary. Animatable.

var xAcceleration: CGFloat

The x component of an acceleration vector applied to cell.

var yAcceleration: CGFloat

The y component of an acceleration vector applied to cell.

var zAcceleration: CGFloat

The z component of an acceleration vector applied to cell.

Using Key-Value Coding Extensions

class func defaultValue(forKey: String) -> Any?

Returns the default value of the property with the specified key.

func shouldArchiveValue(forKey: String) -> Bool

Returns a Boolean value indicating whether the value for a given key should be archived.

See Also

Particle Systems

class CAEmitterLayer

A layer that emits, animates, and renders a particle system.

Beta Software

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

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