Struct AVCaptureDataOutputSynchronizer 

pub struct AVCaptureDataOutputSynchronizer { /* private fields */ }

Available on crate feature AVCaptureDataOutputSynchronizer only.

AVCaptureDataOutputSynchronizer synchronizes the delivery of data from multiple capture data outputs (AVCaptureVideoDataOutput, AVCaptureDepthDataOutput, AVCaptureMetadataOutput, AVCaptureAudioDataOutput) to a single delegate callback.

AVCaptureDataOutputSynchronizer is initialized with an array of data outputs (AVCaptureVideoDataOutput, AVCaptureDepthDataOutput, AVCaptureMetadataOutput, or AVCaptureAudioDataOutput) from which you’d like to receive a single, synchronized delegate callback. The first output in the array acts as the primary data output and determines when the synchronized callback is delivered. When data is received for the primary data output, it is held until all other data outputs have received data with an equal or later presentation time stamp, or it has been determined that there is no data for a particular output at the primary data output’s pts. Once all other outputs are ready, a single delegate callback is sent with all the data aligned with the primary data output’s data. Separate delegate callbacks are sent for any other data received with presentation time stamps earlier than the next primary data output time.

For instance, if you specify a video data output as your first (primary) output and a metadata output for detected faces as your second output, your data callback will not be called until there is face data ready for a video frame, or it is assured that there is no face metadata for that particular video frame.

Note that the AVCaptureDataOutputSynchronizer overrides each data output’s -setSampleBufferDelegate:queue:, -setDepthDataDelegate:queue:, or -setMetadataObjectsDelegate:queue: method call. -[AVCaptureVideoDataOutput alwaysDiscardsLateVideoFrames] and -[AVCaptureDepthDataOutput alwaysDiscardsLateDepthData] properties are honored.

See also Apple’s documentation

Implementations

impl AVCaptureDataOutputSynchronizer

pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

pub unsafe fn new() -> Retained<Self>

pub unsafe fn initWithDataOutputs( this: Allocated<Self>, data_outputs: &NSArray<AVCaptureOutput>, ) -> Retained<Self>

Available on crate feature AVCaptureOutputBase only.

Instantiates an AVCaptureDataOutputSynchronizer from one or more capture data outputs.

Parameter dataOutputs: An array of capture data outputs where the first is the primary output.

Returns: A newly initialized AVCaptureDataOutputSynchronizer instance.

pub unsafe fn dataOutputs(&self) -> Retained<NSArray<AVCaptureOutput>>

Available on crate feature AVCaptureOutputBase only.

The data outputs provided in the initializer method.

pub unsafe fn setDelegate_queue( &self, delegate: Option<&ProtocolObject<dyn AVCaptureDataOutputSynchronizerDelegate>>, delegate_callback_queue: Option<&DispatchQueue>, )

Available on crate feature dispatch2 only.

Sets the receiver’s delegate that will accept synchronized data and the dispatch queue on which the delegate will be called.

Parameter delegate: An object conforming to the AVCaptureDataOutputSynchronizerDelegate protocol that will receive synchronized data from the provided data outputs.

Parameter delegateCallbackQueue: A dispatch queue on which all AVCaptureDataOutputSynchronizerDelegate methods will be called.

AVCaptureDataOutputSynchronizer gathers data from its dataOutputs, and when it determines that all data has been received for a given timestamp, it calls the specified delegate on the specified delegateCallbackQueue. AVCaptureDataOutputSynchronizer overrides all the data outputs’ delegates and callbacks. Data outputs under the control of AVCaptureDataOutputSynchronizer do not fire delegate callbacks. Delegate callbacks are restored to individual data outputs when you call this method with nil as your delegate and NULL as your delegateCallbackQueue.

A serial dispatch queue must be used to guarantee that synchronized data will be delivered in order. The delegateCallbackQueue parameter may not be NULL, except when setting the delegate to nil otherwise -setDelegate:queue: throws an NSInvalidArgumentException.

Safety

delegate_callback_queue possibly has additional threading requirements.

pub unsafe fn delegate( &self, ) -> Option<Retained<ProtocolObject<dyn AVCaptureDataOutputSynchronizerDelegate>>>

The receiver’s delegate.

The value of this property is an object conforming to the AVCaptureDataOutputSynchronizerDelegate protocol that will receive synchronized data output. The delegate is set using the -setDelegate:queue: method. This property is key-value observable.

pub unsafe fn delegateCallbackQueue(&self) -> Option<Retained<DispatchQueue>>

Available on crate feature dispatch2 only.

The dispatch queue on which all AVCaptureDataOutputSynchronizerDelegate methods will be called.

The value of this property is a dispatch_queue_t. The queue is set using the -setDelegate:queue: method.

Methods from Deref<Target = NSObject>

pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>

pub fn class(&self) -> &'static AnyClass

Dynamically find the class of this object.

Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

pub unsafe fn get_ivar<T>(&self, name: &str) -> &T

where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Use Ivar::load instead.

Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

pub fn downcast_ref<T>(&self) -> Option<&T>

where T: DowncastTarget,

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}

Trait Implementations

impl AsRef<AVCaptureDataOutputSynchronizer> for AVCaptureDataOutputSynchronizer

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<AnyObject> for AVCaptureDataOutputSynchronizer

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<NSObject> for AVCaptureDataOutputSynchronizer

fn as_ref(&self) -> &NSObject

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<AnyObject> for AVCaptureDataOutputSynchronizer

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVCaptureDataOutputSynchronizer

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVCaptureDataOutputSynchronizer

const NAME: &'static str = "AVCaptureDataOutputSynchronizer"

The name of the Objective-C class that this type represents.

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVCaptureDataOutputSynchronizer as ClassType>::Super as ClassType>::ThreadKind

Whether the type can be used from any thread, or from only the main thread.

fn class() -> &'static AnyClass

Get a reference to the Objective-C class that this type represents.

fn as_super(&self) -> &Self::Super

Get an immutable reference to the superclass.

impl Debug for AVCaptureDataOutputSynchronizer

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for AVCaptureDataOutputSynchronizer

type Target = NSObject

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Hash for AVCaptureDataOutputSynchronizer

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for AVCaptureDataOutputSynchronizer

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for AVCaptureDataOutputSynchronizer

fn isEqual(&self, other: Option<&AnyObject>) -> bool

where Self: Sized + Message,

Check whether the object is equal to an arbitrary other object.

fn hash(&self) -> usize

where Self: Sized + Message,

An integer that can be used as a table address in a hash table structure.

fn isKindOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of the class, or one of its subclasses.

fn is_kind_of<T>(&self) -> bool

where T: ClassType, Self: Sized + Message,

👎Deprecated: use isKindOfClass directly, or cast your objects with AnyObject::downcast_ref

Check if the object is an instance of the class type, or one of its subclasses.

fn isMemberOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of a specific class, without checking subclasses.

fn respondsToSelector(&self, aSelector: Sel) -> bool

where Self: Sized + Message,

Check whether the object implements or inherits a method with the given selector.

fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool

where Self: Sized + Message,

Check whether the object conforms to a given protocol.

fn description(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object.

fn debugDescription(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object to use when debugging.

fn isProxy(&self) -> bool

where Self: Sized + Message,

Check whether the receiver is a subclass of the NSProxy root class instead of the usual NSObject.

fn retainCount(&self) -> usize

where Self: Sized + Message,

The reference count of the object.

impl PartialEq for AVCaptureDataOutputSynchronizer

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for AVCaptureDataOutputSynchronizer

const ENCODING_REF: Encoding = <NSObject as ::objc2::RefEncode>::ENCODING_REF

The Objective-C type-encoding for a reference of this type.

impl DowncastTarget for AVCaptureDataOutputSynchronizer

impl Eq for AVCaptureDataOutputSynchronizer