Struct AVCapturePhotoOutputReadinessCoordinator 

pub struct AVCapturePhotoOutputReadinessCoordinator { /* private fields */ }

Available on crate feature AVCapturePhotoOutput only.

AVCapturePhotoOutputReadinessCoordinator notifies its delegate of changes in an AVCapturePhotoOutput’s captureReadiness property and can be used to coordinate UI updates on the main queue with use of AVCapturePhotoOutput on a background queue.

AVCapturePhotoOutputReadinessCoordinator tracks its output’s captureReadiness and incorporates additional requests registered via -startTrackingCaptureRequestUsingPhotoSettings:. This allows clients to synchronously update shutter button availability and appearance and on the main thread while calling -[AVCapturePhotoOutput capturePhotoWithSettings:delegate:] asynchronously on a background queue.

See also Apple’s documentation

Implementations

impl AVCapturePhotoOutputReadinessCoordinator

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

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

pub unsafe fn initWithPhotoOutput( this: Allocated<Self>, photo_output: &AVCapturePhotoOutput, ) -> Retained<Self>

Available on crate feature AVCaptureOutputBase only.

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

The receiver’s delegate, called on the main queue.

The value of this property is an object conforming to the AVCapturePhotoOutputReadinessCoordinatorDelegate protocol that will receive a callback when the captureReadiness property changes. Callbacks are delivered on the main queue, allowing UI updates to be done directly in the callback. A callback with the initial value of captureReadiness is delivered when delegate is set.

pub unsafe fn setDelegate( &self, delegate: Option<&ProtocolObject<dyn AVCapturePhotoOutputReadinessCoordinatorDelegate>>, )

Setter for delegate.

This is a weak property.

pub unsafe fn captureReadiness(&self) -> AVCapturePhotoOutputCaptureReadiness

A value specifying whether the coordinator’s photo output is ready to respond to new capture requests in a timely manner.

The value incorporates the photo output’s captureReadiness and any requests registered using -startTrackingCaptureRequestUsingPhotoSettings:. The value is updated before calling the -readinessCoordinator:captureReadinessDidChange: callback. See AVCapturePhotoOutput’s captureReadiness documentation for a discussion of how to update shutter availability and appearance based on the captureReadiness value. This property is key-value observable and all change notifications are delivered on the main queue, allowing UI updates to be done directly in the callback.

pub unsafe fn startTrackingCaptureRequestUsingPhotoSettings( &self, settings: &AVCapturePhotoSettings, )

Track the capture request represented by the specified photo settings until it is enqueued to the photo output and update captureReadiness to include this request.

Parameter settings: The AVCapturePhotoSettings which will be passed to -[AVCapturePhotoOutput capturePhotoWithSettings:delegate] for this capture request.

The captureReadiness property is updated to include the tracked request until the the photo output receives a settings object with the same or a newer uniqueID. It is recommended that the same photo settings be passed to -[AVCapturePhotoOutput capturePhotoWithSettings:delegate] to ensure the captureReadiness value is consistent once the capture begins. When called on the main queue the delegate callback is invoked synchronously before returning to ensure shutter availability is updated immediately and prevent queued touch events from initiating unwanted captures. The -startTrackingCaptureRequestUsingPhotoSettings: method can be called while in the SessionNotRunning state to allow the shutter button to be interactive while the session is being started on a background queue. An NSInvalidArgumentException is thrown if the photo settings are invalid.

pub unsafe fn stopTrackingCaptureRequestUsingPhotoSettingsUniqueID( &self, settings_unique_id: i64, )

Stop tracking the capture request represented by the specified photo settings uniqueID and update captureReadiness to no longer include this request.

Parameter settingsUniqueID: The AVCapturePhotoSettings.uniqueID of the settings passed to -startTrackingCaptureRequestUsingPhotoSettings:.

Tracking automatically stops when -[AVCapturePhotoOutput capturePhotoWithSettings:delegate] is called with a photo settings objects with the same or a newer uniqueID, but in cases where an error or other condition prevents calling -capturePhotoWithSettings:delegate tracking should be explicitly stopped to ensure the captureReadiness value is up to date. When called on the main queue the delegate callback is invoked synchronously before returning to ensure shutter availability is updated immediately.

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<AVCapturePhotoOutputReadinessCoordinator> for AVCapturePhotoOutputReadinessCoordinator

fn as_ref(&self) -> &Self

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

impl AsRef<AnyObject> for AVCapturePhotoOutputReadinessCoordinator

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVCapturePhotoOutputReadinessCoordinator

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for AVCapturePhotoOutputReadinessCoordinator

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVCapturePhotoOutputReadinessCoordinator

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVCapturePhotoOutputReadinessCoordinator

const NAME: &'static str = "AVCapturePhotoOutputReadinessCoordinator"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVCapturePhotoOutputReadinessCoordinator 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 AVCapturePhotoOutputReadinessCoordinator

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

Formats the value using the given formatter.

impl Deref for AVCapturePhotoOutputReadinessCoordinator

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVCapturePhotoOutputReadinessCoordinator

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 AVCapturePhotoOutputReadinessCoordinator

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for AVCapturePhotoOutputReadinessCoordinator

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 AVCapturePhotoOutputReadinessCoordinator

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 AVCapturePhotoOutputReadinessCoordinator

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

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

impl DowncastTarget for AVCapturePhotoOutputReadinessCoordinator

impl Eq for AVCapturePhotoOutputReadinessCoordinator