Struct AVCaptureAudioPreviewOutput

#[repr(C)]
pub struct AVCaptureAudioPreviewOutput { /* private fields */ }

Available on crate features AVCaptureAudioPreviewOutput and AVCaptureOutputBase only.

AVCaptureAudioPreviewOutput is a concrete subclass of AVCaptureOutput that can be used to preview the audio being captured.

Instances of AVCaptureAudioPreviewOutput have an associated Core Audio output device that can be used to play audio being captured by the capture session. The unique ID of a Core Audio device can be obtained from its kAudioDevicePropertyDeviceUID property.

See also Apple’s documentation

Implementations

impl AVCaptureAudioPreviewOutput

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

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

pub unsafe fn outputDeviceUniqueID(&self) -> Option<Retained<NSString>>

Specifies the unique ID of the Core Audio output device being used to play preview audio.

The value of this property is an NSString containing the unique ID of the Core Audio device to be used for output, or nil if the default system output should be used.

pub unsafe fn setOutputDeviceUniqueID( &self, output_device_unique_id: Option<&NSString>, )

Setter for outputDeviceUniqueID.

pub unsafe fn volume(&self) -> c_float

Specifies the preview volume of the output.

The value of this property is the preview volume of the receiver, where 1.0 is the maximum volume and 0.0 is muted.

pub unsafe fn setVolume(&self, volume: c_float)

Setter for volume.

Methods from Deref<Target = AVCaptureOutput>

pub unsafe fn connections(&self) -> Retained<NSArray<AVCaptureConnection>>

Available on crate feature AVCaptureSession only.

The connections that describe the flow of media data to the receiver from AVCaptureInputs.

The value of this property is an NSArray of AVCaptureConnection objects, each describing the mapping between the receiver and the AVCaptureInputPorts of one or more AVCaptureInputs.

pub unsafe fn connectionWithMediaType( &self, media_type: &AVMediaType, ) -> Option<Retained<AVCaptureConnection>>

Available on crate features AVCaptureSession and AVMediaFormat only.

Returns the first connection in the connections array with an inputPort of the specified mediaType.

Parameter mediaType: An AVMediaType constant from AVMediaFormat.h, e.g. AVMediaTypeVideo.

This convenience method returns the first AVCaptureConnection in the receiver’s connections array that has an AVCaptureInputPort of the specified mediaType. If no connection with the specified mediaType is found, nil is returned.

pub unsafe fn transformedMetadataObjectForMetadataObject_connection( &self, metadata_object: &AVMetadataObject, connection: &AVCaptureConnection, ) -> Option<Retained<AVMetadataObject>>

Available on crate features AVCaptureSession and AVMetadataObject only.

Converts an AVMetadataObject’s visual properties to the receiver’s coordinates.

Parameter metadataObject: An AVMetadataObject originating from the same AVCaptureInput as the receiver.

Parameter connection: The receiver’s connection whose AVCaptureInput matches that of the metadata object to be converted.

Returns: An AVMetadataObject whose properties are in output coordinates.

AVMetadataObject bounds may be expressed as a rect where {0,0} represents the top left of the picture area, and {1,1} represents the bottom right on an unrotated picture. Face metadata objects likewise express yaw and roll angles with respect to an unrotated picture. -transformedMetadataObjectForMetadataObject:connection: converts the visual properties in the coordinate space of the supplied AVMetadataObject to the coordinate space of the receiver. The conversion takes orientation, mirroring, and scaling into consideration. If the provided metadata object originates from an input source other than the preview layer’s, nil will be returned.

If an AVCaptureVideoDataOutput instance’s connection’s videoOrientation or videoMirrored properties are set to non-default values, the output applies the desired mirroring and orientation by physically rotating and or flipping sample buffers as they pass through it. AVCaptureStillImageOutput, on the other hand, does not physically rotate its buffers. It attaches an appropriate kCGImagePropertyOrientation number to captured still image buffers (see ImageIO/CGImageProperties.h) indicating how the image should be displayed on playback. Likewise, AVCaptureMovieFileOutput does not physically apply orientation/mirroring to its sample buffers – it uses a QuickTime track matrix to indicate how the buffers should be rotated and/or flipped on playback.

transformedMetadataObjectForMetadataObject:connection: alters the visual properties of the provided metadata object to match the physical rotation / mirroring of the sample buffers provided by the receiver through the indicated connection. I.e., for video data output, adjusted metadata object coordinates are rotated/mirrored. For still image and movie file output, they are not.

pub unsafe fn metadataOutputRectOfInterestForRect( &self, rect_in_output_coordinates: CGRect, ) -> CGRect

Available on crate feature objc2-core-foundation only.

Converts a rectangle in the receiver’s coordinate space to a rectangle of interest in the coordinate space of an AVCaptureMetadataOutput whose capture device is providing input to the receiver.

Parameter rectInOutputCoordinates: A CGRect in the receiver’s coordinates.

Returns: A CGRect in the coordinate space of the metadata output whose capture device is providing input to the receiver.

AVCaptureMetadataOutput rectOfInterest is expressed as a CGRect where {0,0} represents the top left of the picture area, and {1,1} represents the bottom right on an unrotated picture. This convenience method converts a rectangle in the coordinate space of the receiver to a rectangle of interest in the coordinate space of an AVCaptureMetadataOutput whose AVCaptureDevice is providing input to the receiver. The conversion takes orientation, mirroring, and scaling into consideration. See -transformedMetadataObjectForMetadataObject:connection: for a full discussion of how orientation and mirroring are applied to sample buffers passing through the output.

pub unsafe fn rectForMetadataOutputRectOfInterest( &self, rect_in_metadata_output_coordinates: CGRect, ) -> CGRect

Available on crate feature objc2-core-foundation only.

Converts a rectangle of interest in the coordinate space of an AVCaptureMetadataOutput whose capture device is providing input to the receiver to a rectangle in the receiver’s coordinates.

Parameter rectInMetadataOutputCoordinates: A CGRect in the coordinate space of the metadata output whose capture device is providing input to the receiver.

Returns: A CGRect in the receiver’s coordinates.

AVCaptureMetadataOutput rectOfInterest is expressed as a CGRect where {0,0} represents the top left of the picture area, and {1,1} represents the bottom right on an unrotated picture. This convenience method converts a rectangle in the coordinate space of an AVCaptureMetadataOutput whose AVCaptureDevice is providing input to the coordinate space of the receiver. The conversion takes orientation, mirroring, and scaling into consideration. See -transformedMetadataObjectForMetadataObject:connection: for a full discussion of how orientation and mirroring are applied to sample buffers passing through the output.

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.

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<AVCaptureAudioPreviewOutput> for AVCaptureAudioPreviewOutput

fn as_ref(&self) -> &Self

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

impl AsRef<AVCaptureOutput> for AVCaptureAudioPreviewOutput

fn as_ref(&self) -> &AVCaptureOutput

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

impl AsRef<AnyObject> for AVCaptureAudioPreviewOutput

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVCaptureAudioPreviewOutput

fn as_ref(&self) -> &NSObject

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

impl Borrow<AVCaptureOutput> for AVCaptureAudioPreviewOutput

fn borrow(&self) -> &AVCaptureOutput

Immutably borrows from an owned value.

impl Borrow<AnyObject> for AVCaptureAudioPreviewOutput

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVCaptureAudioPreviewOutput

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVCaptureAudioPreviewOutput

const NAME: &'static str = "AVCaptureAudioPreviewOutput"

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

type Super = AVCaptureOutput

The superclass of this class.

type ThreadKind = <<AVCaptureAudioPreviewOutput 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 AVCaptureAudioPreviewOutput

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

Formats the value using the given formatter.

impl Deref for AVCaptureAudioPreviewOutput

type Target = AVCaptureOutput

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVCaptureAudioPreviewOutput

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 AVCaptureAudioPreviewOutput

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for AVCaptureAudioPreviewOutput

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 AVCaptureAudioPreviewOutput

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 AVCaptureAudioPreviewOutput

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

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

impl DowncastTarget for AVCaptureAudioPreviewOutput

impl Eq for AVCaptureAudioPreviewOutput