Struct AVCaptureDeviceRotationCoordinator 

pub struct AVCaptureDeviceRotationCoordinator { /* private fields */ }

Available on crate feature AVCaptureDevice only.

The AVCaptureDeviceRotationCoordinator allows clients to monitor rotations of a given AVCaptureDevice instance and be provided the video rotation angle that should be applied for horizon-level preview and capture relative to gravity.

Each instance of AVCaptureDeviceRotationCoordinator allows a client to coordinate with changes to the rotation of an AVCaptureDevice to ensure the camera’s video preview and captured output are horizon-level. The coordinator delivers key-value updates on the main queue.

See also Apple’s documentation

Implementations

impl AVCaptureDeviceRotationCoordinator

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

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

pub unsafe fn initWithDevice_previewLayer( this: Allocated<Self>, device: &AVCaptureDevice, preview_layer: Option<&CALayer>, ) -> Retained<Self>

Available on crate feature objc2-quartz-core and non-watchOS only.

Returns an AVCaptureDeviceRotationCoordinator instance that provides updates to the amount of rotation that should be applied for horizon-level preview and capture relative to gravity.

Parameter device: The device for which to monitor rotation.

Parameter previewLayer: A layer displaying the camera’s video preview. If nil, the coordinator will return 0 degrees of rotation for horizon-level preview.

Returns: An AVCaptureDeviceRotationCoordinator from which rotation angles for preview and capture can be obtained.

An AVCaptureDeviceRotationCoordinator is only applicable to video devices. The given device and layer determine the amount of rotation that should be applied for horizon-level preview and capture.

pub unsafe fn device(&self) -> Option<Retained<AVCaptureDevice>>

The the device for which the coordinator provides video rotation angles.

The value of this property is the AVCaptureDevice instance that was used to create the coordinator. The coordinator holds a weak reference to the device.

pub unsafe fn previewLayer(&self) -> Option<Retained<CALayer>>

Available on crate feature objc2-quartz-core and non-watchOS only.

The CALayer for which the coordinator calculates video rotation angles for horizon-level preview.

The value of this property is the CALayer instance that was used to create the coordinator. Clients may specify an AVCaptureVideoPreviewLayer or other CALayer instance that displays a camera’s video preview. The coordinator holds a weak reference to the layer. The coordinator will return 0 degrees of rotation from -videoRotationAngleForHorizonLevelPreview if a layer was not specified at initialization, the layer is not in a view hierarchy, or the layer has been deallocated.

pub unsafe fn videoRotationAngleForHorizonLevelPreview(&self) -> CGFloat

Available on crate feature objc2-core-foundation only.

Returns a video rotation angle in degrees for displaying the camera’s video preview in the given CALayer.

The video rotation angle represents by how much the camera’s video preview should be rotated for display in the CALayer to be horizon-level relative to gravity. An angle of 0 degrees means that video will be output in the camera’s unrotated, native sensor orientation. The video rotation angle for preview may differ between cameras at different positions. For example when an iOS device is held in portrait orientation, the video preview for built-in cameras may need to be rotated by 90 degrees while the video preview for an external camera should not be rotated. External cameras return 0 degrees of rotation even if they physically rotate when their position in physical space is unknown. This property is key-value observable and delivers updates on the main queue.

pub unsafe fn videoRotationAngleForHorizonLevelCapture(&self) -> CGFloat

Available on crate feature objc2-core-foundation only.

Returns a video rotation angle in degrees for horizon-level capture from this camera.

The video rotation angle represents by how much the photos or movies captured from the camera should be rotated to be horizon-level relative to gravity. A video rotation angle of 0 degrees means that the output will be in the camera’s unrotated, native sensor orientation. The video rotation angle for capture may differ between cameras. For example when an iOS device is held in portrait orientation, photos and movies captured from built-in cameras may need to be rotated by 90 degrees while the photos and movies from an external camera should not be rotated. External cameras return 0 degrees of rotation even if they physically rotate when their position in physical space is unknown. The video rotation angle returned from this property is distinct from the angle returned by -videoRotationAngleForHorizonLevelPreview because in certain combinations of device and interface orientations, the video rotation angle needed for horizon-level preview may not match the amount of rotation needed for horizon-level capture. This property is key-value observable and delivers updates on the main queue.

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<AVCaptureDeviceRotationCoordinator> for AVCaptureDeviceRotationCoordinator

fn as_ref(&self) -> &Self

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

impl AsRef<AnyObject> for AVCaptureDeviceRotationCoordinator

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVCaptureDeviceRotationCoordinator

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for AVCaptureDeviceRotationCoordinator

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVCaptureDeviceRotationCoordinator

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVCaptureDeviceRotationCoordinator

const NAME: &'static str = "AVCaptureDeviceRotationCoordinator"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVCaptureDeviceRotationCoordinator 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 AVCaptureDeviceRotationCoordinator

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

Formats the value using the given formatter.

impl Deref for AVCaptureDeviceRotationCoordinator

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVCaptureDeviceRotationCoordinator

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 AVCaptureDeviceRotationCoordinator

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for AVCaptureDeviceRotationCoordinator

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 AVCaptureDeviceRotationCoordinator

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 AVCaptureDeviceRotationCoordinator

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

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

impl DowncastTarget for AVCaptureDeviceRotationCoordinator

impl Eq for AVCaptureDeviceRotationCoordinator