Struct AVCaptureVideoPreviewLayer 

pub struct AVCaptureVideoPreviewLayer { /* private fields */ }

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

A CoreAnimation layer subclass for previewing the visual output of an AVCaptureSession.

An AVCaptureVideoPreviewLayer instance is a subclass of CALayer and is therefore suitable for insertion in a layer hierarchy as part of a graphical interface. One creates an AVCaptureVideoPreviewLayer instance with the capture session to be previewed, using +layerWithSession: or -initWithSession:. Using the “ videoGravity“ property, one can influence how content is viewed relative to the layer bounds. On some hardware configurations, the orientation of the layer can be manipulated using @“orientation” and @“mirrored”.

See also Apple’s documentation

Implementations

impl AVCaptureVideoPreviewLayer

pub unsafe fn layerWithSession(session: &AVCaptureSession) -> Retained<Self>

Available on crate feature AVCaptureSession only.

Creates an AVCaptureVideoPreviewLayer for previewing the visual output of the specified AVCaptureSession.

Parameter session: The AVCaptureSession instance to be previewed.

Returns: A newly initialized AVCaptureVideoPreviewLayer instance.

pub unsafe fn initWithSession( this: Allocated<Self>, session: &AVCaptureSession, ) -> Retained<Self>

Available on crate feature AVCaptureSession only.

Creates an AVCaptureVideoPreviewLayer for previewing the visual output of the specified AVCaptureSession.

Parameter session: The AVCaptureSession instance to be previewed.

Returns: A newly initialized AVCaptureVideoPreviewLayer instance.

pub unsafe fn layerWithSessionWithNoConnection( session: &AVCaptureSession, ) -> Retained<Self>

Available on crate feature AVCaptureSession only.

Creates an AVCaptureVideoPreviewLayer for previewing the visual output of the specified AVCaptureSession, but creates no connections to any of the session’s eligible video inputs. Only use this initializer if you intend to manually form a connection between a desired AVCaptureInputPort and the receiver using AVCaptureSession’s -addConnection: method.

Parameter session: The AVCaptureSession instance to be previewed.

Returns: A newly initialized AVCaptureVideoPreviewLayer instance.

pub unsafe fn initWithSessionWithNoConnection( this: Allocated<Self>, session: &AVCaptureSession, ) -> Retained<Self>

Available on crate feature AVCaptureSession only.

Creates an AVCaptureVideoPreviewLayer for previewing the visual output of the specified AVCaptureSession, but creates no connections to any of the session’s eligible video inputs. Only use this initializer if you intend to manually form a connection between a desired AVCaptureInputPort and the receiver using AVCaptureSession’s -addConnection: method.

Parameter session: The AVCaptureSession instance to be previewed.

Returns: A newly initialized AVCaptureVideoPreviewLayer instance.

pub unsafe fn session(&self) -> Option<Retained<AVCaptureSession>>

Available on crate feature AVCaptureSession only.

The AVCaptureSession instance being previewed by the receiver.

The session is retained by the preview layer.

pub unsafe fn setSession(&self, session: Option<&AVCaptureSession>)

Available on crate feature AVCaptureSession only.

Setter for session.

pub unsafe fn setSessionWithNoConnection(&self, session: &AVCaptureSession)

Available on crate feature AVCaptureSession only.

method setSessionWithNoConnection:

Attaches the receiver to a given session without implicitly forming a connection to the first eligible video AVCaptureInputPort. Only use this setter if you intend to manually form a connection between a desired AVCaptureInputPort and the receiver using AVCaptureSession’s -addConnection: method.

The session is retained by the preview layer.

pub unsafe fn connection(&self) -> Option<Retained<AVCaptureConnection>>

Available on crate feature AVCaptureSession only.

The AVCaptureConnection instance describing the AVCaptureInputPort to which the receiver is connected.

When calling initWithSession: or setSession: with a valid AVCaptureSession instance, a connection is formed to the first eligible video AVCaptureInput. If the receiver is detached from a session, the connection property becomes nil.

pub unsafe fn videoGravity(&self) -> Retained<AVLayerVideoGravity>

Available on crate feature AVAnimation only.

A string defining how the video is displayed within an AVCaptureVideoPreviewLayer bounds rect.

Options are AVLayerVideoGravityResize, AVLayerVideoGravityResizeAspect and AVLayerVideoGravityResizeAspectFill. AVLayerVideoGravityResizeAspect is default. See <AVFoundation /AVAnimation.h> for a description of these options.

pub unsafe fn setVideoGravity(&self, video_gravity: &AVLayerVideoGravity)

Available on crate feature AVAnimation only.

Setter for videoGravity.

This is copied when set.

pub unsafe fn isPreviewing(&self) -> bool

A BOOL value indicating whether the receiver is currently rendering video frames from its source.

An AVCaptureVideoPreviewLayer begins previewing when -[AVCaptureSession startRunning] is called. When associated with an AVCaptureMultiCamSession, all video preview layers are guaranteed to be previewing by the time the blocking call to -startRunning or -commitConfiguration returns. While a session is running, you may enable or disable a video preview layer’s connection to re-start or stop the flow of video to the layer. Once you’ve set enabled to YES, you can observe this property changing from NO to YES and synchronize any UI to take place precisely when the video resumes rendering to the video preview layer.

pub unsafe fn captureDevicePointOfInterestForPoint( &self, point_in_layer: CGPoint, ) -> CGPoint

Available on crate feature objc2-core-foundation only.

Converts a point in layer coordinates to a point of interest in the coordinate space of the capture device providing input to the layer.

Parameter pointInLayer: A CGPoint in layer coordinates.

Returns: A CGPoint in the coordinate space of the capture device providing input to the layer.

AVCaptureDevice pointOfInterest is expressed as a CGPoint 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 point in the coordinate space of the receiver to a point of interest in the coordinate space of the AVCaptureDevice providing input to the receiver. The conversion takes frameSize and videoGravity into consideration.

pub unsafe fn pointForCaptureDevicePointOfInterest( &self, capture_device_point_of_interest: CGPoint, ) -> CGPoint

Available on crate feature objc2-core-foundation only.

Converts a point of interest in the coordinate space of the capture device providing input to the layer to a point in layer coordinates.

Parameter captureDevicePointOfInterest: A CGPoint in the coordinate space of the capture device providing input to the layer.

Returns: A CGPoint in layer coordinates.

AVCaptureDevice pointOfInterest is expressed as a CGPoint 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 point in the coordinate space of the AVCaptureDevice providing input to the coordinate space of the receiver. The conversion takes frame size and videoGravity into consideration.

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

Available on crate feature objc2-core-foundation only.

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

Parameter rectInLayerCoordinates: A CGRect in layer coordinates.

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

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 frame size and videoGravity into consideration.

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 layer to a rectangle in layer coordinates.

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

Returns: A CGRect in layer 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 frame size and videoGravity into consideration.

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

Available on crate feature AVMetadataObject only.

Converts an AVMetadataObject’s visual properties to layer coordinates.

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

Returns: An AVMetadataObject whose properties are in layer 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: converts the visual properties in the coordinate space of the supplied AVMetadataObject to the coordinate space of the receiver. The conversion takes orientation, mirroring, layer bounds and videoGravity into consideration. If the provided metadata object originates from an input source other than the preview layer’s, nil will be returned.

pub unsafe fn isOrientationSupported(&self) -> bool

👎Deprecated: Use AVCaptureConnection’s isVideoOrientationSupported instead.

Specifies whether or not the preview layer supports orientation.

Changes in orientation are not supported on all hardware configurations. An application should check the value of “ orientationSupported“ before attempting to manipulate the orientation of the receiver. This property is deprecated. Use AVCaptureConnection’s -isVideoOrientationSupported instead.

pub unsafe fn orientation(&self) -> AVCaptureVideoOrientation

👎Deprecated: Use AVCaptureConnection’s videoOrientation instead.

Available on crate feature AVCaptureSession only.

Specifies the orientation of the preview layer.

AVCaptureVideoOrientation and its constants are defined in AVCaptureSession.h. The value of “ orientationSupported“ must be YES in order to set @“orientation”. An exception will be raised if this requirement is ignored. This property is deprecated. Use AVCaptureConnection’s -videoOrientation instead.

pub unsafe fn setOrientation(&self, orientation: AVCaptureVideoOrientation)

👎Deprecated: Use AVCaptureConnection’s videoOrientation instead.

Available on crate feature AVCaptureSession only.

Setter for orientation.

pub unsafe fn isMirroringSupported(&self) -> bool

👎Deprecated: Use AVCaptureConnection’s isVideoMirroringSupported instead.

Specifies whether or not the preview layer supports mirroring.

Mirroring is not supported on all hardware configurations. An application should check the value of “ mirroringSupported“ before attempting to manipulate mirroring on the receiver. This property is deprecated. Use AVCaptureConnection’s -isVideoMirroringSupported instead.

pub unsafe fn automaticallyAdjustsMirroring(&self) -> bool

👎Deprecated: Use AVCaptureConnection’s automaticallyAdjustsVideoMirroring instead.

Specifies whether or not the value of “ mirrored“ can change based on configuration of the session.

For some session configurations, preview will be mirrored by default. When the value of this property is YES, the value of “ mirrored“ may change depending on the configuration of the session, for example after switching to a different AVCaptureDeviceInput. The default value is YES. This property is deprecated. Use AVCaptureConnection’s -automaticallyAdjustsVideoMirroring instead.

pub unsafe fn setAutomaticallyAdjustsMirroring( &self, automatically_adjusts_mirroring: bool, )

👎Deprecated: Use AVCaptureConnection’s automaticallyAdjustsVideoMirroring instead.

Setter for automaticallyAdjustsMirroring.

pub unsafe fn isMirrored(&self) -> bool

👎Deprecated: Use AVCaptureConnection’s videoMirrored instead.

Specifies whether or not the preview is flipped over a vertical axis.

For most applications, it is unnecessary to manipulate preview mirroring manually if “ automaticallyAdjustsMirroring“ is set to YES. The value of @“automaticallyAdjustsMirroring” must be NO in order to set @“mirrored”. The value of @“mirroringSupported” must be YES in order to set @“mirrored”. An exception will be raised if the value of @“mirrored” is mutated without respecting these requirements. This property is deprecated. Use AVCaptureConnection’s -videoMirrored instead.

pub unsafe fn setMirrored(&self, mirrored: bool)

👎Deprecated: Use AVCaptureConnection’s videoMirrored instead.

Setter for isMirrored.

pub unsafe fn isDeferredStartSupported(&self) -> bool

A BOOL value that indicates whether the preview layer supports deferred start.

You can only set the deferredStartEnabled property to true if the preview layer supports deferred start.

pub unsafe fn isDeferredStartEnabled(&self) -> bool

A BOOL value that indicates whether to defer starting this preview layer.

When this value is true, the session does not prepare the output’s resources until some time after AVCaptureSession/startRunning returns. You can start the visual parts of your user interface (e.g. preview) prior to other parts (e.g. photo/movie capture, metadata output, etc..) to improve startup performance. Set this value to false if your app needs video preview immediately for startup, and true if it does not.

By default, this value is false for AVCaptureVideoPreviewLayer objects, since this object is used to display preview. For best session start performance, set deferredStartEnabled to false for preview layers. If your app contains multiple preview layers, you may want to display the main preview layer as soon as possible and allow the remaining layers to display subsequently. In this case, set deferredStartEnabled to true for the remaining layers.

• Note: Setting this property to the same value for all outputs, including AVCaptureVideoPreviewLayer and AVCaptureOutput, is equivalent to not using deferred start.

If deferredStartSupported is false, setting this property value to true results in the session throwing an NSInvalidArgumentException.

• Note: Set this value before calling AVCaptureSession/commitConfiguration as it requires a lengthy reconfiguration of the capture render pipeline.

pub unsafe fn setDeferredStartEnabled(&self, deferred_start_enabled: bool)

Setter for isDeferredStartEnabled.

impl AVCaptureVideoPreviewLayer

Methods declared on superclass CALayer.

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

Layer creation and initialization. *

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

pub unsafe fn initWithLayer( this: Allocated<Self>, layer: &AnyObject, ) -> Retained<Self>

Safety

layer should be of the correct type.

impl AVCaptureVideoPreviewLayer

Methods declared on superclass NSObject.

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

Methods from Deref<Target = CALayer>

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

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

pub fn shouldArchiveValueForKey(&self, key: &NSString) -> bool

pub fn isHidden(&self) -> bool

pub fn setHidden(&self, hidden: bool)

Setter for isHidden.

pub fn isDoubleSided(&self) -> bool

pub fn setDoubleSided(&self, double_sided: bool)

Setter for isDoubleSided.

pub fn isGeometryFlipped(&self) -> bool

pub fn setGeometryFlipped(&self, geometry_flipped: bool)

Setter for isGeometryFlipped.

pub fn contentsAreFlipped(&self) -> bool

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

pub fn removeFromSuperlayer(&self)

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

pub unsafe fn setSublayers(&self, sublayers: Option<&NSArray<CALayer>>)

Setter for sublayers.

This is copied when set.

pub fn addSublayer(&self, layer: &CALayer)

pub fn insertSublayer_atIndex(&self, layer: &CALayer, idx: u32)

pub fn insertSublayer_below(&self, layer: &CALayer, sibling: Option<&CALayer>)

pub fn insertSublayer_above(&self, layer: &CALayer, sibling: Option<&CALayer>)

pub unsafe fn replaceSublayer_with( &self, old_layer: &CALayer, new_layer: &CALayer, )

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

pub unsafe fn setMask(&self, mask: Option<&CALayer>)

Setter for mask.

pub fn masksToBounds(&self) -> bool

pub fn setMasksToBounds(&self, masks_to_bounds: bool)

Setter for masksToBounds.

pub unsafe fn contents(&self) -> Option<Retained<AnyObject>>

Layer content properties and methods. *

pub unsafe fn setContents(&self, contents: Option<&AnyObject>)

Setter for contents.

Safety

contents should be of the correct type.

pub fn contentsGravity(&self) -> Retained<NSString>

pub fn setContentsGravity(&self, contents_gravity: &NSString)

Setter for contentsGravity.

This is copied when set.

pub fn contentsFormat(&self) -> Retained<NSString>

pub fn setContentsFormat(&self, contents_format: &NSString)

Setter for contentsFormat.

This is copied when set.

pub fn wantsExtendedDynamicRangeContent(&self) -> bool

👎Deprecated: Use preferredDynamicRange instead

pub fn setWantsExtendedDynamicRangeContent( &self, wants_extended_dynamic_range_content: bool, )

👎Deprecated: Use preferredDynamicRange instead

Setter for wantsExtendedDynamicRangeContent.

pub fn toneMapMode(&self) -> Retained<NSString>

pub fn setToneMapMode(&self, tone_map_mode: &NSString)

Setter for toneMapMode.

This is copied when set.

pub fn preferredDynamicRange(&self) -> Retained<NSString>

pub fn setPreferredDynamicRange(&self, preferred_dynamic_range: &NSString)

Setter for preferredDynamicRange.

This is copied when set.

pub fn wantsDynamicContentScaling(&self) -> bool

pub fn setWantsDynamicContentScaling(&self, wants_dynamic_content_scaling: bool)

Setter for wantsDynamicContentScaling.

pub fn minificationFilter(&self) -> Retained<NSString>

pub fn setMinificationFilter(&self, minification_filter: &NSString)

Setter for minificationFilter.

This is copied when set.

pub fn magnificationFilter(&self) -> Retained<NSString>

pub fn setMagnificationFilter(&self, magnification_filter: &NSString)

Setter for magnificationFilter.

This is copied when set.

pub fn minificationFilterBias(&self) -> f32

pub fn setMinificationFilterBias(&self, minification_filter_bias: f32)

Setter for minificationFilterBias.

pub fn isOpaque(&self) -> bool

pub fn setOpaque(&self, opaque: bool)

Setter for isOpaque.

pub fn display(&self)

pub fn setNeedsDisplay(&self)

pub fn needsDisplay(&self) -> bool

pub fn displayIfNeeded(&self)

pub fn needsDisplayOnBoundsChange(&self) -> bool

pub fn setNeedsDisplayOnBoundsChange( &self, needs_display_on_bounds_change: bool, )

Setter for needsDisplayOnBoundsChange.

pub fn drawsAsynchronously(&self) -> bool

pub fn setDrawsAsynchronously(&self, draws_asynchronously: bool)

Setter for drawsAsynchronously.

pub fn edgeAntialiasingMask(&self) -> CAEdgeAntialiasingMask

pub fn setEdgeAntialiasingMask( &self, edge_antialiasing_mask: CAEdgeAntialiasingMask, )

Setter for edgeAntialiasingMask.

pub fn allowsEdgeAntialiasing(&self) -> bool

pub fn setAllowsEdgeAntialiasing(&self, allows_edge_antialiasing: bool)

Setter for allowsEdgeAntialiasing.

pub fn maskedCorners(&self) -> CACornerMask

pub fn setMaskedCorners(&self, masked_corners: CACornerMask)

Setter for maskedCorners.

pub fn cornerCurve(&self) -> Retained<NSString>

pub fn setCornerCurve(&self, corner_curve: &NSString)

Setter for cornerCurve.

This is copied when set.

pub fn opacity(&self) -> f32

pub fn setOpacity(&self, opacity: f32)

Setter for opacity.

pub fn allowsGroupOpacity(&self) -> bool

pub fn setAllowsGroupOpacity(&self, allows_group_opacity: bool)

Setter for allowsGroupOpacity.

pub fn compositingFilter(&self) -> Option<Retained<AnyObject>>

pub unsafe fn setCompositingFilter( &self, compositing_filter: Option<&AnyObject>, )

Setter for compositingFilter.

Safety

compositing_filter should be of the correct type.

pub fn filters(&self) -> Option<Retained<NSArray>>

pub unsafe fn setFilters(&self, filters: Option<&NSArray>)

Setter for filters.

This is copied when set.

Safety

filters generic should be of the correct type.

pub fn backgroundFilters(&self) -> Option<Retained<NSArray>>

pub unsafe fn setBackgroundFilters(&self, background_filters: Option<&NSArray>)

Setter for backgroundFilters.

This is copied when set.

Safety

background_filters generic should be of the correct type.

pub fn shouldRasterize(&self) -> bool

pub fn setShouldRasterize(&self, should_rasterize: bool)

Setter for shouldRasterize.

pub fn shadowOpacity(&self) -> f32

pub fn setShadowOpacity(&self, shadow_opacity: f32)

Setter for shadowOpacity.

pub fn autoresizingMask(&self) -> CAAutoresizingMask

Layout methods. *

pub fn setAutoresizingMask(&self, autoresizing_mask: CAAutoresizingMask)

Setter for autoresizingMask.

pub fn layoutManager( &self, ) -> Option<Retained<ProtocolObject<dyn CALayoutManager>>>

pub fn setLayoutManager( &self, layout_manager: Option<&ProtocolObject<dyn CALayoutManager>>, )

Setter for layoutManager.

pub fn setNeedsLayout(&self)

pub fn needsLayout(&self) -> bool

pub fn layoutIfNeeded(&self)

pub fn layoutSublayers(&self)

pub fn actionForKey( &self, event: &NSString, ) -> Option<Retained<ProtocolObject<dyn CAAction>>>

pub fn actions( &self, ) -> Option<Retained<NSDictionary<NSString, ProtocolObject<dyn CAAction>>>>

pub fn setActions( &self, actions: Option<&NSDictionary<NSString, ProtocolObject<dyn CAAction>>>, )

Setter for actions.

This is copied when set.

pub fn removeAllAnimations(&self)

pub fn removeAnimationForKey(&self, key: &NSString)

pub fn animationKeys(&self) -> Option<Retained<NSArray<NSString>>>

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

Miscellaneous properties. *

pub fn setName(&self, name: Option<&NSString>)

Setter for name.

This is copied when set.

pub fn delegate(&self) -> Option<Retained<ProtocolObject<dyn CALayerDelegate>>>

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

Setter for delegate.

This is a weak property.

pub fn style(&self) -> Option<Retained<NSDictionary>>

pub unsafe fn setStyle(&self, style: Option<&NSDictionary>)

Setter for style.

This is copied when set.

Safety

style generic should be of the correct type.

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<AVCaptureVideoPreviewLayer> for AVCaptureVideoPreviewLayer

fn as_ref(&self) -> &Self

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

impl AsRef<AnyObject> for AVCaptureVideoPreviewLayer

fn as_ref(&self) -> &AnyObject

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

impl AsRef<CALayer> for AVCaptureVideoPreviewLayer

fn as_ref(&self) -> &CALayer

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

impl AsRef<NSObject> for AVCaptureVideoPreviewLayer

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for AVCaptureVideoPreviewLayer

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<CALayer> for AVCaptureVideoPreviewLayer

fn borrow(&self) -> &CALayer

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVCaptureVideoPreviewLayer

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl CAMediaTiming for AVCaptureVideoPreviewLayer

fn speed(&self) -> f32

where Self: Sized + Message,

fn setSpeed(&self, speed: f32)

where Self: Sized + Message,

Setter for speed.

fn repeatCount(&self) -> f32

where Self: Sized + Message,

fn setRepeatCount(&self, repeat_count: f32)

where Self: Sized + Message,

Setter for repeatCount.

fn autoreverses(&self) -> bool

where Self: Sized + Message,

fn setAutoreverses(&self, autoreverses: bool)

where Self: Sized + Message,

Setter for autoreverses.

fn fillMode(&self) -> Retained<NSString>

where Self: Sized + Message,

fn setFillMode(&self, fill_mode: &NSString)

where Self: Sized + Message,

Setter for fillMode.

impl ClassType for AVCaptureVideoPreviewLayer

const NAME: &'static str = "AVCaptureVideoPreviewLayer"

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

type Super = CALayer

The superclass of this class.

type ThreadKind = <<AVCaptureVideoPreviewLayer 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 AVCaptureVideoPreviewLayer

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

Formats the value using the given formatter.

impl Deref for AVCaptureVideoPreviewLayer

type Target = CALayer

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVCaptureVideoPreviewLayer

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 AVCaptureVideoPreviewLayer

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSCoding for AVCaptureVideoPreviewLayer

unsafe fn encodeWithCoder(&self, coder: &NSCoder)

where Self: Sized + Message,

Safety

unsafe fn initWithCoder( this: Allocated<Self>, coder: &NSCoder, ) -> Option<Retained<Self>>

where Self: Sized + Message,

Safety

impl NSObjectProtocol for AVCaptureVideoPreviewLayer

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 NSSecureCoding for AVCaptureVideoPreviewLayer

fn supportsSecureCoding() -> bool

where Self: Sized + ClassType,

impl PartialEq for AVCaptureVideoPreviewLayer

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 AVCaptureVideoPreviewLayer

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

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

impl DowncastTarget for AVCaptureVideoPreviewLayer

impl Eq for AVCaptureVideoPreviewLayer