Struct CNDetection 

pub struct CNDetection { /* private fields */ }

Available on crate feature CNDetection only.

A cinematic detection of a subject.

Specifies the type, distance (as disparity), bounds (as a normalized rectangle), and time (as CMTime) of the detection. Detections obtained from the cinematic script include a detectionID that can be used to track the detection over time. Some types of detections also include a detectionGroupID that associates related detections (e.g. the face and torso of the same person).

See also Apple’s documentation

Implementations

impl CNDetection

pub unsafe fn initWithTime_detectionType_normalizedRect_focusDisparity( this: Allocated<Self>, time: CMTime, detection_type: CNDetectionType, normalized_rect: CGRect, focus_disparity: c_float, ) -> Retained<Self>

Available on crate features objc2-core-foundation and objc2-core-media only.

Initialize a cinematic detection.

For playback and edit, most detections are obtained by from the cinematic script rather than being created. However, if you need to add a custom track, you can build an array of detections to create one. Any detections you create will not have a valid detectionID until the custom track is added to the cinematic script. Doing so will return the assigned detectionID. Any detections newly obtained from the cinematic script will have their assigned detectionID.

• Parameters:
• time: the presentation time of the frame in which the detection occurred
• detectionType: the type of object that was detected (face, torso, cat, dog, etc.)
• normalizedRect: the rectangle within the image where the object occurs, normalized such that (0.0, 0.0) is the top-left and (1.0, 1.0) is the bottom-right
• focusDisparity: the disparity to use in order to focus on the object (use the static disparity method to compute if unknown)

pub unsafe fn time(&self) -> CMTime

Available on crate feature objc2-core-media only.

The presentation time of the frame in which the detection occurred.

pub unsafe fn detectionType(&self) -> CNDetectionType

The type of object that was detected (face, torso, cat, dog, etc.)

pub unsafe fn normalizedRect(&self) -> CGRect

Available on crate feature objc2-core-foundation only.

The rectangle within the image where the object occurs, normalized such that (0.0, 0.0) is the top-left and (1.0, 1.0) is the bottom-right.

pub unsafe fn focusDisparity(&self) -> c_float

The disparity to use in order to focus on the object. If the disparity is unknown, use the class method to find it: disparityInNormalizedRect:sourceDisparity:detectionType:priorDisparity:.

pub unsafe fn detectionID(&self) -> CNDetectionID

An unique identifier assigned by the cinematic script to all detections of the same subject and detection type across time. If you build a custom detection track, the detectionID will be assigned when you add it to the script.

pub unsafe fn detectionGroupID(&self) -> CNDetectionGroupID

An unique identifier assigned by the cinematic script to all detections of the same subject and related detection types across time. For example, the face/torso detections of the same person are assigned the same detectionGroupID.

pub unsafe fn isValidDetectionID(detection_id: CNDetectionID) -> bool

Determine whether a given detectionID is valid

pub unsafe fn isValidDetectionGroupID( detection_group_id: CNDetectionGroupID, ) -> bool

Determine whether a given detectionGroupID is valid

pub unsafe fn accessibilityLabelForDetectionType( detection_type: CNDetectionType, ) -> Retained<NSString>

A localized accessibility label converting a specific detection type into a broad category (person, pet, etc.).

pub unsafe fn disparityInNormalizedRect_sourceDisparity_detectionType_priorDisparity( normalized_rect: CGRect, source_disparity: &CVPixelBuffer, detection_type: CNDetectionType, prior_disparity: c_float, ) -> c_float

Available on crate features objc2-core-foundation and objc2-core-video only.

Determine the disparity to use to focus on the object in the rectangle.

• Parameters:
• disparityBuffer: A pixel buffer from the cinematic disparity track for the frame in which the object occurs.
• normalizedRect: The rectangle within the disparity buffer where the object occurs, normalized such that (0.0, 0.0) is the top-left and (1.0, 1.0) is the bottom-right of the disparity buffer.
• detectionType: The type of object expected within the rectangle. Pass CNDetectionTypeUnknown if unknown.
• priorDisparity: The disparity of the object in the prior frame. This helps ensure the object is not mistaken for another that enters the same rectangle. Pass NAN if there is no known prior, such as in the first frame in which the object is being tracked.

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

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

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<AnyObject> for CNDetection

fn as_ref(&self) -> &AnyObject

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

impl AsRef<CNDetection> for CNDetection

fn as_ref(&self) -> &Self

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

impl AsRef<NSObject> for CNDetection

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for CNDetection

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for CNDetection

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for CNDetection

const NAME: &'static str = "CNDetection"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<CNDetection 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 CopyingHelper for CNDetection

type Result = CNDetection

The immutable counterpart of the type, or Self if the type has no immutable counterpart.

impl Debug for CNDetection

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

Formats the value using the given formatter.

impl Deref for CNDetection

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for CNDetection

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 CNDetection

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSCopying for CNDetection

fn copy(&self) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Returns a new instance that’s a copy of the receiver.

unsafe fn copyWithZone(&self, zone: *mut NSZone) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Returns a new instance that’s a copy of the receiver.

impl NSObjectProtocol for CNDetection

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 CNDetection

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 CNDetection

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

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

impl DowncastTarget for CNDetection

impl Eq for CNDetection

impl Send for CNDetection

impl Sync for CNDetection