Struct VNTrajectoryObservation

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

Available on crate feature VNObservation only.

The VNTrajectoryObservation describes a detected trajectory with the points on the trajectory and the equation describing the trajectory. The observation also reprorts the duration describing when the trajectory was first detected (which will be in the past).

See also Apple’s documentation

Implementations

impl VNTrajectoryObservation

pub unsafe fn detectedPoints(&self) -> Retained<NSArray<VNPoint>>

Available on crate feature VNGeometry only.

The centroids of the contour being detected along the trajectory.

These are the unprocessed centroid points of the detected contour that is tracked on the trajectory. The points may be slightly off the ideal trajectory as these are the measured points that fall within the allowed tolerance. The maximum number or past points is limited by the maximum trajectory length set in the request.

pub unsafe fn projectedPoints(&self) -> Retained<NSArray<VNPoint>>

Available on crate feature VNGeometry only.

The centroids of the calculated trajectory from the detected points.

These are the calculated centroid points along the ideal trajectory described by the parabolic equation. The equation and the projected points of the detected trajectory get refined over time. The maximum number of cached points is limited by the maximum points needed to describe the trajectory together with the parabolic equation.

pub unsafe fn movingAverageRadius(&self) -> CGFloat

Available on crate feature objc2-core-foundation only.

The moving average radius of the object being tracked.

This is the radius of the object at each detected point (used to determine the trajectory) averaged.

impl VNTrajectoryObservation

Methods declared on superclass NSObject.

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

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

Methods from Deref<Target = VNObservation>

pub unsafe fn uuid(&self) -> Retained<NSUUID>

The unique identifier assigned to an observation.

pub unsafe fn confidence(&self) -> VNConfidence

Available on crate feature VNTypes only.

The level of confidence normalized to [0, 1] where 1 is most confident. The only exception is results coming from VNCoreMLRequest, where confidence values are forwarded as is from relevant CoreML models

Confidence can always be returned as 1.0 if confidence is not supported or has no meaning

pub unsafe fn timeRange(&self) -> CMTimeRange

Available on crate feature objc2-core-media only.

The duration of the observation reporting when first detected and how long it is valid.

The duration of the observation when used with a sequence of buffers. If a request does not support a timeRange or the timeRange is not known, the start time and duration will be set to 0.

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 VNTrajectoryObservation

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for VNTrajectoryObservation

fn as_ref(&self) -> &NSObject

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

impl AsRef<VNObservation> for VNTrajectoryObservation

fn as_ref(&self) -> &VNObservation

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

impl AsRef<VNTrajectoryObservation> for VNTrajectoryObservation

fn as_ref(&self) -> &Self

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

impl Borrow<AnyObject> for VNTrajectoryObservation

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for VNTrajectoryObservation

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl Borrow<VNObservation> for VNTrajectoryObservation

fn borrow(&self) -> &VNObservation

Immutably borrows from an owned value.

impl ClassType for VNTrajectoryObservation

const NAME: &'static str = "VNTrajectoryObservation"

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

type Super = VNObservation

The superclass of this class.

type ThreadKind = <<VNTrajectoryObservation 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 VNTrajectoryObservation

type Result = VNTrajectoryObservation

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

impl Debug for VNTrajectoryObservation

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

Formats the value using the given formatter.

impl Deref for VNTrajectoryObservation

type Target = VNObservation

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for VNTrajectoryObservation

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 VNTrajectoryObservation

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSCopying for VNTrajectoryObservation

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 VNTrajectoryObservation

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 VNTrajectoryObservation

unsafe fn supportsSecureCoding() -> bool

where Self: Sized + ClassType,

impl PartialEq for VNTrajectoryObservation

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 VNTrajectoryObservation

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

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

impl VNRequestRevisionProviding for VNTrajectoryObservation

unsafe fn requestRevision(&self) -> NSUInteger

where Self: Sized + Message,

Available on crate feature VNRequestRevisionProviding only.

The revision of the VNRequest subclass that was used to generate the object that implements this protocol.

impl DowncastTarget for VNTrajectoryObservation

impl Eq for VNTrajectoryObservation

impl NSCoding for VNTrajectoryObservation