Struct VNFaceLandmarkRegion2D

Source

#[repr(C)]
pub struct VNFaceLandmarkRegion2D { /* private fields */ }

Available on crate feature VNFaceLandmarks only.

Expand description

VNFaceLandmarkRegion2D gives access to the 2D landmark points for the region. The points are stored as vector_float2 and must not be modified.

Implementations§

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impl VNFaceLandmarkRegion2D

Source

pub unsafe fn normalizedPoints(&self) -> *const CGPoint

Available on crate feature objc2-core-foundation only.

Obtains the array of normalized landmark points.

Provides the address of a buffer containing the array of CGPoints representing the landmark points. This buffer is owned by the target object and is guaranteed to exist as long as the VNFaceLandmarkRegion2D does.

Returns: the address of the array of pointCount points.

Source

pub unsafe fn pointsInImageOfSize(&self, image_size: CGSize) -> NonNull<CGPoint>

Available on crate feature objc2-core-foundation only.

Provides the array of landmark points in the coordinate space of a specific image size.

Provides the address of a buffer containing the array of CGPoints representing the landmark points in the coordinate space of a specific image size. This buffer is owned by the target object and is guaranteed to exist as long as the VNFaceLandmarkRegion2D does.

Parameter imageSize: The pixel dimensions of the image in which the landmark points are being presented.

Returns: the address of the array of pointCount points, or NULL if the conversion could not take place.

Source

pub unsafe fn precisionEstimatesPerPoint( &self, ) -> Option<Retained<NSArray<NSNumber>>>

Obtains the array of accuracy placement estimates per landmark point.

Provides the NSArray object containing landmarks accuracy placement estimates per landmark point. This property is only populated when VNDetectFaceLandmarksRequest object is configured with VNRequestFaceLandmarksConstellation76Points. It is set to nil for other constellations

Returns: NSArray object of NSNumber(s) initialized to floating point values.

Source

pub unsafe fn pointsClassification(&self) -> VNPointsClassification

Available on crate feature VNTypes only.

Describes how to interpret the points provided by the region.

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impl VNFaceLandmarkRegion2D

Methods declared on superclass VNFaceLandmarkRegion.

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

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

Methods from Deref<Target = VNFaceLandmarkRegion>§

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pub unsafe fn pointCount(&self) -> NSUInteger

pointCount returns the amount of points in a given region. This can be zero if no points for a region could be found.

Methods from Deref<Target = NSObject>§

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pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

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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());

Source

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.

Source

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`
    }
}