Struct VNInstanceMaskObservation

Source

pub struct VNInstanceMaskObservation { /* private fields */ }

Available on crate feature VNObservation only.

Expand description

An observation resulting from an instance mask generation request. It contains an instance mask that labels instances in the mask that labels per pixel an instance.

Implementations§

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impl VNInstanceMaskObservation

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pub unsafe fn instanceMask(&self) -> Retained<CVPixelBuffer>

Available on crate feature objc2-core-video only.

The resulting mask represents all instances in a mask image where 0 represents the background and all other values represent the indices of the instances identified. Note that a pixel can only correspond to one instance and not multiple instances.

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pub unsafe fn allInstances(&self) -> Retained<NSIndexSet>

*The IndexSet that encompases all instances except the background

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pub unsafe fn generateMaskForInstances_error( &self, instances: &NSIndexSet, ) -> Result<Retained<CVPixelBuffer>, Retained<NSError>>

Available on crate feature objc2-core-video only.

The low res mask from the selected instances in the resolution of the performed analysis which is not upscaled to the image resolution.

Parameter instances: An NSIndexSet of selected instances where 0 is the background. An empty set selects all instances but the background

Parameter error: The address of a variable that will be populated with the error that describes the failure. If the caller does not require this information, NULL can be passed. The pixel format of kCVPixelFormatType_OneComponent32Float

Source

pub unsafe fn generateMaskedImageOfInstances_fromRequestHandler_croppedToInstancesExtent_error( &self, instances: &NSIndexSet, request_handler: &VNImageRequestHandler, crop_result: bool, ) -> Result<Retained<CVPixelBuffer>, Retained<NSError>>

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

High res image with everything but the selected instances removed to transparent black.

Parameter instances: An NSIndexSet of selected instances where 0 is the background.

Parameter croppedToInstancesExtent: Crops the image to the smallest rectangle containg all instances with remaining alpha elements. Setting this value to NO does not perform any cropping.

Parameter error: The address of a variable that will be populated with the error that describes the failure. If the caller does not require this information, NULL can be passed.

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pub unsafe fn generateScaledMaskForImageForInstances_fromRequestHandler_error( &self, instances: &NSIndexSet, request_handler: &VNImageRequestHandler, ) -> Result<Retained<CVPixelBuffer>, Retained<NSError>>

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

High res mask with the selected instances preserved while everything else is removed to transparent black.

Parameter forInstances: An NSIndexSet of selected instances where 0 is the background.

Parameter error: The address of a variable that will be populated with the error that describes the failure. If the caller does not require this information, NULL can be passed.

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impl VNInstanceMaskObservation

Methods declared on superclass NSObject.

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

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

Methods from Deref<Target = VNObservation>§

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

The unique identifier assigned to an observation.

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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

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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>§

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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`
    }
}