Struct VTOpticalFlowParameters 

pub struct VTOpticalFlowParameters { /* private fields */ }

Available on crate features VTFrameProcessor_OpticalFlow and objc2 only.

An object that contains both input and output parameters the frame processor needs to generate optical flow between two frames.

Use this object in the processWithParameters call of VTFrameProcessor class. The output parameter for this class is destinationOpticalFlow where the processor returns the output flow (as mutable VTFrameProcessorOpticalFlow) back to you once the processWithParameters completes.

VTOpticalFlowParameters are frame-level parameters.

See also Apple’s documentation

Implementations

impl VTOpticalFlowParameters

pub unsafe fn initWithSourceFrame_nextFrame_submissionMode_destinationOpticalFlow( this: Allocated<Self>, source_frame: &VTFrameProcessorFrame, next_frame: &VTFrameProcessorFrame, submission_mode: VTOpticalFlowParametersSubmissionMode, destination_optical_flow: &VTFrameProcessorOpticalFlow, ) -> Option<Retained<Self>>

Available on crate feature VTFrameProcessorFrame only.

Creates a new optical flow parameters object.

Returns nil if sourceFrame or nextFrame is nil, or if sourceFrame and nextFrame have different pixel formats.

• Parameters:
• sourceFrame: Current source frame; must be non nil.
• nextFrame: Next source frame in presentation time order.
• submissionMode: Provides a hint to let the processor know whether you are submitting frames in presentation sequence. For more information about supported modes see VTOpticalFlowParametersSubmissionMode.
• destinationOpticalFlow: User allocated VTFrameProcessorOpticalFlow that receives the results.

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

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

pub unsafe fn sourceFrame(&self) -> Retained<VTFrameProcessorFrame>

Available on crate feature VTFrameProcessorFrame only.

Current source frame, which must be non nil.

pub unsafe fn nextFrame(&self) -> Retained<VTFrameProcessorFrame>

Available on crate feature VTFrameProcessorFrame only.

The next source frame in presentation time order.

pub unsafe fn submissionMode(&self) -> VTOpticalFlowParametersSubmissionMode

Ordering of the input frames in this submission relative to the previous submission.

pub unsafe fn destinationOpticalFlow( &self, ) -> Retained<VTFrameProcessorOpticalFlow>

Available on crate feature VTFrameProcessorFrame only.

Output optical flow calculated by the processor.

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 VTOpticalFlowParameters

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for VTOpticalFlowParameters

fn as_ref(&self) -> &NSObject

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

impl AsRef<VTOpticalFlowParameters> for VTOpticalFlowParameters

fn as_ref(&self) -> &Self

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

impl Borrow<AnyObject> for VTOpticalFlowParameters

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for VTOpticalFlowParameters

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for VTOpticalFlowParameters

const NAME: &'static str = "VTOpticalFlowParameters"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<VTOpticalFlowParameters 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 VTOpticalFlowParameters

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

Formats the value using the given formatter.

impl Deref for VTOpticalFlowParameters

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for VTOpticalFlowParameters

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 VTOpticalFlowParameters

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for VTOpticalFlowParameters

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 VTOpticalFlowParameters

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 VTOpticalFlowParameters

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

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

impl VTFrameProcessorParameters for VTOpticalFlowParameters

unsafe fn sourceFrame(&self) -> Retained<VTFrameProcessorFrame>

where Self: Sized + Message,

Available on crate features VTFrameProcessorParameters and objc2 and VTFrameProcessorFrame only.

Use VTFrameProcessorFrame that contains the current source frame for all processing features; must be non-null.

unsafe fn destinationFrame(&self) -> Retained<VTFrameProcessorFrame>

where Self: Sized + Message,

Available on crate features VTFrameProcessorParameters and objc2 and VTFrameProcessorFrame only.

Destination frame that contains the destination frame for processors which output a single processed frame.

unsafe fn destinationFrames(&self) -> Retained<NSArray<VTFrameProcessorFrame>>

where Self: Sized + Message,

Available on crate features VTFrameProcessorParameters and objc2 and VTFrameProcessorFrame and objc2-foundation only.

Array of destination frames for processors which may output more than one processed frame.

impl DowncastTarget for VTOpticalFlowParameters

impl Eq for VTOpticalFlowParameters