Struct AVCaptionRenderer 

pub struct AVCaptionRenderer { /* private fields */ }

Available on crate feature AVCaptionRenderer only.

An instance of AVCaptionRenderer represents a service that can render the captions for a particular time

An instance of AVCaptionRenderer performs drawing of a caption “scene” from a population of captions given a time. If there are no captions or no captions at the specified time, “emptiness” will still be drawn (e.g., flood filling with zero alpha or a color).

See also Apple’s documentation

Implementations

impl AVCaptionRenderer

pub unsafe fn captions(&self) -> Retained<NSArray<AVCaption>>

Available on crate feature AVCaption only.

A NSArray holding captions to consider for rendering.

This is the array of AVCaptions to consider when drawing. The array can contain no captions.

pub unsafe fn setCaptions(&self, captions: &NSArray<AVCaption>)

Available on crate feature AVCaption only.

Setter for captions.

This is copied when set.

pub unsafe fn bounds(&self) -> CGRect

Available on crate feature objc2-core-foundation only.

A CGRect holding bounds for the drawing of caption scene(s).

This is a CGRect indicating where captions are drawn using renderInContext:atTime: Once established, this CGRect is used in each call to renderInContext:atTime: until it is changed to another value. This should be set up earlier than drawing.

pub unsafe fn setBounds(&self, bounds: CGRect)

Available on crate feature objc2-core-foundation only.

Setter for bounds.

pub unsafe fn captionSceneChangesInRange( &self, considered_time_range: CMTimeRange, ) -> Retained<NSArray<AVCaptionRendererScene>>

Available on crate feature objc2-core-media only.

Determine render time ranges within an enclosing time range to account for visual changes among captions.

Returns: An NSArray of AVCaptionRendererScenes; perhaps empty if there are no captions intersecting with the consideredTimeRange

This is an optional service useful for optimizing drawing. A client can perform drawing without it.

As captions may become active and inactive throughout the timeline, this method will return a NSArray holding scene objects with time ranges on whose edges there’s a visual change. The client can use the ranges of time between these edges with -renderInContext:atTime: to ensure all visual changes are rendered. The returned time ranges consider activation/deactivation of captions, temporal overlapping, and intra-caption timing requirements (e.g., character reveal animations). Time ranges may be returned where no captions are active as this is also a change in the caption “scene”.

The returned NSArray contains AVCaptionRendererScenes, each holding the CMTimeRange of that scene but potentially other information that may be useful to the client during renderering.

The consideredTimeRange parameter is a CMTimeRange expressing the limits for consideration. The extent of this range does not need to correspond to the timing of captions. It might be the range from 0 to some duration. For efficiency, the range can be limited to a window of time. It is also possible to use the range anchored at a time and extending in the direction of playback.

pub unsafe fn renderInContext_forTime(&self, ctx: &CGContext, time: CMTime)

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

Draw the captions corresponding to a time established by the AVCaptions to a CGContext.

Captions are drawn into the CGContextRef based upon their activation at the specified time. If there are no captions or no captions at the specified time, “emptiness” will still be drawn (e.g., flood filling with zero alpha or a color).

impl AVCaptionRenderer

Methods declared on superclass NSObject.

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<AVCaptionRenderer> for AVCaptionRenderer

fn as_ref(&self) -> &Self

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

impl AsRef<AnyObject> for AVCaptionRenderer

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVCaptionRenderer

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for AVCaptionRenderer

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVCaptionRenderer

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVCaptionRenderer

const NAME: &'static str = "AVCaptionRenderer"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVCaptionRenderer 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 AVCaptionRenderer

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

Formats the value using the given formatter.

impl Deref for AVCaptionRenderer

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVCaptionRenderer

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 AVCaptionRenderer

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for AVCaptionRenderer

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 AVCaptionRenderer

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 AVCaptionRenderer

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

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

impl DowncastTarget for AVCaptionRenderer

impl Eq for AVCaptionRenderer