Struct GCStylus 

pub struct GCStylus { /* private fields */ }

Available on crate feature GCStylus only.

An object that represents a physical stylus connected to the device.

Use the styli property to get the currently connect stylus accessories when your application starts. Register for GCStylusDidConnectNotification and GCStylusDidDisconnectNotification to get notified when a stylus connects of disconnects while your application is running.

// Register for notifications
NotificationCenter.default.addObserver(self, selector: #selector(stylus(didConnect:)), name: NSNotification.Name.GCStylusDidConnect, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(stylus(didDisconnect:)), name: NSNotification.Name.GCStylusDidConnect, object: nil)

// Query current stylus devices
for stylus in GCStylus.styluses {
...
}

// Later, handle connection
func stylus(didConnect notification: Notification) {
guard let stylus = notification.object as? GCStylus else { return }
...
}

Check the productCategory to determine the type of stylus. A spatial stylus - capable of 6DoF tracking by Apple Vision Pro - has a GCProductCategorySpatialStylus category.

Use the input property to get the input profile of the stylus. A spatial stylus includes a pressure sensitive tip and an input cluster composed of two buttons.

• The primary button (GCInputStylusPrimaryButton) is the front button (closest to the stylus tip) in the input cluster of the stylus. This button is frequently used grab virtual objects.

• The secondary button (GCInputStylusSecondaryButton) is the middle button in the input cluster. It can measures pressure/force levels. It’s intended to be used for controlling in-air drawing, selection, and generic interactions.

• The tip is also represented as a button (GCInputStylusTip).

guard let input = stylus.input else { return }
input.inputStateQueueDepth = 20
input.inputStateAvailableHandler = { input in
// This block will be enqueued for execution when the state of
// any stylus input changes.

// Iterate through all input state changes since last execution of
// the block.
while let nextState = input.nextInputState() {
// Use the value of `pressedInput.isPressed` for binary
// interactions, such as object selection.
let primaryButtonPressed = nextState.buttons[.stylusPrimaryButton]?.pressedInput.isPressed
let secondaryButtonPressed = nextState.buttons[.stylusSecondaryButton]?.pressedInput.isPressed
// Use the normalized press value for analog actions such as
// controlling virtual ink flow.
let secondaryButtonPressure = nextState.buttons[.stylusSecondaryButton]?.pressedInput.value
let tipPressure = nextState.buttons[.stylusTip]?.pressedInput.value

...
}
}

Use the haptics property to get the haptics profile of the stylus. A spatial stylus may optionally support haptic feedback to a single locality - GCHapticsLocalityDefault.

See also Apple’s documentation

Implementations

impl GCStylus

pub unsafe fn input( &self, ) -> Option<Retained<ProtocolObject<dyn GCDevicePhysicalInput>>>

Available on crate features GCDevicePhysicalInput and GCDevicePhysicalInputState only.

Gets the input profile for the stylus.

The input profile is represented as an object conforming to the GCDevicePhysicalInput protocol. Use this object to discover available inputs on the stylus, including buttons and pressure sensors, and get notified when the state of those inputs change.

pub unsafe fn haptics(&self) -> Option<Retained<GCDeviceHaptics>>

Available on crate feature GCDeviceHaptics only.

Gets the haptics profile for the stylus, if supported.

The haptics profile is represented as a GCDeviceHaptics instance, from which you can create CHHapticEngine instances targeting the haptic actuator(s) in the accessory.

Not all stylus accessories support haptic feedback. If the accessory does not support haptic feedback, this property is nil.

Note: Haptics are a drain on the accessory’s battery, and can be distracting when used excessively. Use haptic feedback judiciously and in response to meaningful user interactions.

impl GCStylus

Methods declared on superclass NSObject.

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

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

impl GCStylus

Discovery.

pub unsafe fn styli() -> Retained<NSArray<GCStylus>>

Get the collection of stylus accessories currently connected to the device.

This property returns an array of all currently connected stylus accessories. The array is empty when no stylus accessories are connected. The array updates automatically as stylus accessories connect and disconnect.

To be notified when the array changes, register for the GCStylusDidConnectNotification and GCStylusDidDisconnectNotification.

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 GCStylus

fn as_ref(&self) -> &AnyObject

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

impl AsRef<GCStylus> for GCStylus

fn as_ref(&self) -> &Self

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

impl AsRef<NSObject> for GCStylus

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for GCStylus

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for GCStylus

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for GCStylus

const NAME: &'static str = "GCStylus"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<GCStylus 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 GCStylus

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

Formats the value using the given formatter.

impl Deref for GCStylus

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl GCDevice for GCStylus

unsafe fn handlerQueue(&self) -> Retained<DispatchQueue>

where Self: Sized + Message,

Available on crate features GCDevice and dispatch2 only.

The dispatch queue that element value change handlers are submitted on. The default queue is main, and setting this to any other queue will make value change handlers dispatch async on the given queue. This is useful if the main game loop of the application is not on main, or if input logic is handled on another thread from the main game loop.

unsafe fn setHandlerQueue(&self, handler_queue: &DispatchQueue)

where Self: Sized + Message,

Available on crate features GCDevice and dispatch2 only.

Setter for handlerQueue.

unsafe fn vendorName(&self) -> Option<Retained<NSString>>

where Self: Sized + Message,

Available on crate feature GCDevice only.

A vendor supplied name. May be nil, and is not guaranteed to be unique. This should not be used as a key in a dictionary, but simply as a way to present some basic information about the device in testing or to the user.

unsafe fn productCategory(&self) -> Retained<NSString>

where Self: Sized + Message,

Available on crate feature GCDevice only.

The product category the device belongs to. This is useful for setting appropriate UI elements based on what type of device is connected.

unsafe fn physicalInputProfile(&self) -> Retained<GCPhysicalInputProfile>

where Self: Sized + Message,

👎Deprecated: Use the physicalInputProfile property on GCController instead. For GCKeyboard, use the keyboardInput property. For GCMouse, use the mouseInput property.

Available on crate features GCDevice and GCPhysicalInputProfile only.

Gets the physical input profile for the device.

impl Hash for GCStylus

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 GCStylus

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for GCStylus

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 GCStylus

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 GCStylus

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

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

impl DowncastTarget for GCStylus

impl Eq for GCStylus