GCStylus
An object that represents a physical stylus connected to the device.
Declaration
class GCStylusMentioned in
Overview
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
@objc 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.