Components

Every primitive maps to a control the system already has. Where a platform has no equivalent, the node is not created: the layout leaves the gap it had measured and the host says why, once, in the log. Nothing is drawn by hand to fill in for a missing control.

Support matrix

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Every platformiOS · iPadOSAndroidmacOStvOSvisionOSwatchOSWear OS

Primitive	iOS · iPadOS	Android	macOS	tvOS	visionOS	watchOS	Wear OS
an-view	Available	Available	Available	Available	Available	Available	Available
an-text	Available	Available	Available	Available	Available	Available	Available
an-image	Available	Available	Available	Available	Available	Available	Available
an-icon	Available	Available	Available	Available	Available	Available	Available
an-scroll-view	Available	Available	Available	Available	Available	Available	Available
an-button	Available	Available	Available	Available	Available	Available	Available
an-text-input	Available	Available	Available	Available	Available	Available	Available
an-textarea	Available	Available	Available	Available	Available	Not available	Available
an-switch	Available	Available	Available	Not available	Available	Available	Available
an-slider	Available	Available	Available	Not available	Available	Available	Available
an-stepper	Available	Available	Available	Not available	Available	Available	Available
an-progress-bar	Available	Available	Available	Available	Available	Available	Available
an-activity-indicator	Available	Available	Available	Available	Available	Available	Available
an-select	Available	Available	Available	Available	Available	Available	Not available
an-date-picker	Available	Available	Available	Not available	Available	Available	Not available
an-segmented-control	Available	Available	Available	Available	Available	Not available	Not available
an-search-bar	Available	Available	Available	Available	Available	Not available	Not available
an-tab-bar	Available	Available	Available	Available	Available	Not available	Not available
an-navigation-bar	Available	Available	title bartitle bar	Available	Available	Not available	Not available
an-stack-view	Available	Available	Available	Available	Available	Available	Available
an-modal	Available	Available	Available	Available	Available	Available	Available
an-alert	Available	Available	Available	Available	Available	Available	Available
an-web-view	Available	Available	Available	Not available	Available	Not available	Not available
an-map-view	Available	tilestiles	Available	Available	Available	Not available	Available
an-video-view	Available	Available	Available	Available	Available	Not available	Available
	25	25	25	20	25	17	18

AvailableAvailable, differentlyNot available

an-custom is not in the table either, and for a different reason: it is not a control this framework mounts but a hole a plugin mounts its own view through, so what it becomes depends entirely on which plugin. It works everywhere except watchOS, where there is no view hierarchy to put one in. See a view a plugin brings.

an-safe-area is not in the table because it is not a primitive: it is a component built on top of an-view that turns the insets the host reports into padding. It mounts everywhere, but on watchOS the insets are always zero — the app owns the whole screen and the system reserves no queryable margin — so there it does nothing. On Wear OS it is how the round screen’s margin arrives.

Two entries are neither a yes nor a no, and both are explained where they happen: on macOS an-navigation-bar puts its title in the window’s title bar, because a Mac already has one and drawing a second inside the content would be painting two; on Android an-map-view draws OpenStreetMap tiles on a canvas, because the platform ships no map — Google’s lives in Play Services behind an API key.

What each one becomes

Primitive	iOS · iPadOS	Android	macOS	watchOS
an-view	UIView	ViewGroup	NSView	ZStack
an-text	UILabel	TextView	NSTextField	Text
an-image	UIImageView	ImageView	NSImageView	Image
an-icon	SF Symbol	Material Symbols	SF Symbol	SF Symbol
an-scroll-view	UIScrollView	ScrollView	NSScrollView	ScrollView
an-button	UIButton	MaterialButton	NSButton	Button
an-text-input	UITextField	EditText	NSTextField	TextField
an-textarea	UITextView	EditText	NSTextView	—
an-switch	UISwitch	MaterialSwitch	NSSwitch	Toggle
an-slider	UISlider	Slider	NSSlider	Slider
an-stepper	UIStepper	two icon buttons	NSStepper	Stepper
an-progress-bar	UIProgressView	LinearProgressIndicator	NSProgressIndicator	ProgressView
an-select	UIButton + UIMenu	Spinner	NSPopUpButton	Picker
an-date-picker	UIDatePicker	system dialog	NSDatePicker	DatePicker
an-tab-bar	UITabBarController	BottomNavigationView	NSSegmentedControl	—
an-alert	UIAlertController	MaterialAlertDialog	NSAlert	.alert
an-web-view	WKWebView	android.webkit.WebView	WKWebView	—
an-video-view	AVPlayerViewController	VideoView	AVPlayerView	—

Props every primitive takes

These live on the base, so they work on all 25.

Prop	Type	What it does
backgroundColor	string	#rgb, #rrggbbaa, rgb(), rgba() and a handful of names.
borderRadius	number	Also per corner: borderTopLeftRadius and its three siblings.
borderWidth, borderColor	number, string
opacity	number
translateX, translateY, scale, scaleX, scaleY, rotate	number	Deliberately outside layout: a moved view still occupies its old place, so there is nothing to recompute and it can follow a finger.
animate	number	Milliseconds. From then on changes to that view are animated by the platform, on its own drawing thread. animateDelay and animateEasing go with it.
cursor	NativeCursor	macOS only — a finger has no shape.
testID	string	Ends up in accessibilityIdentifier.

Accessibility

Prop	Type	What it does
accessibilityLabel	string	The name a screen reader announces. System controls bring their own; set this when theirs does not say the right thing.
accessibilityHint	string	What activating it does, read after the name.
accessibilityRole	NativeRole	button, link, header, image, text, checkbox, radio, switch, slider, search, summary, none.
accessibilityValue	string	What it reads right now: “35%”, “three of seven”.
accessibilityState	NativeAccessibilityState	disabled, selected, checked (true, false or 'mixed'), expanded, busy.
accessible	boolean	Whether this is one element or a container to navigate into. false hides it and its contents — what decoration needs.

Events every primitive emits

Event	Payload	Notes
(press), (doublePress), (longPress)	{x, y}	On tvOS these arrive from the remote’s centre button, not a touch.
(pan)	translation, velocity, state	Translation is from where the finger started, not from the previous event.
(pinch), (rotation)	scale / radians	Not on tvOS: the remote surface is single-touch.
(swipeLeft/Right/Up/Down)	{x, y}	Each direction attaches its own recogniser, so listening for one costs nothing for the other three.
(hover)	{hovered, x, y}	macOS only.
(focus), (blur)	{value?}	The whole platform on a TV; the keyboard on a phone.
(crown), (crownIdle)	{delta, offset, velocity}	The digital crown, on both watches. Delivered to whichever view holds focus.
(layout)	{x, y, width, height}	Emitted by the core, not by a platform — it is the one computing the frame, so it is free everywhere.
(safeArea)	insets	Changes on rotation and when the keyboard opens.

An event a platform cannot deliver warns when you subscribe to it, rather than staying silent. That is the difference between a gap and a bug.