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Merge pull request #59 from PureSwift/feature/accessibility
Add accessibility modifiers
2 parents 022b05e + 4d12c82 commit 4cdc464

5 files changed

Lines changed: 222 additions & 0 deletions

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‎AndroidSwiftUICore/Sources/AndroidSwiftUICore/Modifiers/Accessibility.swift‎

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//
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// Accessibility.swift
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// AndroidSwiftUICore
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//
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// Accessibility describes a view to assistive technology rather than changing
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// how it looks, so every one of these folds into Compose semantics: a label
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// becomes the content description, a value becomes the state description,
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// traits become a role, and hiding clears the subtree's semantics outright.
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//
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/// Roles that change how assistive technology announces a view.
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public struct AccessibilityTraits: OptionSet, Sendable {
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public let rawValue: Int
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public init(rawValue: Int) { self.rawValue = rawValue }
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public static let isButton = AccessibilityTraits(rawValue: 1 << 0)
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public static let isHeader = AccessibilityTraits(rawValue: 1 << 1)
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public static let isSelected = AccessibilityTraits(rawValue: 1 << 2)
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public static let isImage = AccessibilityTraits(rawValue: 1 << 3)
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/// The names the interpreter maps to Compose semantics.
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internal var names: [String] {
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var names: [String] = []
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if contains(.isButton) { names.append("button") }
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if contains(.isHeader) { names.append("header") }
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if contains(.isSelected) { names.append("selected") }
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if contains(.isImage) { names.append("image") }
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return names
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}
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}
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public struct _AccessibilityModifier: RenderModifier {
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let kind: String
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let args: [String: PropValue]
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public var _modifierNode: ModifierNode { ModifierNode(kind: kind, args: args) }
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}
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public extension View {
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/// The description assistive technology reads for this view.
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func accessibilityLabel<S: StringProtocol>(_ label: S) -> ModifiedContent<Self, _AccessibilityModifier> {
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modifier(_AccessibilityModifier(kind: "accessibilityLabel", args: ["text": .string(String(label))]))
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}
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/// The view's current value, announced after its label.
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func accessibilityValue<S: StringProtocol>(_ value: S) -> ModifiedContent<Self, _AccessibilityModifier> {
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modifier(_AccessibilityModifier(kind: "accessibilityValue", args: ["text": .string(String(value))]))
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}
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/// Removes the view, and everything inside it, from the accessibility tree.
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func accessibilityHidden(_ hidden: Bool) -> ModifiedContent<Self, _AccessibilityModifier> {
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modifier(_AccessibilityModifier(kind: "accessibilityHidden", args: ["value": .bool(hidden)]))
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}
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func accessibilityAddTraits(_ traits: AccessibilityTraits) -> ModifiedContent<Self, _AccessibilityModifier> {
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modifier(_AccessibilityModifier(
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kind: "accessibilityAddTraits",
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args: ["traits": .array(traits.names.map { .string($0) })]
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))
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}
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/// A stable handle for UI tests. Never announced.
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func accessibilityIdentifier<S: StringProtocol>(_ identifier: S) -> ModifiedContent<Self, _AccessibilityModifier> {
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modifier(_AccessibilityModifier(kind: "accessibilityIdentifier", args: ["id": .string(String(identifier))]))
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}
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}

‎AndroidSwiftUICore/Tests/AndroidSwiftUICoreTests/EvaluatorTests.swift‎

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@@ -737,3 +737,60 @@ struct PreferenceTests {
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#expect(outer == 70) // the inner reduction reached the outer one
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}
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}
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@Suite("Accessibility")
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struct AccessibilityTests {
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private func arg(_ node: RenderNode, _ kind: String, _ key: String) -> PropValue? {
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node.modifiers.first { $0.kind == kind }?.args[key]
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}
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@Test("Label, value, and identifier emit their text")
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func describes() {
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let node = ViewHost(
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Text("7")
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.accessibilityLabel("Unread messages")
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.accessibilityValue("7 items")
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.accessibilityIdentifier("inbox-count")
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).evaluate()
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#expect(arg(node, "accessibilityLabel", "text") == .string("Unread messages"))
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#expect(arg(node, "accessibilityValue", "text") == .string("7 items"))
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#expect(arg(node, "accessibilityIdentifier", "id") == .string("inbox-count"))
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}
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@Test("Hiding is explicit in both directions")
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func hidden() {
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let hidden = ViewHost(Text("decorative").accessibilityHidden(true)).evaluate()
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#expect(arg(hidden, "accessibilityHidden", "value") == .bool(true))
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// false must still emit — it has to be able to override an inherited hide
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let shown = ViewHost(Text("visible").accessibilityHidden(false)).evaluate()
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#expect(arg(shown, "accessibilityHidden", "value") == .bool(false))
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}
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@Test("Traits emit as a set of names")
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func traits() {
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let node = ViewHost(
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Text("Chapter").accessibilityAddTraits([.isHeader, .isButton])
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).evaluate()
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guard case .array(let names)? = arg(node, "accessibilityAddTraits", "traits") else {
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Issue.record("missing traits"); return
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}
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#expect(names.contains(.string("header")))
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#expect(names.contains(.string("button")))
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#expect(!names.contains(.string("selected")))
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}
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@Test("Accessibility describes without disturbing the view")
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func nonVisual() {
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// the node type, props, and children must be identical with and without
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// a description — these modifiers only add semantics
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let plain = ViewHost(VStack { Text("hello") }).evaluate()
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let described = ViewHost(
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VStack { Text("hello") }.accessibilityLabel("greeting")
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).evaluate()
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#expect(plain.type == described.type)
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#expect(plain.children.count == described.children.count)
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#expect(firstTextString(plain) == firstTextString(described))
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}
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}

‎Demo/App.swiftpm/Sources/AccessibilityPlaygrounds.swift‎

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#if canImport(AndroidSwiftUI)
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import AndroidSwiftUI
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#else
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import SwiftUI
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#endif
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struct AccessibilityPlayground: View {
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@State private var unread = 7
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var body: some View {
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ScrollView {
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VStack(alignment: .leading, spacing: 0) {
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Example("accessibilityLabel") {
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// reads as "Unread messages", not "7"
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Text("7")
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.accessibilityLabel("Unread messages")
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}
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Example("accessibilityValue") {
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Text("Volume")
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.accessibilityLabel("Volume")
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.accessibilityValue("30 percent")
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}
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Example("accessibilityHidden") {
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VStack(alignment: .leading, spacing: 8) {
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Text("kept in the tree")
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Text("decorative-flourish")
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.accessibilityHidden(true)
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}
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}
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Example("accessibilityAddTraits") {
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VStack(alignment: .leading, spacing: 8) {
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Text("Chapter One")
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.accessibilityAddTraits(.isHeader)
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Text("Tap to continue")
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.accessibilityAddTraits(.isButton)
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}
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}
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Example("accessibilityIdentifier") {
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Text("Checkout")
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.accessibilityIdentifier("checkout-button")
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}
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}
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}
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.navigationTitle("Accessibility")
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}
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}

‎Demo/App.swiftpm/Sources/Catalog.swift‎

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CatalogEntry(id: "tab", title: "TabView", screen: AnyCatalogScreen(TabViewPlayground())),
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CatalogEntry(id: "sheet", title: "Sheet", screen: AnyCatalogScreen(SheetPlayground())),
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CatalogEntry(id: "alert", title: "Alert", screen: AnyCatalogScreen(AlertPlayground())),
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CatalogEntry(id: "accessibility", title: "Accessibility", screen: AnyCatalogScreen(AccessibilityPlayground())),
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CatalogEntry(id: "state", title: "State", screen: AnyCatalogScreen(StatePlayground())),
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CatalogEntry(id: "preference", title: "Preferences", screen: AnyCatalogScreen(PreferencePlayground())),
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CatalogEntry(id: "environment", title: "Environment", screen: AnyCatalogScreen(EnvironmentPlayground())),

‎Demo/swiftui/src/commonMain/kotlin/com/pureswift/swiftui/Render.kt‎

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@@ -149,6 +149,15 @@ import androidx.compose.ui.draw.rotate
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import androidx.compose.ui.draw.scale
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import androidx.compose.ui.draw.shadow
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import androidx.compose.ui.graphics.Brush
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import androidx.compose.ui.semantics.semantics
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import androidx.compose.ui.semantics.clearAndSetSemantics
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import androidx.compose.ui.semantics.contentDescription
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import androidx.compose.ui.semantics.stateDescription
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import androidx.compose.ui.semantics.heading
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import androidx.compose.ui.semantics.selected
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import androidx.compose.ui.semantics.Role
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import androidx.compose.ui.semantics.role
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import androidx.compose.ui.platform.testTag
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import androidx.compose.ui.graphics.Color
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import androidx.compose.ui.layout.ContentScale
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import androidx.compose.ui.graphics.ImageBitmap
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}
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}
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// Accessibility folds into Compose semantics rather than changing
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// any visual property.
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"accessibilityLabel" -> {
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val text = entry.args.string("text")
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if (text == null) modifier else modifier.semantics { contentDescription = text }
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}
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"accessibilityValue" -> {
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val text = entry.args.string("text")
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if (text == null) modifier else modifier.semantics { stateDescription = text }
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}
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// clearAndSetSemantics drops this node AND its subtree from the
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// tree, which is what hiding has to mean for a container.
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"accessibilityHidden" -> {
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val hidden = entry.args.string("value") == "true"
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if (hidden) modifier.clearAndSetSemantics { } else modifier
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}
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"accessibilityAddTraits" -> {
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val traits = (entry.args["traits"] as? kotlinx.serialization.json.JsonArray)
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?.mapNotNull { (it as? kotlinx.serialization.json.JsonPrimitive)?.content }
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.orEmpty()
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modifier.semantics {
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if (traits.contains("button")) role = Role.Button
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if (traits.contains("image")) role = Role.Image
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if (traits.contains("header")) heading()
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if (traits.contains("selected")) selected = true
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}
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}
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// A test handle, never announced.
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"accessibilityIdentifier" -> {
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val id = entry.args.string("id")
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if (id == null) modifier else modifier.testTag(id)
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}
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// Dim disabled content; controls also drop interactivity via their
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// own `enabled` parameter (e.g. Button).
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"disabled" -> {
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"tint", "onAppear", "onDisappear", "task", "onChange", "animation", "tag", "tabItem",
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"transition", "focused", "longPress", "drag", "contentMode", "progressViewStyle",
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"buttonStyle", "pickerStyle", "toggleStyle", "textFieldStyle",
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"accessibilityLabel", "accessibilityValue", "accessibilityHidden",
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"accessibilityAddTraits", "accessibilityIdentifier",
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)
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// Folds a frame entry: fixed size, fill (maxWidth/Height .infinity), bounded

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