Update ColorScheme (#165)

Author: Kyle-Ye

Sources/OpenSwiftUICore/Data/Environment/EnvironmentModifier.swift

@@ -0,0 +1,18 @@
+//
+//  EnvironmentModifier.swift
+//  OpenSwiftUICore
+//
+//  Audited for iOS 18.0
+//  Status: TODO
+
+package import OpenGraphShims
+
+package protocol EnvironmentModifier: _GraphInputsModifier {
+    static func makeEnvironment(modifier: Attribute<Self>, environment: inout EnvironmentValues)
+}
+
+extension EnvironmentModifier {
+    package static func _makeInputs(modifier: _GraphValue<Self>, inputs: inout _GraphInputs) {
+        preconditionFailure("TODO")
+    }
+}

Sources/OpenSwiftUICore/Graphic/Color/ColorSchema.swift

@@ -0,0 +1,250 @@
+//
+//  ColorScheme.swift
+//  OpenSwiftUI
+//
+//  Audited for iOS 18.0
+//  Status: Complete
+//  ID: 387C753F3FFD2899BCB77252214CFCC6 (SwiftUI)
+//  ID: 0E72AB1FBE33AED1E73FF06F3DA3A071 (SwiftUICore)
+
+package import OpenGraphShims
+
+// MARK: - ColorScheme
+
+/// The possible color schemes, corresponding to the light and dark appearances.
+///
+/// You receive a color scheme value when you read the
+/// ``EnvironmentValues/colorScheme`` environment value. The value tells you if
+/// a light or dark appearance currently applies to the view. OpenSwiftUI updates
+/// the value whenever the appearance changes, and redraws views that
+/// depend on the value. For example, the following ``Text`` view automatically
+/// updates when the user enables Dark Mode:
+///
+///     @Environment(\.colorScheme) private var colorScheme
+///
+///     var body: some View {
+///         Text(colorScheme == .dark ? "Dark" : "Light")
+///     }
+///
+/// Set a preferred appearance for a particular view hierarchy to override
+/// the user's Dark Mode setting using the ``View/preferredColorScheme(_:)``
+/// view modifier.
+public enum ColorScheme: CaseIterable, Sendable {
+    /// The color scheme that corresponds to a light appearance.
+    case light
+    
+    /// The color scheme that corresponds to a dark appearance.
+    case dark
+}
+
+// MARK: - ColorSchemeContrast
+
+/// The contrast between the app's foreground and background colors.
+///
+/// You receive a contrast value when you read the
+/// ``EnvironmentValues/colorSchemeContrast`` environment value. The value
+/// tells you if a standard or increased contrast currently applies to the view.
+/// OpenSwiftUI updates the value whenever the contrast changes, and redraws
+/// views that depend on the value. For example, the following ``Text`` view
+/// automatically updates when the user enables increased contrast:
+///
+///     @Environment(\.colorSchemeContrast) private var colorSchemeContrast
+///
+///     var body: some View {
+///         Text(colorSchemeContrast == .standard ? "Standard" : "Increased")
+///     }
+///
+/// The user sets the contrast by selecting the Increase Contrast option in
+/// Accessibility > Display in System Preferences on macOS, or
+/// Accessibility > Display & Text Size in the Settings app on iOS.
+/// Your app can't override the user's choice. For
+/// information about using color and contrast in your app, see
+/// [Accessibility](https://developer.apple.com/design/human-interface-guidelines/accessibility#Color-and-effects).
+/// in the Human Interface Guidelines.
+public enum ColorSchemeContrast: CaseIterable, Sendable {
+    
+    /// OpenSwiftUI displays views with standard contrast between the app's
+    /// foreground and background colors.
+    case standard
+    
+    /// OpenSwiftUI displays views with increased contrast between the app's
+    /// foreground and background colors.
+    case increased
+}
+
+// MARK: - View + ColorScheme
+
+extension View {
+    /// Sets this view's color scheme.
+    ///
+    /// Use `colorScheme(_:)` to set the color scheme for the view to which you
+    /// apply it and any subviews. If you want to set the color scheme for all
+    /// views in the presentation, use ``View/preferredColorScheme(_:)``
+    /// instead.
+    ///
+    /// - Parameter colorScheme: The color scheme for this view.
+    ///
+    /// - Returns: A view that sets this view's color scheme.
+    @inlinable
+    nonisolated public func colorScheme(_ colorScheme: ColorScheme) -> some View {
+        environment(\.colorScheme, colorScheme)
+    }
+}
+
+// MARK: - ColorScheme + EnvironmentValues
+
+extension EnvironmentValues {
+    /// The color scheme of this environment.
+    ///
+    /// Read this environment value from within a view to find out if OpenSwiftUI
+    /// is currently displaying the view using the ``ColorScheme/light`` or
+    /// ``ColorScheme/dark`` appearance. The value that you receive depends on
+    /// whether the user has enabled Dark Mode, possibly superseded by
+    /// the configuration of the current presentation's view hierarchy.
+    ///
+    ///     @Environment(\.colorScheme) private var colorScheme
+    ///
+    ///     var body: some View {
+    ///         Text(colorScheme == .dark ? "Dark" : "Light")
+    ///     }
+    ///
+    /// You can set the `colorScheme` environment value directly,
+    /// but that usually isn't what you want. Doing so changes the color
+    /// scheme of the given view and its child views but *not* the views
+    /// above it in the view hierarchy. Instead, set a color scheme using the
+    /// ``View/preferredColorScheme(_:)`` modifier, which also propagates the
+    /// value up through the view hierarchy to the enclosing presentation, like
+    /// a sheet or a window.
+    ///
+    /// When adjusting your app's user interface to match the color scheme,
+    /// consider also checking the ``EnvironmentValues/colorSchemeContrast``
+    /// property, which reflects a system-wide contrast setting that the user
+    /// controls. For information, see
+    /// [Accessibility](https://developer.apple.com/design/human-interface-guidelines/accessibility#Color-and-effects).
+    /// in the Human Interface Guidelines.
+    ///
+    /// > Note: If you only need to provide different colors or
+    /// images for different color scheme and contrast settings, do that in
+    /// your app's Asset Catalog. See
+    /// [Asset management](https://developer.apple.com/documentation/xcode/asset-management).
+    public var colorScheme: ColorScheme {
+        get { self[ColorSchemeKey.self] }
+        set { self[ColorSchemeKey.self] = newValue }
+    }
+    
+    package var explicitPreferredColorScheme: ColorScheme? {
+        get { self[ExplicitPreferredColorSchemeKey.self] }
+        set { self[ExplicitPreferredColorSchemeKey.self] = newValue }
+    }
+    
+    package var systemColorScheme: ColorScheme {
+        get { self[SystemColorSchemeKey.self] }
+        set { self[SystemColorSchemeKey.self] = newValue }
+    }
+    
+    /// The contrast associated with the color scheme of this environment.
+    ///
+    /// Read this environment value from within a view to find out if OpenSwiftUI
+    /// is currently displaying the view using ``ColorSchemeContrast/standard``
+    /// or ``ColorSchemeContrast/increased`` contrast. The value that you read
+    /// depends entirely on user settings, and you can't change it.
+    ///
+    ///     @Environment(\.colorSchemeContrast) private var colorSchemeContrast
+    ///
+    ///     var body: some View {
+    ///         Text(colorSchemeContrast == .standard ? "Standard" : "Increased")
+    ///     }
+    ///
+    /// When adjusting your app's user interface to match the contrast,
+    /// consider also checking the ``EnvironmentValues/colorScheme`` property
+    /// to find out if OpenSwiftUI is displaying the view with a light or dark
+    /// appearance. For information, see
+    /// [Accessibility](https://developer.apple.com/design/human-interface-guidelines/accessibility#Color-and-effects).
+    /// in the Human Interface Guidelines.
+    ///
+    /// > Note: If you only need to provide different colors or
+    /// images for different color scheme and contrast settings, do that in
+    /// your app's Asset Catalog. See
+    /// [Asset management](https://developer.apple.com/documentation/xcode/asset-management).
+    public var colorSchemeContrast: ColorSchemeContrast {
+        self[ColorSchemeContrastKey.self]
+    }
+    
+    public var _colorSchemeContrast: ColorSchemeContrast {
+        get { self[ColorSchemeContrastKey.self] }
+        set { self[ColorSchemeContrastKey.self] = newValue }
+    }
+}
+
+private struct ColorSchemeKey: EnvironmentKey {
+    static let defaultValue: ColorScheme = .light
+}
+
+private struct SystemColorSchemeKey: EnvironmentKey {
+    static let defaultValue: ColorScheme = .light
+}
+
+private struct ExplicitPreferredColorSchemeKey: EnvironmentKey {
+    static let defaultValue: ColorScheme? = nil
+}
+
+private struct ColorSchemeContrastKey: EnvironmentKey {
+    static var defaultValue: ColorSchemeContrast = .standard
+}
+
+// MARK: - SystemColorSchemeModifier
+
+@MainActor
+@preconcurrency
+package struct SystemColorSchemeModifier: ViewModifier, PrimitiveViewModifier, EnvironmentModifier {
+    package var isEnabled: Bool
+    
+    package init(isEnabled: Bool) {
+        self.isEnabled = isEnabled
+    }
+    
+    nonisolated package static func makeEnvironment(modifier: Attribute<SystemColorSchemeModifier>, environment: inout EnvironmentValues) {
+        guard modifier.value.isEnabled else { return }
+        environment.colorScheme = environment.systemColorScheme
+    }
+
+    package typealias Body = Never
+}
+
+// MARK: - ColorScheme + ProtobufEnum
+
+extension ColorScheme: ProtobufEnum {
+    package var protobufValue: UInt {
+        switch self {
+            case .light: return 0
+            case .dark: return 1
+        }
+    }
+    
+    package init?(protobufValue: UInt) {
+        switch protobufValue {
+            case 0: self = .light
+            case 1: self = .dark
+            default: return nil
+        }
+    }
+}
+
+// MARK: - ColorSchemeContrast + ProtobufEnum
+
+extension ColorSchemeContrast: ProtobufEnum {
+    package var protobufValue: UInt {
+        switch self {
+            case .standard: return 0
+            case .increased: return 1
+        }
+    }
+    
+    package init?(protobufValue: UInt) {
+        switch protobufValue {
+            case 0: self = .standard
+            case 1: self = .increased
+            default: return nil
+        }
+    }
+}