Add BlurTransition support

Sources/OpenSwiftUICore/Animation/Transition/BlurTransition.swift

@@ -0,0 +1,169 @@
+//
+//  BlurTransition.swift
+//  OpenSwiftUICore
+//
+//  Audited for 6.5.4
+//  Status: Complete
+//  ID: A4BD5A1CB1233579E2E5EB40492B5E89 (SwiftUI)
+
+public import Foundation
+
+// MARK: - AnyTransition + blur
+
+@_spi(Private)
+@available(OpenSwiftUI_v5_0, *)
+extension AnyTransition {
+
+    /// Creates a transition that blurs the view when being inserted or removed.
+    ///
+    /// - Parameter radius: The blur radius. The default value is `10`.
+    ///
+    /// - Returns: A transition that applies a blur effect.
+    public static func blur(radius: CGFloat = 10) -> AnyTransition {
+        .init(BlurAndFadeTransition(radius: radius))
+    }
+}
+
+// MARK: - Transition + blurReplace
+
+@available(OpenSwiftUI_v5_0, *)
+extension Transition where Self == BlurReplaceTransition {
+
+    /// A transition that animates the insertion or removal of a view
+    /// by combining blurring and scaling effects.
+    @MainActor
+    @preconcurrency
+    public static func blurReplace(_ config: BlurReplaceTransition.Configuration = .downUp) -> Self {
+        return Self(configuration: config)
+    }
+
+    /// A transition that animates the insertion or removal of a view
+    /// by combining blurring and scaling effects.
+    @_alwaysEmitIntoClient
+    @MainActor
+    @preconcurrency
+    public static var blurReplace: BlurReplaceTransition {
+        blurReplace(.downUp)
+    }
+}
+
+// MARK: - BlurReplaceTransition
+
+/// A transition that animates the insertion or removal of a view by
+/// combining blurring and scaling effects.
+@available(OpenSwiftUI_v5_0, *)
+@MainActor
+@preconcurrency
+public struct BlurReplaceTransition: Transition {
+
+    // MARK: - BlurReplaceTransition.Configuration
+
+    /// Configuration properties for a transition.
+    public struct Configuration: Equatable {
+        package enum Storage: Equatable {
+            case downUp
+            case upUp
+        }
+
+        package var storage: Storage
+
+        package init(_ storage: Storage) {
+            self.storage = storage
+        }
+
+        /// A configuration that requests a transition that scales the
+        /// view down while removing it and up while inserting it.
+        public static let downUp = Configuration(.downUp)
+
+        /// A configuration that requests a transition that scales the
+        /// view up while both removing and inserting it.
+        public static let upUp = Configuration(.upUp)
+    }
+
+    /// The transition configuration.
+    public var configuration: Configuration
+
+    /// Creates a new transition.
+    ///
+    /// - Parameter configuration: the transition configuration.
+    public init(configuration: Configuration) {
+        self.configuration = configuration
+    }
+
+    public func body(content: Content, phase: TransitionPhase) -> some View {
+        let scale: CGFloat = switch phase {
+        case .identity: 1.0
+        case .willAppear: 0.9
+        case .didDisappear: configuration.storage == .upUp ? 1.1 : 0.9
+        }
+        content
+            .opacity(phase.isIdentity ? 1 : 0)
+            .blur(radius: phase.isIdentity ? 0 : 7)
+            .scaleEffect(scale)
+    }
+
+    public func _makeContentTransition(transition: inout _Transition_ContentTransition) {
+        guard case .effects = transition.operation else {
+            transition.result = .bool(true)
+            return
+        }
+        transition.result = .effects(configuration.effects)
+    }
+}
+
+@available(*, unavailable)
+extension BlurReplaceTransition: Sendable {}
+
+@available(*, unavailable)
+extension BlurReplaceTransition.Configuration: Sendable {}
+
+// MARK: - BlurReplaceTransition.Configuration + effects
+
+@available(OpenSwiftUI_v5_0, *)
+extension BlurReplaceTransition.Configuration {
+
+    fileprivate var effects: [ContentTransition.Effect] {
+        let opacityEffect = ContentTransition.Effect(
+            type: .opacity,
+            begin: 0.33,
+            duration: 0.67
+        )
+        let blurEffect = ContentTransition.Effect(
+            type: .blur(radius: 7),
+            begin: 0.33,
+            duration: 0.67
+        )
+        let scaleEffect = ContentTransition.Effect(
+            type: .scale(0.9),
+            begin: 0.33,
+            duration: 0.67,
+            flags: .init(rawValue: storage == .upUp ? 1 : 0)
+        )
+        return [opacityEffect, blurEffect, scaleEffect]
+    }
+}
+
+// MARK: - BlurAndFadeTransition
+
+private struct BlurAndFadeTransition: Transition {
+    var radius: CGFloat
+
+    func body(content: Content, phase: TransitionPhase) -> some View {
+        content
+            .blur(radius: phase.isIdentity ? 0 : radius)
+            .opacity(phase.isIdentity ? 1 : 0)
+    }
+
+    func _makeContentTransition(transition: inout _Transition_ContentTransition) {
+        guard case .effects = transition.operation else {
+            transition.result = .bool(true)
+            return
+        }
+        let blurEffect = ContentTransition.Effect(.blur(radius: radius))
+        let opacityEffect = ContentTransition.Effect(.opacity)
+        transition.result = .effects([blurEffect, opacityEffect])
+    }
+}
+
+@available(*, unavailable)
+extension BlurAndFadeTransition: Sendable {}