Add AbsoluteEdge support (#155)

Author: Kyle-Ye

Sources/OpenSwiftUICore/Layout/LayoutAdjustments/Edge/AbsoluteEdge.swift

@@ -0,0 +1,68 @@
+//
+//  AbsoluteEdge.swift
+//  OpenSwiftUICore
+//
+//  Audited for iOS 18.0
+//  Status: Complete
+
+package enum AbsoluteEdge: Int8, CaseIterable, Hashable {
+    case top, left, bottom, right
+    
+    package struct Set: OptionSet {
+        package let rawValue: Int8
+        package init(rawValue: Int8) { self.rawValue = rawValue }
+        package static let top: AbsoluteEdge.Set = .init(.top)
+        package static let left: AbsoluteEdge.Set = .init(.left)
+        package static let bottom: AbsoluteEdge.Set = .init(.bottom)
+        package static let right: AbsoluteEdge.Set = .init(.right)
+        package static let all: AbsoluteEdge.Set = [.top, .left, .bottom, .right]
+        package static let horizontal: AbsoluteEdge.Set = [.left, .right]
+        package static let vertical: AbsoluteEdge.Set = [.top, .bottom]
+        package init(_ e: AbsoluteEdge) {
+            self.init(rawValue: 1 << e.rawValue)
+        }
+        package func contains(_ e: AbsoluteEdge) -> Bool {
+            self.contains(.init(e))
+        }
+    }
+}
+
+extension AbsoluteEdge.Set {
+    package init(_ edges: Edge.Set, layoutDirection: LayoutDirection) {
+        var result: AbsoluteEdge.Set = []
+        if edges.contains(.top) {
+            result.insert(.top)
+        }
+        if edges.contains(.leading) {
+            switch layoutDirection {
+            case .leftToRight: result.insert(.left)
+            case .rightToLeft: result.insert(.right)
+            }
+        }
+        if edges.contains(.bottom) {
+            result.insert(.bottom)
+        }
+        if edges.contains(.trailing) {
+            switch layoutDirection {
+            case .leftToRight: result.insert(.right)
+            case .rightToLeft: result.insert(.left)
+            }
+        }
+        self = result
+    }
+}
+
+extension AbsoluteEdge {
+    package var horizontal: Bool {
+        self == .left || self == .right
+    }
+    
+    package var opposite: AbsoluteEdge {
+        switch self {
+        case .top: .bottom
+        case .left: .right
+        case .bottom: .top
+        case .right: .left
+        }
+    }
+}

Tests/OpenSwiftUICoreTests/Layout/LayoutAdjustments/Alignment/AlignmentIDTests.swift

@@ -1,9 +1,6 @@
 //
 //  AlignmentIDTests.swift
-//
-//
-//  Created by Kyle on 2023/12/16.
-//
+//  OpenSwiftUICoreTests
 
 @testable import OpenSwiftUICore
 import Testing

Tests/OpenSwiftUICoreTests/Layout/LayoutAdjustments/Edge/AbsoluteEdgeTests.swift

@@ -0,0 +1,55 @@
+//
+//  AbsoluteEdgeTests.swift
+//  OpenSwiftUICoreTests
+
+import Testing
+import OpenSwiftUICore
+
+struct AbsoluteEdgeTests {   
+    @Test
+    func absoluteEdgeValues() {
+        #expect(AbsoluteEdge.top.rawValue == 0)
+        #expect(AbsoluteEdge.left.rawValue == 1)
+        #expect(AbsoluteEdge.bottom.rawValue == 2)
+        #expect(AbsoluteEdge.right.rawValue == 3)
+    }
+    
+    @Test
+    func absoluteEdgeSetInitialization() {
+        let topSet = AbsoluteEdge.Set(.top)
+        let leftSet = AbsoluteEdge.Set(.left)
+        let bottomSet = AbsoluteEdge.Set(.bottom)
+        let rightSet = AbsoluteEdge.Set(.right)
+        
+        #expect(topSet.rawValue == 1 << 0)
+        #expect(leftSet.rawValue == 1 << 1)
+        #expect(bottomSet.rawValue == 1 << 2)
+        #expect(rightSet.rawValue == 1 << 3)
+    }
+    
+    @Test
+    func absoluteEdgeSetContains() {
+        let horizontalSet = AbsoluteEdge.Set.horizontal
+        #expect(horizontalSet.contains(.left))
+        #expect(horizontalSet.contains(.right))
+        #expect(!horizontalSet.contains(.top))
+        #expect(!horizontalSet.contains(.bottom))
+    }
+    
+    @Test
+    func absoluteEdgeSetFromEdgeSet() {
+        // Test LTR layout direction
+        let ltrSet = AbsoluteEdge.Set(.leading, layoutDirection: .leftToRight)
+        #expect(ltrSet.contains(.left))
+        #expect(!ltrSet.contains(.right))
+        #expect(!ltrSet.contains(.top))
+        #expect(!ltrSet.contains(.bottom))
+        
+        // Test RTL layout direction
+        let rtlSet = AbsoluteEdge.Set(.leading, layoutDirection: .rightToLeft)
+        #expect(rtlSet.contains(.right))
+        #expect(!rtlSet.contains(.left))
+        #expect(!rtlSet.contains(.top))
+        #expect(!rtlSet.contains(.bottom))
+    }
+}