Add StrokeStyle and FillStyle

Sources/OpenSwiftUI/View/Animation/TODO/Animatable.swift

@@ -7,9 +7,16 @@
 
 // MARK: - Animatable
 
+/// A type that describes how to animate a property of a view.
 public protocol Animatable {
+    /// The type defining the data to animate.
     associatedtype AnimatableData: VectorArithmetic
+
+    /// The data to animate.
     var animatableData: AnimatableData { get set }
+
+    /// Replaces `value` with an animated version of the value, using
+    /// `inputs`.
     static func _makeAnimatable(value: inout _GraphValue<Self>, inputs: _GraphInputs)
 }
 

Sources/OpenSwiftUI/View/Shape/FillStyle.swift

@@ -0,0 +1,38 @@
+//
+//  FillStyle.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: Complete
+
+/// A style for rasterizing vector shapes.
+@frozen
+public struct FillStyle: Equatable {
+
+    /// A Boolean value that indicates whether to use the even-odd rule when
+    /// rendering a shape.
+    ///
+    /// When `isOEFilled` is `false`, the style uses the non-zero winding number
+    /// rule.
+    public var isEOFilled: Bool
+
+    /// A Boolean value that indicates whether to apply antialiasing to the
+    /// edges of a shape.
+    public var isAntialiased: Bool
+
+    /// Creates a new fill style with the specified settings.
+    ///
+    /// - Parameters:
+    ///   - eoFill: A Boolean value that indicates whether to use the even-odd
+    ///     rule for rendering a shape. Pass `false` to use the non-zero winding
+    ///     number rule instead.
+    ///   - antialiased: A Boolean value that indicates whether to use
+    ///     antialiasing when rendering the edges of a shape.
+    @inlinable
+    public init(eoFill: Bool = false, antialiased: Bool = true) {
+        self.isEOFilled = eoFill
+        self.isAntialiased = antialiased
+    }
+}
+
+extension FillStyle: Sendable {}

Sources/OpenSwiftUI/View/Shape/StrokeStyle.swift

@@ -0,0 +1,82 @@
+//
+//  StrokeStyle.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: Complete
+
+#if canImport(CoreGraphics)
+import CoreGraphics
+#else
+/// Line join styles
+public enum CGLineJoin: Int32, @unchecked Sendable {
+    case miter = 0
+    case round = 1
+    case bevel = 2
+}
+
+/// Line cap styles
+public enum CGLineCap : Int32, @unchecked Sendable {
+    case butt = 0
+    case round = 1
+    case square = 2
+}
+#endif
+
+/// The characteristics of a stroke that traces a path.
+@frozen
+public struct StrokeStyle: Equatable {
+    /// The width of the stroked path.
+    public var lineWidth: CGFloat
+
+    /// The endpoint style of a line.
+    public var lineCap: CGLineCap
+
+    /// The join type of a line.
+    public var lineJoin: CGLineJoin
+
+    /// A threshold used to determine whether to use a bevel instead of a
+    /// miter at a join.
+    public var miterLimit: CGFloat
+
+    /// The lengths of painted and unpainted segments used to make a dashed line.
+    public var dash: [CGFloat]
+
+    /// How far into the dash pattern the line starts.
+    public var dashPhase: CGFloat
+
+    /// Creates a new stroke style from the given components.
+    ///
+    /// - Parameters:
+    ///   - lineWidth: The width of the segment.
+    ///   - lineCap: The endpoint style of a segment.
+    ///   - lineJoin: The join type of a segment.
+    ///   - miterLimit: The threshold used to determine whether to use a bevel
+    ///     instead of a miter at a join.
+    ///   - dash: The lengths of painted and unpainted segments used to make a
+    ///     dashed line.
+    ///   - dashPhase: How far into the dash pattern the line starts.
+    public init(lineWidth: CGFloat = 1, lineCap: CGLineCap = .butt, lineJoin: CGLineJoin = .miter, miterLimit: CGFloat = 10, dash: [CGFloat] = [CGFloat](), dashPhase: CGFloat = 0) {
+        self.lineWidth = lineWidth
+        self.lineCap = lineCap
+        self.lineJoin = lineJoin
+        self.miterLimit = miterLimit
+        self.dash = dash
+        self.dashPhase = dashPhase
+    }
+}
+
+extension StrokeStyle: Animatable {
+    public var animatableData: AnimatablePair<CGFloat, AnimatablePair<CGFloat, CGFloat>> {
+        get {
+            AnimatablePair(lineWidth, AnimatablePair(miterLimit, dashPhase))
+        }
+        set {
+            lineWidth = newValue.first
+            miterLimit = newValue.second.first
+            dashPhase = newValue.second.second
+        }
+    }
+}
+
+extension StrokeStyle: Sendable {}