Add Shape interface

Sources/OpenSwiftUI/View/Shape/ForegroundStyle.swift

@@ -0,0 +1,29 @@
+@frozen
+public struct ForegroundStyle: ShapeStyle {
+    @inlinable
+    public init() {}
+
+    public static func _makeView<S>(view: _GraphValue<_ShapeView<S, ForegroundStyle>>, inputs: _ViewInputs) -> _ViewOutputs where S: Shape {
+        fatalError("TODO")
+    }
+}
+
+#if OPENSWIFTUI_SUPPORT_2021_API
+
+extension ForegroundStyle {
+    public func _apply(to shape: inout _ShapeStyle_Shape) {
+        fatalError("TODO")
+    }
+
+    public static func _apply(to type: inout _ShapeStyle_ShapeType) {
+        fatalError("TODO")
+    }
+}
+
+extension ShapeStyle where Self == ForegroundStyle {
+    @_alwaysEmitIntoClient
+    public static var foreground: ForegroundStyle {
+        .init()
+    }
+}
+#endif

Sources/OpenSwiftUI/View/Shape/Rectangle.swift

@@ -0,0 +1,25 @@
+import Foundation
+
+/// A rectangular shape aligned inside the frame of the view containing it.
+@frozen
+public struct Rectangle: Shape {
+    public func path(in rect: CGRect) -> Path {
+        fatalError("TODO")
+    }
+
+    /// Creates a new rectangle shape.
+    @inlinable
+    public init() {}
+
+    public typealias AnimatableData = EmptyAnimatableData
+
+    public typealias Body = _ShapeView<Rectangle, ForegroundStyle>
+}
+
+
+extension Shape where Self == Rectangle {
+    /// A rectangular shape aligned inside the frame of the view containing it.
+    public static var rect: Rectangle {
+        Rectangle()
+    }
+}

Sources/OpenSwiftUI/View/Shape/Shape.swift

@@ -0,0 +1,51 @@
+//
+//  Shape.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: WIP
+
+import Foundation
+
+/// A 2D shape that you can use when drawing a view.
+///
+/// Shapes without an explicit fill or stroke get a default fill based on the
+/// foreground color.
+///
+/// You can define shapes in relation to an implicit frame of reference, such as
+/// the natural size of the view that contains it. Alternatively, you can define
+/// shapes in terms of absolute coordinates.
+public protocol Shape: Animatable, View {
+    /// Describes this shape as a path within a rectangular frame of reference.
+    ///
+    /// - Parameter rect: The frame of reference for describing this shape.
+    ///
+    /// - Returns: A path that describes this shape.
+    func path(in rect: CGRect) -> Path
+
+    #if OPENSWIFTUI_SUPPORT_2021_API
+    /// An indication of how to style a shape.
+    ///
+    /// OpenSwiftUI looks at a shape's role when deciding how to apply a
+    /// ``ShapeStyle`` at render time. The ``Shape`` protocol provides a
+    /// default implementation with a value of ``ShapeRole/fill``. If you
+    /// create a composite shape, you can provide an override of this property
+    /// to return another value, if appropriate.
+    static var role: ShapeRole { get }
+    #endif
+}
+
+extension Shape {
+    public var body: _ShapeView<Self, ForegroundStyle> {
+        _ShapeView(shape: self, style: ForegroundStyle())
+    }
+}
+
+#if OPENSWIFTUI_SUPPORT_2021_API
+
+extension Shape {
+    public static var role: ShapeRole {
+        .fill
+    }
+}
+#endif

Sources/OpenSwiftUI/View/Shape/ShapeRole.swift

@@ -0,0 +1,27 @@
+//
+//  ShapeRole.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: Complete
+
+#if OPENSWIFTUI_SUPPORT_2021_API
+
+/// Ways of styling a shape.
+public enum ShapeRole: Sendable {
+    /// Indicates to the shape's style that SwiftUI fills the shape.
+    case fill
+
+    /// Indicates to the shape's style that SwiftUI applies a stroke to
+    /// the shape's path.
+    case stroke
+
+    /// Indicates to the shape's style that SwiftUI uses the shape as a
+    /// separator.
+    case separator
+}
+
+extension ShapeRole: Equatable {}
+extension ShapeRole: Hashable {}
+
+#endif

Sources/OpenSwiftUI/View/Shape/ShapeStyle.swift

@@ -0,0 +1,38 @@
+public protocol ShapeStyle {
+  @available(*, deprecated, message: "obsolete")
+  static func _makeView<S>(view: _GraphValue<_ShapeView<S, Self>>, inputs: _ViewInputs) -> _ViewOutputs where S : Shape
+
+    #if OPENSWIFTUI_SUPPORT_2021_API
+    func _apply(to shape: inout _ShapeStyle_Shape)
+
+    static func _apply(to type: inout _ShapeStyle_ShapeType)
+    #endif
+}
+
+
+#if OPENSWIFTUI_SUPPORT_2021_API
+
+public struct _ShapeStyle_Shape {
+    // TODO
+}
+
+public struct _ShapeStyle_ShapeType {
+    // TODO
+}
+
+extension ShapeStyle {
+    public static func _makeView<S>(view: _GraphValue<_ShapeView<S, Self>>, inputs: _ViewInputs) -> _ViewOutputs where S: Shape {
+        fatalError("TODO")
+    }
+
+    public func _apply(to shape: inout _ShapeStyle_Shape) {
+        fatalError("TODO")
+    }
+
+    public static func _apply(to type: inout _ShapeStyle_ShapeType) {
+        fatalError("TODO")
+    }
+}
+
+
+#endif

Sources/OpenSwiftUI/View/Shape/ShapeView.swift

@@ -0,0 +1,20 @@
+@frozen
+public struct _ShapeView<Content, Style>: PrimitiveView where Content : Shape, Style: ShapeStyle {
+    public var shape: Content
+    public var style: Style
+    public var fillStyle: FillStyle
+
+    @inlinable
+    public init(shape: Content, style: Style, fillStyle: FillStyle = FillStyle()) {
+        self.shape = shape
+        self.style = style
+        self.fillStyle = fillStyle
+    }
+
+
+    public static func _makeView(view: _GraphValue<_ShapeView<Content, Style>>, inputs: _ViewInputs) -> _ViewOutputs {
+        fatalError("TODO")
+    }
+
+    public typealias Body = Never
+}