Revise ShapeStyle and add Gradients (#435)

Author: carson-katri

Package.swift

@@ -209,7 +209,7 @@ let package = Package(
           condition: .when(platforms: [.macOS])
         ),
       ],
-      exclude: ["__Snapshots__"]
+      exclude: ["__Snapshots__", "RenderingTests/__Snapshots__"]
     ),
   ]
 )

Sources/TokamakCore/Shapes/Shape.swift

@@ -34,7 +34,7 @@ public extension Shape {
 }
 
 public extension ShapeStyle where Self: View, Self.Body == _ShapeView<Rectangle, Self> {
-  var body: some View {
+  var body: Body {
     _ShapeView(shape: Rectangle(), style: self)
   }
 }

Sources/TokamakCore/Shapes/ShapeStyles/BackgroundStyle.swift

@@ -75,8 +75,12 @@ public extension View {
 
   public func modifyEnvironment(_ values: inout EnvironmentValues) {
     values._backgroundStyle = .init(
-      styles: (primary: style, secondary: style, tertiary: style),
+      styles: (primary: style, secondary: style, tertiary: style, quaternary: style),
       environment: values
     )
   }
 }
+
+public extension ShapeStyle where Self == BackgroundStyle {
+  static var background: Self { .init() }
+}

Sources/TokamakCore/Shapes/ShapeStyles/ContentStyles.swift

@@ -71,8 +71,9 @@ public extension View {
   }
 }
 
-@frozen public struct _ForegroundStyleModifier<Primary, Secondary, Tertiary>: ViewModifier,
-  EnvironmentModifier
+@frozen public struct _ForegroundStyleModifier<
+  Primary, Secondary, Tertiary
+>: ViewModifier, EnvironmentModifier
   where Primary: ShapeStyle, Secondary: ShapeStyle, Tertiary: ShapeStyle
 {
   public var primary: Primary
@@ -90,6 +91,13 @@ public extension View {
 
   public typealias Body = Never
   public func modifyEnvironment(_ values: inout EnvironmentValues) {
-    values._foregroundStyle = .init(styles: (primary, secondary, tertiary), environment: values)
+    values._foregroundStyle = .init(
+      styles: (primary, secondary, tertiary, tertiary),
+      environment: values
+    )
   }
 }
+
+public extension ShapeStyle where Self == ForegroundStyle {
+  static var foreground: Self { .init() }
+}

Sources/TokamakCore/Shapes/ShapeStyles/ForegroundStyle.swift

@@ -0,0 +1,152 @@
+// Copyright 2020-2021 Tokamak contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+//  Created by Carson Katri on 8/7/21.
+//
+
+import Foundation
+
+@frozen public struct AngularGradient: ShapeStyle, View {
+  internal var gradient: Gradient
+  internal var center: UnitPoint
+  internal var startAngle: Angle
+  internal var endAngle: Angle
+
+  public init(
+    gradient: Gradient,
+    center: UnitPoint,
+    startAngle: Angle = .zero,
+    endAngle: Angle = .zero
+  ) {
+    self.gradient = gradient
+    self.center = center
+    self.startAngle = startAngle
+    self.endAngle = endAngle
+  }
+
+  public init(colors: [Color], center: UnitPoint, startAngle: Angle, endAngle: Angle) {
+    self.init(
+      gradient: Gradient(colors: colors),
+      center: center,
+      startAngle: startAngle,
+      endAngle: endAngle
+    )
+  }
+
+  public init(stops: [Gradient.Stop], center: UnitPoint, startAngle: Angle, endAngle: Angle) {
+    self.init(
+      gradient: Gradient(stops: stops),
+      center: center,
+      startAngle: startAngle,
+      endAngle: endAngle
+    )
+  }
+
+  public init(gradient: Gradient, center: UnitPoint, angle: Angle = .zero) {
+    self.init(gradient: gradient, center: center, startAngle: angle, endAngle: angle)
+  }
+
+  public init(colors: [Color], center: UnitPoint, angle: Angle = .zero) {
+    self.init(
+      gradient: Gradient(colors: colors),
+      center: center,
+      angle: angle
+    )
+  }
+
+  public init(stops: [Gradient.Stop], center: UnitPoint, angle: Angle = .zero) {
+    self.init(
+      gradient: Gradient(stops: stops),
+      center: center,
+      angle: angle
+    )
+  }
+
+  public typealias Body = _ShapeView<Rectangle, Self>
+
+  public func _apply(to shape: inout _ShapeStyle_Shape) {
+    shape.result = .resolved(
+      .gradient(
+        gradient,
+        style: .angular(center: center, startAngle: startAngle, endAngle: endAngle)
+      )
+    )
+  }
+
+  public static func _apply(to type: inout _ShapeStyle_ShapeType) {}
+}
+
+public extension ShapeStyle where Self == AngularGradient {
+  static func angularGradient(
+    _ gradient: Gradient,
+    center: UnitPoint,
+    startAngle: Angle,
+    endAngle: Angle
+  ) -> AngularGradient {
+    .init(
+      gradient: gradient, center: center,
+      startAngle: startAngle, endAngle: endAngle
+    )
+  }
+
+  static func angularGradient(
+    colors: [Color],
+    center: UnitPoint,
+    startAngle: Angle,
+    endAngle: Angle
+  ) -> AngularGradient {
+    .init(
+      colors: colors, center: center,
+      startAngle: startAngle, endAngle: endAngle
+    )
+  }
+
+  static func angularGradient(
+    stops: [Gradient.Stop],
+    center: UnitPoint,
+    startAngle: Angle,
+    endAngle: Angle
+  ) -> AngularGradient {
+    .init(
+      stops: stops, center: center,
+      startAngle: startAngle, endAngle: endAngle
+    )
+  }
+}
+
+public extension ShapeStyle where Self == AngularGradient {
+  static func conicGradient(
+    _ gradient: Gradient,
+    center: UnitPoint,
+    angle: Angle = .zero
+  ) -> AngularGradient {
+    .init(gradient: gradient, center: center, angle: angle)
+  }
+
+  static func conicGradient(
+    colors: [Color],
+    center: UnitPoint,
+    angle: Angle = .zero
+  ) -> AngularGradient {
+    .init(colors: colors, center: center, angle: angle)
+  }
+
+  static func conicGradient(
+    stops: [Gradient.Stop],
+    center: UnitPoint,
+    angle: Angle = .zero
+  ) -> AngularGradient {
+    .init(stops: stops, center: center, angle: angle)
+  }
+}