#43: Add DesignKit package

* Begin implementing DesignKit package.
* Use element-design-tokens repo.
* Rename Fonts to align with Colours.

.gitignore

@@ -9,6 +9,15 @@ xcuserdata/
 *.dSYM.zip
 *.dSYM
 
+## SwiftPM
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/config/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc
+
 # fastlane
 #
 # It is recommended to not store the screenshots in the git repo.
@@ -26,4 +35,4 @@ Tools/Scripts/element-android
 
 ## macOS Files
 .DS_Store
-._*
+._*

DesignKit/Sources/Buttons/PrimaryActionButtonStyle.swift

@@ -0,0 +1,83 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// 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.
+//
+
+import SwiftUI
+import DesignTokens
+
+public struct PrimaryActionButtonStyle: ButtonStyle {
+    @Environment(\.isEnabled) private var isEnabled
+    @Environment(\.colorScheme) private var colorScheme
+
+    public var customColor: Color?
+
+    private var fontColor: Color {
+        // Always white unless disabled with a dark theme.
+        .white.opacity(colorScheme == .dark && !isEnabled ? 0.3 : 1.0)
+    }
+
+    private var backgroundColor: Color {
+        customColor ?? .element.accent
+    }
+
+    public init(customColor: Color? = nil) {
+        self.customColor = customColor
+    }
+
+    public func makeBody(configuration: Self.Configuration) -> some View {
+        configuration.label
+            .padding(12.0)
+            .frame(maxWidth: .infinity)
+            .foregroundColor(fontColor)
+            .font(.element.body)
+            .background(backgroundColor.opacity(backgroundOpacity(when: configuration.isPressed)))
+            .cornerRadius(8.0)
+    }
+
+    private func backgroundOpacity(when isPressed: Bool) -> CGFloat {
+        guard isEnabled else { return 0.3 }
+        return isPressed ? 0.6 : 1.0
+    }
+}
+
+public struct PrimaryActionButtonStyle_Previews: PreviewProvider {
+    public static var states: some View {
+        VStack {
+            Button("Enabled") { /* preview */ }
+                .buttonStyle(PrimaryActionButtonStyle())
+
+            Button("Disabled") { /* preview */  }
+                .buttonStyle(PrimaryActionButtonStyle())
+                .disabled(true)
+
+            Button { /* preview */  } label: {
+                Text("Clear BG")
+                    .foregroundColor(.element.alert)
+            }
+            .buttonStyle(PrimaryActionButtonStyle(customColor: .clear))
+
+            Button("Red BG") { /* preview */  }
+                .buttonStyle(PrimaryActionButtonStyle(customColor: .element.alert))
+        }
+        .padding()
+    }
+
+    public static var previews: some View {
+        states
+            .preferredColorScheme(.light)
+        states
+            .preferredColorScheme(.dark)
+    }
+}

DesignKit/Sources/Buttons/SecondaryActionButtonStyle.swift

@@ -0,0 +1,82 @@
+//
+// Copyright 2021 New Vector Ltd
+//
+// 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.
+//
+
+import SwiftUI
+import DesignTokens
+
+public struct SecondaryActionButtonStyle: ButtonStyle {
+    @Environment(\.isEnabled) private var isEnabled
+
+    public var customColor: Color?
+
+    public init(customColor: Color? = nil) {
+        self.customColor = customColor
+    }
+
+    public func makeBody(configuration: Self.Configuration) -> some View {
+        configuration.label
+            .padding(12.0)
+            .frame(maxWidth: .infinity)
+            .foregroundColor(strokeColor(configuration.isPressed))
+            .font(.element.body)
+            .background(RoundedRectangle(cornerRadius: 8)
+                            .strokeBorder()
+                            .foregroundColor(strokeColor(configuration.isPressed)))
+            .opacity(isEnabled ? 1.0 : 0.6)
+    }
+
+    private func strokeColor(_ isPressed: Bool) -> Color {
+        if let customColor = customColor {
+            return customColor
+        }
+
+        return isPressed ? .element.accent.opacity(0.6) : .element.accent
+    }
+}
+
+public struct SecondaryActionButtonStyle_Previews: PreviewProvider {
+    public static var previews: some View {
+        Group {
+            states
+        }
+        .preferredColorScheme(.light)
+        Group {
+            states
+        }
+        .preferredColorScheme(.dark)
+    }
+
+    public static var states: some View {
+        VStack {
+            Button("Enabled") { /* preview */ }
+                .buttonStyle(SecondaryActionButtonStyle())
+
+            Button("Disabled") { /* preview */ }
+                .buttonStyle(SecondaryActionButtonStyle())
+                .disabled(true)
+
+            Button { /* preview */ } label: {
+                Text("Clear BG")
+                    .foregroundColor(.element.alert)
+            }
+            .buttonStyle(SecondaryActionButtonStyle(customColor: .clear))
+
+            Button("Red BG") { /* preview */ }
+                .buttonStyle(SecondaryActionButtonStyle(customColor: .element.alert))
+        }
+        .padding()
+    }
+}

DesignKit/Sources/Fonts/ElementFonts.swift

@@ -0,0 +1,69 @@
+//
+// Copyright 2021 New Vector Ltd
+//
+// 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.
+//
+
+import SwiftUI
+
+public extension Font {
+    /// The fonts used by Element as defined in https://www.figma.com/file/X4XTH9iS2KGJ2wFKDqkyed/Compound?node-id=1362%3A0
+    static let element = ElementFonts(values: ElementSharedFonts())
+}
+
+/// Struct for holding fonts for use in SwiftUI.
+public struct ElementFonts: Fonts {
+    public let largeTitle: Font
+    public let largeTitleB: Font
+    public let title1: Font
+    public let title1B: Font
+    public let title2: Font
+    public let title2B: Font
+    public let title3: Font
+    public let title3SB: Font
+    public let headline: Font
+    public let subheadline: Font
+    public let body: Font
+    public let bodySB: Font
+    public let callout: Font
+    public let calloutSB: Font
+    public let footnote: Font
+    public let footnoteSB: Font
+    public let caption1: Font
+    public let caption1SB: Font
+    public let caption2: Font
+    public let caption2SB: Font
+
+    public init(values: ElementSharedFonts) {
+        largeTitle = values.largeTitle.font
+        largeTitleB = values.largeTitleB.font
+        title1 = values.title1.font
+        title1B = values.title1B.font
+        title2 = values.title2.font
+        title2B = values.title2B.font
+        title3 = values.title3.font
+        title3SB = values.title3SB.font
+        headline = values.headline.font
+        subheadline = values.subheadline.font
+        body = values.body.font
+        bodySB = values.bodySB.font
+        callout = values.callout.font
+        calloutSB = values.calloutSB.font
+        footnote = values.footnote.font
+        footnoteSB = values.footnoteSB.font
+        caption1 = values.caption1.font
+        caption1SB = values.caption1SB.font
+        caption2 = values.caption2.font
+        caption2SB = values.caption2SB.font
+    }
+}