Merge pull request #4 from 5sw/figma

Import colors from Figma library

.github/workflows/release.yml

@@ -24,7 +24,7 @@ jobs:
               head "https://github.com/${{ github.repository }}.git"
               license "MIT"
 
-              depends_on :xcode => ["12.0", :build]
+              depends_on :xcode => ["14.0", :build]
 
               def install
                 system "make", "install", "prefix=#{prefix}"

.github/workflows/test.yml

@@ -5,7 +5,7 @@ on:
 
 jobs:
   BuildAndTest:
-    runs-on: macos-latest
+    runs-on: macos-12
     steps:
       - uses: actions/checkout@v1
 

.swift-version

@@ -1 +1 @@
-5.3
+5.7

Example/.gitignore

@@ -0,0 +1,2 @@
+Example.*
+!Example.txt

Example/Example.txt

@@ -0,0 +1,10 @@
+Base/Green #8fd151
+Base/PaleGreen #d0f9a9
+Base/Red rgb(249, 39, 7)
+TransparentRed rgba(255, 0, 0, 128)
+Base/Yellow #ff0
+
+Error @Base/Red
+Warning @Base/Yellow
+Good @Base/Green
+

Package.resolved

@@ -1,16 +1,23 @@
 {
-  "object": {
+  "pins" : [
-    "pins": [
+    {
-      {
+      "identity" : "rbbjson",
-        "package": "swift-argument-parser",
+      "kind" : "remoteSourceControl",
-        "repositoryURL": "https://github.com/apple/swift-argument-parser",
+      "location" : "https://github.com/robb/RBBJSON",
-        "state": {
+      "state" : {
-          "branch": null,
+        "branch" : "main",
-          "revision": "92646c0cdbaca076c8d3d0207891785b3379cbff",
+        "revision" : "102c970283e105d7c5be2e29630db29c808c20eb"
-          "version": "0.3.1"
-        }
       }
-    ]
+    },
-  },
+    {
-  "version": 1
+      "identity" : "swift-argument-parser",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-argument-parser",
+      "state" : {
+        "revision" : "9f39744e025c7d377987f30b03770805dcb0bcd1",
+        "version" : "1.1.4"
+      }
+    }
+  ],
+  "version" : 2
 }

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.3
+// swift-tools-version:5.7
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
@@ -6,27 +6,25 @@ import PackageDescription
 let package = Package(
     name: "MakeColors",
     platforms: [
-        .macOS(.v10_15),
+        .macOS("12.0"),
     ],
     dependencies: [
-        .package(url: "https://github.com/apple/swift-argument-parser", .upToNextMinor(from: "0.3.1")),
+        .package(url: "https://github.com/apple/swift-argument-parser", .upToNextMinor(from: "1.1.4")),
+        .package(url: "https://github.com/robb/RBBJSON", branch: "main"),
     ],
     targets: [
-        .target(
+        .executableTarget(
             name: "MakeColors",
-            dependencies: [
-                "LibMakeColors",
-            ]
-        ),
-        .target(
-            name: "LibMakeColors",
             dependencies: [
                 .product(name: "ArgumentParser", package: "swift-argument-parser"),
             ]
         ),
         .testTarget(
             name: "MakeColorsTests",
-            dependencies: ["LibMakeColors"]
+            dependencies: [
+                "MakeColors",
+                .product(name: "RBBJSON", package: "RBBJSON"),
+            ]
         ),
     ]
 )

README.md

@@ -11,21 +11,61 @@ brew tap 5sw/makecolors
 brew install make-colors
 ```
 
+If you don’t use Homebrew you can also install directly from source. Clone the repository or download the release and run `make install` inside the working copy.
+
+## Usage
+
+```
+USAGE: make-colors <input> [--ios] [--android] [--html] [--prefix <prefix>] [--output <output>] [--dump]
+
+ARGUMENTS:
+  <input>                 The color list to process. 
+        Use - to process the standard input.
+
+OPTIONS:
+  --ios/--android/--html  The formatter to use. (default: ios)
+  --prefix <prefix>       Prefix for color names. 
+  --output <output>       Output file to write. 
+        Use - for standard output.
+        Default is the input file name with the appropriate file extension. If
+        the input is - the default is standard output.
+        Note that asset catalogs cannot be written to standard output.
+  --dump                  List read colors on console. 
+  -h, --help              Show help information.
+```
+
 ## Input format
 
 Each line in your input contains one color definition. That is a name followed by the actual color. We support RGB colors in a few formats similar to CSS:
 
 ```
-Color/Color1 #fff
+Base/Green #8fd151
-Color/Color2 #abcdeff0
+Base/PaleGreen #d0f9a9
-Color/Color3 rgb(12, 13, 53)
+Base/Red rgb(249, 39, 7)
-Color/Color4 rgba(250, 250, 250, 128)
+TransparentRed rgba(255, 0, 0, 128)
+Base/Yellow #ff0
+```
+
+Grayscale colors can be produced with the `white(value)` and `white(value, alpha)` syntax. A value of zero means black while a value of 255 is pure white. 
+
+```
+Black white(0)
+MediumGray white(128)
+TransparentGray white(128, 128)
+```
+
+HSV colors can be specified as `hsv(hue, saturation, value)` or `hsva(hue, saturation, value, alpha)` syntax. Hue is specified as degrees with the `°` or `deg` suffix.
+
+```
+HSV/Yellow hsv(60°, 255, 255)
 ```
 
 Colors can also reference other colors by prefixing them with an `@` sign:
 
 ```
-ColorAlias @Color/Color1
+Error @Base/Red
+Warning @Base/Yellow
+Good @Base/Green
 ```
 
 ## Output format
@@ -34,17 +74,41 @@ ColorAlias @Color/Color1
 
 The optional prefix followed by a `/` is added in front of the color name. Then for each part separate by / a new folder that provides namespace is inserted in the asset catalogs. Spaces are inserted between CamelCase words. Color references are inserted as copies of the original color.
 
+For the given example input the generated asset catalog looks like this: 
+
+![](Docs/assetcatalog.png)
+
 ### Android resource XML (`--android`)
 
 The optional prefix, followed by a underscore is added in front of the name. Names are converted from CamelCase to snake_case and / is replaced by underscores as well. Color references the generated color resource also references the original color.
 
+The generated XML for the example input looks like this:
+
+```
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="base_green">#8FD151</color>
+    <color name="base_pale_green">#D0F9A9</color>
+    <color name="base_red">#F92707</color>
+    <color name="base_yellow">#FFFF00</color>
+    <color name="transparent_red">#FF000080</color>
+    <color name="error">@color/base_red</color>
+    <color name="good">@color/base_green</color>
+    <color name="warning">@color/base_yellow</color>
+</resources>
+</xml>
+```
+
 ### HTML preview (`--html`)
 
 Generates a simple HTML table with the color names, values and a sample.
 
+The generated HTML looks like this:
+
+![](Docs/html.png)
+
 ## Future work
 
-- Support other color formats (HSV, ...)
 - Calculate derived colors (blend, change hue/saturation/brightness/alpha)
 - Support for dark/light mode
 - Improved error reporting in the parser

Sources/LibMakeColors/MakeColors.swift

@@ -1,83 +0,0 @@
-import ArgumentParser
-import Foundation
-
-private struct GeneratorOption: EnumerableFlag, CustomStringConvertible {
-    static let allCases: [GeneratorOption] = [
-        .init(type: AssetCatalogGenerator.self),
-        .init(type: AndroidGenerator.self),
-        .init(type: HTMLGenerator.self),
-    ]
-
-    let type: Generator.Type
-
-    var description: String {
-        type.option
-    }
-
-    static func == (lhs: GeneratorOption, rhs: GeneratorOption) -> Bool {
-        lhs.type == rhs.type
-    }
-}
-
-enum Errors: Error {
-    case syntaxError
-    case duplicateColor(String)
-    case missingReference(String)
-    case cyclicReference(String)
-}
-
-public final class MakeColors: ParsableCommand, Context {
-    @Argument(help: "The color list to proces")
-    var input: String
-
-    @Flag(help: "The formatter to use")
-    private var formatter = GeneratorOption.allCases[0]
-
-    @Option(help: "Prefix for color names")
-    var prefix: String?
-
-    @Option(help: "Output file")
-    var output: String?
-
-    public init() {}
-
-    public func run() throws {
-        let url = URL(fileURLWithPath: input)
-        let string = try String(contentsOf: url)
-
-        let scanner = Scanner(string: string)
-        scanner.charactersToBeSkipped = .whitespaces
-
-        let data = try scanner.colorList()
-
-        for (key, color) in data.sorted() {
-            let resolved = try data.resolve(key)
-            switch color {
-            case .color:
-                print(key.insertCamelCaseSeparators(), resolved, separator: ": ")
-
-            case let .reference(referenced):
-                print(
-                    "\(key.insertCamelCaseSeparators()) (@\(referenced.insertCamelCaseSeparators()))",
-                    resolved,
-                    separator: ": "
-                )
-            }
-        }
-
-        let generator = formatter.type.init(context: self)
-        let fileWrapper = try generator.generate(data: data)
-
-        let writeURL = outputURL(extension: formatter.type.defaultExtension)
-        try fileWrapper.write(to: writeURL, options: .atomic, originalContentsURL: nil)
-    }
-
-    func outputURL(extension: String) -> URL {
-        if let output = output {
-            return URL(fileURLWithPath: output)
-        } else {
-            let basename = URL(fileURLWithPath: input).deletingPathExtension().lastPathComponent
-            return URL(fileURLWithPath: basename).appendingPathExtension(`extension`)
-        }
-    }
-}

Sources/MakeColors/Generators/AssetCatalogGenerator.swift

@@ -1,7 +1,7 @@
 import Foundation
 
 final class AssetCatalogGenerator: Generator {
-    static let defaultExtension = "xcasset"
+    static let defaultExtension = "xcassets"
     static let option = "ios"
 
     let context: Context
@@ -58,7 +58,7 @@ private let infoTag = """
 }
 """
 
-private extension Color {
+extension Color {
     func json() -> String {
         """
         {
@@ -67,10 +67,10 @@ private extension Color {
             "color" : {
                 "color-space" : "srgb",
                 "components" : {
-                "alpha" : "\(Float(alpha) / 256)",
+                "alpha" : "\(Double(alpha) / 0xFF)",
-                "blue" : "0x\(String(blue, radix: 16))",
+                "blue" : "0x\(blue, radix: 16, width: 2)",
-                "green" : "0x\(String(green, radix: 16))",
+                "green" : "0x\(green, radix: 16, width: 2)",
-                "red" : "0x\(String(red, radix: 16))"
+                "red" : "0x\(red, radix: 16, width: 2)"
                 }
             },
             "idiom" : "universal"
@@ -88,6 +88,22 @@ private extension Color {
     }
 }
 
+extension String.StringInterpolation {
+    mutating func appendInterpolation<I: BinaryInteger>(
+        _ value: I,
+        radix: Int,
+        width: Int = 0,
+        uppercase: Bool = true
+    ) {
+        var string = String(value, radix: radix, uppercase: uppercase)
+        if width > string.count {
+            string.insert(contentsOf: String(repeating: "0", count: width - string.count), at: string.startIndex)
+        }
+
+        appendLiteral(string)
+    }
+}
+
 private let group = """
 {
   "properties" : {

Sources/MakeColors/Generators/Generator.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-protocol Generator: class {
+protocol Generator: AnyObject {
     static var defaultExtension: String { get }
     static var option: String { get }
 
@@ -9,7 +9,7 @@ protocol Generator: class {
     func generate(data: [String: ColorDef]) throws -> FileWrapper
 }
 
-protocol Context: class {
+protocol Context: AnyObject {
     var prefix: String? { get }
 }
 

Sources/MakeColors/Importers/Figma/FigmaImporter.swift

@@ -0,0 +1,151 @@
+import Foundation
+
+enum FigmaErrors: Error {
+    case invalidUrl
+    case missingToken
+    case invalidResponse
+    case missingColor(String)
+}
+
+class FigmaImporter: Importer {
+    let key: String
+    let token: String
+    let outputName: String
+
+    required init(source: String) throws {
+        // https://www.figma.com/file/:key/:title
+        guard
+            let url = URL(string: source),
+            url.host == "www.figma.com",
+            url.pathComponents.count >= 4,
+            url.pathComponents[1] == "file"
+        else {
+            throw FigmaErrors.invalidUrl
+        }
+
+        key = url.pathComponents[2]
+        outputName = url.pathComponents[3]
+
+        guard let token = ProcessInfo.processInfo.environment["FIGMA_TOKEN"] else {
+            throw FigmaErrors.missingToken
+        }
+
+        self.token = token
+    }
+
+    func read() async throws -> [String: ColorDef] {
+        let styles = try await request(StylesResponse.self, path: "/v1/files/\(key)/styles").meta.styles
+            .filter { $0.styleType == "FILL" }
+
+        let ids = styles.map(\.nodeId).joined(separator: ",")
+
+        let nodes = try await request(
+            NodesResponse.self,
+            path: "/v1/files/\(key)/nodes",
+            query: [URLQueryItem(name: "ids", value: ids)]
+        )
+        .nodes
+
+        var result: [String: ColorDef] = [:]
+        result.reserveCapacity(styles.count)
+
+        for style in styles {
+            guard
+                let node = nodes[style.nodeId],
+                let fill = node.document.fills.first(where: { $0.type == "SOLID" })
+            else {
+                throw FigmaErrors.missingColor(style.name)
+            }
+
+            if node.document.fills.count > 1 {
+                print("Warning: Multiple fills defined for \(style.name)")
+            }
+
+            if fill.blendMode != "NORMAL" {
+                print("Warning: Blend mode \(fill.blendMode) used for \(style.name)")
+            }
+
+            guard !result.keys.contains(style.name) else {
+                throw Errors.duplicateColor(style.name)
+            }
+
+            result[style.name] = .color(Color(fill.color))
+        }
+
+        return result
+    }
+
+    func request<T: Decodable>(_: T.Type = T.self, path: String, query: [URLQueryItem]? = nil) async throws -> T {
+        var components = URLComponents()
+        components.scheme = "https"
+        components.host = "api.figma.com"
+        components.path = path
+        components.queryItems = query
+
+        guard let url = components.url else {
+            fatalError("Cannot create url. Components: \(components)")
+        }
+
+        var request = URLRequest(url: url)
+        request.setValue(token, forHTTPHeaderField: "X-Figma-Token")
+
+        let (data, response) = try await URLSession.shared.data(for: request)
+
+        guard let response = response as? HTTPURLResponse else {
+            fatalError("Non-HTTP-Response received: \(response)")
+        }
+
+        guard response.statusCode == 200 else {
+            throw FigmaErrors.invalidResponse
+        }
+
+        let decoder = JSONDecoder()
+        decoder.keyDecodingStrategy = .convertFromSnakeCase
+        return try decoder.decode(T.self, from: data)
+    }
+}
+
+struct StylesResponse: Decodable {
+    var meta: Meta
+    struct Meta: Decodable {
+        var styles: [Style]
+    }
+
+    struct Style: Decodable {
+        var nodeId: String
+        var styleType: String
+        var name: String
+        var description: String
+    }
+}
+
+struct NodesResponse: Decodable {
+    var nodes: [String: Node]
+
+    struct Node: Decodable {
+        var document: Document
+    }
+
+    struct Document: Decodable {
+        var fills: [Fill]
+    }
+
+    struct Fill: Decodable {
+        var blendMode: String
+        var type: String
+        var color: Color
+    }
+
+    struct Color: Decodable {
+        var r, g, b, a: Float
+    }
+}
+
+extension Color {
+    init(_ color: NodesResponse.Color) {
+        red = UInt8(truncatingIfNeeded: Int(color.r * 0xFF))
+        green = UInt8(truncatingIfNeeded: Int(color.g * 0xFF))
+        blue = UInt8(truncatingIfNeeded: Int(color.b * 0xFF))
+        alpha = UInt8(truncatingIfNeeded: Int(color.a * 0xFF))
+    }
+}

Sources/MakeColors/Importers/Importer.swift

@@ -0,0 +1,15 @@
+protocol Importer {
+    init(source: String) throws
+
+    func read() async throws -> [String: ColorDef]
+
+    var outputName: String { get }
+
+    static var option: String { get }
+}
+
+extension Importer {
+    static var option: String {
+        String(describing: self).droppingSuffix("Importer").lowercased()
+    }
+}

Sources/MakeColors/Importers/List/ListImporter.swift

@@ -0,0 +1,38 @@
+import Foundation
+
+struct ListImporter: Importer {
+    let input: String
+    var outputName: String
+
+    init(source: String) {
+        input = source
+        outputName = URL(fileURLWithPath: source).deletingPathExtension().lastPathComponent
+    }
+
+    func read() throws -> [String: ColorDef] {
+        let scanner = Scanner(string: try readInput())
+        scanner.charactersToBeSkipped = .whitespaces
+
+        return try scanner.colorList()
+    }
+
+    func readInput() throws -> String {
+        if input == "-" {
+            return try readStdin()
+        }
+
+        let url = URL(fileURLWithPath: input)
+        return try String(contentsOf: url)
+    }
+
+    func readStdin() throws -> String {
+        guard
+            let data = try FileHandle.standardInput.readToEnd(),
+            let input = String(data: data, encoding: .utf8)
+        else {
+            throw Errors.cannotReadStdin
+        }
+
+        return input
+    }
+}

Sources/MakeColors/Importers/List/Scanner+ColorParser.swift

@@ -19,17 +19,70 @@ extension Scanner {
             }
         }
 
-        if string("rgba"), string("("), let components = commaSeparated(), components.count == 4, string(")") {
+        if string("rgba"), let components = argumentList(4) {
             return Color(components)
         }
 
-        if string("rgb"), string("("), let components = commaSeparated(), components.count == 3, string(")") {
+        if string("rgb"), let components = argumentList(3) {
             return Color(components)
         }
 
+        if string("white"), let arguments = argumentList(min: 1, max: 2) {
+            return Color(white: arguments)
+        }
+
+        if string("hsva") {
+            return readHSV(alpha: true)
+        }
+
+        if string("hsv") {
+            return readHSV(alpha: false)
+        }
+
         return nil
     }
 
+    private func readHSV(alpha readAlpha: Bool) -> Color? {
+        guard
+            string("("),
+            let hue = degrees(),
+            string(","),
+            let saturation = component(),
+            string(","),
+            let value = component()
+        else { return nil }
+
+        let alpha: UInt8
+
+        if readAlpha {
+            guard
+                string(","),
+                let value = component()
+            else { return nil }
+            alpha = value
+        } else {
+            alpha = 0xFF
+        }
+
+        guard string(")") else { return nil }
+
+        return Color(hue: hue, saturation: saturation, value: value, alpha: alpha)
+    }
+
+    func degrees() -> Int? {
+        guard let int = scanInt() else { return nil }
+
+        if string("%") {
+            guard 0...100 ~= int else { return nil }
+            return (360 * int) / 100
+        } else if string("°") || string("deg") {
+            return int
+        } else {
+            guard 0...0xFF ~= int else { return nil }
+            return (360 * int) / 0xFF
+        }
+    }
+
     func colorReference() -> String? {
         guard string("@") else { return nil }
         return name()
@@ -57,7 +110,7 @@ extension Scanner {
 
     func colorLine() -> (String, ColorDef)? {
         guard
-            let name = self.name(),
+            let name = name(),
             let def = colorDef(),
             endOfLine()
         else {
@@ -91,17 +144,50 @@ extension Scanner {
         return result
     }
 
+    // swiftlint:disable:next discouraged_optional_collection
+    func argumentList(_ count: Int) -> [UInt8]? {
+        argumentList(min: count, max: count)
+    }
+
+    // swiftlint:disable:next discouraged_optional_collection
+    func argumentList(min: Int, max: Int? = nil) -> [UInt8]? {
+        let max = max ?? Int.max
+        guard
+            string("("),
+            let arguments = commaSeparated(),
+            string(")"),
+            (min...max) ~= arguments.count
+        else {
+            return nil
+        }
+
+        return arguments
+    }
+
     // swiftlint:disable:next discouraged_optional_collection
     func commaSeparated() -> [UInt8]? {
         var result: [UInt8] = []
         repeat {
-            guard let int = scanInt(), let component = UInt8(exactly: int) else {
+            guard let component = component() else {
                 return nil
             }
             result.append(component)
         } while string(",")
         return result
     }
+
+    func component() -> UInt8? {
+        guard var int = scanInt() else {
+            return nil
+        }
+
+        if string("%") {
+            guard 0...100 ~= int else { return nil }
+            int = int * 0xFF / 100
+        }
+
+        return UInt8(exactly: int)
+    }
 }
 
 private extension Scanner {
@@ -111,7 +197,7 @@ private extension Scanner {
 }
 
 private extension CharacterSet {
-    static let hex = CharacterSet(charactersIn: "0123456789abcdef")
+    static let hex = CharacterSet(charactersIn: "0123456789abcdefABCDEF")
     static let name = alphanumerics.union(CharacterSet(charactersIn: "_/"))
 }
 

Sources/MakeColors/MakeColors.swift

@@ -0,0 +1,150 @@
+import ArgumentParser
+import Foundation
+
+private struct GeneratorOption: EnumerableFlag, CustomStringConvertible {
+    static let allCases: [GeneratorOption] = [
+        .init(type: AssetCatalogGenerator.self),
+        .init(type: AndroidGenerator.self),
+        .init(type: HTMLGenerator.self),
+    ]
+
+    let type: Generator.Type
+
+    var description: String {
+        type.option
+    }
+
+    static func == (lhs: GeneratorOption, rhs: GeneratorOption) -> Bool {
+        lhs.type == rhs.type
+    }
+}
+
+private struct ImporterOption: CaseIterable, ExpressibleByArgument, CustomStringConvertible {
+    static let allCases: [ImporterOption] = [
+        .list,
+        .init(type: FigmaImporter.self),
+    ]
+
+    static let list = ImporterOption(type: ListImporter.self)
+
+    let type: Importer.Type
+
+    init(type: Importer.Type) {
+        self.type = type
+    }
+
+    init?(argument: String) {
+        guard
+            let found = Self.allCases
+                .first(where: { $0.description.caseInsensitiveCompare(argument) == .orderedSame })
+        else {
+            return nil
+        }
+        self = found
+    }
+
+    var description: String {
+        type.option
+    }
+
+    static func == (lhs: ImporterOption, rhs: ImporterOption) -> Bool {
+        lhs.type == rhs.type
+    }
+}
+
+enum Errors: Error {
+    case syntaxError
+    case duplicateColor(String)
+    case missingReference(String)
+    case cyclicReference(String)
+    case cannotWriteWrapperToStdout
+    case cannotReadStdin
+}
+
+enum HelpTexts {
+    static let input = ArgumentHelp(
+        "The color list to process.",
+        discussion: """
+        Use - to process the standard input.
+        """
+    )
+
+    static let output = ArgumentHelp(
+        "Output file to write.",
+        discussion: """
+        Use - for standard output.
+        Default is the input file name with the appropriate file extension. \
+        If the input is - the default is standard output.
+        Note that asset catalogs cannot be written to standard output.
+        """
+    )
+}
+
+@main
+public final class MakeColors: AsyncParsableCommand, Context {
+    @Argument(help: HelpTexts.input)
+    var input: String
+
+    @Flag(help: "The formatter to use.")
+    private var formatter = GeneratorOption.allCases[0]
+
+    @Option(help: "The importer to use.")
+    private var importer = ImporterOption.list
+
+    @Option(help: "Prefix for color names.")
+    var prefix: String?
+
+    @Option(help: HelpTexts.output)
+    var output: String?
+
+    @Flag(help: "List read colors on console.")
+    var dump = false
+
+    public init() {}
+
+    public func run() async throws {
+        let importer = try importer.type.init(source: input)
+        let data = try await importer.read()
+
+        if dump {
+            try dump(data: data)
+        }
+
+        let generator = formatter.type.init(context: self)
+        let fileWrapper = try generator.generate(data: data)
+
+        try writeOutput(fileWrapper, name: output ?? "\(importer.outputName).\(formatter.type.defaultExtension)")
+    }
+
+    func dump(data: [String: ColorDef]) throws {
+        for (key, color) in data.sorted() {
+            let resolved = try data.resolve(key)
+            switch color {
+            case .color:
+                print(key.insertCamelCaseSeparators(), resolved, separator: ": ")
+
+            case let .reference(referenced):
+                print(
+                    "\(key.insertCamelCaseSeparators()) (@\(referenced.insertCamelCaseSeparators()))",
+                    resolved,
+                    separator: ": "
+                )
+            }
+        }
+    }
+
+    func writeOutput(_ wrapper: FileWrapper, name: String) throws {
+        if shouldWriteToStdout {
+            guard wrapper.isRegularFile, let contents = wrapper.regularFileContents else {
+                throw Errors.cannotWriteWrapperToStdout
+            }
+
+            FileHandle.standardOutput.write(contents)
+        } else {
+            let writeURL = URL(fileURLWithPath: name)
+            try wrapper.write(to: writeURL, options: .atomic, originalContentsURL: nil)
+        }
+    }
+
+    var shouldWriteToStdout: Bool { output == "-" || (input == "-" && output == nil) }
+}

Sources/MakeColors/Model/Color+HSV.swift

@@ -0,0 +1,45 @@
+extension Color {
+    init(hue: Int, saturation: UInt8, value: UInt8, alpha: UInt8 = 0xFF) {
+        let degrees = abs(hue % 360)
+
+        let saturation = Double(saturation) / 0xFF
+        let value = Double(value) / 0xFF
+
+        // swiftlint:disable identifier_name - Wish I knew what these actually mean.
+        let C = saturation * value
+        let X = C * (1 - abs((Double(degrees) / 60).truncatingRemainder(dividingBy: 2) - 1))
+        let m = value - C
+        // swiftlint:enable identifier_name
+
+        let result: (r: Double, g: Double, b: Double)
+        switch degrees {
+        case 0..<60:
+            result = (C, X, 0)
+
+        case 60..<120:
+            result = (X, C, 0)
+
+        case 120..<180:
+            result = (0, C, X)
+
+        case 180..<240:
+            result = (0, X, C)
+
+        case 240..<300:
+            result = (X, 0, C)
+
+        case 300..<360:
+            result = (C, 0, X)
+
+        default:
+            fatalError("Degrees out of range")
+        }
+
+        self.init(
+            red: UInt8(((result.r + m) * 0xFF).rounded()),
+            green: UInt8(((result.g + m) * 0xFF).rounded()),
+            blue: UInt8(((result.b + m) * 0xFF).rounded()),
+            alpha: alpha
+        )
+    }
+}

Sources/MakeColors/Model/Color.swift

@@ -19,6 +19,14 @@ struct Color: CustomStringConvertible, Equatable {
         alpha = array.count == 4 ? array[3] : 0xFF
     }
 
+    init(white array: [UInt8]) {
+        precondition(array.count == 1 || array.count == 2)
+        red = array[0]
+        green = array[0]
+        blue = array[0]
+        alpha = array.count == 2 ? array[1] : 0xFF
+    }
+
     var description: String {
         let alphaSuffix = alpha != 0xFF ? String(format: "%02X", alpha) : ""
         return String(format: "#%02X%02X%02X%@", red, green, blue, alphaSuffix)

Sources/MakeColors/main.swift

@@ -1,3 +0,0 @@
-import LibMakeColors
-
-MakeColors.main()

Tests/MakeColorsTests/AssetCatalogFormattingTest.swift

@@ -0,0 +1,26 @@
+@testable import MakeColors
+import RBBJSON
+import XCTest
+
+class AssetCatalogFormattingTest: XCTestCase {
+    func testColorProducedValidJSON() throws {
+        let color = Color(red: 0xFF, green: 0xF0, blue: 0x0F)
+        let data = Data(color.json().utf8)
+
+        let json = try JSONDecoder().decode(RBBJSON.self, from: data)
+
+        XCTAssertEqual(json.info.author, .string("de.5sw.MakeColors"))
+        XCTAssertEqual(json.info.version, .number(1))
+
+        XCTAssertEqual(Array(json.colors[any: .child]).count, 1)
+
+        XCTAssertEqual(json.colors[0].idiom, .string("universal"))
+
+        let jsonColor = json.colors[0].color
+        XCTAssertEqual(jsonColor["color-space"], .string("srgb"))
+        XCTAssertEqual(jsonColor.components.alpha, .string("1.0"))
+        XCTAssertEqual(jsonColor.components.red, .string("0xFF"))
+        XCTAssertEqual(jsonColor.components.green, .string("0xF0"))
+        XCTAssertEqual(jsonColor.components.blue, .string("0x0F"))
+    }
+}

Tests/MakeColorsTests/ColorHSVTest.swift

@@ -0,0 +1,39 @@
+@testable import MakeColors
+import XCTest
+
+final class ColorHSVTest: XCTestCase {
+    func testHSV0Degrees() {
+        let color = Color(hue: 0, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0xFF, green: 0, blue: 0))
+    }
+
+    func testHSV60Degrees() {
+        let color = Color(hue: 60, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0xFF, green: 0xFF, blue: 0))
+    }
+
+    func testHSV120Degrees() {
+        let color = Color(hue: 120, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0, green: 0xFF, blue: 0))
+    }
+
+    func testHSV180Degrees() {
+        let color = Color(hue: 180, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0, green: 0xFF, blue: 0xFF))
+    }
+
+    func testHSV240Degrees() {
+        let color = Color(hue: 240, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0, green: 0, blue: 0xFF))
+    }
+
+    func testHSV300Degrees() {
+        let color = Color(hue: 300, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0xFF, green: 0, blue: 0xFF))
+    }
+
+    func testHSV360Degrees() {
+        let color = Color(hue: 360, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0xFF, green: 0, blue: 0))
+    }
+}

Tests/MakeColorsTests/ColorParserTest.swift

@@ -1,40 +1,123 @@
-@testable import LibMakeColors
+@testable import MakeColors
 import XCTest
 
 final class ColorParserTest: XCTestCase {
     func testScanningThreeDigitColor() throws {
-        let scanner = Scanner(string: "#abc")
+        let color = scanColor("#abc")
-        let color = scanner.color()
+        XCTAssertEqual(Color(red: 0xAA, green: 0xBB, blue: 0xCC), color)
+    }
+
+    func testScanningThreeDigitColorUppercase() throws {
+        let color = scanColor("#ABc")
         XCTAssertEqual(Color(red: 0xAA, green: 0xBB, blue: 0xCC), color)
     }
 
     func testScanningFourDigitColor() throws {
-        let scanner = Scanner(string: "#abcd")
+        let color = scanColor("#abcd")
-        let color = scanner.color()
         XCTAssertEqual(Color(red: 0xAA, green: 0xBB, blue: 0xCC, alpha: 0xDD), color)
     }
 
     func testScanningSixDigitColor() throws {
-        let scanner = Scanner(string: "#abcdef")
+        let color = scanColor("#abcdef")
-        let color = scanner.color()
         XCTAssertEqual(Color(red: 0xAB, green: 0xCD, blue: 0xEF), color)
     }
 
     func testScanningEightDigitColor() throws {
-        let scanner = Scanner(string: "#abcdef17")
+        let color = scanColor("#abcdef17")
-        let color = scanner.color()
         XCTAssertEqual(Color(red: 0xAB, green: 0xCD, blue: 0xEF, alpha: 0x17), color)
     }
 
     func testScanningRGBColor() throws {
-        let scanner = Scanner(string: "rgb(1,2,3)")
+        let color = scanColor("rgb(1,2,3)")
-        let color = scanner.color()
         XCTAssertEqual(Color(red: 1, green: 2, blue: 3), color)
     }
 
     func testScanningRGBAColor() throws {
-        let scanner = Scanner(string: "rgba(1,2,3,4)")
+        let color = scanColor("rgba(1,2,3,4)")
-        let color = scanner.color()
         XCTAssertEqual(Color(red: 1, green: 2, blue: 3, alpha: 4), color)
     }
+
+    func testScanningWhite() throws {
+        let color = scanColor("white(255)")
+        XCTAssertEqual(Color(red: 255, green: 255, blue: 255, alpha: 255), color)
+    }
+
+    func testScanningWhiteWithAlpha() throws {
+        let color = scanColor("white(255, 128)")
+        XCTAssertEqual(Color(red: 255, green: 255, blue: 255, alpha: 128), color)
+    }
+
+    func testWhiteFailsWithoutArguments() throws {
+        let color = scanColor("white()")
+        XCTAssertNil(color)
+    }
+
+    func testWhiteFailsWith3Arguments() throws {
+        let color = scanColor("white(1,2,3)")
+        XCTAssertNil(color)
+    }
+
+    func testScanningColorWithPercentage() throws {
+        let color = scanColor("rgba(100%, 0, 50%, 100%)")
+        XCTAssertEqual(color, Color(red: 255, green: 0, blue: 127, alpha: 255))
+    }
+
+    func testReadingComponentAsByte() throws {
+        let scanner = Scanner(string: "128")
+        XCTAssertEqual(scanner.component(), 128)
+        XCTAssertTrue(scanner.isAtEnd)
+    }
+
+    func testReadingComponentAs100Percent() throws {
+        let scanner = Scanner(string: "100%")
+        XCTAssertEqual(scanner.component(), 0xFF)
+        XCTAssertTrue(scanner.isAtEnd)
+    }
+
+    func testReadingComponentAs0Percent() throws {
+        let scanner = Scanner(string: "0%")
+        XCTAssertEqual(scanner.component(), 0)
+        XCTAssertTrue(scanner.isAtEnd)
+    }
+
+    func testReadingComponentAs50PercentRoundsDown() throws {
+        let scanner = Scanner(string: "50%")
+        XCTAssertEqual(scanner.component(), 127)
+        XCTAssertTrue(scanner.isAtEnd)
+    }
+
+    func testScanningDegreesAsByte() throws {
+        let scanner = Scanner(string: "128")
+        XCTAssertEqual(scanner.degrees(), 180)
+    }
+
+    func testScanningDegreesAsPercentage() throws {
+        let scanner = Scanner(string: "50%")
+        XCTAssertEqual(scanner.degrees(), 180)
+    }
+
+    func testScanningDegrees() throws {
+        let scanner = Scanner(string: "120°")
+        XCTAssertEqual(scanner.degrees(), 120)
+    }
+
+    func testScanningDegreesWithDegSuffix() throws {
+        let scanner = Scanner(string: "120 deg")
+        XCTAssertEqual(scanner.degrees(), 120)
+    }
+
+    func testScanningHSVColor() throws {
+        XCTAssertEqual(scanColor("hsv(60°, 255, 100%)"), Color(red: 0xFF, green: 0xFF, blue: 0))
+    }
+
+    func testScanningHSVAColor() throws {
+        XCTAssertEqual(scanColor("hsva(60°, 50%, 255, 99)"), Color(red: 0xFF, green: 0xFF, blue: 128, alpha: 99))
+    }
+
+    private func scanColor(_ input: String) -> Color? {
+        let scanner = Scanner(string: input)
+        let result = scanner.color()
+        XCTAssertTrue(result == nil || scanner.isAtEnd)
+        return result
+    }
 }