Add Bold and Italics Support To Themes (#289)

### Description

- Adds bold and italics support to the editor theme type.

> [!WARNING]
> This is a API-breaking change, merging this will require a minor
version update when releasing.

### Related Issues

- closes #283 

### Checklist

- [x] I read and understood the [contributing
guide](https://github.com/CodeEditApp/CodeEdit/blob/main/CONTRIBUTING.md)
as well as the [code of
conduct](https://github.com/CodeEditApp/CodeEdit/blob/main/CODE_OF_CONDUCT.md)
- [x] The issues this PR addresses are related to each other
- [x] My changes generate no new warnings
- [x] My code builds and runs on my machine
- [x] My changes are all related to the related issue above
- [x] I documented my code

### Screenshots

Update example app default theme with bold and italics on strings,
italics on comments, and bold on keywords.


https://github.com/user-attachments/assets/136331a2-ddcd-4fe8-a5e7-536055cf6249

Example/CodeEditSourceEditorExample/CodeEditSourceEditorExample/Extensions/EditorTheme+Default.swift

@@ -12,22 +12,22 @@ import CodeEditSourceEditor
 extension EditorTheme {
     static var standard: EditorTheme {
         EditorTheme(
-            text: .init(hex: "000000"),
-            insertionPoint: .init(hex: "000000"),
-            invisibles: .init(hex: "D6D6D6"),
-            background: .init(hex: "FFFFFF"),
-            lineHighlight: .init(hex: "ECF5FF"),
-            selection: .init(hex: "B2D7FF"),
-            keywords: .init(hex: "9B2393"),
-            commands: .init(hex: "326D74"),
-            types: .init(hex: "0B4F79"),
-            attributes: .init(hex: "815F03"),
-            variables: .init(hex: "0F68A0"),
-            values: .init(hex: "6C36A9"),
-            numbers: .init(hex: "1C00CF"),
-            strings: .init(hex: "C41A16"),
-            characters: .init(hex: "1C00CF"),
-            comments: .init(hex: "267507")
+            text: Attribute(color: NSColor(hex: "000000")),
+            insertionPoint: NSColor(hex: "000000"),
+            invisibles: Attribute(color: NSColor(hex: "D6D6D6")),
+            background: NSColor(hex: "FFFFFF"),
+            lineHighlight: NSColor(hex: "ECF5FF"),
+            selection: NSColor(hex: "B2D7FF"),
+            keywords: Attribute(color: NSColor(hex: "9B2393"), bold: true),
+            commands: Attribute(color: NSColor(hex: "326D74")),
+            types: Attribute(color: NSColor(hex: "0B4F79")),
+            attributes: Attribute(color: NSColor(hex: "815F03")),
+            variables: Attribute(color: NSColor(hex: "0F68A0")),
+            values: Attribute(color: NSColor(hex: "6C36A9")),
+            numbers: Attribute(color: NSColor(hex: "1C00CF")),
+            strings: Attribute(color: NSColor(hex: "C41A16"), bold: true, italic: true),
+            characters: Attribute(color: NSColor(hex: "1C00CF")),
+            comments: Attribute(color: NSColor(hex: "267507"), italic: true)
         )
     }
 }

Sources/CodeEditSourceEditor/Controller/TextViewController+Highlighter.swift

@@ -29,7 +29,7 @@ extension TextViewController {
 extension TextViewController: ThemeAttributesProviding {
     public func attributesFor(_ capture: CaptureName?) -> [NSAttributedString.Key: Any] {
         [
-            .font: font,
+            .font: theme.fontFor(for: capture, from: font),
             .foregroundColor: theme.colorFor(capture),
             .kern: textView.kern
         ]

Sources/CodeEditSourceEditor/Controller/TextViewController.swift

@@ -262,7 +262,7 @@ public class TextViewController: NSViewController {
         self.textView = TextView(
             string: string,
             font: font,
-            textColor: theme.text,
+            textColor: theme.text.color,
             lineHeightMultiplier: lineHeightMultiple,
             wrapLines: wrapLines,
             isEditable: isEditable,

Sources/CodeEditSourceEditor/Theme/EditorTheme.swift

@@ -7,43 +7,58 @@
 
 import SwiftUI
 
-/// A collection of `NSColor` used for syntax higlighting
-public struct EditorTheme {
+/// A collection of attributes used for syntax highlighting and other colors for the editor.
+///
+/// Attributes of a theme that do not apply to text (background, line highlight) are a single `NSColor` for simplicity.
+/// All other attributes use the ``EditorTheme/Attribute`` type to store
+public struct EditorTheme: Equatable {
+    /// Represents attributes that can be applied to style text.
+    public struct Attribute: Equatable, Hashable, Sendable {
+        public let color: NSColor
+        public let bold: Bool
+        public let italic: Bool
 
-    public var text: NSColor
+        public init(color: NSColor, bold: Bool = false, italic: Bool = false) {
+            self.color = color
+            self.bold = bold
+            self.italic = italic
+        }
+    }
+
+    public var text: Attribute
     public var insertionPoint: NSColor
-    public var invisibles: NSColor
+    public var invisibles: Attribute
     public var background: NSColor
     public var lineHighlight: NSColor
     public var selection: NSColor
-    public var keywords: NSColor
-    public var commands: NSColor
-    public var types: NSColor
-    public var attributes: NSColor
-    public var variables: NSColor
-    public var values: NSColor
-    public var numbers: NSColor
-    public var strings: NSColor
-    public var characters: NSColor
-    public var comments: NSColor
+    public var keywords: Attribute
+    public var commands: Attribute
+    public var types: Attribute
+    public var attributes: Attribute
+    public var variables: Attribute
+    public var values: Attribute
+    public var numbers: Attribute
+    public var strings: Attribute
+    public var characters: Attribute
+    public var comments: Attribute
 
     public init(
-        text: NSColor,
+        text: Attribute,
         insertionPoint: NSColor,
-        invisibles: NSColor,
+        invisibles: Attribute,
         background: NSColor,
         lineHighlight: NSColor,
         selection: NSColor,
-        keywords: NSColor,
-        commands: NSColor,
-        types: NSColor,
-        attributes: NSColor,
-        variables: NSColor,
-        values: NSColor,
-        numbers: NSColor,
-        strings: NSColor,
-        characters: NSColor,
-        comments: NSColor
+        keywords: Attribute,
+        commands: Attribute,
+        types: Attribute,
+        attributes: Attribute,
+        variables: Attribute,
+        values: Attribute,
+        numbers: Attribute,
+        strings: Attribute,
+        characters: Attribute,
+        comments: Attribute
     ) {
         self.text = text
         self.insertionPoint = insertionPoint
@@ -63,10 +78,10 @@ public struct EditorTheme {
         self.comments = comments
     }
 
-    /// Get the color from ``theme`` for the specified capture name.
-    /// - Parameter capture: The capture name
-    /// - Returns: A `NSColor`
-    func colorFor(_ capture: CaptureName?) -> NSColor {
+    /// Maps a capture type to the attributes for that capture determined by the theme.
+    /// - Parameter capture: The capture to map to.
+    /// - Returns: Theme attributes for the capture.
+    private func mapCapture(_ capture: CaptureName?) -> Attribute {
         switch capture {
         case .include, .constructor, .keyword, .boolean, .variableBuiltin,
                 .keywordReturn, .keywordFunction, .repeat, .conditional, .tag:
@@ -82,25 +97,35 @@ public struct EditorTheme {
         default: return text
         }
     }
-}
 
-extension EditorTheme: Equatable {
-    public static func == (lhs: EditorTheme, rhs: EditorTheme) -> Bool {
-        return lhs.text == rhs.text &&
-        lhs.insertionPoint == rhs.insertionPoint &&
-        lhs.invisibles == rhs.invisibles &&
-        lhs.background == rhs.background &&
-        lhs.lineHighlight == rhs.lineHighlight &&
-        lhs.selection == rhs.selection &&
-        lhs.keywords == rhs.keywords &&
-        lhs.commands == rhs.commands &&
-        lhs.types == rhs.types &&
-        lhs.attributes == rhs.attributes &&
-        lhs.variables == rhs.variables &&
-        lhs.values == rhs.values &&
-        lhs.numbers == rhs.numbers &&
-        lhs.strings == rhs.strings &&
-        lhs.characters == rhs.characters &&
-        lhs.comments == rhs.comments
+    /// Get the color from ``theme`` for the specified capture name.
+    /// - Parameter capture: The capture name
+    /// - Returns: A `NSColor`
+    func colorFor(_ capture: CaptureName?) -> NSColor {
+        return mapCapture(capture).color
+    }
+
+    /// Returns the correct font with attributes (bold and italics) for a given capture name.
+    /// - Parameters:
+    ///   - capture: The capture name.
+    ///   - font: The font to add attributes to.
+    /// - Returns: A new font that has the correct attributes for the capture.
+    func fontFor(for capture: CaptureName?, from font: NSFont) -> NSFont {
+        let attributes = mapCapture(capture)
+        guard attributes.bold || attributes.italic else {
+            return font
+        }
+
+        var font = font
+
+        if attributes.bold {
+            font = NSFontManager.shared.convert(font, toHaveTrait: .boldFontMask)
+        }
+
+        if attributes.italic {
+            font = NSFontManager.shared.convert(font, toHaveTrait: .italicFontMask)
+        }
+
+        return font
     }
 }

Tests/CodeEditSourceEditorTests/Mock.swift

@@ -69,22 +69,22 @@ enum Mock {
 
     static func theme() -> EditorTheme {
         EditorTheme(
-            text: .textColor,
+            text: EditorTheme.Attribute(color: .textColor),
             insertionPoint: .textColor,
-            invisibles: .gray,
+            invisibles: EditorTheme.Attribute(color: .gray),
             background: .textBackgroundColor,
             lineHighlight: .highlightColor,
             selection: .selectedTextColor,
-            keywords: .systemPink,
-            commands: .systemBlue,
-            types: .systemMint,
-            attributes: .systemTeal,
-            variables: .systemCyan,
-            values: .systemOrange,
-            numbers: .systemYellow,
-            strings: .systemRed,
-            characters: .systemRed,
-            comments: .systemGreen
+            keywords: EditorTheme.Attribute(color: .systemPink),
+            commands: EditorTheme.Attribute(color: .systemBlue),
+            types: EditorTheme.Attribute(color: .systemMint),
+            attributes: EditorTheme.Attribute(color: .systemTeal),
+            variables: EditorTheme.Attribute(color: .systemCyan),
+            values: EditorTheme.Attribute(color: .systemOrange),
+            numbers: EditorTheme.Attribute(color: .systemYellow),
+            strings: EditorTheme.Attribute(color: .systemRed),
+            characters: EditorTheme.Attribute(color: .systemRed),
+            comments: EditorTheme.Attribute(color: .systemGreen)
         )
     }
 

Tests/CodeEditSourceEditorTests/TextViewControllerTests.swift

@@ -12,24 +12,7 @@ final class TextViewControllerTests: XCTestCase {
     var theme: EditorTheme!
 
     override func setUpWithError() throws {
-        theme = EditorTheme(
-            text: .textColor,
-            insertionPoint: .textColor,
-            invisibles: .gray,
-            background: .textBackgroundColor,
-            lineHighlight: .highlightColor,
-            selection: .selectedTextColor,
-            keywords: .systemPink,
-            commands: .systemBlue,
-            types: .systemMint,
-            attributes: .systemTeal,
-            variables: .systemCyan,
-            values: .systemOrange,
-            numbers: .systemYellow,
-            strings: .systemRed,
-            characters: .systemRed,
-            comments: .systemGreen
-        )
+        theme = Mock.theme()
         controller = TextViewController(
             string: "",
             language: .default,