Merge pull request #3 from iSapozhnik/codex/textdiff-styling-ergonomics

Redesign styling API with additions/removals styles

Author: iSapozhnik

README.md

@@ -87,15 +87,19 @@ import SwiftUI
 import TextDiff
 
 let customStyle = TextDiffStyle(
-    additionFillColor: NSColor.systemGreen.withAlphaComponent(0.28),
-    additionStrokeColor: NSColor.systemGreen.withAlphaComponent(0.75),
-    deletionFillColor: NSColor.systemRed.withAlphaComponent(0.24),
-    deletionStrokeColor: NSColor.systemRed.withAlphaComponent(0.75),
-    unchangedTextColor: .labelColor,
+    additionsStyle: TextDiffChangeStyle(
+        fillColor: NSColor.systemGreen.withAlphaComponent(0.28),
+        strokeColor: NSColor.systemGreen.withAlphaComponent(0.75)
+    ),
+    removalsStyle: TextDiffChangeStyle(
+        fillColor: NSColor.systemRed.withAlphaComponent(0.24),
+        strokeColor: NSColor.systemRed.withAlphaComponent(0.75),
+        strikethrough: true
+    ),
+    textColor: .labelColor,
     font: .monospacedSystemFont(ofSize: 15, weight: .regular),
     chipCornerRadius: 5,
     chipInsets: NSEdgeInsets(top: 1, left: 3, bottom: 1, right: 3),
-    deletionStrikethrough: true,
     interChipSpacing: 4,
     lineSpacing: 2
 )
@@ -111,6 +115,8 @@ struct StyledDemoView: View {
 }
 ```
 
+Change-specific colors and text treatment live under `additionsStyle` and `removalsStyle`. Shared layout and typography stay on `TextDiffStyle` (`font`, `chipInsets`, `interChipSpacing`, `lineSpacing`, etc.).
+
 ## Behavior Notes
 
 - Tokenization uses `NLTokenizer` (`.word`) and reconstructs punctuation/whitespace by filling range gaps.

Sources/TextDiff/AppKit/DiffTokenLayouter.swift

@@ -139,7 +139,7 @@ enum DiffTokenLayouter {
             .foregroundColor: textColor(for: segment, style: style)
         ]
 
-        if style.deletionStrikethrough, segment.kind == .delete, segment.tokenKind != .whitespace {
+        if style.removalsStyle.strikethrough, segment.kind == .delete, segment.tokenKind != .whitespace {
             attributes[.strikethroughStyle] = NSUnderlineStyle.single.rawValue
         }
 
@@ -163,26 +163,26 @@ enum DiffTokenLayouter {
     private static func textColor(for segment: DiffSegment, style: TextDiffStyle) -> NSColor {
         switch segment.kind {
         case .equal:
-            return style.unchangedTextColor
+            return style.textColor
         case .delete:
-            if let override = style.deletionTextColorOverride {
+            if let override = style.removalsStyle.textColorOverride {
                 return override
             }
-            return adaptiveChipTextColor(for: style.deletionFillColor)
+            return adaptiveChipTextColor(for: style.removalsStyle.fillColor)
         case .insert:
-            if let override = style.additionTextColorOverride {
+            if let override = style.additionsStyle.textColorOverride {
                 return override
             }
-            return adaptiveChipTextColor(for: style.additionFillColor)
+            return adaptiveChipTextColor(for: style.additionsStyle.fillColor)
         }
     }
 
     private static func chipFillColorForOperation(_ kind: DiffOperationKind, style: TextDiffStyle) -> NSColor? {
         switch kind {
         case .delete:
-            return style.deletionFillColor
+            return style.removalsStyle.fillColor
         case .insert:
-            return style.additionFillColor
+            return style.additionsStyle.fillColor
         case .equal:
             return nil
         }
@@ -191,9 +191,9 @@ enum DiffTokenLayouter {
     private static func chipStrokeColorForOperation(_ kind: DiffOperationKind, style: TextDiffStyle) -> NSColor? {
         switch kind {
         case .delete:
-            return style.deletionStrokeColor
+            return style.removalsStyle.strokeColor
         case .insert:
-            return style.additionStrokeColor
+            return style.additionsStyle.strokeColor
         case .equal:
             return nil
         }

Sources/TextDiff/TextDiffChangeStyle.swift

@@ -0,0 +1,29 @@
+import AppKit
+import Foundation
+
+/// Concrete change style used for additions and removals.
+public struct TextDiffChangeStyle: TextDiffStyling, @unchecked Sendable {
+    public var fillColor: NSColor
+    public var strokeColor: NSColor
+    public var textColorOverride: NSColor?
+    public var strikethrough: Bool
+
+    public init(
+        fillColor: NSColor,
+        strokeColor: NSColor,
+        textColorOverride: NSColor? = nil,
+        strikethrough: Bool = false
+    ) {
+        self.fillColor = fillColor
+        self.strokeColor = strokeColor
+        self.textColorOverride = textColorOverride
+        self.strikethrough = strikethrough
+    }
+
+    public init(_ styling: some TextDiffStyling) {
+        self.fillColor = styling.fillColor
+        self.strokeColor = styling.strokeColor
+        self.textColorOverride = styling.textColorOverride
+        self.strikethrough = styling.strikethrough
+    }
+}

Sources/TextDiff/TextDiffChangeStyleDefaults.swift

@@ -0,0 +1,17 @@
+import AppKit
+
+public extension TextDiffChangeStyle {
+    static let defaultAddition = TextDiffChangeStyle(
+        fillColor: NSColor.systemGreen.withAlphaComponent(0.22),
+        strokeColor: NSColor.systemGreen.withAlphaComponent(0.65),
+        textColorOverride: nil,
+        strikethrough: false
+    )
+
+    static let defaultRemoval = TextDiffChangeStyle(
+        fillColor: NSColor.systemRed.withAlphaComponent(0.22),
+        strokeColor: NSColor.systemRed.withAlphaComponent(0.65),
+        textColorOverride: nil,
+        strikethrough: false
+    )
+}

Sources/TextDiff/TextDiffStyle.swift

@@ -3,30 +3,19 @@ import Foundation
 
 /// Visual configuration for rendering text diff segments.
 public struct TextDiffStyle: @unchecked Sendable {
-    /// Fill color used for inserted token chips.
-    public var additionFillColor: NSColor
-    /// Stroke color used for inserted token chips.
-    public var additionStrokeColor: NSColor
-    /// Optional text color override for inserted tokens.
-    public var additionTextColorOverride: NSColor?
-
-    /// Fill color used for deleted token chips.
-    public var deletionFillColor: NSColor
-    /// Stroke color used for deleted token chips.
-    public var deletionStrokeColor: NSColor
-    /// Optional text color override for deleted tokens.
-    public var deletionTextColorOverride: NSColor?
+    /// Visual style used for inserted token chips.
+    public var additionsStyle: TextDiffChangeStyle
+    /// Visual style used for deleted token chips.
+    public var removalsStyle: TextDiffChangeStyle
 
     /// Text color used for unchanged tokens.
-    public var unchangedTextColor: NSColor
+    public var textColor: NSColor
     /// Font used for all rendered tokens.
     public var font: NSFont
     /// Corner radius applied to changed-token chips.
     public var chipCornerRadius: CGFloat
     /// Insets used to draw changed-token chips. Horizontal insets are floored to 3 points by the renderer.
     public var chipInsets: NSEdgeInsets
-    /// Controls whether deleted lexical tokens are drawn with a strikethrough.
-    public var deletionStrikethrough: Bool
     /// Minimum visual gap between adjacent changed lexical chips.
     public var interChipSpacing: CGFloat
     /// Additional vertical spacing between wrapped lines.
@@ -35,54 +24,67 @@ public struct TextDiffStyle: @unchecked Sendable {
     /// Creates a style for rendering text diffs.
     ///
     /// - Parameters:
-    ///   - additionFillColor: Fill color used for inserted token chips.
-    ///   - additionStrokeColor: Stroke color used for inserted token chips.
-    ///   - additionTextColorOverride: Optional text color override for inserted tokens.
-    ///   - deletionFillColor: Fill color used for deleted token chips.
-    ///   - deletionStrokeColor: Stroke color used for deleted token chips.
-    ///   - deletionTextColorOverride: Optional text color override for deleted tokens.
-    ///   - unchangedTextColor: Text color used for unchanged tokens.
+    ///   - additionsStyle: Change style used for inserted token chips.
+    ///   - removalsStyle: Change style used for deleted token chips.
+    ///   - textColor: Text color used for unchanged tokens.
     ///   - font: Font used for all rendered tokens.
     ///   - chipCornerRadius: Corner radius applied to changed-token chips.
     ///   - chipInsets: Insets applied around changed-token text when drawing chips.
-    ///   - deletionStrikethrough: Whether deleted lexical tokens use a strikethrough.
     ///   - interChipSpacing: Gap between adjacent changed lexical chips.
     ///   - lineSpacing: Additional vertical spacing between wrapped lines.
     public init(
-        additionFillColor: NSColor,
-        additionStrokeColor: NSColor,
-        additionTextColorOverride: NSColor? = nil,
-        deletionFillColor: NSColor,
-        deletionStrokeColor: NSColor,
-        deletionTextColorOverride: NSColor? = nil,
-        unchangedTextColor: NSColor = .labelColor,
+        additionsStyle: TextDiffChangeStyle = .defaultAddition,
+        removalsStyle: TextDiffChangeStyle = .defaultRemoval,
+        textColor: NSColor = .labelColor,
         font: NSFont = .monospacedSystemFont(ofSize: 14, weight: .regular),
         chipCornerRadius: CGFloat = 4,
         chipInsets: NSEdgeInsets = NSEdgeInsets(top: 1, left: 3, bottom: 1, right: 3),
-        deletionStrikethrough: Bool = false,
         interChipSpacing: CGFloat = 0,
         lineSpacing: CGFloat = 2
     ) {
-        self.additionFillColor = additionFillColor
-        self.additionStrokeColor = additionStrokeColor
-        self.additionTextColorOverride = additionTextColorOverride
-        self.deletionFillColor = deletionFillColor
-        self.deletionStrokeColor = deletionStrokeColor
-        self.deletionTextColorOverride = deletionTextColorOverride
-        self.unchangedTextColor = unchangedTextColor
+        self.additionsStyle = additionsStyle
+        self.removalsStyle = removalsStyle
+        self.textColor = textColor
         self.font = font
         self.chipCornerRadius = chipCornerRadius
         self.chipInsets = chipInsets
-        self.deletionStrikethrough = deletionStrikethrough
         self.interChipSpacing = interChipSpacing
         self.lineSpacing = lineSpacing
     }
 
+    /// Creates a style by converting protocol-based operation styles to concrete change styles.
+    ///
+    /// - Parameters:
+    ///   - additionsStyle: Protocol-based style for inserted token chips.
+    ///   - removalsStyle: Protocol-based style for deleted token chips.
+    ///   - textColor: Text color used for unchanged tokens.
+    ///   - font: Font used for all rendered tokens.
+    ///   - chipCornerRadius: Corner radius applied to changed-token chips.
+    ///   - chipInsets: Insets applied around changed-token text when drawing chips.
+    ///   - interChipSpacing: Gap between adjacent changed lexical chips.
+    ///   - lineSpacing: Additional vertical spacing between wrapped lines.
+    public init(
+        additionsStyle: some TextDiffStyling,
+        removalsStyle: some TextDiffStyling,
+        textColor: NSColor = .labelColor,
+        font: NSFont = .monospacedSystemFont(ofSize: 14, weight: .regular),
+        chipCornerRadius: CGFloat = 4,
+        chipInsets: NSEdgeInsets = NSEdgeInsets(top: 1, left: 3, bottom: 1, right: 3),
+        interChipSpacing: CGFloat = 0,
+        lineSpacing: CGFloat = 2
+    ) {
+        self.init(
+            additionsStyle: TextDiffChangeStyle(additionsStyle),
+            removalsStyle: TextDiffChangeStyle(removalsStyle),
+            textColor: textColor,
+            font: font,
+            chipCornerRadius: chipCornerRadius,
+            chipInsets: chipInsets,
+            interChipSpacing: interChipSpacing,
+            lineSpacing: lineSpacing
+        )
+    }
+
     /// The default style tuned for system green insertions and system red deletions.
-    public static let `default` = TextDiffStyle(
-        additionFillColor: NSColor.systemGreen.withAlphaComponent(0.22),
-        additionStrokeColor: NSColor.systemGreen.withAlphaComponent(0.65),
-        deletionFillColor: NSColor.systemRed.withAlphaComponent(0.22),
-        deletionStrokeColor: NSColor.systemRed.withAlphaComponent(0.65)
-    )
+    public static let `default` = TextDiffStyle()
 }

Sources/TextDiff/TextDiffStyling.swift

@@ -0,0 +1,13 @@
+import AppKit
+
+/// Change-specific visual configuration used for addition/removal rendering.
+public protocol TextDiffStyling {
+    /// Fill color used for chip backgrounds.
+    var fillColor: NSColor { get }
+    /// Stroke color used for chip outlines.
+    var strokeColor: NSColor { get }
+    /// Optional text color override for chip text.
+    var textColorOverride: NSColor? { get }
+    /// Whether changed lexical content should render with a strikethrough.
+    var strikethrough: Bool { get }
+}

Sources/TextDiff/TextDiffView.swift

@@ -50,17 +50,21 @@ public struct TextDiffView: View {
 
 #Preview("TextDiffView") {
     let style = TextDiffStyle(
-        additionFillColor: .systemGreen.withAlphaComponent(0.28),
-        additionStrokeColor: .systemGreen.withAlphaComponent(0.75),
-        additionTextColorOverride: .labelColor,
-        deletionFillColor: .systemRed.withAlphaComponent(0.24),
-        deletionStrokeColor: .systemRed.withAlphaComponent(0.75),
-        deletionTextColorOverride: .secondaryLabelColor,
-        unchangedTextColor: .labelColor,
+        additionsStyle: TextDiffChangeStyle(
+            fillColor: .systemGreen.withAlphaComponent(0.28),
+            strokeColor: .systemGreen.withAlphaComponent(0.75),
+            textColorOverride: .labelColor
+        ),
+        removalsStyle: TextDiffChangeStyle(
+            fillColor: .systemRed.withAlphaComponent(0.24),
+            strokeColor: .systemRed.withAlphaComponent(0.75),
+            textColorOverride: .secondaryLabelColor,
+            strikethrough: true
+        ),
+        textColor: .labelColor,
         font: .systemFont(ofSize: 16, weight: .regular),
         chipCornerRadius: 3,
         chipInsets: NSEdgeInsets(top: 0, left: 0, bottom: 0, right: 0),
-        deletionStrikethrough: true,
         interChipSpacing: 1,
         lineSpacing: 2
     )

Tests/TextDiffTests/NSTextDiffSnapshotTests.swift

@@ -49,7 +49,7 @@ struct NSTextDiffSnapshotTests {
     @Test
     func custom_style_spacing_strikethrough() {
         var style = TextDiffStyle.default
-        style.deletionStrikethrough = true
+        style.removalsStyle.strikethrough = true
         style.interChipSpacing = 1
 
         assertNSTextDiffSnapshot(

Tests/TextDiffTests/NSTextDiffViewTests.swift

@@ -86,7 +86,7 @@ func nsTextDiffViewStyleChangeDoesNotRecomputeDiff() {
     }
 
     var style = TextDiffStyle.default
-    style.deletionStrikethrough = true
+    style.removalsStyle.strikethrough = true
     view.style = style
 
     #expect(callCount == 1)
@@ -106,7 +106,7 @@ func nsTextDiffViewSetContentBatchesRecompute() {
     }
 
     var style = TextDiffStyle.default
-    style.deletionStrikethrough = true
+    style.removalsStyle.strikethrough = true
     view.setContent(
         original: "old-2",
         updated: "new-2",
@@ -131,7 +131,7 @@ func nsTextDiffViewSetContentStyleOnlyDoesNotRecomputeDiff() {
     }
 
     var style = TextDiffStyle.default
-    style.deletionStrikethrough = true
+    style.removalsStyle.strikethrough = true
     view.setContent(
         original: "old",
         updated: "new",