gitdiff

Render git diff output, simple as that.

Overview

gitdiff is a native Swift renderer and SwiftUI component for rendering Git diffs on iOS. It offers accurate, efficient and customized diff visualization with the look and feel of tools like GitHub or GitLab.

Showcase

Installation

Swift Package Manager

dependencies: [
    .package(url: "https://github.com/tornikegomareli/gitdiff.git", from: "0.0.5")
]

Or add through Xcode: File → Add Package Dependencies

Quick Start

import SwiftUI
import gitdiff

struct ContentView: View {
    let diffText = """
        @@ -1,3 +1,3 @@
        -let oldValue = "Hello"
        +let newValue = "World"
         let unchanged = true
        """

    var body: some View {
        DiffRenderer(diffText: diffText)
            .diffTheme(.dark)
    }
}

Themes

gitdiff comes with three crafted themes:

Light (GitHub Style)	Dark	GitLab
Clean and familiar	Easy on the eyes	Simple and clean

Using Built-in Themes

DiffRenderer(diffText: diffContent)
    .diffTheme(.light)    // GitHub-style
    .diffTheme(.dark)     // Modern dark theme
    .diffTheme(.gitlab)   // GitLab's style

Creating Custom Themes

let customTheme = DiffTheme(
    addedBackground: Color.green.opacity(0.2),
    addedText: Color.green,
    removedBackground: Color.red.opacity(0.2),
    removedText: Color.red,
    contextBackground: Color(UIColor.systemBackground),
    contextText: Color.primary,
    lineNumberBackground: Color.gray.opacity(0.1),
    lineNumberText: Color.secondary,
    headerBackground: Color.blue.opacity(0.1),
    headerText: Color.blue,
    fileHeaderBackground: Color.gray.opacity(0.05),
    fileHeaderText: Color.primary
)

DiffRenderer(diffText: diffContent)
    .diffTheme(customTheme)

Configuration

View Modifiers

Chain modifiers for quick configuration:

DiffRenderer(diffText: diffContent)
    .diffTheme(.dark)
    .diffLineNumbers(true)
    .diffFont(size: 14, weight: .medium)
    .diffLineSpacing(.comfortable)
    .diffWordWrap(true)

Configuration Object

For reusable configurations:

let codeReviewConfig = DiffConfiguration(
    theme: .light,
    showLineNumbers: true,
    showFileHeaders: true,
    fontSize: 13,
    fontWeight: .regular,
    lineSpacing: .comfortable,
    wordWrap: false
)

DiffRenderer(diffText: diffContent)
    .environment(\.diffConfiguration, codeReviewConfig)

Preset Configurations

Ready-to-use configurations for common scenarios:

// For code reviews - compact and efficient
.environment(\.diffConfiguration, .codeReview)

// For presentations - large and readable
.environment(\.diffConfiguration, .presentation)

Advanced Usage

Working with the Parser

For custom rendering needs:

let parser = DiffParser()
let files = parser.parse(diffText)

ForEach(files) { file in
    VStack(alignment: .leading) {
        Text(file.displayName)
            .font(.headline)

        ForEach(file.hunks) { hunk in
            Text(hunk.header)
                .font(.caption)
                .foregroundColor(.secondary)

            ForEach(hunk.lines) { line in
                // Custom line rendering
            }
        }
    }
}

Integration Examples

With Git Commands:

let gitOutput = shell("git diff HEAD~1")
DiffRenderer(diffText: gitOutput)

In a Code Review App:

struct PullRequestView: View {
    let pullRequest: PullRequest
    @State private var showLineNumbers = true

    var body: some View {
        ScrollView {
            DiffRenderer(diffText: pullRequest.diff)
                .diffTheme(.light)
                .diffLineNumbers(showLineNumbers)
        }
        .toolbar {
            Toggle("Line Numbers", isOn: $showLineNumbers)
        }
    }
}

View Modifiers

• .diffTheme(_ theme: DiffTheme) - Apply a color theme
• .diffLineNumbers(_ show: Bool) - Toggle line numbers (legacy; prefer .diffLineNumberStyle(_:))
• .diffLineNumberStyle(_ style: LineNumberStyle) - Gutter style: .hidden, .single (mobile-friendly compact column), .dual (desktop old/new)
• .diffFileHeaders(_ show: Bool) - Toggle file headers (the diff --git / --- / +++ block)
• .diffHunkHeaders(_ show: Bool) - Toggle the per-hunk @@ -a,b +c,d @@ separator
• .diffFont(size: CGFloat?, weight: Font.Weight?, design: Font.Design?) - Configure font
• .diffLineSpacing(_ spacing: LineSpacing) - Set line spacing
• .diffWordWrap(_ wrap: Bool) - Enable word wrapping
• .diffConfiguration(_ config: DiffConfiguration) - Apply complete configuration
• .diffParser(_ parser: any DiffParsing) - Plug in a custom parser (see below)

Mobile-friendly defaults

For phones and other narrow viewports the .dual gutter is cramped and the @@ hunk header is rarely useful. A typical mobile renderer looks like:

DiffRenderer(diffText: text)
    .diffLineNumberStyle(.single)   // one column, new# for + / old# for -
    .diffHunkHeaders(false)         // hide @@ -a,b +c,d @@
    .diffTheme(.dark)

There's also a .mobile preset that bundles these:

DiffRenderer(diffText: text)
    .diffConfiguration(.mobile)

Custom Diff Formats

DiffRenderer accepts unified-diff text by default. To consume any other format — annotated diffs, server-side payloads, JSON patches, language-server output — implement DiffParsing and inject it via the .diffParser(_:) modifier:

import gitdiff

struct MyAnnotatedDiffParser: DiffParsing {
    let filePath: String

    func parse(_ diffText: String) async throws -> [DiffFile] {
        // Map your custom format → [DiffFile] using the public initializers
        // on DiffFile / DiffHunk / DiffLine. The renderer doesn't care how
        // you produced the model.
        [
            DiffFile(
                oldPath: filePath,
                newPath: filePath,
                hunks: [
                    DiffHunk(
                        oldStart: 1, oldCount: 1, newStart: 1, newCount: 1,
                        header: "",
                        lines: [
                            DiffLine(type: .removed, content: "old", oldLineNumber: 1, newLineNumber: nil),
                            DiffLine(type: .added, content: "new", oldLineNumber: nil, newLineNumber: 1),
                        ]
                    )
                ]
            )
        ]
    }
}

// Inject — default stays `UnifiedDiffParser` if no override.
DiffRenderer(diffText: myRawText)
    .diffParser(MyAnnotatedDiffParser(filePath: "foo.swift"))
    .diffTheme(.dark)

Example App

Explore all features with the included example app:

1. Open GitDiffExample/GitDiffExample.xcodeproj
2. Run the app to see:
   • Live theme switching
   • Interactive customization
   • Various diff examples
   • Code snippets

Performance

• Efficient parsing of large diffs
• Smooth scrolling performance
• Minimal memory footprint
• No external dependencies

Requirements

• iOS 15.0+
• Swift 5.9+
• Xcode 15.0+

Contributing

Any ideas or improvements? Create pull requests.

License

MIT License - see LICENSE for details.