Lightpad

Lightpad is a Qt 6-based code editor with a modern UI, built-in language tooling, and an extensible plugin system. It targets fast editing, project-level workflows, and developer-friendly features like LSP, Git, and debugging.

Highlights

• Multi-language syntax highlighting with a plugin-based registry
• Autocompletion with keyword, snippet, and LSP providers
• LSP features: completion, hover, go-to definition, references, rename, and diagnostics
• Debug Adapter Protocol (DAP) client with breakpoints, sessions, watches, and debug console
• Git integration: status, diff gutter, staging, commits, branches, remotes, and stash
• Command palette, file quick open, go to symbol/line
• Multi-cursor editing and split editors (horizontal/vertical)
• Problems panel, breadcrumbs, minimap, and integrated terminal
• Run and format templates with per-project assignments
• Image viewer and optional PDF viewer (Qt6Pdf)

Supported languages (built-in syntax plugins)

Cpp, Python, JavaScript, TypeScript, Java, Rust, Go, HTML, CSS, JSON, YAML, Markdown, Shell, Make, CMake, Bazel, Meson, Ninja

Build requirements

• C++17 compiler
• CMake 3.16+
• Qt 6 (Core, Widgets, Gui)
• Optional: Qt6Pdf + Qt6PdfWidgets for the PDF viewer
  • Disable with -DENABLE_PDF_SUPPORT=OFF

Build on Linux (Ubuntu/Debian)

sudo apt-get update
sudo apt-get install -y build-essential cmake qt6-base-dev qt6-pdf-dev libqt6pdf6 libqt6pdfwidgets6

git clone https://github.com/djeada/Lightpad.git
cd Lightpad
cmake -S . -B build -DBUILD_TESTS=ON
cmake --build build

Run it:

./build/App/Lightpad

Run tests (optional):

ctest --test-dir build --output-on-failure

Build with Makefile shortcuts

make install
make build
make run

Build on macOS

brew install qt cmake
git clone https://github.com/djeada/Lightpad.git
cd Lightpad
cmake -S . -B build -DBUILD_TESTS=ON
cmake --build build
./build/App/Lightpad.app/Contents/MacOS/Lightpad

Build on Windows

1. Install Qt 6 and CMake.
2. Configure and build with CMake (CLI or GUI).
3. The binary is produced in the build output directory.

Diagnostics

For plugin and startup diagnostics, run:

LIGHTPAD_LOG_LEVEL=debug ./build/App/Lightpad

Project configuration

Lightpad stores project-specific settings in a .lightpad/ directory at the project root:

• run_config.json for run template assignments
• format_config.json for formatter assignments
• highlight_config.json for language overrides
• debug/launch.json, debug/breakpoints.json, debug/watches.json

User settings are stored in:

• Linux: ~/.config/lightpad/settings.json (fallback: ~/.config/lightpad/)
• Windows: %LOCALAPPDATA%/Lightpad/settings.json
• macOS: ~/Library/Application Support/Lightpad/settings.json

Plugins are discovered from:

• App dir: <app>/plugins
• User: AppDataLocation/plugins
• Linux system: /usr/lib/lightpad/plugins, /usr/local/lib/lightpad/plugins

Documentation

• User manual: docs/USER_MANUAL.md
• Keyboard shortcuts: docs/KEYBOARD_SHORTCUTS.md
• Go to Definition: docs/GO_TO_DEFINITION.md
• Plugin development: docs/PLUGIN_DEVELOPMENT.md
• Syntax plugins: docs/SYNTAX_PLUGINS.md

Contributing

See CONTRIBUTING.md for the workflow and guidelines.

License

GPL-3.0. See LICENSE for details.

Third-Party Licenses

This application uses the Qt framework, which is available under LGPLv3. Qt is a registered trademark of The Qt Company Ltd. and its subsidiaries. Licensing details: https://www.qt.io/licensing/ Qt source code: https://www.qt.io/download-open-source