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A modular, desktop rich-text editor built with Python and PyQt6, designed to explore how real-world document editors manage state, formatting, and user interaction.
Showcase.NoteApp.mp4
Showcase.Unit.Tests.mp4
Showcase.Persistence.mp4
Showcase.ImageInsertion.mp4
 Main Window |
 Text Formatting |
 Headings |
 Resize Image |
 Table Formatting |
 Search Bar |
 Lists |
 Line Spacing |
 PDF Export |
NoteApp is a feature-rich desktop editor that supports multi-document workflows, structured content (tables, images), and persistent sessions.
The goal of this project was not just to replicate common editor features, but to design a system that handles document state, formatting consistency, and user interaction at scale.
The application is structured around separation of concerns between UI, document state, and persistence:
-
UI Layer (MainWindow / Controllers / Widgets)
MainWindowhandles layout, tab management, file I/O, search/replace, and print/PDF- Formatting operations are delegated to
FormattingController - Toolbar construction and theming are delegated to
ToolbarController - Right-click context menus are delegated to
ContextMenuController - Custom widgets: SearchBar, StatusBarWidget, TablePropertiesDialog
-
Editor / Document Layer
- Manages text state, cursor behavior, and formatting operations
- Encapsulates each document per tab for isolation
-
Persistence Layer
- Handles saving/loading documents (HTML and TXT)
- Ensures formatting is preserved across sessions
-
Session Manager
- Stores open tabs and restores them on launch
- Maintains continuity across application restarts
-
HTML as storage format
- Chosen to preserve rich text, images, and structure without designing a custom format
-
Multi-tab document model
- Each tab maintains independent state to avoid cross-document interference
-
Controller pattern for MainWindow
MainWindowwas previously 2000+ lines; formatting logic, toolbar construction, and context menu logic have been extracted into dedicated controllers, making each concern independently testable and easier to extend
-
Local-first design
- No external dependencies or cloud integration, which ensures performance and reliability
-
PyQt6 for UI
- Enables fine-grained control over desktop interactions and complex widgets
-
Rich text consistency
- Managing overlapping styles (bold, headings, colors) without conflicts required careful formatting control
-
Dynamic table manipulation
- Supporting row/column updates and styling without breaking layout integrity
-
Session persistence
- Ensuring tabs, file paths, and UI state are safely restored across launches
-
State synchronization
- Keeping UI indicators (e.g., unsaved ●) consistent with actual document changes
- Multi-tab editing with drag reordering
- Session recovery on restart
- HTML and plain text file support
- Drag & drop file opening
- Rich text styling (headings, inline formatting, colors)
- Lists, indentation, and alignment controls
- Clear formatting system
- Superscript & Subscript support
- Code blocks with monospace formatting
- Line spacing control (Single, 1.5x, Double)
- Fully editable tables (rows, columns, styling)
- Image insertion with resizing and scaling
- Hyperlink creation and editing (Ctrl+Click navigation)
- Horizontal line separators
- Find & replace with match tracking
- Replace functionality (Ctrl+H)
- Status bar (cursor position, word count)
- Keyboard-first workflow across all major actions
- Print support with PDF export
- Light / Dark theme toggle (Ctrl+Shift+D), preference persisted across sessions
The application is structured as a layered desktop system where user interactions flow from the UI into document logic and persistence.
[User Actions]
↓
(MainWindow)
[MainWindow (app/main_window.py)]
↓
├─→ handles keyboard shortcuts
├─→ handles menu clicks
├─→ handles toolbar buttons
├─→ handles drag & drop
↓
├─→ _setup_ui
├─→ _create_menu_bar
├─→ _setup_shortcuts
└─→ _setup_timers
↓
├─→ owns tab list
├─→ wires signals
└─→ drives UI state
↓
├───────────────────────────────────────────────────────────────────┐
↓ ↓
[app/controllers/] [models/] [services/] [widgets/] [config/]
↓ ↓
├─→ FormattingController │
│ bold, italic, underline, color, │
│ alignment, lists, tables, │
│ links, images, code blocks │
│ │
├─→ ToolbarController │
│ builds two-row toolbar widget, │
│ owns all button references, │
│ applies light/dark theme │
│ │
└─→ ContextMenuController │
right-click menu, table row/col │
actions, image resize dialog │
│
├─→ constants (AppConfig, StyleSheet)
│
├─→ SearchBar, StatusBarWidget,
│ TablePropertiesDialog
│
├─→ FileOperations (read/write/delete),
│ SettingsManager (geometry, recent files,
│ session restore)
│
└─→ DocumentTab, LinkAwareTextEdit,
is_modified, mark_saved,
get_content_html
(all layers interact with ↓)
[Qt Document (in‑memory)]
↓
├─→ QTextDocument
├─→ undo/redo stack
├─→ rich‑text cursor
└─→ embedded images
[Filesystem]
↑ ↓
├─→ .html
├─→ .txt
├─→ .bak backups
└─→ UTF‑8 / latin‑1 encoding
[QSettings]
↑ ↓
├─→ window geometry
├─→ open tabs
└─→ recent files
A full list of keyboard shortcuts is available in SHORTCUTS.md.
- HTML (.html) — Full formatting and structure preserved
- TXT (.txt) — Plain text fallback
- Automatic mode detection on load
- Designing a stateful desktop application
- Managing multiple documents concurrently
- Handling structured content (tables, media)
- Building persistent systems (session recovery)
- Creating responsive and intuitive UI workflows
- Applying the controller pattern to decompose a large UI class into focused, testable units
- Plugin system for extensibility
- Performance optimization for large documents
- .docx support via python-docx
- More Export options (besides PDF, which has been implemented)
- Cloud sync and backup
- Spell checking
- Auto-save recovery
The application includes a comprehensive test suite using pytest and pytest-qt:
# Run all tests
pytest tests/ -v
# Run specific test category
pytest tests/test_document_tab.py -v
# Run with coverage report
pytest tests/ --cov=. --cov-report=html
- Python 3.10+
- PyQt6
- pytest (optional, for running tests)
git clone https://github.com/DerYokoya/NoteApp.git
cd NoteApp
pip install -r requirements.txt
python main.py
# Run tests (optional)
pip install pytest pytest-qt
pytest tests/ -v