Architecture

A bird's-eye view of the modules that make Kartoza Screencaster tick.

Layout

src/
├── main.cpp                     Application entry, QApplication setup
├── gui/
│   ├── mainwindow.cpp           Top-level window with tab navigation
│   ├── recordpage.cpp           Record tab — wraps the canvas + controls
│   ├── canvas.cpp               WYSIWYG canvas (paint / drag / preview)
│   ├── historypage.cpp          History tab — recording browser
│   ├── settingspage.cpp         Settings tab
│   ├── processingpage.cpp       Post-recording progress page
│   ├── assetgallery.cpp         Reusable asset picker
│   └── tray.cpp                 System tray integration
├── recorder/
│   └── recorder.cpp             ffmpeg + gst-launch subprocess orchestration
├── merger/
│   └── merger.cpp               ffmpeg post-processing pipeline
├── monitor/
│   └── monitor.cpp              Display enumeration (xrandr / Qt / Hyprland / Sway / COSMIC)
├── webcam/
│   └── webcam.cpp               Webcam preview capture
├── platform/
│   └── platform.cpp             OS / display server / compositor detection;
│                                supportsWlrCapture() picks wlr vs portal capture
├── portal/
│   └── portal.cpp               xdg-desktop-portal QtDBus wrapper (Linux only)
├── dbus/
│   └── dbusservice.cpp          Session-bus service for global shortcuts (Linux only)
├── config/
│   └── config.cpp               QSettings-backed persistent state
└── youtube/
    └── youtube.cpp              YouTube OAuth + Upload API client

Runtime flow

graph LR
    A[main.cpp] --> B[MainWindow]
    B --> C[RecordPage]
    B --> D[HistoryPage]
    B --> E[SettingsPage]
    C --> F[Canvas]
    C --> G[Recorder]
    G --> H[ffmpeg / gst-launch subprocesses]
    G --> I[Merger]
    I --> J[ffmpeg post-processing]
    F --> K[Portal]
    K --> L[xdg-desktop-portal D-Bus]
    F --> M[Monitor]
    F --> N[Webcam]
    D --> O[YouTube]

Threading

• The GUI runs on the main Qt thread.
• Subprocesses (ffmpeg, gst-launch) run as QProcess children with stderr piped back to the main thread for logging.
• Merger post-processing runs on a worker thread; progress is reported via signals.
• Canvas preview capture runs on the Qt thread pool — each frame request is one task.