Custom Linux Desktop Environment

Difficulty	Advanced
Team Size	3-5 people
Time	~40-50 hours
Demo-ready by	Step 5
Prerequisites	C/C++, X11/Wayland basics, Linux internals
Built by	GNOME, KDE Plasma, XFCE, Sway

Skills you'll earn: Window management (X11/Wayland), compositor rendering, D-Bus IPC, system tray protocols, theme engines

Start with drawing a window. End with a usable desktop environment.

Step 1: Draw a window on screen (~3-4 hours)

A desktop environment manages windows. Start with one.

• Set up a minimal Linux system with X11 or Wayland
• Write a C program using Xlib (or the Wayland equivalent) that creates a window
• Set the window's size, position, and title
• Draw a colored rectangle inside it
• Handle the close event

You now have: A window on a bare X11 session.

Step 2: Build a window manager (~4-5 hours)

Multiple windows overlap with no way to move or resize them. That's the window manager's job.

• Write a minimal X11 window manager: intercept MapRequest, ConfigureRequest, and ButtonPress events
• Add window decorations: a title bar with the window name and a close button
• Click and drag the title bar to move the window
• Drag window edges to resize

You now have: A basic window manager.

Step 3: Taskbar / panel (~4-5 hours)

You can't tell what's running or switch between windows.

• Create a panel window that sits at the top or bottom of the screen
• List open windows as buttons in the panel
• Click a button to focus that window
• Show the current date and time on the right side

You now have: A taskbar.

Step 4: Application launcher (~3-4 hours)

You have windows but no way to start programs.

• Add a launcher button (or keyboard shortcut) that opens a search dialog
• Scan /usr/share/applications/ for .desktop files
• Filter by name as the user types
• Launch the selected application with exec

You now have: An app launcher.

Step 5: Desktop wallpaper and icons (~4-5 hours)

The background is plain gray.

• Render a background image behind all windows (the root window)
• Let users set the wallpaper from settings
• Add desktop icons: files/folders on the desktop surface
• Double-click an icon to open the associated application

You now have: A desktop surface.

Step 6: Multi-workspace (~4-5 hours)

One screen isn't enough space.

• Implement virtual desktops (workspaces)
• Keyboard shortcuts to switch: Super+1, Super+2, etc.
• Each workspace has its own set of visible windows
• Show workspace indicators in the panel

You now have: Virtual desktops.

Step 7: System tray and notifications (~3-4 hours)

• Add a system tray area in the panel for background apps
• Implement a notification daemon: apps send notifications, the DE displays them as popups
• Follow the freedesktop.org notification spec

Step 8: Settings and theming (~4-5 hours)

• Build a settings application to configure wallpaper, theme, font, keybindings
• Support GTK theme integration so apps look consistent
• Save settings to a config file

Useful Resources

• Xlib Programming Manual
• How X Window Managers Work
• Wayland Book — if targeting Wayland
• freedesktop.org specifications
• TinyWM — a 50-line window manager for reference

Where to go from here

• Compositor with transparency and shadows (picom-style)
• Lock screen and session management
• Display settings (multi-monitor, resolution)
• File manager integration
• Wayland port for modern display server support