alttab

A lightweight Alt+Tab window switcher for X11 with live thumbnails.

Features

• Alt+Tab window switching with visual overlay
• Live window thumbnails via XComposite
• Window icons from _NET_WM_ICON
• MRU (most-recently-used) window ordering
• Keyboard navigation (Tab, Shift+Tab, Enter, Escape)
• Customizable hotkey, colors, and tile sizes

Dependencies

Build dependencies:

• GCC (or compatible C11 compiler)
• make
• pkg-config
• libx11-dev
• libxcomposite-dev
• libxrender-dev
• libcairo2-dev

On Debian/Ubuntu:

sudo apt install build-essential pkg-config libx11-dev libxcomposite-dev libxrender-dev libcairo2-dev

On Fedora:

sudo dnf install gcc make pkg-config libX11-devel libXcomposite-devel libXrender-devel cairo-devel

On Arch Linux:

sudo pacman -S base-devel libx11 libxcomposite libxrender cairo

Building

make

Installation

sudo make install

This installs alttab to /usr/local/bin. To install to a different location:

sudo make install PREFIX=/usr

To uninstall:

sudo make uninstall

Usage

Run the program:

alttab

Use Alt+Tab to cycle through windows. Release Alt to confirm selection, or press Escape to cancel.

Command-Line Options

Option	Description
-h, --help	Show help message
-V, --version	Show version
-k, --key=KEY	Trigger key (default: Tab)
-m, --mod=MOD	Modifier key: Mod1, Alt, Mod4, Super, Shift, Control (default: Mod1)
-b, --bg-color=RGBA	Background color (default: #1a1a1ad9)
-s, --highlight-color=RGBA	Selection highlight color (default: #4d80cce6)
-W, --tile-width=PX	Tile width in pixels (default: 200)
-H, --tile-height=PX	Tile height in pixels (default: 150)
-T, --no-thumbnails	Disable thumbnail capture
-v, --verbose	Enable debug logging

Colors can be specified as #RRGGBBAA (hex) or r,g,b,a (floats 0.0-1.0).

Examples

# Use Super+Tab instead of Alt+Tab
alttab --mod=Super

# Darker background with larger tiles
alttab --bg-color=#000000cc --tile-width=250 --tile-height=200

# Disable thumbnails (faster, icons only)
alttab --no-thumbnails

Autostart at Login

Using ~/.xinitrc (startx)

Add to your ~/.xinitrc before the window manager:

alttab &

Using Desktop Entry (Display Manager)

Create ~/.config/autostart/alttab.desktop:

[Desktop Entry]
Type=Application
Name=alttab
Exec=alttab
X-GNOME-Autostart-enabled=true

Using systemd User Service

Create ~/.config/systemd/user/alttab.service:

[Unit]
Description=Alt+Tab window switcher
After=graphical-session.target

[Service]
ExecStart=/usr/local/bin/alttab
Restart=on-failure

[Install]
WantedBy=graphical-session.target

Enable and start:

systemctl --user daemon-reload
systemctl --user enable alttab.service
systemctl --user start alttab.service

Window Manager Config

For i3, add to ~/.config/i3/config:

exec --no-startup-id alttab

For Openbox, add to ~/.config/openbox/autostart:

alttab &

Troubleshooting

"Failed to grab hotkey": Another program is already using Alt+Tab. Either close that program or use a different key combination with --mod and --key.

No thumbnails appearing: Your compositor may not support XComposite, or you're running without a compositor. Try running with a compositor like picom or compton, or use --no-thumbnails.

License

MIT