Demo video

QKeysOnScreen shows the current keys you're pressing on the screen. It is QiPress / Keypose / KeyCastr for GNU/Linux.

QKeysOnConsole does the same but on the current terminal.

It uses PyQt5 for the GUI and evdev to read your keys, making it much better than key-mon. See "Comparison with key-mon" below.

QKeysOnScreen was inspired by the widget in the top right of the screen in TempleOS. I had never written a non-trivial Qt application before, and needed to make an ED25519 key manager. I started writing this to learn Qt, but by the time I was finished it was a full featured application.

QKeysOnScreen is completely GUI driven and has no command line options. You can configure it by right clicking the main window to see a list of options. QKeysOnScreen is very configurable, just about every aspect of it can be configured. You can change the font, color, window size, divider, ignored keys, and fadeout behavior. If you can think of more useful options, please open a GitHub issue.

QKeysOnConsole has no options as yet but may some day.

• Qt 5 (tested only on Qt 5.5.0)
• PyQt5
• Python 3
• python-evdev

Next packages should be installed using your package manager:

• python3-pyqt5.qtx11extras
• python3-evdev

QKeysOnScreen uses the Linux kernel's evdev interface. This makes it very fast and accurate, but also makes setup a bit tricky.

Owing to the Linux kernel's security, it does not just allow any unprivileged user to capture keyboard events. This is a good thing™, because in its essence QKeysOnScreen is a keylogger, except it doesn't save or send the keys anywhere, it just displays them on the screen.

There are three ways to give QKeysOnScreen the permissions it needs:

• Run it with sudo. This is by far the simplest and most secure way, as it only gives permission to QKeysOnScreen and no other applications. However, it may not be ideal if you want your Qt widget styling to carry over, or if you want to run it from the desktop menu.

• Add yourself to the group that the input devices are in, so your user can read them. This group is usually called input or plugdev, but you can check for sure by doing ls -l /dev/input/event0. The word after root is the input group. Then do sudo gpasswd -a your_username input_group_here. Then, log out and log in, and QKeysOnScreen should now start under your user.

• Add a udev rule. I don't know how (and believe me, I tried really hard), so please open a GitHub issue if you find out how so I can write how here.

1. key-mon uses GTK, and that's just for heretics.
2. key-mon does not persist keys properly. It has a key timeout, but it has no way to show keys until the next one is pressed.
3. key-mon is unmaintained, and is hosted on Google Code. RIP
4. key-mon has no key history window.
5. key-mon is buggy. For example, key-mon does not understand Ctrl-C if the Preferences window is open, and can only be killed by kill -9. key-mon's "Highly Visible Click" functionality, while there (I'll add it to QKOS soon), is incredibly buggy. Sometimes the circle around clicks persists for minutes longer than it should.
6. key-mon is bound to X11 in an unhealthy way. key-mon uses the X11 RECORD extension, which means it doesn't work with Wayland. QKeysOnScreen uses evdev. If you open a tty on one monitor, QKeysOnScreen will continue to work with the keys you are pressing in that tty, and QKeysOnScreen works perfectly with Wayland.