SlackBuildsOrg/multimedia/vkeybd

vkeybd (virtual piano keyboard)

vkeybd is a virtual keyboard for AWE/OSS, MIDI/OSS and ALSA
drivers. It is a simple fake of a MIDI keyboard on X-window
system. Enjoy music with your mouse and computer keyboard.

Make sure to have a MIDI synth configured in order to play music
with this program - if you use the optional dependency TiMidity++,
for example, run it in ALSA server mode (timidity -iA) before starting
vkeybd, then use aconnect to link the ALSA sequencer input (vkeybd)
and output (timidity) ports.

Also, you may want to provide a custom keymap to vkeybd (~/.vkeybdmap)