Pads and LED buttons

In plain words

Pads are the rubber squares of a drum machine: hit one and it plays a sound. LED buttons are the small switches with a light, like mute, solo or record.

Pad

ui.audio.Pad(text="KICK", color="#ff9f3d",
             on_press=lambda e: engine.node("drums").trigger(),
             on_release=lambda e: None)

• press fires when the pad is pressed, with a velocity from 1 to 127 in event.value (like MIDI): the lower on the pad you click, the harder the hit. velocity=False always sends 100.
• release fires when the button is released or the pointer leaves the pad.
• lit=True lights it from outside: a sequencer’s current step, a note coming from a keyboard. The pad glows in its color, so a grid of them shows the rhythm at a glance.

Property	Default	What it does
text	""	The label in the middle.
color	"accent"	The color it lights up in.
lit	False	Lit from outside.
velocity	True	Velocity from where it is pressed.
width, height	72, 72	Size in pixels.

LED button

ui.audio.LedButton(text="MUTE", on=self.muted, color="warning",
                   on_toggle=lambda e: setattr(self, "muted", e.value))

A dark key with a small light. It toggles on each click (toggle gives True or False), or with momentary=True it lights only while held (press / release), like a tap-tempo key.

Property	Default	What it does
text	""	The label.
on	False	Whether it is lit.
color	"success"	The light’s color (a theme token or hex).
variant	"fl"	"fl" (square key), "round" (bigger LED, round key) or "pill".
momentary	False	Lit only while held.
icon_name	""	A Lucide icon next to the label ("play", "circle"…).

Events: on_toggle, on_press, on_release.

Tip

Play pads from the computer keyboard too: map keys in on_key and set lit from your app’s state, so the pad lights whether it was clicked or typed.