void Preview_Pressed(int index) => fade.MIDIEnter(new Signal(null, null, (byte)LaunchpadGrid.GridToSignal(index), new Color()));
void PadPressed(int index) => Grid.SetColor(index, GetColor(_filter[LaunchpadGrid.GridToSignal(index)] = drawingState));
void PadChanged(int index, bool state)
{
Launchpad lp = Track.Get(_preview)?.Launchpad;
_preview.MIDIEnter(new Signal(lp, lp, (byte)LaunchpadGrid.GridToSignal(index), new Color((byte)(state? 63 : 0))));
}
void PadStarted(int index)
{
drawingState = !_filter[LaunchpadGrid.GridToSignal(index)];
old = _filter.Filter.ToArray();
}