# Send a MIDI polyphonic key pressure message

``

    midi_poly_pressure  note (midi), value (midi)

Sends a MIDI polyphonic key pressure message to all connected devices on all channels. Use the `port:` and `channel:` opts to restrict which MIDI ports and channels are used.

Note number and pressure value can be passed as a note such as `:e3` and decimal values will be rounded down or up to the nearest whole number - so values between 3.5 and 4 will be rounded up to 4 and values between 3.49999… and 3 will be rounded down to 3.

You may also optionally pass the pressure value as a floating point value between 0 and 1 such as 0.2 or 0.785 (which will be mapped to MIDI values between 0 and 127) using the `val_f:` opt.

MIDI 1.0 Specification - Channel Voice Messages - Polyphonic Key Pressure (Aftertouch)

Introduced in v3.0

## Options

channel: | Channel(s) to send to
port: | MIDI port(s) to send to
value: | Pressure value as a MIDI number.
val_f: | Pressure value as a value between 0 and 1 (will be converted to a MIDI value)
on: | If specified and false/nil/0 will stop the midi poly pressure message from being sent out. (Ensures all opts are evaluated in this call to `midi_poly_pressure` regardless of value).

## Examples

# Example 1
``
    midi_poly_pressure 100, 32
| ``
    #=> Sends a MIDI poly key pressure message to control note 100 with value 32 to all ports and channels
# Example 2
``
    midi_poly_pressure :e7, 32
| ``
    #=> Sends a MIDI poly key pressure message to control note 100 with value 32 to all ports and channels
# Example 3
``
    midi_poly_pressure 100, 32, channel: 5
| ``
    #=> Sends MIDI poly key pressure message to control note 100 with value 32 on channel 5 to all ports
# Example 4
``
    midi_poly_pressure 100, val_f: 0.8, channel: 5
| ``
    #=> Sends a MIDI poly key pressure message to control note 100 with value 102 on channel 5 to all ports
# Example 5
``
    midi_poly_pressure 100, value: 102, channel: [1, 5]
| ``
    #=> Sends MIDI poly key pressure message to control note 100 with value 102 on channel 1 and 5 to all ports