Rt  Midi
1 Installation
make-rtmidi-in
make-rtmidi-out
rtmidi-ports
rtmidi-open-port
rtmidi-close-port
rtmidi-send-message
2 Example
7.0

RtMidi

This package provides Racket bindings for the RtMidi package. It is currently undocmented, this file notwithstanding.

1 Installation

This package is not self-contained. It depends on the RtMidi package, and also requires you to compile a dynamic library used to connect to the RtMidi code.

At this point, this means that installing this package will require you to locate the package directory where this package is installed.

The best way to do this is probably to install the package using raco pkg install or the package manager, and then to evaluate

(collection-path "rtmidi")

to see where the directory lives.

Once you’ve located the collection directory, you’ll need to extract http://www.music.mcgill.ca/~gary/rtmidi/release/rtmidi-2.1.0.tar.gz to the collection directory. Then run ‘make $PLATFORM‘, where ‘PLATFORM‘ is one of ‘linux‘, ‘macosx‘, or ‘windows‘.

The wrapper is C++98 and should compile with any modern C++ compiler.

I haven’t tried the Windows build with this Makefile; you might need to make some adjustments.

 (require rtmidi) package: rtmidi

Some stubs:

procedure

(make-rtmidi-in)  rtmidi-out?

...

procedure

(make-rtmidi-out)  rtmidi-out?

...

procedure

(rtmidi-ports in)  (listof string?)

  in : rtmidi-in/out?
...

procedure

(rtmidi-open-port in-or-out idx)  void?

  in-or-out : rtmidi-in/out?
  idx : nat-or-false?
...

procedure

(rtmidi-close-port in-or-out)  void?

  in-or-out : rtmidi-in/out?
...

procedure

(rtmidi-send-message out msg)  void?

  out : rtmidi-out?
  msg : (listof byte?)
...

2 Example

Here’s a file that uses these functions:

#lang racket
(require rtmidi)
 
; Create RtMidiIn and RtMidiOut
(define in (make-rtmidi-in))
(define out (make-rtmidi-out))
 
; List input and output ports
(define in-ports (rtmidi-ports in))
(printf "Input ports: ~a~n" in-ports)
 
(define out-ports (rtmidi-ports out))
(printf "Output ports: ~a~n" out-ports)
 
; Open the first input and output port, if any
 
(match in-ports
  [(cons a-port other-ports) (rtmidi-open-port in 0)]
  [other (printf (current-error-port) "no input ports\n")])
 
(match out-ports
  [(cons a-port other-ports) (rtmidi-open-port out 0)]
  [other (printf (current-error-port) "no output ports\n")])
 
; Send a note
(rtmidi-send-message out (list 144 65 127))
(sleep 0.2)
(rtmidi-send-message out (list 128 65 127))
 
; Read incoming messages until break
(let loop ()
  (pretty-print (sync in))
  (loop))