Qt based library that communicate with MIDI
- Send and receive MIDI Messages
- Easily open Virtual MIDI ports on Unix based machines
It is a CMake project. you can either build it using:
cmake -S . -B build
cmake --build buildOr use it as a subdirectory
add_subdirectory(path/to/Qmidi EXCLUDE_FROM_ALL)
target_link_libraries(mytarget PUBLIC QMidi)#include <QApplication>
#include <QDebug>
#include <QMidi>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
// The QMidi object represents a pair of in & out midi ports
// you can create as many as you wish if you want more ports.
// The default constructor chooses the first available API for your OS
// and should be ready to use in most cases
QMidi midi;
// If you're on a unix-base system and want to use an alternative API
// say jackd, you can explicitly set it like so:
midi.setApi(QMidiApi::JACK);
// You can query available APIs using:
for(auto api : QMidi::availableApi())
qDebug() << api;
// You can also set a custom client name, so you're application
// has the correct name displayed
midi.setClientName("Super Midi 3000");
// After each call, you can check whether there's been an error using:
if(midi.hasError())
qWarning() << midi.error() << midi.errorString();
// You can query available MIDI interfaces using the following:
for(const auto& i : midi.availableInterfaces())
{
qDebug() << "Index:" << i.index();
qDebug() << "Name:" << i.name();
qDebug() << "API:" << i.api();
qDebug() << "Directions (in/out):" << i.directions();
// Or simply
qDebug() << i;
}
// Say the first interface is the one you want to use
// you need to set it using:
const auto& i = midi.availableInterfaces().constFirst();
midi.setInputInterface(i);
midi.setOutputInterface(i);
// Now you can open the midi ports and start using them
midi.open();
// Alternatively, on unix-based system you can open
// Virtual ports that will allow your application to
// be detected by others as MIDI interface
midi.openVirtual("My Virtual Port");
// From there you can use the set of signals and slots to
// send and recieve midi data
// you can get the raw message and do the processing yourself
QObject::connect(&midi, &QMidi::messageReceived, [](const QByteArray& data)
{
qDebug() << "Message received:" << data;
});
// but you can get all the different message types with the appropriate signals
QObject::connect(&midi, &QMidi::midiNoteOff, [](quint8 chan, quint8 note, quint8 vel)
{
qDebug() << "Note On received on channel" << chan;
qDebug() << "Node:" << static_cast<QMidiNode>(note);
qDebug() << "Velocity:" << vel;
})
// You can also send MIDI messages using similarly named slots.
// Both raw message and individual message type slots are available:
midi.sendNoteOn(0, QMidiNode::ASharp_5, 127);
midi.sendNoteOff(0, QMidiNode::ASharp_5, 0);
// All those methods are slots for easily connect with other Qt objects
// For example, you can do an easy pass-through with the following:
QObject::connect(&midi, &QMidi::messageReceived,
&midi, &QMidi::sendMessage);
a.exec();
}