#!/usr/bin/env python3 """A utility to receive MIDI messages and display them in a PyQt5 GUI text box.""" ################################################################ # Written in 2018 by Garth Zeglin # To the extent possible under law, the author has dedicated all copyright # and related and neighboring rights to this software to the public domain # worldwide. This software is distributed without any warranty. # You should have received a copy of the CC0 Public Domain Dedication along with this software. # If not, see . ################################################################ # standard Python libraries from __future__ import print_function import os, sys, struct, time, logging, functools, queue # for documentation on the PyQt5 API, see http://pyqt.sourceforge.net/Docs/PyQt5/index.html from PyQt5 import QtCore, QtGui, QtWidgets, QtNetwork # for documentation on python-rtmidi: https://pypi.org/project/python-rtmidi/ import rtmidi ################################################################ class MIDIDisplay(QtWidgets.QMainWindow): """A custom main window which provides all GUI controls.""" def __init__( self, *args, **kwargs): super(MIDIDisplay,self).__init__() # create the GUI elements self.setupUi() # finish initialization self.show() # manage the console output across threads self.console_queue = queue.Queue() self.console_timer = QtCore.QTimer() self.console_timer.timeout.connect(self._poll_console_queue) self.console_timer.start(50) # units are milliseconds return # ------------------------------------------------------------------------------------------------ def setupUi(self): self.setWindowTitle("MIDI Display") self.resize(500, 300) self.centralwidget = QtWidgets.QWidget(self) self.setCentralWidget(self.centralwidget) self.verticalLayout = QtWidgets.QVBoxLayout(self.centralwidget) self.verticalLayout.setContentsMargins(-1, -1, -1, 9) # left, top, right, bottom # generate fields for configuring the MIDI listener self.inputSelectorLayout = QtWidgets.QHBoxLayout() self.inputSelectorLabel = QtWidgets.QLabel() self.inputSelectorLabel.setText("MIDI source:") self.inputSelector = QtWidgets.QComboBox() self.inputSelector.addItem("") self.inputSelectorLayout.addWidget(self.inputSelectorLabel) self.inputSelectorLayout.addWidget(self.inputSelector) self.verticalLayout.addLayout(self.inputSelectorLayout) self.inputSelector.activated['QString'].connect(self.chooseInput) # generate a text area self.consoleOutput = QtWidgets.QPlainTextEdit() self.consoleOutput.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAsNeeded) self.verticalLayout.addWidget(self.consoleOutput) # set up the status bar which appears at the bottom of the window self.statusbar = QtWidgets.QStatusBar(self) self.setStatusBar(self.statusbar) # set up the main menu self.menubar = QtWidgets.QMenuBar(self) self.menubar.setGeometry(QtCore.QRect(0, 0, 500, 22)) self.menubar.setNativeMenuBar(False) self.menubar.setObjectName("menubar") self.menuTitle = QtWidgets.QMenu(self.menubar) self.setMenuBar(self.menubar) self.actionQuit = QtWidgets.QAction(self) self.menuTitle.addAction(self.actionQuit) self.menubar.addAction(self.menuTitle.menuAction()) self.menuTitle.setTitle("File") self.actionQuit.setText("Quit") self.actionQuit.setShortcut("Ctrl+Q") self.actionQuit.triggered.connect(self.quitSelected) return # --- window and qt event processing ------------------------------------------------------------- def show_status(self, string): self.statusbar.showMessage(string) def _poll_console_queue(self): """Write any queued console text to the console text area from the main thread.""" while not self.console_queue.empty(): string = str(self.console_queue.get()) self.consoleOutput.appendPlainText(string) return def write(self, string): """Write output to the console text area in a thread-safe way. Qt only allows calls from the main thread, but the service routines run on separate threads.""" self.console_queue.put(string) return def quitSelected(self): self.write("User selected quit.") self.close() def closeEvent(self, event): self.write("Received window close event.") super(MIDIDisplay,self).closeEvent(event) # -------------------------------------------------------------------------------------------------- def chooseInput(self, name): """Called when the user selects a MIDI source.""" self.show_status("Listening to %s." % name) self.main.open_input(name) return ################################################################ class MainApp(object): """Main application object holding any non-GUI related state.""" def __init__(self): # global state self.listener_address = "localhost" self.listener_portnum = 3761 self.port = None # create the interface window self.window = MIDIDisplay() self.window.main = self # Initialize the MIDI input system and read the currently available ports. self.midi_in = rtmidi.MidiIn() self.midi_ports = self.midi_in.get_ports() for port in self.midi_ports: self.window.inputSelector.addItem(port) self.window.show_status("Please choose a source to display MIDI.") return def open_input(self, name): if self.midi_in.is_port_open(): self.midi_in.close_port() self.midi_in = rtmidi.MidiIn() self.midi_ports = self.midi_in.get_ports() idx = self.midi_ports.index(name) self.midi_in.open_port(idx) self.midi_in.set_callback(self.midi_received) def midi_received(self, data, unused): msg, delta_time = data self.window.write("%f: %s" % (delta_time, str(msg))) ################################################################ def main(): # initialize the Qt system itself app = QtWidgets.QApplication(sys.argv) # create the main application controller main = MainApp() # run the event loop until the user is done logging.info("Starting event loop.") sys.exit(app.exec_()) ################################################################ # Main script follows. This sequence is executed when the script is initiated from the command line. if __name__ == "__main__": main()