qtinter — Interop between asyncio and Qt for Python

qtinter is a Python module that brings together asyncio and Qt for Python, allowing you to use one from the other seamlessly.

Read the full documentation or check out the quickstart below.

Installation

$ pip install qtinter

Using asyncio from Qt

To use asyncio-based libraries in Qt for Python, enclose app.exec() inside context manager qtinter.using_asyncio_from_qt().

Example (taken from examples/clock.py):

"""Display LCD-style digital clock"""

import asyncio
import datetime
import qtinter  # <-- import module
from PySide6 import QtWidgets

class Clock(QtWidgets.QLCDNumber):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setDigitCount(8)

    def showEvent(self, event):
        self._task = asyncio.create_task(self._tick())

    def hideEvent(self, event):
        self._task.cancel()

    async def _tick(self):
        while True:
            t = datetime.datetime.now()
            self.display(t.strftime("%H:%M:%S"))
            await asyncio.sleep(1.0 - t.microsecond / 1000000 + 0.05)

if __name__ == "__main__":
    app = QtWidgets.QApplication([])

    widget = Clock()
    widget.setWindowTitle("qtinter - Digital Clock example")
    widget.resize(300, 50)

    with qtinter.using_asyncio_from_qt():  # <-- enable asyncio in qt code
        widget.show()
        app.exec()

Using Qt from asyncio

To use Qt components from asyncio-based code, enclose the asyncio entry-point inside context manager qtinter.using_qt_from_asyncio().

Example (taken from examples/color.py):

"""Display the RGB code of a color chosen by the user"""

import asyncio
import qtinter  # <-- import module
from PySide6 import QtWidgets

async def choose_color():
    dialog = QtWidgets.QColorDialog()
    dialog.show()
    future = asyncio.Future()
    dialog.finished.connect(future.set_result)
    result = await future
    if result == QtWidgets.QDialog.DialogCode.Accepted:
        return dialog.selectedColor().name()
    else:
        return None

if __name__ == "__main__":
    app = QtWidgets.QApplication([])
    with qtinter.using_qt_from_asyncio():  # <-- enable qt in asyncio code
        color = asyncio.run(choose_color())
        if color is not None:
            print(color)

Using modal dialogs

To execute a modal dialog without blocking the asyncio event loop, wrap the dialog entry-point in qtinter.modal() and await on it.

Example (taken from examples/hit_100.py):

import asyncio
import qtinter
from PySide6 import QtWidgets

async def main():
    async def counter():
        nonlocal n
        while True:
            print(f"\r{n}", end='', flush=True)
            await asyncio.sleep(0.025)
            n += 1

    n = 0
    counter_task = asyncio.create_task(counter())
    await qtinter.modal(QtWidgets.QMessageBox.information)(
        None, "Hit 100", "Click OK when you think you hit 100.")
    counter_task.cancel()
    if n == 100:
        print("\nYou did it!")
    else:
        print("\nTry again!")

if __name__ == "__main__":
    app = QtWidgets.QApplication([])
    with qtinter.using_qt_from_asyncio():
        asyncio.run(main())

Requirements

qtinter supports the following:

• Python version: 3.7 or higher
• Qt binding: PyQt5, PyQt6, PySide2, PySide6
• Operating system: Linux, MacOS, Windows

License

BSD License.

Contributing

Please raise an issue if you have any questions. Pull requests are more than welcome!

Credits

qtinter is derived from qasync but rewritten from scratch. qasync is derived from asyncqt, which is derived from quamash.