Qt app with asyncio

An example demonstrating a qt app with a wgpu viz inside.

This is the same as the qt_app.py example, except this uses the asyncio compatible mode that was introduced in Pyside 6.6.

For more info see:

# ruff: noqa: N802

import time
import asyncio

from PySide6 import QtWidgets, QtAsyncio
from rendercanvas.qt import QRenderWidget
from rendercanvas.utils.cube import setup_drawing_sync


def async_connect(signal, async_function):
    # Unfortunately, the signal.connect() methods don't detect
    # coroutine functions, so we have to wrap it in a function that creates
    # a Future for the coroutine (which will then run in the current event-loop).
    #
    # The docs on QtAsyncio do something like
    #
    #     self.button.clicked.connect(
    #         lambda: asyncio.ensure_future(self.whenButtonClicked()
    #     )
    #
    # But that's ugly, so we create a little convenience function
    def proxy():
        return asyncio.ensure_future(async_function())

    signal.connect(proxy)


class ExampleWidget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.resize(640, 480)
        self.setWindowTitle("Rendering in Qt with asyncio")

        splitter = QtWidgets.QSplitter()

        self.button = QtWidgets.QPushButton("Hello world", self)
        self.canvas = QRenderWidget(splitter, update_mode="continuous")
        self.output = QtWidgets.QTextEdit(splitter)

        # self.button.clicked.connect(self.whenButtonClicked)  # see above :(
        async_connect(self.button.clicked, self.whenButtonClicked)

        splitter.addWidget(self.canvas)
        splitter.addWidget(self.output)
        splitter.setSizes([400, 300])

        layout = QtWidgets.QHBoxLayout()
        layout.addWidget(self.button, 0)
        layout.addWidget(splitter, 1)
        self.setLayout(layout)

        self.show()

    def addLine(self, line):
        t = self.output.toPlainText()
        t += "\n" + line
        self.output.setPlainText(t)

    async def whenButtonClicked(self):
        self.addLine("Waiting 1 sec ...")
        await asyncio.sleep(1)
        self.addLine(f"Clicked at {time.time():0.1f}")


app = QtWidgets.QApplication([])
example = ExampleWidget()

draw_frame = setup_drawing_sync(example.canvas)
example.canvas.request_draw(draw_frame)

# Enter Qt event-loop the asyncio-compatible way
QtAsyncio.run()

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