如何在用 pickle 加载或转储时阻止动画 QCursor 冻结？

Question

作为 post 的后续问题，我想知道是否可以扩展游标的功能，以便在使用 pickle 转储或保存数据时，光标的动画不会冻结。

from PyQt5 import QtCore, QtGui, QtWidgets
import pickle
import gzip
import numpy as np


class ManagerCursor(QtCore.QObject):
    def __init__(self, parent=None):
        super(ManagerCursor, self).__init__(parent)
        self._movie = None
        self._widget = None
        self._last_cursor = None

    def setMovie(self, movie):
        if isinstance(self._movie, QtGui.QMovie):
            if not self._movie != QtGui.QMovie.NotRunning:
                self._movie.stop()
            del self._movie
        self._movie = movie
        self._movie.frameChanged.connect(self.on_frameChanged)
        self._movie.started.connect(self.on_started)
        self._movie.finished.connect(self.restore_cursor)

    def setWidget(self, widget):
        self._widget = widget

    @QtCore.pyqtSlot()
    def on_started(self):
        if self._widget is not None:
            self._last_cursor = self._widget.cursor()

    @QtCore.pyqtSlot()
    def restore_cursor(self):
        if self._widget is not None:
            if self._last_cursor is not None:
                self._widget.setCursor(self._last_cursor)
        self._last_cursor = None

    @QtCore.pyqtSlot()
    def start(self):
        if self._movie is not None:
            self._movie.start()

    @QtCore.pyqtSlot()
    def stop(self):
        if self._movie is not None:
            self._movie.stop()
            self.restore_cursor()

    @QtCore.pyqtSlot()
    def on_frameChanged(self):
        pixmap = self._movie.currentPixmap()
        cursor = QtGui.QCursor(pixmap)
        if self._widget is not None:
            if self._last_cursor is None:
                self._last_cursor = self._widget.cursor()
            self._widget.setCursor(cursor)


class Progress(QtWidgets.QDialog):
    def __init__(self):
        super().__init__()
        progress = QtWidgets.QProgressBar()
        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(progress)


class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)
        start_btn = QtWidgets.QPushButton("start", clicked=self.on_start)
        stop_btn = QtWidgets.QPushButton("stop", clicked=self.on_stop)
        dump_btn = QtWidgets.QPushButton("dump", clicked=self.dump)
        load_btn = QtWidgets.QPushButton("load", clicked=self.load)

        self.file = 'test'

        text_edit = QtWidgets.QTextEdit()
        self.popup = None

        self._manager = ManagerCursor(self)
        movie = QtGui.QMovie('../assets/comet_resized.gif')
        self._manager.setMovie(movie)
        self._manager.setWidget(self)

        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(start_btn)
        lay.addWidget(stop_btn)
        lay.addWidget(dump_btn)
        lay.addWidget(load_btn)
        lay.addWidget(text_edit)
        lay.addStretch()

    @QtCore.pyqtSlot()
    def dump(self):
        self._manager.start()
        self.popup = Progress()
        self.popup.show()
        data = [np.full(1000, 1000) for i in range(100000)]
        with gzip.open(self.file, 'wb') as output_file:
            pickle.dump(data, output_file, pickle.HIGHEST_PROTOCOL)

    def load(self):
        self._manager.start()
        self.popup = Progress()
        self.popup.show()
        with gzip.open(self.file, 'rb') as input_file:
            data = pickle.load(input_file)

    @QtCore.pyqtSlot()
    def on_start(self):
        self._manager.start()

    @QtCore.pyqtSlot()
    def on_stop(self):
        self._manager.stop()


if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = Widget()
    w.resize(640, 480)
    w.show()
    sys.exit(app.exec_())

Answer 1

不应在主线程中执行繁重的任务，因为它们会通过冻结 GUI 来阻塞事件循环，必须在另一个线程中执行。

from functools import partial
import gzip
import pickle

from PyQt5 import QtCore, QtGui, QtWidgets

import numpy as np


class Worker(QtCore.QObject):
    dumpStarted = QtCore.pyqtSignal()
    dumpFinished = QtCore.pyqtSignal()

    dataChanged = QtCore.pyqtSignal(object)
    loadStarted = QtCore.pyqtSignal()
    loadFinished = QtCore.pyqtSignal()

    @QtCore.pyqtSlot(str, object)
    def dump(self, filename, data):
        self.dumpStarted.emit()
        with gzip.open(filename, "wb") as output_file:
            pickle.dump(data, output_file, pickle.HIGHEST_PROTOCOL)
        self.dumpFinished.emit()

    @QtCore.pyqtSlot(str)
    def load(self, filename):
        self.loadStarted.emit()
        with gzip.open(filename, "rb") as input_file:
            data = pickle.load(input_file)
            self.dataChanged.emit(data)
        self.loadFinished.emit()


class ManagerCursor(QtCore.QObject):
    def __init__(self, parent=None):
        super(ManagerCursor, self).__init__(parent)
        self._movie = None
        self._widget = None
        self._last_cursor = None

    def setMovie(self, movie):
        if isinstance(self._movie, QtGui.QMovie):
            if not self._movie != QtGui.QMovie.NotRunning:
                self._movie.stop()
            del self._movie
        self._movie = movie
        self._movie.frameChanged.connect(self.on_frameChanged)
        self._movie.started.connect(self.on_started)
        self._movie.finished.connect(self.restore_cursor)

    def setWidget(self, widget):
        self._widget = widget

    @QtCore.pyqtSlot()
    def on_started(self):
        if self._widget is not None:
            self._last_cursor = self._widget.cursor()

    @QtCore.pyqtSlot()
    def restore_cursor(self):
        if self._widget is not None:
            if self._last_cursor is not None:
                self._widget.setCursor(self._last_cursor)
        self._last_cursor = None

    @QtCore.pyqtSlot()
    def start(self):
        if self._movie is not None:
            self._movie.start()

    @QtCore.pyqtSlot()
    def stop(self):
        if self._movie is not None:
            self._movie.stop()
            self.restore_cursor()

    @QtCore.pyqtSlot()
    def on_frameChanged(self):
        pixmap = self._movie.currentPixmap()
        cursor = QtGui.QCursor(pixmap)
        if self._widget is not None:
            if self._last_cursor is None:
                self._last_cursor = self._widget.cursor()
            self._widget.setCursor(cursor)


class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)
        start_btn = QtWidgets.QPushButton("start", clicked=self.on_start)
        stop_btn = QtWidgets.QPushButton("stop", clicked=self.on_stop)
        dump_btn = QtWidgets.QPushButton("dump", clicked=self.dump)
        load_btn = QtWidgets.QPushButton("load", clicked=self.load)

        self.file = "test"

        text_edit = QtWidgets.QTextEdit()
        self.popup = None

        self._manager = ManagerCursor(self)
        movie = QtGui.QMovie("giphy.gif")
        self._manager.setMovie(movie)
        self._manager.setWidget(self)

        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(start_btn)
        lay.addWidget(stop_btn)
        lay.addWidget(dump_btn)
        lay.addWidget(load_btn)
        lay.addWidget(text_edit)
        lay.addStretch()

        thread = QtCore.QThread(self)
        thread.start()

        self._worker = Worker()
        self._worker.moveToThread(thread)

        self._worker.dumpStarted.connect(self._manager.start)
        self._worker.dumpFinished.connect(self._manager.stop)
        self._worker.dumpStarted.connect(partial(dump_btn.setEnabled, False))
        self._worker.dumpFinished.connect(partial(dump_btn.setEnabled, True))

        self._worker.loadStarted.connect(self._manager.start)
        self._worker.loadFinished.connect(self._manager.stop)
        self._worker.loadStarted.connect(partial(load_btn.setEnabled, False))
        self._worker.loadFinished.connect(partial(load_btn.setEnabled, True))
        self._worker.dataChanged.connect(self.on_data_changed)

    @QtCore.pyqtSlot()
    def dump(self):
        data = [np.full(1000, 1000) for i in range(100000)]
        wrapper = partial(self._worker.dump, self.file, data)
        QtCore.QTimer.singleShot(0, wrapper)

    @QtCore.pyqtSlot()
    def load(self):
        wrapper = partial(self._worker.load, self.file)
        QtCore.QTimer.singleShot(0, wrapper)

    @QtCore.pyqtSlot(object)
    def on_data_changed(self, data):
        print(data)

    @QtCore.pyqtSlot()
    def on_start(self):
        self._manager.start()

    @QtCore.pyqtSlot()
    def on_stop(self):
        self._manager.stop()


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = Widget()
    w.resize(640, 480)
    w.show()
    sys.exit(app.exec_())

如何在用 pickle 加载或转储时阻止动画 QCursor 冻结？

How to stop an animated QCursor from freezing when loading or dumping with pickle?

python

animation

cursor

pyqt5

pickle