setPixmap crashing when trying to show image in label

问题

I have created a minimal example with pyqt designer, that changes the text of a label when a button is pressed and is supposed to present a screenshot in the window, via the label.

Unfortunately, the example just crashes when it tries to show the screenshot in the label.

from PIL.ImageQt import ImageQt
from PyQt5 import QtCore, QtGui, QtWidgets
from pyscreenshot import grab

class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(503, 382)
        self.pushButton = QtWidgets.QPushButton(Form)
        self.pushButton.setGeometry(QtCore.QRect(70, 30, 75, 23))
        self.pushButton.setObjectName("pushButton")
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(80, 100, 47, 14))
        self.label.setObjectName("label")

        self.retranslateUi(Form)
        self.pushButton.clicked.connect(lambda: self.take_screenshot())
        QtCore.QMetaObject.connectSlotsByName(Form)

    def take_screenshot(self):
        self.label.setText("1?")
        screenshot = grab()
        self.label.setText("2")
        qim = ImageQt(screenshot)
        pix = QtGui.QPixmap.fromImage(qim)
        self.label.setText("3")
        self.label.setPixmap(pix)



    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.pushButton.setText(_translate("Form", "PushButton"))
        self.label.setText(_translate("Form", "TextLabel"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Form = QtWidgets.QWidget()
    ui = Ui_Form()
    ui.setupUi(Form)
    Form.show()
    sys.exit(app.exec_())

回答1:

"screenshot" shares the same memory with "qimg", and as screenshot it is a local variable that when eliminated the associated memory is also eliminated so the QPbelmap of the QLabel when trying to access information will generate a Segmentation fault. The solution is to make a copy so that they do not share the same memory

def take_screenshot(self):
    screenshot = grab()
    qim = ImageQt(screenshot).copy()
    pix = QtGui.QPixmap.fromImage(qim)
    self.label.setPixmap(pix)
    self.label.adjustSize()

来源：https://stackoverflow.com/questions/61354609/setpixmap-crashing-when-trying-to-show-image-in-label

标签

python

pyqt

pyqt5

screenshot

qpixmap