如何在 QGraphicsView 中显示 png 或 jpeg？

Question

我有一个 pyqt5 GUI，我有一个 window，当我单击一个按钮（称为“显示图像”）时，它需要显示一个 output 图像。

我已经制作了功能并将它们链接到按钮，但是当我按下按钮时，图像不显示。

有人可以帮助我以正确的方式实现这一目标吗？

这是我的代码：

from PyQt5.QtCore import QCoreApplication, QRectF
from PyQt5.QtGui import QPixmap
from PyQt5 import QtCore, QtGui, QtWidgets, Qt
from PIL import Image, ImageQt, ImageEnhance
import sys
import time

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(1200, 600)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.graphicsView = QtWidgets.QGraphicsView(self.centralwidget)
        self.graphicsView.setGeometry(QtCore.QRect(560, 0, 640, 480))
        self.graphicsView.setObjectName("graphicsView")
        self.RunButton = QtWidgets.QPushButton(self.centralwidget)
        self.RunButton.setGeometry(QtCore.QRect(560, 490, 99, 41))
        self.RunButton.setObjectName("RunButton")
        self.ShowIButton = QtWidgets.QPushButton(self.centralwidget)
        self.ShowIButton.setGeometry(QtCore.QRect(660, 490, 99, 41))
        self.ShowIButton.setObjectName("ShowIButton")
        MainWindow.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 1200, 25))
        self.menubar.setObjectName("menubar")
        self.menuFile = QtWidgets.QMenu(self.menubar)
        self.menuFile.setObjectName("menuFile")
        self.menuStudy = QtWidgets.QMenu(self.menubar)
        self.menuStudy.setObjectName("menuStudy")
        self.menuDocuments = QtWidgets.QMenu(self.menubar)
        self.menuDocuments.setObjectName("menuDocuments")
        self.menuHelp = QtWidgets.QMenu(self.menubar)
        self.menuHelp.setObjectName("menuHelp")
        self.menuTools = QtWidgets.QMenu(self.menubar)
        self.menuTools.setObjectName("menuTools")
        MainWindow.setMenuBar(self.menubar)
        self.actionAbout = QtWidgets.QAction(MainWindow)
        self.actionAbout.setObjectName("actionAbout")
        self.actionNew = QtWidgets.QAction(MainWindow)
        self.actionNew.setObjectName("actionNew")
        self.actionOpen = QtWidgets.QAction(MainWindow)
        self.actionOpen.setObjectName("actionOpen")
        self.actionOpen_2 = QtWidgets.QAction(MainWindow)
        self.actionOpen_2.setObjectName("actionOpen_2")
        self.actionSave = QtWidgets.QAction(MainWindow)
        self.actionSave.setObjectName("actionSave")
        self.actionSave_As = QtWidgets.QAction(MainWindow)
        self.actionSave_As.setObjectName("actionSave_As")
        self.actionClose = QtWidgets.QAction(MainWindow)
        self.actionClose.setObjectName("actionClose")
        self.actionQuit = QtWidgets.QAction(MainWindow)
        self.actionQuit.setObjectName("actionQuit")
        self.actionTrain_Baseline = QtWidgets.QAction(MainWindow)
        self.actionTrain_Baseline.setObjectName("actionTrain_Baseline")
        self.actionTrain_Data_Set = QtWidgets.QAction(MainWindow)
        self.actionTrain_Data_Set.setObjectName("actionTrain_Data_Set")
        self.actionPatient = QtWidgets.QAction(MainWindow)
        self.actionPatient.setObjectName("actionPatient")
        self.actionGroup = QtWidgets.QAction(MainWindow)
        self.actionGroup.setObjectName("actionGroup")
        self.actionView = QtWidgets.QAction(MainWindow)
        self.actionView.setObjectName("actionView")
        self.menuFile.addAction(self.actionNew)
        self.menuFile.addAction(self.actionOpen_2)
        self.menuFile.addAction(self.actionSave)
        self.menuFile.addAction(self.actionSave_As)
        self.menuFile.addAction(self.actionClose)
        self.menuFile.addAction(self.actionQuit)
        self.menuStudy.addAction(self.actionPatient)
        self.menuStudy.addAction(self.actionGroup)
        self.menuDocuments.addAction(self.actionView)
        self.menuHelp.addAction(self.actionAbout)
        self.menuTools.addSeparator()
        self.menuTools.addAction(self.actionTrain_Baseline)
        self.menuTools.addAction(self.actionTrain_Data_Set)
        self.menubar.addAction(self.menuFile.menuAction())
        self.menubar.addAction(self.menuStudy.menuAction())
        self.menubar.addAction(self.menuDocuments.menuAction())
        self.menubar.addAction(self.menuTools.menuAction())
        self.menubar.addAction(self.menuHelp.menuAction())

        self.retranslateUi(MainWindow)
        self.ShowIButton.clicked.connect(self.graphicsView.show)
        #SQtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWIndow"))
        self.RunButton.setText(_translate("MainWindow", "Run"))
        self.ShowIButton.setText(_translate("MainWindow", "Show Image"))
        self.menuFile.setTitle(_translate("MainWindow", "File"))
        self.menuStudy.setTitle(_translate("MainWindow", "Study"))
        self.menuDocuments.setTitle(_translate("MainWindow", "Documents"))
        self.menuHelp.setTitle(_translate("MainWindow", "Help"))
        self.menuTools.setTitle(_translate("MainWindow", "Tools"))
        self.actionAbout.setText(_translate("MainWindow", "About"))
        self.actionNew.setText(_translate("MainWindow", "New"))
        self.actionOpen.setText(_translate("MainWindow", "Open"))
        self.actionOpen_2.setText(_translate("MainWindow", "Open"))
        self.actionSave.setText(_translate("MainWindow", "Save"))
        self.actionSave_As.setText(_translate("MainWindow", "Save As ..."))
        self.actionClose.setText(_translate("MainWindow", "Close"))
        self.actionQuit.setText(_translate("MainWindow", "Quit"))
        self.actionTrain_Baseline.setText(_translate("MainWindow", "Train Baseline"))
        self.actionTrain_Data_Set.setText(_translate("MainWindow", "Train Data Set"))
        self.actionPatient.setText(_translate("MainWindow", "Patient"))
        self.actionGroup.setText(_translate("MainWindow", "Group"))
        self.actionView.setText(_translate("MainWindow", "View"))

    def do_test(self):
        img = Image.open('image1.png')
        enhancer = ImageEnhance.Brightness(img)
        for i in range(1, 8):
            img = enhancer.enhance(i)
            self.display_image(img)
            QCoreApplication.processEvents()  # let Qt do his work
            time.sleep(0.5)

    def display_image(self, img):
        self.graphicsView.clear()
        w, h = img.size
        self.imgQ = ImageQt.ImageQt(img)  # we need to hold reference to imgQ, or it will crash
        pixMap = QPixmap.fromImage(self.imgQ)
        self.graphicsView.addPixmap(pixMap)
        self.graphicsView.fitInView(QRectF(0, 0, w, h), Qt.KeepAspectRatio)
        self.graphicsView.update()


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

Answer 1

_{正如@musicamante指出的那样，您不应该修改 pyuic 生成的文件，因此请恢复它，我假设它被称为 gui.py} 。

考虑到上述情况，您的代码有以下错误：

• 您正在将 clicked 信号连接到 QGraphicsView 的 show 方法，这将导致 QGraphicsView 在按下按钮时显示，但 QGraphicsView 已经显示，因此它什么也不做。 相反，您应该调用 do_test 方法。

• 您的 QGraphicsView 没有场景，因此您无法放置任何东西。

• 与其尝试几个 QGraphicsPixmapItem，不如重用它，只更新相关的 QPixmap。

• 不要在 GUI 中使用 time.sleep，如果要执行周期性任务，则必须使用带有 QTimer 的计数器。

一个可能的解决方案是以下代码：

from PyQt5 import QtCore, QtGui, QtWidgets

from PIL import Image, ImageQt, ImageEnhance

from gui import Ui_MainWindow


class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setupUi(self)
        self.ShowIButton.clicked.connect(self.do_test)

        self.scene = QtWidgets.QGraphicsScene(self)
        self.graphicsView.setScene(self.scene)

        self.pixmap_item = self.scene.addPixmap(QtGui.QPixmap())

        self.level = 1
        self.enhancer = None
        self.timer = QtCore.QTimer(interval=500, timeout=self.on_timeout)

    @QtCore.pyqtSlot()
    def do_test(self):
        input_img = Image.open("image1.png")
        self.enhancer = ImageEnhance.Brightness(input_img)
        self.timer.start()
        self.ShowIButton.setDisabled(True)

    @QtCore.pyqtSlot()
    def on_timeout(self):
        if self.enhancer is not None:
            result_img = self.enhancer.enhance(self.level)
            qimage = ImageQt.ImageQt(result_img)
            self.pixmap_item.setPixmap(QtGui.QPixmap.fromImage(qimage))
        if self.level > 7:
            self.timer.stop()
            self.enhancer = None
            self.level = 0
            self.ShowIButton.setDisabled(False)
        self.level += 1


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())