如何在 QGraphicsView 中显示 png 或 jpeg？

Question

我有一个 pyqt5 GUI，其中有一个 window 当我单击按钮（称为“显示图像”）时需要显示输出图像。

我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。

有人能帮我找到实现这个目标的正确方法吗？

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 所指出的，你不应该修改 pyuic 生成的文件，所以要恢复它，我假设它叫做 gui.py}。

综合以上情况，您的代码存在以下错误：

您正在将点击信号连接到 QGraphicsView 的 show 方法，这将导致在按下按钮时显示 QGraphicsView，但 QGraphicsView 已经显示，因此它什么都不做。相反，您应该调用 do_test 方法。
你的QGraphicsView没有场景所以你不能放置任何东西。
与其尝试多个 QGraphicsPixmapItem，不如重用它，只更新关联的 QPixmap。
不要在 GUI 中使用 time.sleep，如果你想做周期性任务，那么你将不得不使用带有 QTimer 的计数器。

一个可能的解决方案是下面的代码：

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_())

如何在 QGraphicsView 中显示 png 或 jpeg？

How can I display a png or jpeg in a QGraphicsView?

python

qgraphicsview

python-2.7

pyqt5