如何在QGraphicsView中显示PNG或JPEG

Question

我有一个pyqt5 GUI，其中有一个窗口，当我单击按钮时需要显示输出图像(称为"显示图像"(。

我制作了一些功能并将它们链接到按钮，但当我按下按钮时，图像不会显示。

实现这一目标的正确方法是什么？

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，所以要还原它，我会假设它被称为gui。py}.

考虑到以上情况，您的代码有以下错误：

• 您正在将单击的信号连接到QGraphicsView的显示方法，这将导致按下按钮时显示QGraphicsView，但QGraphics视图已经显示，因此它将不起任何作用。相反，您应该调用do_test方法。

• QGraphicsView没有场景，因此无法放置任何内容。

• 与其尝试几个一个QGraphicsPixmapItem，不如重用它，只更新关联的QPixmap。

• 不要在GUI中使用time.sleep，如果要执行定期任务，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_())