用python3+PyQt5改写Python Qt GUI快速编程的第6章实例主窗口

本文是对Python Qt GUI快速编程的第6章的例子MainWindow改写成python3+PyQt5的编码。改动中，本人发现了不少的坑要改动，下文大概列出一些需要更改的重点，并且附上改动后的代码，代码在Python3.5+PyQt5.7的环境下运行并测试正常。请大家参考学习。
此实例有以下程序：
/home/yrd/eric_workspace/charter6/Ui_newimagedlg.py
/home/yrd/eric_workspace/charter6/newimagedlg.py
/home/yrd/eric_workspace/charter6/helpform.py
/home/yrd/eric_workspace/charter6/resizedlg.py
/home/yrd/eric_workspace/charter6/mainwindow.py
资源文件:
/home/yrd/eric_workspace/charter6/resources.qrc
/home/yrd/eric_workspace/charter6/images
/home/yrd/eric_workspace/charter6/help
可在网路上寻找作者这本书的的代码资源获得资源文件。
重点内容：
1，因为settings.value(“RecentFiles”)本身就是list类型，故
self.recentFiles = settings.value(“RecentFiles”).toStringList()
改动为
self.recentFiles=settings.value(“RecentFiles”)
2，类型转换问题

self.restoreGeometry(
      settings.value("MainWindow/Geometry").toByteArray())
self.restoreState(settings.value("MainWindow/State").toByteArray())

改动为

self.restoreGeometry(
     QByteArray(settings.value("MainWindow/Geometry")))
self.restoreState(QByteArray(settings.value("MainWindow/State")))  

3，引入库的问题，有很多，只列一个例子：
from PyQt5.QtPrintSupport import QPrinter,QPrintDialog
4，实例中的坑，QFileDialog.getSaveFileName和QFileDialog.getOpenFileName所返回的结果是一个tupple。第一为文件名，第二个为文件类型。

fname,tpye = QFileDialog.getSaveFileName(self,
       "Image Changer - Save Image", fname,
       "Image files ({0})".format(" ".join(formats)))

fname,tpye = QFileDialog.getOpenFileName(self,
       "Image Changer - Choose Image", dir,
       "Image files ({0})".format(" ".join(formats)))

5，PyQt5开发中应该以python的字符串类型取代Qstring类型。self.recentFiles是list类型，故用append或insert而非prepend。

    def addRecentFile(self, fname):
        if fname is None:
            return
        if not self.recentFiles.contains(fname):
            self.recentFiles.prepend(QString(fname))
            while self.recentFiles.count() > 9:
                self.recentFiles.takeLast()
改成
    def addRecentFile(self, fname):
        if fname is None:
            return
        if fname not in self.recentFiles:
            self.recentFiles.insert(0,fname)
            while len(self.recentFiles) > 9:
                self.recentFiles.pop()

6，信号槽的问题，现举个例子：
self.connect(action, SIGNAL(“triggered()”),self.loadFile)
改成
action.triggered[bool].connect(self.loadFile)
槽self.loadFile根据实际情况也做了些变动。

---

需要通过pyrcc5将resources.qrc转换成py文件，并在主程序引入。
pyrcc5 -o resources_rc.py resources.qrc

/home/yrd/eric_workspace/charter6/resources.qrc

version="1.0">

<file alias="filenew.png">images/filenew.pngfile>
<file alias="fileopen.png">images/fileopen.pngfile>
<file alias="filesave.png">images/filesave.pngfile>
<file alias="filesaveas.png">images/filesaveas.pngfile>
<file alias="fileprint.png">images/fileprint.pngfile>
<file alias="filequit.png">images/filequit.pngfile>
<file alias="editinvert.png">images/editinvert.pngfile>
<file alias="editswap.png">images/editswap.pngfile>
<file alias="editzoom.png">images/editzoom.pngfile>
<file alias="editmirror.png">images/editmirror.pngfile>
<file alias="editunmirror.png">images/editunmirror.pngfile>
<file alias="editmirrorhoriz.png">images/editmirrorhoriz.pngfile>
<file alias="editmirrorvert.png">images/editmirrorvert.pngfile>
<file alias="back.png">images/back.pngfile>
<file alias="home.png">images/home.pngfile>
<file alias="icon.png">images/icon.pngfile>

<file>help/editmenu.htmlfile>
<file>help/filemenu.htmlfile>
<file>help/index.htmlfile>

---

/home/yrd/eric_workspace/charter6/Ui_newimagedlg.py

# -*- coding: utf-8 -*-

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_NewImageDlg(object):
    def setupUi(self, NewImageDlg):
        NewImageDlg.setObjectName("NewImageDlg")
        NewImageDlg.resize(287, 214)
        self.gridlayout = QtWidgets.QGridLayout(NewImageDlg)
        self.gridlayout.setContentsMargins(9, 9, 9, 9)
        self.gridlayout.setSpacing(6)
        self.gridlayout.setObjectName("gridlayout")
        self.buttonBox = QtWidgets.QDialogButtonBox(NewImageDlg)
        self.buttonBox.setOrientation(QtCore.Qt.Horizontal)
        self.buttonBox.setStandardButtons(QtWidgets.QDialogButtonBox.Cancel|QtWidgets.QDialogButtonBox.Ok)
        self.buttonBox.setObjectName("buttonBox")
        self.gridlayout.addWidget(self.buttonBox, 5, 1, 1, 2)
        spacerItem = QtWidgets.QSpacerItem(269, 16, QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Expanding)
        self.gridlayout.addItem(spacerItem, 4, 0, 1, 3)
        self.colorLabel = QtWidgets.QLabel(NewImageDlg)
        self.colorLabel.setFrameShape(QtWidgets.QFrame.StyledPanel)
        self.colorLabel.setFrameShadow(QtWidgets.QFrame.Raised)
        self.colorLabel.setText("")
        self.colorLabel.setScaledContents(True)
        self.colorLabel.setObjectName("colorLabel")
        self.gridlayout.addWidget(self.colorLabel, 3, 1, 1, 1)
        self.label_3 = QtWidgets.QLabel(NewImageDlg)
        self.label_3.setObjectName("label_3")
        self.gridlayout.addWidget(self.label_3, 3, 0, 1, 1)
        self.colorButton = QtWidgets.QPushButton(NewImageDlg)
        self.colorButton.setObjectName("colorButton")
        self.gridlayout.addWidget(self.colorButton, 3, 2, 1, 1)
        self.brushComboBox = QtWidgets.QComboBox(NewImageDlg)
        self.brushComboBox.setObjectName("brushComboBox")
        self.gridlayout.addWidget(self.brushComboBox, 2, 1, 1, 2)
        self.label_4 = QtWidgets.QLabel(NewImageDlg)
        self.label_4.setObjectName("label_4")
        self.gridlayout.addWidget(self.label_4, 2, 0, 1, 1)
        self.label = QtWidgets.QLabel(NewImageDlg)
        self.label.setObjectName("label")
        self.gridlayout.addWidget(self.label, 0, 0, 1, 1)
        self.label_2 = QtWidgets.QLabel(NewImageDlg)
        self.label_2.setObjectName("label_2")
        self.gridlayout.addWidget(self.label_2, 1, 0, 1, 1)
        self.heightSpinBox = QtWidgets.QSpinBox(NewImageDlg)
        self.heightSpinBox.setAlignment(QtCore.Qt.AlignRight)
        self.heightSpinBox.setMinimum(8)
        self.heightSpinBox.setMaximum(512)
        self.heightSpinBox.setSingleStep(4)
        self.heightSpinBox.setProperty("value", 64)
        self.heightSpinBox.setObjectName("heightSpinBox")
        self.gridlayout.addWidget(self.heightSpinBox, 1, 1, 1, 1)
        self.widthSpinBox = QtWidgets.QSpinBox(NewImageDlg)
        self.widthSpinBox.setAlignment(QtCore.Qt.AlignRight)
        self.widthSpinBox.setMinimum(8)
        self.widthSpinBox.setMaximum(512)
        self.widthSpinBox.setSingleStep(4)
        self.widthSpinBox.setProperty("value", 64)
        self.widthSpinBox.setObjectName("widthSpinBox")
        self.gridlayout.addWidget(self.widthSpinBox, 0, 1, 1, 1)
        self.label_4.setBuddy(self.brushComboBox)
        self.label.setBuddy(self.widthSpinBox)
        self.label_2.setBuddy(self.heightSpinBox)

        self.retranslateUi(NewImageDlg)
        self.buttonBox.accepted.connect(NewImageDlg.accept)
        self.buttonBox.rejected.connect(NewImageDlg.reject)
        QtCore.QMetaObject.connectSlotsByName(NewImageDlg)
        NewImageDlg.setTabOrder(self.widthSpinBox, self.heightSpinBox)
        NewImageDlg.setTabOrder(self.heightSpinBox, self.brushComboBox)
        NewImageDlg.setTabOrder(self.brushComboBox, self.colorButton)
        NewImageDlg.setTabOrder(self.colorButton, self.buttonBox)

    def retranslateUi(self, NewImageDlg):
        _translate = QtCore.QCoreApplication.translate
        NewImageDlg.setWindowTitle(_translate("NewImageDlg", "Image Chooser - New Image"))
        self.label_3.setText(_translate("NewImageDlg", "Color"))
        self.colorButton.setText(_translate("NewImageDlg", "&Color..."))
        self.label_4.setText(_translate("NewImageDlg", "&Brush pattern:"))
        self.label.setText(_translate("NewImageDlg", "&Width:"))
        self.label_2.setText(_translate("NewImageDlg", "&Height:"))
        self.heightSpinBox.setSuffix(_translate("NewImageDlg", " px"))
        self.widthSpinBox.setSuffix(_translate("NewImageDlg", " px"))

---

/home/yrd/eric_workspace/charter6/newimagedlg.py

# -*- coding: utf-8 -*-

"""
Module implementing NewImageDlg.
"""

from PyQt5.QtCore import pyqtSlot,Qt,QVariant
from PyQt5.QtWidgets import QDialog,QApplication,QColorDialog
from PyQt5.QtGui import QPixmap,QBrush,QPainter

from Ui_newimagedlg import Ui_NewImageDlg


class NewImageDlg(QDialog, Ui_NewImageDlg):
    """
    Class documentation goes here.
    """
    def __init__(self, parent=None):
        """
        Constructor

        @param parent reference to the parent widget
        @type QWidget
        """
        super(NewImageDlg, self).__init__(parent)
        self.setupUi(self)
        self.color = Qt.red
        for value, text in (
            (Qt.SolidPattern, "Solid"),
            (Qt.Dense1Pattern, "Dense #1"),
            (Qt.Dense2Pattern, "Dense #2"),
            (Qt.Dense3Pattern, "Dense #3"),
            (Qt.Dense4Pattern, "Dense #4"),
            (Qt.Dense5Pattern, "Dense #5"),
            (Qt.Dense6Pattern, "Dense #6"),
            (Qt.Dense7Pattern, "Dense #7"),
            (Qt.HorPattern, "Horizontal"),
            (Qt.VerPattern, "Vertical"),
            (Qt.CrossPattern, "Cross"),
            (Qt.BDiagPattern, "Backward Diagonal"),
            (Qt.FDiagPattern, "Forward Diagonal"),
            (Qt.DiagCrossPattern, "Diagonal Cross")):
            self.brushComboBox.addItem(text, QVariant(value))


        self.colorButton.clicked.connect(self.getColor)
        self.brushComboBox.activated.connect(self.setColor)
        self.setColor()
        self.widthSpinBox.setFocus()

    def getColor(self):
        color = QColorDialog.getColor(Qt.black, self)
        if color.isValid():
            self.color = color
            self.setColor()


    def setColor(self):
        pixmap = self._makePixmap(60, 30)
        self.colorLabel.setPixmap(pixmap)


    def image(self):
        pixmap = self._makePixmap(self.widthSpinBox.value(),
                                  self.heightSpinBox.value())
        return QPixmap.toImage(pixmap)


    def _makePixmap(self, width, height):
        pixmap = QPixmap(width, height)
        style = self.brushComboBox.itemData(
                self.brushComboBox.currentIndex())
        brush = QBrush(self.color, Qt.BrushStyle(style))
        painter = QPainter(pixmap)
        painter.fillRect(pixmap.rect(), Qt.white)
        painter.fillRect(pixmap.rect(), brush)
        return pixmap

---

/home/yrd/eric_workspace/charter6/helpform.py

# -*- coding: utf-8 -*-

from PyQt5.QtCore import QUrl, Qt
from PyQt5.QtWidgets import QAction, QApplication, QDialog,QLabel, QTextBrowser, QToolBar, QVBoxLayout
from PyQt5.QtGui import QIcon,QKeySequence
import resources_rc

class HelpForm(QDialog):

    def __init__(self, page, parent=None):
        super(HelpForm, self).__init__(parent)
        self.setAttribute(Qt.WA_DeleteOnClose)
        self.setAttribute(Qt.WA_GroupLeader)

        backAction = QAction(QIcon(":/back.png"), "&Back", self)
        backAction.setShortcut(QKeySequence.Back)
        homeAction = QAction(QIcon(":/home.png"), "&Home", self)
        homeAction.setShortcut("Home")
        self.pageLabel = QLabel()

        toolBar = QToolBar()
        toolBar.addAction(backAction)
        toolBar.addAction(homeAction)
        toolBar.addWidget(self.pageLabel)
        self.textBrowser = QTextBrowser()

        layout = QVBoxLayout()
        layout.addWidget(toolBar)
        layout.addWidget(self.textBrowser, 1)
        self.setLayout(layout)

        backAction.triggered.connect(self.tbackward)
        homeAction.triggered.connect(self.thome)
        self.textBrowser.sourceChanged.connect(self.updatePageTitle)

        self.textBrowser.setSearchPaths([":/help"])
        self.textBrowser.setSource(QUrl(page))
        self.resize(400, 600)
        self.setWindowTitle("{0} Help".format(
                QApplication.applicationName()))


    def updatePageTitle(self):
        self.pageLabel.setText(self.textBrowser.documentTitle())
    def tbackward(self):
        self.textBrowser.backward()
    def thome(self):
        self.textBrowser.home()

---

/home/yrd/eric_workspace/charter6/resizedlg.py

# -*- coding: utf-8 -*-

from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import (QApplication, QDialog, QDialogButtonBox,
        QGridLayout, QLabel, QSpinBox)


class ResizeDlg(QDialog):

    def __init__(self, width, height, parent=None):
        super(ResizeDlg, self).__init__(parent)

        widthLabel = QLabel("&Width:")
        self.widthSpinBox = QSpinBox()
        widthLabel.setBuddy(self.widthSpinBox)
        self.widthSpinBox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
        self.widthSpinBox.setRange(4, width * 4)
        self.widthSpinBox.setValue(width)
        heightLabel = QLabel("&Height:")
        self.heightSpinBox = QSpinBox()
        heightLabel.setBuddy(self.heightSpinBox)
        self.heightSpinBox.setAlignment(Qt.AlignRight|
                                        Qt.AlignVCenter)
        self.heightSpinBox.setRange(4, height * 4)
        self.heightSpinBox.setValue(height)

        buttonBox = QDialogButtonBox(QDialogButtonBox.Ok|
                                     QDialogButtonBox.Cancel)

        layout = QGridLayout()
        layout.addWidget(widthLabel, 0, 0)
        layout.addWidget(self.widthSpinBox, 0, 1)
        layout.addWidget(heightLabel, 1, 0)
        layout.addWidget(self.heightSpinBox, 1, 1)
        layout.addWidget(buttonBox, 2, 0, 1, 2)
        self.setLayout(layout)

        buttonBox.accepted.connect(self.accept)
        buttonBox.rejected.connect(self.reject)

        self.setWindowTitle("Image Changer - Resize")


    def result(self):
        return self.widthSpinBox.value(), self.heightSpinBox.value()

---

/home/yrd/eric_workspace/charter6/mainwindow.py

# -*- coding: utf-8 -*-

"""
Module implementing MainWindow.
"""

from PyQt5.QtCore import pyqtSlot,Qt,PYQT_VERSION_STR,QT_VERSION_STR,QSettings,QTimer,QFile, QFileInfo,QByteArray,QVariant
from PyQt5.QtWidgets import QMainWindow,QDockWidget,QLabel,QDockWidget,QListWidget,QApplication,\
                            QFrame,QAction,QActionGroup,QMessageBox,QSpinBox,QFileDialog,QInputDialog
from PyQt5.QtGui import QImage,QIcon,QKeySequence,QPixmap,QImageReader,QImageWriter,QPainter
from PyQt5.QtPrintSupport import QPrinter,QPrintDialog
import helpform
import newimagedlg
import resizedlg
import platform
import sys
import resources_rc
import os
__version__ = "1.0.0"
class MainWindow(QMainWindow):
    """
    Class documentation goes here.
    """
    def __init__(self, parent=None):
        """
        Constructor

        @param parent reference to the parent widget
        @type QWidget
        """
        super(MainWindow, self).__init__(parent)

        self.image = QImage()
        self.dirty = False
        self.filename = None
        self.mirroredvertically = False
        self.mirroredhorizontally = False

        self.imageLabel = QLabel()
        self.imageLabel.setMinimumSize(200, 200)
        self.imageLabel.setAlignment(Qt.AlignCenter)
        self.imageLabel.setContextMenuPolicy(Qt.ActionsContextMenu)
        self.setCentralWidget(self.imageLabel)

        logDockWidget = QDockWidget("Log", self)
        logDockWidget.setObjectName("LogDockWidget")
        logDockWidget.setAllowedAreas(Qt.LeftDockWidgetArea|
                                      Qt.RightDockWidgetArea)
        self.listWidget = QListWidget()
        logDockWidget.setWidget(self.listWidget)
        self.addDockWidget(Qt.RightDockWidgetArea, logDockWidget)

        self.printer = None

        self.sizeLabel = QLabel()
        self.sizeLabel.setFrameStyle(QFrame.StyledPanel|QFrame.Sunken)
        status = self.statusBar()
        status.setSizeGripEnabled(False)
        status.addPermanentWidget(self.sizeLabel)
        status.showMessage("Ready", 5000)#clearMessage()

        fileNewAction = self.createAction("&New...", self.fileNew,
                                          QKeySequence.New, "filenew", "Create an image file")
        fileOpenAction = self.createAction("&Open...", self.fileOpen,
                                           QKeySequence.Open, "fileopen",
                                           "Open an existing image file")
        fileSaveAction = self.createAction("&Save", self.fileSave,
                                           QKeySequence.Save, "filesave", "Save the image")
        fileSaveAsAction = self.createAction("Save &As...",
                                             self.fileSaveAs, icon="filesaveas",
                                             tip="Save the image using a new name")
        filePrintAction = self.createAction("&Print", self.filePrint,
                                            QKeySequence.Print, "fileprint", "Print the image")
        fileQuitAction = self.createAction("&Quit", self.close,
                                           "Ctrl+Q", "filequit", "Close the application")        

        editInvertAction = self.createAction("&Invert",
                                             self.editInvert, "Ctrl+I", "editinvert",
                                             "Invert the image's colors", True, "toggled(bool)")
        editSwapRedAndBlueAction = self.createAction("Sw&ap Red and Blue",
                                                     self.editSwapRedAndBlue, "Ctrl+A", "editswap",
                                                     "Swap the image's red and blue color components", True,
                                                     "toggled(bool)")
        editZoomAction = self.createAction("&Zoom...", self.editZoom,
                                           "Alt+Z", "editzoom", "Zoom the image")

        editResizeAction = self.createAction("&Resize...",
                                             self.editResize, "Ctrl+R", "editresize",
                                             "Resize the image")        
        mirrorGroup = QActionGroup(self)
        editUnMirrorAction = self.createAction("&Unmirror",
                                               self.editUnMirror, "Ctrl+U", "editunmirror",
                                               "Unmirror the image", True, "toggled(bool)")
        mirrorGroup.addAction(editUnMirrorAction)
        editMirrorHorizontalAction = self.createAction(
            "Mirror &Horizontally", self.editMirrorHorizontal,
            "Ctrl+H", "editmirrorhoriz",
            "Horizontally mirror the image", True, "toggled(bool)")
        mirrorGroup.addAction(editMirrorHorizontalAction)
        editMirrorVerticalAction = self.createAction(
            "Mirror &Vertically", self.editMirrorVertical,
            "Ctrl+V", "editmirrorvert",
            "Vertically mirror the image", True, "toggled(bool)")
        mirrorGroup.addAction(editMirrorVerticalAction)
        editUnMirrorAction.setChecked(True)

        helpAboutAction = self.createAction("&About Image Changer",
                                            self.helpAbout)
        helpHelpAction = self.createAction("&Help", self.helpHelp,
                                           QKeySequence.HelpContents)

        #file Menu
        self.fileMenu = self.menuBar().addMenu("&File")
        self.fileMenuActions = (fileNewAction, fileOpenAction,
                                fileSaveAction, fileSaveAsAction, None, filePrintAction,
                                fileQuitAction)

        self.fileMenu.aboutToShow.connect(self.updateFileMenu)
        #edit Menu
        editMenu = self.menuBar().addMenu("&Edit")
        self.addActions(editMenu, (editInvertAction,
                                   editSwapRedAndBlueAction, editZoomAction,editResizeAction))        
        #mirrorMenu
        mirrorMenu = editMenu.addMenu(QIcon(":/editmirror.png"),
                                      "&Mirror")
        self.addActions(mirrorMenu, (editUnMirrorAction,
                                     editMirrorHorizontalAction, editMirrorVerticalAction))   
        #help Menu
        helpMenu = self.menuBar().addMenu("&Help")
        self.addActions(helpMenu, (helpAboutAction, helpHelpAction))   


        #tool bar
        fileToolbar = self.addToolBar("File")
        fileToolbar.setObjectName("FileToolBar")
        self.addActions(fileToolbar, (fileNewAction, fileOpenAction,
                                      fileSaveAsAction))
        editToolbar = self.addToolBar("Edit")
        editToolbar.setObjectName("EditToolBar")
        self.addActions(editToolbar, (editInvertAction,
                                      editSwapRedAndBlueAction, editUnMirrorAction,
                                      editMirrorVerticalAction, editMirrorHorizontalAction))
        self.zoomSpinBox = QSpinBox()
        self.zoomSpinBox.setRange(1, 400)
        self.zoomSpinBox.setSuffix(" %")
        self.zoomSpinBox.setValue(100)
        self.zoomSpinBox.setToolTip("Zoom the image")
        self.zoomSpinBox.setStatusTip(self.zoomSpinBox.toolTip())
        self.zoomSpinBox.setFocusPolicy(Qt.NoFocus)
        self.zoomSpinBox.valueChanged[int].connect(self.showImage)
        editToolbar.addWidget(self.zoomSpinBox)

        self.addActions(self.imageLabel, (editInvertAction,
                                          editSwapRedAndBlueAction, editUnMirrorAction,
                                          editMirrorVerticalAction, editMirrorHorizontalAction))

        self.resetableActions = ((editInvertAction, False),
                                 (editSwapRedAndBlueAction, False),
                                 (editUnMirrorAction, True))

        settings = QSettings("MyCompany", "MyApp")

        self.recentFiles=settings.value("RecentFiles")
        #self.recentFiles = []
        self.restoreGeometry(
            QByteArray(settings.value("MainWindow/Geometry")))
        self.restoreState(QByteArray(settings.value("MainWindow/State")))          
        self.setWindowTitle("Image Changer")
        self.updateFileMenu()
        QTimer.singleShot(0, self.loadInitialFile)


    def createAction(self, text, slot=None, shortcut=None, icon=None,
                     tip=None, checkable=False, signal="triggered()"):
        action = QAction(text, self)
        if icon is not None:
            action.setIcon(QIcon(":/{0}.png".format(icon)))
        if shortcut is not None:
            action.setShortcut(shortcut)
        if tip is not None:
            action.setToolTip(tip)
            action.setStatusTip(tip)
        if slot is not None and signal=="triggered()":
            action.triggered.connect(slot)
        if slot is not None and signal=="toggled(bool)":
            action.toggled[bool].connect(slot)        
        if checkable:
            action.setCheckable(True)
        return action


    def addActions(self, target, actions):
        for action in actions:
            if action is None:
                target.addSeparator()
            else:
                target.addAction(action)

    def updateFileMenu(self):
        self.fileMenu.clear()
        self.addActions(self.fileMenu, self.fileMenuActions[:-1])
        current = self.filename
        recentFiles = []
        #self.recentFiles=[]
        for fname in self.recentFiles:
            if fname != current and QFile.exists(fname):
                #recentFiles.insert(0,fname)
                recentFiles.append(fname)
        if recentFiles:
            self.fileMenu.addSeparator()
            for i, fname in enumerate(recentFiles):
                action = QAction(QIcon(":/icon.png"),
                                 "&{0} {1}".format(i + 1, QFileInfo(
                                     fname).fileName()), self)
                action.setData(QVariant(fname))
                action.triggered[bool].connect(self.loadFile)
                self.fileMenu.addAction(action)
        self.fileMenu.addSeparator()
        self.fileMenu.addAction(self.fileMenuActions[-1])        


    def okToContinue(self):
        if self.dirty:
            reply = QMessageBox.question(self,
                    "Image Changer - Unsaved Changes",
                    "Save unsaved changes?",
                    QMessageBox.Yes|QMessageBox.No|QMessageBox.Cancel)
            if reply == QMessageBox.Cancel:
                return False
            elif reply == QMessageBox.Yes:
                return self.fileSave()
        return True                
    def fileNew(self):
        if not self.okToContinue():
            return
        dialog = newimagedlg.NewImageDlg(self)
        if dialog.exec_():
            self.addRecentFile(self.filename)
            self.image = QImage()
            for action, check in self.resetableActions:
                action.setChecked(check)
            self.image = dialog.image()
            self.filename = None
            self.dirty = True
            self.showImage()
            self.sizeLabel.setText("{0} x {1}".format(self.image.width(),
                                                      self.image.height()))
            self.updateStatus("Created new image")        
    def fileOpen(self):
        if not self.okToContinue():
            return
        dir = (os.path.dirname(self.filename)
               if self.filename is not None else ".")
        formats = (["*.{0}".format(format.data().decode("ascii").lower())
                for format in QImageReader.supportedImageFormats()])
        fname,tpye = QFileDialog.getOpenFileName(self,
                "Image Changer - Choose Image", dir,
                "Image files ({0})".format(" ".join(formats)))
        if fname:
            self.loadFile(True,fname)        

    def fileSave(self):
        if self.image.isNull():
            return True
        if self.filename is None:
            return self.fileSaveAs()
        else:
            if self.image.save(self.filename, None):
                self.updateStatus("Saved as {0}".format(self.filename))
                self.dirty = False
                return True
            else:
                self.updateStatus("Failed to save {0}".format(
                                  self.filename))
                return False

    def fileSaveAs(self):
        if self.image.isNull():
            return True
        fname = self.filename if self.filename is not None else "."
        formats = (["*.{0}".format(format.data().decode("ascii").lower())
                for format in QImageWriter.supportedImageFormats()])
        fname,tpye = QFileDialog.getSaveFileName(self,
                "Image Changer - Save Image", fname,
                "Image files ({0})".format(" ".join(formats)))
        if fname:
            if "." not in fname:
                fname += ".png"
            self.addRecentFile(fname)
            self.filename = fname
            return self.fileSave()
        return False        
    def filePrint(self):
        if self.image.isNull():
            return
        if self.printer is None:
            self.printer = QPrinter(QPrinter.HighResolution)
            self.printer.setPageSize(QPrinter.Letter)
        form = QPrintDialog(self.printer, self)
        if form.exec_():
            painter = QPainter(self.printer)
            rect = painter.viewport()
            size = self.image.size()
            size.scale(rect.size(), Qt.KeepAspectRatio)
            painter.setViewport(rect.x(), rect.y(), size.width(),
                                size.height())
            painter.drawImage(0, 0, self.image)        

    def loadFile(self,actiontrigger=False,fname=None):
        if fname is None:
            action = self.sender()
            if isinstance(action, QAction):
                fname = str(action.data())
                if not self.okToContinue():
                    return
            else:
                return
        print(fname)
        if fname:
            self.filename = None
            image = QImage(fname)
            if image.isNull():
                message = "Failed to read {0}".format(fname)
            else:
                self.addRecentFile(fname)
                self.image = QImage()
                for action, check in self.resetableActions:
                    action.setChecked(check)
                self.image = image
                self.filename = fname
                self.showImage()
                self.dirty = False
                self.sizeLabel.setText("{0} x {1}".format(
                                       image.width(), image.height()))
                message = "Loaded {0}".format(os.path.basename(fname))
            self.updateStatus(message)      
    def loadInitialFile(self):
        settings = QSettings()
        fname = str(settings.value("LastFile"))
        if fname and QFile.exists(fname):
            self.loadFile(fname)

    def addRecentFile(self, fname):
        if fname is None:
            return
        if fname not in self.recentFiles:
            self.recentFiles.insert(0,fname)
            while len(self.recentFiles) > 9:
                self.recentFiles.pop()

    def updateStatus(self, message):
        self.statusBar().showMessage(message, 5000)
        self.listWidget.addItem(message)
        if self.filename is not None:
            self.setWindowTitle("Image Changer - {0}[*]".format(
                                os.path.basename(self.filename)))
        elif not self.image.isNull():
            self.setWindowTitle("Image Changer - Unnamed[*]")
        else:
            self.setWindowTitle("Image Changer[*]")
        self.setWindowModified(self.dirty)

    def editInvert(self, on):
        if self.image.isNull():
            return
        self.image.invertPixels()
        self.showImage()
        self.dirty = True
        self.updateStatus("Inverted" if on else "Uninverted")


    def editSwapRedAndBlue(self, on):
        if self.image.isNull():
            return
        self.image = self.image.rgbSwapped()
        self.showImage()
        self.dirty = True
        self.updateStatus(("Swapped Red and Blue"
                           if on else "Unswapped Red and Blue"))

    def editZoom(self):
        if self.image.isNull():
            return
        percent, ok = QInputDialog.getInt(self,
                "Image Changer - Zoom", "Percent:",
                self.zoomSpinBox.value(), 1, 400)
        if ok:
            self.zoomSpinBox.setValue(percent)


    def editUnMirror(self, on):
        if self.image.isNull():
            return
        if self.mirroredhorizontally:
            self.editMirrorHorizontal(False)
        if self.mirroredvertically:
            self.editMirrorVertical(False)


    def editMirrorHorizontal(self, on):
        if self.image.isNull():
            return
        self.image = self.image.mirrored(True, False)
        self.showImage()
        self.mirroredhorizontally = not self.mirroredhorizontally
        self.dirty = True
        self.updateStatus(("Mirrored Horizontally"
                           if on else "Unmirrored Horizontally"))


    def editMirrorVertical(self, on):
        if self.image.isNull():
            return
        self.image = self.image.mirrored(False, True)
        self.showImage()
        self.mirroredvertically = not self.mirroredvertically
        self.dirty = True
        self.updateStatus(("Mirrored Vertically"
                           if on else "Unmirrored Vertically"))           



    def editResize(self):
        if self.image.isNull():
            return
        form = resizedlg.ResizeDlg(self.image.width(),
                                   self.image.height(), self)
        if form.exec_():
            width, height = form.result()
            if (width == self.image.width() and
                height == self.image.height()):
                self.statusBar().showMessage("Resized to the same size",
                                             5000)
            else:
                self.image = self.image.scaled(width, height)
                self.showImage()
                self.dirty = True
                size = "{0} x {1}".format(self.image.width(),
                                          self.image.height())
                self.sizeLabel.setText(size)
                self.updateStatus("Resized to {0}".format(size))
    def helpAbout(self):
        QMessageBox.about(self, "About Image Changer",
                """Image Changer v {0}
                
Copyright © 2008-9 Qtrac Ltd. 
                All rights reserved.
                
This application can be used to perform
                simple image manipulations.
                
Python {1} - Qt {2} - PyQt {3} on {4}""".format(
                __version__, platform.python_version(),
                QT_VERSION_STR, PYQT_VERSION_STR,
                platform.system()))


    def helpHelp(self):
        form = helpform.HelpForm("index.html", self)
        form.show()

    def showImage(self, percent=None):
        if self.image.isNull():
            return
        if percent is None:
            percent = self.zoomSpinBox.value()
        factor = percent / 100.0
        width = self.image.width() * factor
        height = self.image.height() * factor
        image = self.image.scaled(width, height, Qt.KeepAspectRatio)
        self.imageLabel.setPixmap(QPixmap.fromImage(image))

    def closeEvent(self, event):
        if self.okToContinue():
            settings = QSettings("MyCompany", "MyApp")
            settings.setValue("LastFile", self.filename)
            settings.setValue("RecentFiles", self.recentFiles)
            settings.setValue("MainWindow/Geometry",self.saveGeometry())
            settings.setValue("MainWindow/State", self.saveState())

        else:
            event.ignore()

if __name__ == "__main__":
    app = QApplication(sys.argv)
    form = MainWindow()
    form.show()
    app.exec_()

---

运行结果：