python3+PyQt5 图形项的自定义和交互--实现page Designer应用程序

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本文通过Python3+PyQt5实现《python Qt Gui 快速编程》这本书的page Designer应用程序,采用QGraphicsView,QGraphicsScene,QGraphicsItem,这个程序包含有多个文本,图片和框的页面。有些图形类在PyQt5已过时,所以本代码改动幅度比较大。主要的类或方法的改变如下:
QMatrix==>QTransform
setMatrix==>setTransform
rotate ==> setRotation
本例中,由于event.delta()已过时,还重写了wheelEvent方法:

    def wheelEvent(self, event):        #factor = 1.41 ** (-event.delta() / 240.0)         #factor = 1.41 ** (-abs(event.startX()-event.y()) / 240.0)        factor = event.angleDelta().y()/120.0        if event.angleDelta().y()/120.0 > 0:            factor=2        else:            factor=0.5        self.scale(factor, factor)

为了保持代码可读行,增加了一个类:

class GraphicsPixmapItem(QGraphicsPixmapItem):        #add by yangrongdong    def __init__(self,pixmap):        super(QGraphicsPixmapItem, self).__init__(pixmap)

本例中还有包含菜单的按钮:

            if text == "&Align":                menu = QMenu(self)                for text, arg in (                        ("Align &Left", Qt.AlignLeft),                        ("Align &Right", Qt.AlignRight),                        ("Align &Top", Qt.AlignTop),                        ("Align &Bottom", Qt.AlignBottom)):                    wrapper = functools.partial(self.setAlignment, arg)                    self.wrapped.append(wrapper)                    menu.addAction(text, wrapper)                button.setMenu(menu)

本例中还针对QStyleOptionGraphicsItem.levelOfDetail已过时,改写如下:
option.levelOfDetailFromTransform(self.transform())
下面为完整的代码:

#!/usr/bin/env python3import functoolsimport randomimport sysfrom PyQt5.QtCore import (QByteArray, QDataStream, QFile, QFileInfo,                          QIODevice, QPoint, QPointF, QRectF, Qt)from PyQt5.QtWidgets import (QApplication, QDialog,                             QDialogButtonBox, QFileDialog, QFontComboBox,                             QGraphicsItem, QGraphicsPixmapItem,                             QGraphicsScene, QGraphicsTextItem, QGraphicsView, QGridLayout,                             QHBoxLayout, QLabel, QMenu, QMessageBox,QPushButton, QSpinBox,                             QStyle, QTextEdit, QVBoxLayout)from PyQt5.QtGui import QFont,QCursor,QFontMetrics,QTransform,QPainter,QPen,QPixmapfrom PyQt5.QtPrintSupport import QPrinter,QPrintDialogMAC = Truetry:    from PyQt5.QtGui import qt_mac_set_native_menubarexcept ImportError:    MAC = False#PageSize = (595, 842) # A4 in pointsPageSize = (612, 792) # US Letter in pointsPointSize = 10MagicNumber = 0x70616765FileVersion = 1Dirty = Falseclass TextItemDlg(QDialog):    def __init__(self, item=None, position=None, scene=None, parent=None):        super(QDialog, self).__init__(parent)        self.item = item        self.position = position        self.scene = scene        self.editor = QTextEdit()        self.editor.setAcceptRichText(False)        self.editor.setTabChangesFocus(True)        editorLabel = QLabel("&Text:")        editorLabel.setBuddy(self.editor)        self.fontComboBox = QFontComboBox()        self.fontComboBox.setCurrentFont(QFont("Times", PointSize))        fontLabel = QLabel("&Font:")        fontLabel.setBuddy(self.fontComboBox)        self.fontSpinBox = QSpinBox()        self.fontSpinBox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)        self.fontSpinBox.setRange(6, 280)        self.fontSpinBox.setValue(PointSize)        fontSizeLabel = QLabel("&Size:")        fontSizeLabel.setBuddy(self.fontSpinBox)        self.buttonBox = QDialogButtonBox(QDialogButtonBox.Ok|                                          QDialogButtonBox.Cancel)        self.buttonBox.button(QDialogButtonBox.Ok).setEnabled(False)        if self.item is not None:            self.editor.setPlainText(self.item.toPlainText())            self.fontComboBox.setCurrentFont(self.item.font())            self.fontSpinBox.setValue(self.item.font().pointSize())        layout = QGridLayout()        layout.addWidget(editorLabel, 0, 0)        layout.addWidget(self.editor, 1, 0, 1, 6)        layout.addWidget(fontLabel, 2, 0)        layout.addWidget(self.fontComboBox, 2, 1, 1, 2)        layout.addWidget(fontSizeLabel, 2, 3)        layout.addWidget(self.fontSpinBox, 2, 4, 1, 2)        layout.addWidget(self.buttonBox, 3, 0, 1, 6)        self.setLayout(layout)        self.fontComboBox.currentFontChanged.connect(self.updateUi)        self.fontSpinBox.valueChanged.connect(self.updateUi)        self.editor.textChanged.connect(self.updateUi)        self.buttonBox.accepted.connect(self.accept)        self.buttonBox.rejected.connect(self.reject)        self.setWindowTitle("Page Designer - {0} Text Item".format(                "Add" if self.item is None else "Edit"))        self.updateUi()    def updateUi(self):        font = self.fontComboBox.currentFont()        font.setPointSize(self.fontSpinBox.value())        self.editor.document().setDefaultFont(font)        self.buttonBox.button(QDialogButtonBox.Ok).setEnabled(                bool(self.editor.toPlainText()))    def accept(self):        if self.item is None:            self.item = TextItem("", self.position, self.scene)        font = self.fontComboBox.currentFont()        font.setPointSize(self.fontSpinBox.value())        self.item.setFont(font)        self.item.setPlainText(self.editor.toPlainText())           self.item.update()        global Dirty        Dirty = True        QDialog.accept(self)class TextItem(QGraphicsTextItem):    def __init__(self, text, position, scene,                 font=QFont("Times", PointSize), matrix=QTransform()):        super(TextItem, self).__init__(text)        self.setFlags(QGraphicsItem.ItemIsSelectable|                      QGraphicsItem.ItemIsMovable)        self.setFont(font)        self.setPos(position)        self.setTransform(matrix)        scene.clearSelection()        scene.addItem(self)        self.setSelected(True)        global Dirty        Dirty = True    def parentWidget(self):        return self.scene().views()[0]    def itemChange(self, change, variant):        if change != QGraphicsItem.ItemSelectedChange:            global Dirty            Dirty = True        return QGraphicsTextItem.itemChange(self, change, variant)    def mouseDoubleClickEvent(self, event):        dialog = TextItemDlg(self, self.parentWidget())        dialog.exec_()class GraphicsPixmapItem(QGraphicsPixmapItem):        #add by yangrongdong    def __init__(self,pixmap):        super(QGraphicsPixmapItem, self).__init__(pixmap)class BoxItem(QGraphicsItem):    def __init__(self, position, scene, style=Qt.SolidLine,                 rect=None, matrix=QTransform()):        super(BoxItem, self).__init__()        self.setFlags(QGraphicsItem.ItemIsSelectable|                      QGraphicsItem.ItemIsMovable|                      QGraphicsItem.ItemIsFocusable)        if rect is None:            rect = QRectF(-10 * PointSize, -PointSize, 20 * PointSize,                          2 * PointSize)        self.rect = rect        self.style = style        self.setPos(position)        self.setTransform(matrix)        scene.clearSelection()        scene.addItem(self)        self.setSelected(True)        self.setFocus()        global Dirty        Dirty = True    def parentWidget(self):        return self.scene().views()[0]    def boundingRect(self):        return self.rect.adjusted(-2, -2, 2, 2)    def paint(self, painter, option, widget):        pen = QPen(self.style)        pen.setColor(Qt.black)        pen.setWidth(1)        if option.state & QStyle.State_Selected:            pen.setColor(Qt.blue)        painter.setPen(pen)        painter.drawRect(self.rect)    def itemChange(self, change, variant):        if change != QGraphicsItem.ItemSelectedChange:            global Dirty            Dirty = True        return QGraphicsItem.itemChange(self, change, variant)    def contextMenuEvent(self, event):        wrapped = []        menu = QMenu(self.parentWidget())        for text, param in (                ("&Solid", Qt.SolidLine),                ("&Dashed", Qt.DashLine),                ("D&otted", Qt.DotLine),                ("D&ashDotted", Qt.DashDotLine),                ("DashDo&tDotted", Qt.DashDotDotLine)):            wrapper = functools.partial(self.setStyle, param)            wrapped.append(wrapper)            menu.addAction(text, wrapper)        menu.exec_(event.screenPos())    def setStyle(self, style):        self.style = style        self.update()        global Dirty        Dirty = True    def keyPressEvent(self, event):        factor = PointSize / 4        changed = False        if event.modifiers() & Qt.ShiftModifier:            if event.key() == Qt.Key_Left:                self.rect.setRight(self.rect.right() - factor)                changed = True            elif event.key() == Qt.Key_Right:                self.rect.setRight(self.rect.right() + factor)                changed = True            elif event.key() == Qt.Key_Up:                self.rect.setBottom(self.rect.bottom() - factor)                changed = True            elif event.key() == Qt.Key_Down:                self.rect.setBottom(self.rect.bottom() + factor)                changed = True        if changed:            self.update()            global Dirty            Dirty = True        else:            QGraphicsItem.keyPressEvent(self, event)class GraphicsView(QGraphicsView):    def __init__(self, parent=None):        super(GraphicsView, self).__init__(parent)        self.setDragMode(QGraphicsView.RubberBandDrag)        self.setRenderHint(QPainter.Antialiasing)        self.setRenderHint(QPainter.TextAntialiasing)    def wheelEvent(self, event):        #factor = 1.41 ** (-event.delta() / 240.0)         factor = event.angleDelta().y()/120.0        if event.angleDelta().y()/120.0 > 0:            factor=2        else:            factor=0.5        self.scale(factor, factor)class MainForm(QDialog):    def __init__(self, parent=None):        super(MainForm, self).__init__(parent)        self.filename = ""        self.copiedItem = QByteArray()        self.pasteOffset = 5        self.prevPoint = QPoint()        self.addOffset = 5        self.borders = []        self.printer = QPrinter(QPrinter.HighResolution)        self.printer.setPageSize(QPrinter.Letter)        self.view = GraphicsView()        self.scene = QGraphicsScene(self)        self.scene.setSceneRect(0, 0, PageSize[0], PageSize[1])        self.addBorders()        self.view.setScene(self.scene)        self.wrapped = [] # Needed to keep wrappers alive        buttonLayout = QVBoxLayout()        for text, slot in (                ("Add &Text", self.addText),                ("Add &Box", self.addBox),                ("Add Pi&xmap", self.addPixmap),                ("&Align", None),                ("&Copy", self.copy),                ("C&ut", self.cut),                ("&Paste", self.paste),                ("&Delete...", self.delete),                ("&Rotate", self.rotate),                ("Pri&nt...", self.print_),                ("&Open...", self.open),                ("&Save", self.save),                ("&Quit", self.accept)):            button = QPushButton(text)            if not MAC:                button.setFocusPolicy(Qt.NoFocus)            if slot is not None:                button.clicked.connect(slot)            if text == "&Align":                menu = QMenu(self)                for text, arg in (                        ("Align &Left", Qt.AlignLeft),                        ("Align &Right", Qt.AlignRight),                        ("Align &Top", Qt.AlignTop),                        ("Align &Bottom", Qt.AlignBottom)):                    wrapper = functools.partial(self.setAlignment, arg)                    self.wrapped.append(wrapper)                    menu.addAction(text, wrapper)                button.setMenu(menu)            if text == "Pri&nt...":                buttonLayout.addStretch(5)            if text == "&Quit":                buttonLayout.addStretch(1)            buttonLayout.addWidget(button)        buttonLayout.addStretch()        layout = QHBoxLayout()        layout.addWidget(self.view, 1)        layout.addLayout(buttonLayout)        self.setLayout(layout)        fm = QFontMetrics(self.font())        self.resize(self.scene.width() + fm.width(" Delete... ") + 50,                    self.scene.height() + 50)        self.setWindowTitle("Page Designer")    def addBorders(self):        self.borders = []        rect = QRectF(0, 0, PageSize[0], PageSize[1])        self.borders.append(self.scene.addRect(rect, Qt.yellow))        margin = 5.25 * PointSize        self.borders.append(self.scene.addRect(                rect.adjusted(margin, margin, -margin, -margin),                Qt.yellow))    def removeBorders(self):        while self.borders:            item = self.borders.pop()            self.scene.removeItem(item)            del item    def reject(self):        self.accept()    def accept(self):        self.offerSave()        QDialog.accept(self)    def offerSave(self):        if (Dirty and QMessageBox.question(self,                            "Page Designer - Unsaved Changes",                            "Save unsaved changes?",                            QMessageBox.Yes|QMessageBox.No) ==            QMessageBox.Yes):            self.save()    def position(self):        point = self.mapFromGlobal(QCursor.pos())        if not self.view.geometry().contains(point):            coord = random.randint(36, 144)            point = QPoint(coord, coord)        else:            if point == self.prevPoint:                point += QPoint(self.addOffset, self.addOffset)                self.addOffset += 5            else:                self.addOffset = 5                self.prevPoint = point        return self.view.mapToScene(point)    def addText(self):        dialog = TextItemDlg(position=self.position(),                             scene=self.scene, parent=self)        dialog.exec_()    def addBox(self):        BoxItem(self.position(), self.scene)    def addPixmap(self):        path = (QFileInfo(self.filename).path()            if self.filename else ".")        fname,filetype = QFileDialog.getOpenFileName(self,                "Page Designer - Add Pixmap", path,                "Pixmap Files (*.bmp *.jpg *.png *.xpm)")        if not fname:            return        self.createPixmapItem(QPixmap(fname), self.position())    def createPixmapItem(self, pixmap, position, matrix=QTransform()):        item = GraphicsPixmapItem(pixmap)        item.setFlags(QGraphicsItem.ItemIsSelectable|                      QGraphicsItem.ItemIsMovable)        item.setPos(position)        item.setTransform(matrix)        self.scene.clearSelection()        self.scene.addItem(item)        item.setSelected(True)        global Dirty        Dirty = True        return item    def selectedItem(self):        items = self.scene.selectedItems()        if len(items) == 1:            return items[0]        return None    def copy(self):        item = self.selectedItem()        if item is None:            return        self.copiedItem.clear()        self.pasteOffset = 5        stream = QDataStream(self.copiedItem, QIODevice.WriteOnly)        self.writeItemToStream(stream, item)    def cut(self):        item = self.selectedItem()        if item is None:            return        self.copy()        self.scene.removeItem(item)        del item    def paste(self):        if self.copiedItem.isEmpty():            return        stream = QDataStream(self.copiedItem, QIODevice.ReadOnly)        self.readItemFromStream(stream, self.pasteOffset)        self.pasteOffset += 5    def setAlignment(self, alignment):        # Items are returned in arbitrary order        items = self.scene.selectedItems()        if len(items) <= 1:            return        # Gather coordinate data        leftXs, rightXs, topYs, bottomYs = [], [], [], []        for item in items:            rect = item.sceneBoundingRect()            leftXs.append(rect.x())            rightXs.append(rect.x() + rect.width())            topYs.append(rect.y())            bottomYs.append(rect.y() + rect.height())        # Perform alignment        if alignment == Qt.AlignLeft:            xAlignment = min(leftXs)            for i, item in enumerate(items):                item.moveBy(xAlignment - leftXs[i], 0)        elif alignment == Qt.AlignRight:            xAlignment = max(rightXs)            for i, item in enumerate(items):                item.moveBy(xAlignment - rightXs[i], 0)        elif alignment == Qt.AlignTop:            yAlignment = min(topYs)            for i, item in enumerate(items):                item.moveBy(0, yAlignment - topYs[i])        elif alignment == Qt.AlignBottom:            yAlignment = max(bottomYs)            for i, item in enumerate(items):                item.moveBy(0, yAlignment - bottomYs[i])        global Dirty        Dirty = True    def rotate(self):        for item in self.scene.selectedItems():            item.setRotation(item.rotation()+30)    def delete(self):        items = self.scene.selectedItems()        if (len(items) and QMessageBox.question(self,                "Page Designer - Delete",                "Delete {0} item{1}?".format(len(items),                "s" if len(items) != 1 else ""),                QMessageBox.Yes|QMessageBox.No) ==                QMessageBox.Yes):            while items:                item = items.pop()                self.scene.removeItem(item)                del item            global Dirty            Dirty = True    def print_(self):        dialog = QPrintDialog(self.printer)        if dialog.exec_():            painter = QPainter(self.printer)            painter.setRenderHint(QPainter.Antialiasing)            painter.setRenderHint(QPainter.TextAntialiasing)            self.scene.clearSelection()            self.removeBorders()            self.scene.render(painter)            self.addBorders()    def open(self):        self.offerSave()        path = (QFileInfo(self.filename).path()                if self.filename else ".")        fname,filetype = QFileDialog.getOpenFileName(self,                "Page Designer - Open", path,                "Page Designer Files (*.pgd)")        if not fname:            return        self.filename = fname        fh = None        try:            fh = QFile(self.filename)            if not fh.open(QIODevice.ReadOnly):                raise IOError(str(fh.errorString()))            items = self.scene.items()            while items:                item = items.pop()                self.scene.removeItem(item)                del item            self.addBorders()            stream = QDataStream(fh)            stream.setVersion(QDataStream.Qt_5_7)            magic = stream.readInt32()            if magic != MagicNumber:                raise IOError("not a valid .pgd file")            fileVersion = stream.readInt16()            if fileVersion != FileVersion:                raise IOError("unrecognised .pgd file version")            while not fh.atEnd():                self.readItemFromStream(stream)        except IOError as e:            QMessageBox.warning(self, "Page Designer -- Open Error",                    "Failed to open {0}: {1}".format(self.filename, e))        finally:            if fh is not None:                fh.close()        global Dirty        Dirty = False    def save(self):        if not self.filename:            path = "."            fname,filetype = QFileDialog.getSaveFileName(self,                    "Page Designer - Save As", path,                    "Page Designer Files (*.pgd)")            if not fname:                return            self.filename = fname        fh = None        try:            fh = QFile(self.filename)            if not fh.open(QIODevice.WriteOnly):                raise IOError(str(fh.errorString()))            self.scene.clearSelection()            stream = QDataStream(fh)            stream.setVersion(QDataStream.Qt_5_7)            stream.writeInt32(MagicNumber)            stream.writeInt16(FileVersion)            for item in self.scene.items():                self.writeItemToStream(stream, item)        except IOError as e:            QMessageBox.warning(self, "Page Designer -- Save Error",                    "Failed to save {0}: {1}".format(self.filename, e))        finally:            if fh is not None:                fh.close()        global Dirty        Dirty = False    def readItemFromStream(self, stream, offset=0):        type = ""        position = QPointF()        matrix = QTransform()        rotateangle=0#add by yangrongdong        type=stream.readQString()        stream >> position >> matrix        if offset:            position += QPointF(offset, offset)        if type == "Text":            text = ""            font = QFont()            text=stream.readQString()            stream >> font            rotateangle=stream.readFloat()            tx=TextItem(text, position, self.scene, font, matrix)            tx.setRotation(rotateangle)        elif type == "Box":            rect = QRectF()            stream >> rect            style = Qt.PenStyle(stream.readInt16())            rotateangle=stream.readFloat()            bx=BoxItem(position, self.scene, style, rect, matrix)            bx.setRotation(rotateangle)        elif type == "Pixmap":            pixmap = QPixmap()            stream >> pixmap            rotateangle=stream.readFloat()            px=self.createPixmapItem(pixmap, position, matrix)            px.setRotation(rotateangle)    def writeItemToStream(self, stream, item):        if isinstance(item, TextItem):            stream.writeQString("Text")            stream<<item.pos()<< item.transform()             stream.writeQString(item.toPlainText())            stream<< item.font()            stream.writeFloat(item.rotation())#add by yangrongdong        elif isinstance(item, GraphicsPixmapItem):            stream.writeQString("Pixmap")            stream << item.pos() << item.transform() << item.pixmap()            stream.writeFloat(item.rotation())#add by yangrongdong        elif isinstance(item, BoxItem):            stream.writeQString("Box")            stream<< item.pos() << item.transform() << item.rect            stream.writeInt16(item.style)            stream.writeFloat(item.rotation())#add by yangrongdongapp = QApplication(sys.argv)form = MainForm()rect = QApplication.desktop().availableGeometry()form.resize(int(rect.width() * 0.6), int(rect.height() * 0.9))form.show()app.exec_()

运行结果
这里写图片描述

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