python3+PyQt5图形项的自定义和交互 python3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 python3


import functools
import random
import sys
from 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,QPixmap
from PyQt5.QtPrintSupport import QPrinter,QPrintDialog

MAC = True
try:
 from PyQt5.QtGui import qt_mac_set_native_menubar
except ImportError:
 MAC = False

#PageSize = (595, 842) # A4 in points
PageSize = (612, 792) # US Letter in points
PointSize = 10

MagicNumber = 0x70616765
FileVersion = 1

Dirty = False


class 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 yangrongdong



app = 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