PyQt5利用QPainter绘制各种图形的实例

# 定义多个点
   points = [QPoint(10, 80), QPoint(20, 10), QPoint(80, 30), QPoint(90, 70)]

   # ===直接使用 points 会报错！=========
   # ...
   elif self.shape == self.Points:
      painter.drawPoints(points)

   elif self.shape == self.Polyline:
      painter.drawPolyline(points)

   elif self.shape == self.Polygon:
      painter.drawPolygon(points, 4)

   # ...

   # ===把 points 用 QPolygon()包裹起来才正确！=========
   # ...
   elif self.shape == self.Points:
      painter.drawPoints(QPolygon(points))

   elif self.shape == self.Polyline:
      painter.drawPolyline(QPolygon(points))

   elif self.shape == self.Polygon:
      painter.drawPolygon(QPolygon(points), 4)

   # ...

import sys

from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

class StockDialog(QWidget):
  def __init__(self, parent=None):
    super(StockDialog, self).__init__(parent)
    self.setWindowTitle("利用QPainter绘制各种图形")
    
    mainSplitter = QSplitter(Qt.Horizontal)
    mainSplitter.setOpaqueResize(True)
         
    frame = QFrame(mainSplitter)
    mainLayout = QGridLayout(frame)
    #mainLayout.setMargin(10)
    mainLayout.setSpacing(6)

    label1=QLabel("形状：")
    label2=QLabel("画笔线宽：")
    label3=QLabel("画笔颜色：")
    label4=QLabel("画笔风格：")
    label5=QLabel("画笔顶端：")
    label6=QLabel("画笔连接点：")
    label7=QLabel("画刷风格：")
    label8=QLabel("画刷颜色：")
  
    self.shapeComboBox = QComboBox()
    self.shapeComboBox.addItem("Line", "Line")
    self.shapeComboBox.addItem("Rectangle", "Rectangle")
    self.shapeComboBox.addItem('Rounded Rectangle','Rounded Rectangle')
    self.shapeComboBox.addItem('Ellipse','Ellipse')
    self.shapeComboBox.addItem('Pie','Pie')
    self.shapeComboBox.addItem('Chord','Chord')
    self.shapeComboBox.addItem('Path','Path')
    self.shapeComboBox.addItem('Polygon','Polygon')
    self.shapeComboBox.addItem('Polyline','Polyline')
    self.shapeComboBox.addItem('Arc','Arc')
    self.shapeComboBox.addItem('Points','Points')
    self.shapeComboBox.addItem('Text','Text')
    self.shapeComboBox.addItem('Pixmap','Pixmap')
    
    self.widthSpinBox = QSpinBox()
    self.widthSpinBox.setRange(0,20)
    
    self.penColorFrame = QFrame()
    self.penColorFrame.setAutoFillBackground(True)
    self.penColorFrame.setPalette(QPalette(Qt.blue))
    self.penColorPushButton = QPushButton("更改")
    
    self.penStyleComboBox = QComboBox()
    self.penStyleComboBox.addItem("Solid",Qt.SolidLine)
    self.penStyleComboBox.addItem('Dash', Qt.DashLine)
    self.penStyleComboBox.addItem('Dot', Qt.DotLine)
    self.penStyleComboBox.addItem('Dash Dot', Qt.DashDotLine)
    self.penStyleComboBox.addItem('Dash Dot Dot', Qt.DashDotDotLine)
    self.penStyleComboBox.addItem('None', Qt.NoPen)
    
    self.penCapComboBox = QComboBox()
    self.penCapComboBox.addItem("Flat",Qt.FlatCap)
    self.penCapComboBox.addItem('Square', Qt.SquareCap)
    self.penCapComboBox.addItem('Round', Qt.RoundCap)
    
    self.penJoinComboBox = QComboBox()
    self.penJoinComboBox.addItem("Miter",Qt.MiterJoin)
    self.penJoinComboBox.addItem('Bebel', Qt.BevelJoin)
    self.penJoinComboBox.addItem('Round', Qt.RoundJoin)
    
    self.brushStyleComboBox = QComboBox()
    self.brushStyleComboBox.addItem("Linear Gradient",Qt.LinearGradientPattern)
    self.brushStyleComboBox.addItem('Radial Gradient', Qt.RadialGradientPattern)
    self.brushStyleComboBox.addItem('Conical Gradient', Qt.ConicalGradientPattern)
    self.brushStyleComboBox.addItem('Texture', Qt.TexturePattern)
    self.brushStyleComboBox.addItem('Solid', Qt.SolidPattern)
    self.brushStyleComboBox.addItem('Horizontal', Qt.HorPattern)
    self.brushStyleComboBox.addItem('Vertical', Qt.VerPattern)
    self.brushStyleComboBox.addItem('Cross', Qt.CrossPattern)
    self.brushStyleComboBox.addItem('Backward Diagonal', Qt.BDiagPattern)
    self.brushStyleComboBox.addItem('Forward Diagonal', Qt.FDiagPattern)
    self.brushStyleComboBox.addItem('Diagonal Cross', Qt.DiagCrossPattern)
    self.brushStyleComboBox.addItem('Dense 1', Qt.Dense1Pattern)
    self.brushStyleComboBox.addItem('Dense 2', Qt.Dense2Pattern)
    self.brushStyleComboBox.addItem('Dense 3', Qt.Dense3Pattern)
    self.brushStyleComboBox.addItem('Dense 4', Qt.Dense4Pattern)
    self.brushStyleComboBox.addItem('Dense 5', Qt.Dense5Pattern)
    self.brushStyleComboBox.addItem('Dense 6', Qt.Dense6Pattern)
    self.brushStyleComboBox.addItem('Dense 7', Qt.Dense7Pattern)
    self.brushStyleComboBox.addItem('None', Qt.NoBrush)
    
    self.brushColorFrame = QFrame()
    self.brushColorFrame.setAutoFillBackground(True)
    self.brushColorFrame.setPalette(QPalette(Qt.green))
    self.brushColorPushButton = QPushButton("更改")
                               
    labelCol=0
    contentCol=1
    
    #建立布局
    mainLayout.addWidget(label1,1,labelCol)
    mainLayout.addWidget(self.shapeComboBox,1,contentCol)
    mainLayout.addWidget(label2,2,labelCol)
    mainLayout.addWidget(self.widthSpinBox,2,contentCol)
    mainLayout.addWidget(label3,4,labelCol)
    mainLayout.addWidget(self.penColorFrame,4,contentCol)
    mainLayout.addWidget(self.penColorPushButton,4,3)
    mainLayout.addWidget(label4,6,labelCol)
    mainLayout.addWidget(self.penStyleComboBox,6,contentCol)
    mainLayout.addWidget(label5,8,labelCol)
    mainLayout.addWidget(self.penCapComboBox,8,contentCol)
    mainLayout.addWidget(label6,10,labelCol)
    mainLayout.addWidget(self.penJoinComboBox,10,contentCol)
    mainLayout.addWidget(label7,12,labelCol)
    mainLayout.addWidget(self.brushStyleComboBox,12,contentCol)
    mainLayout.addWidget(label8,14,labelCol)
    mainLayout.addWidget(self.brushColorFrame,14,contentCol)
    mainLayout.addWidget(self.brushColorPushButton,14,3)
    mainSplitter1 = QSplitter(Qt.Horizontal)
    mainSplitter1.setOpaqueResize(True)
    
    stack1 = QStackedWidget()
    stack1.setFrameStyle(QFrame.Panel|QFrame.Raised)
    self.area = PaintArea()
    stack1.addWidget(self.area)    
    frame1 = QFrame(mainSplitter1)
    mainLayout1 = QVBoxLayout(frame1)
    #mainLayout1.setMargin(10)
    mainLayout1.setSpacing(6)
    mainLayout1.addWidget(stack1)

    layout = QGridLayout(self)
    layout.addWidget(mainSplitter1,0,0)
    layout.addWidget(mainSplitter,0,1)
    self.setLayout(layout)
    
    #信号和槽函数
    self.shapeComboBox.activated.connect(self.slotShape)
    self.widthSpinBox.valueChanged.connect(self.slotPenWidth)
    self.penColorPushButton.clicked.connect(self.slotPenColor)
    self.penStyleComboBox.activated.connect(self.slotPenStyle)
    self.penCapComboBox.activated.connect(self.slotPenCap)
    self.penJoinComboBox.activated.connect(self.slotPenJoin)
    self.brushStyleComboBox.activated.connect(self.slotBrush)
    self.brushColorPushButton.clicked.connect(self.slotBrushColor)
    
    self.slotShape(self.shapeComboBox.currentIndex())
    self.slotPenWidth(self.widthSpinBox.value())
    self.slotBrush(self.brushStyleComboBox.currentIndex())    
    
  def slotShape(self,value):
    shape = self.area.Shape[value]
    self.area.setShape(shape)
  
  def slotPenWidth(self,value):
    color = self.penColorFrame.palette().color(QPalette.Window)
    style = Qt.PenStyle(self.penStyleComboBox.itemData(self.penStyleComboBox.currentIndex(),Qt.UserRole))
    cap = Qt.PenCapStyle(self.penCapComboBox.itemData(self.penCapComboBox.currentIndex(),Qt.UserRole))
    join = Qt.PenJoinStyle(self.penJoinComboBox.itemData(self.penJoinComboBox.currentIndex(),Qt.UserRole))
    self.area.setPen(QPen(color,value,style,cap,join))
  
  def slotPenStyle(self,value):
    self.slotPenWidth(value)
  
  def slotPenCap(self,value):
    self.slotPenWidth(value)
  
  def slotPenJoin(self,value):
    self.slotPenWidth(value)
  
  def slotPenColor(self):
    color = QColorDialog.getColor(Qt.blue)
    self.penColorFrame.setPalette(QPalette(color))
    self.area.setPen(QPen(color))
    
  def slotBrushColor(self):
    color = QColorDialog.getColor(Qt.blue)
    self.brushColorFrame.setPalette(QPalette(color))
    self.slotBrush(self.brushStyleComboBox.currentIndex())
  
  def slotBrush(self,value):
    color = self.brushColorFrame.palette().color(QPalette.Window)
    style = Qt.BrushStyle(self.brushStyleComboBox.itemData(value,Qt.UserRole))
    
    if(style == Qt.LinearGradientPattern):
      linearGradient = QLinearGradient(0,0,400,400)
      linearGradient.setColorAt(0.0,Qt.white)
      linearGradient.setColorAt(0.2,color)
      linearGradient.setColorAt(1.0,Qt.black)
      self.area.setBrush(linearGradient)
    elif style ==Qt.RadialGradientPattern:
      radialGradient = QRadialGradient(200, 200, 80, 70, 70);
      radialGradient.setColorAt(0.0, Qt.white)
      radialGradient.setColorAt(0.2, Qt.green)
      radialGradient.setColorAt(1.0, Qt.black)
      self.area.setBrush(radialGradient)
    elif(style == Qt.ConicalGradientPattern):
      conicalGradient = QConicalGradient(200,200,30)
      conicalGradient.setColorAt(0.0,Qt.white)
      conicalGradient.setColorAt(0.2,color)
      conicalGradient.setColorAt(1.0,Qt.black)
      self.area.setBrush(conicalGradient)
    elif(style == Qt.TexturePattern):
      self.area.setBrush(QBrush(QPixmap("images/brick.png")))
    else:
      self.area.setBrush(QBrush(color,style))
    
  
class PaintArea(QWidget):
  def __init__(self):
    super(PaintArea,self).__init__()
    self.Shape = ["Line","Rectangle", 'Rounded Rectangle', "Ellipse", "Pie", 'Chord', 
  "Path","Polygon", "Polyline", "Arc", "Points", "Text", "Pixmap"]
    self.setPalette(QPalette(Qt.white))
    self.setAutoFillBackground(True)
    self.setMinimumSize(400,400)
    self.pen = QPen()
    self.brush = QBrush()    
  
  def setShape(self,s):
    self.shape = s
    self.update()
    
  def setPen(self,p):
    self.pen = p
    self.update()
  
  def setBrush(self,b):
    self.brush = b
    self.update()
  
  def paintEvent(self,QPaintEvent):
    p = QPainter(self)
    p.setPen(self.pen)
    p.setBrush(self.brush)
    
    rect = QRect(50,100,300,200) 
    points = [QPoint(150,100),QPoint(300,150),QPoint(350,250),QPoint(100,300)]
    startAngle = 30 * 16
    spanAngle = 120 * 16
    
    path = QPainterPath();
    path.addRect(150,150,100,100)
    path.moveTo(100,100)
    path.cubicTo(300,100,200,200,300,300)
    path.cubicTo(100,300,200,200,100,100)
    
    if self.shape == "Line":
      p.drawLine(rect.topLeft(),rect.bottomRight())
    elif self.shape == "Rectangle":
      p.drawRect(rect)
    elif self.shape == 'Rounded Rectangle':
      p.drawRoundedRect(rect, 25, 25, Qt.RelativeSize)
    elif self.shape == "Ellipse":
      p.drawEllipse(rect)
    elif self.shape == "Polygon":
      p.drawPolygon(QPolygon(points),Qt.WindingFill)
    elif self.shape == "Polyline":
      p.drawPolyline(QPolygon(points))
    elif self.shape == "Points":
      p.drawPoints(QPolygon(points))
    elif self.shape == "Pie":
      p.drawPie(rect, startAngle, spanAngle)
    elif self.shape == "Arc":
      p.drawArc(rect,startAngle,spanAngle)
    elif self.shape == "Chord":
      p.drawChord(rect, startAngle, spanAngle)
    elif self.shape == "Path":
      p.drawPath(path)
    elif self.shape == "Text":
      p.drawText(rect,Qt.AlignCenter,"Hello Qt!")
    elif self.shape == "Pixmap":
      p.drawPixmap(150,150,QPixmap("images/qt-logo.png"))
    
if __name__=='__main__':
  app = QApplication(sys.argv)
  form = StockDialog()
  form.show()
  app.exec_()