[Qt扒手] PyQt5 基础绘画例子

【说明】

好吧，坦白从宽，我是Qt扒手（不要鄙视我）。这是我根据qt官网提供的C++版本的例子(http://doc.qt.io/qt-5/qtwidgets-painting-basicdrawing-example.html)，改编而成的Python版本。

由于本人没有C++基础，其难度之大，自不待言。

不过，还是毛主席说的好：道路是艰难的，结果是光明的:)

本文基于 win7 + Python3.4 + PyQt5  环境

【效果图】

对比原C++的界面：

【源代码】

 # File: Basic Draw Example.py
 # Author: Robin
 # Date: 2015.2.9
 # C++: http://doc.qt.io/qt-5/qtwidgets-painting-basicdrawing-example.html

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

 class RenderArea(QWidget):
     Shape = range(13)
     (Line, Points, Polyline, Polygon, Rect, RoundedRect,
     Ellipse, Arc, Chord, Pie, Path, Text, Pixmap) = Shape

     def __init__(self, parent=None):
         super(RenderArea, self).__init__(parent)

         self.shape = self.Polygon
         self.pen = Qt.NoPen
         self.brush = Qt.NoBrush
         self.antialiased = False
         self.transformed = False
         self.pixmap = QPixmap()
         self.pixmap.load("images/qt-logo.png")

         self.setBackgroundRole(QPalette.Base)
         self.setAutoFillBackground(True)

     def setShape(self, shape):
         self.shape = shape
         self.update()

     def setPen(self,  pen):
         self.pen = pen
         self.update()

     def setBrush(self,  brush):
         self.brush = brush
         self.update()

     def setAntialiased(self, antialiased):
         self.antialiased = antialiased
         self.update()

     def setTransformed(self, transformed):
         self.transformed = transformed
         self.update()

     def paintEvent(self, event):
         points = [QPoint(10, 80), QPoint(20, 10), QPoint(80, 30), QPoint(90, 70)]
         rect = QRect(10, 20, 80, 60)
         path = QPainterPath()
         path.moveTo(20, 80)
         path.lineTo(20, 30)
         path.cubicTo(80, 0, 50, 50, 80, 80)
         startAngle = 20 * 16
         arcLength = 120 * 16

         painter = QPainter()
         painter.begin(self)
         painter.setPen(self.pen)
         painter.setBrush(self.brush)

         if self.antialiased:
             painter.setRenderHint(QPainter.Antialiasing, True)
         for x in range(0, self.width(), 100):
             for y in range(0, self.height(), 100):
                 painter.save() # 在画笔改变之前保存初始设置，即原点（0,0）处的设置
                 painter.translate(x, y)
                 if self.transformed:
                     painter.translate(50, 50)
                     painter.rotate(60.0)
                     painter.scale(0.6, 0.9)
                     painter.translate(-50, -50)
                 if self.shape == self.Line:
                     painter.drawLine(rect.bottomLeft(), rect.topRight())
                 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), Qt.WindingFill)
                 elif self.shape == self.Rect:
                     painter.drawRect(rect)
                 elif self.shape == self.RoundedRect:
                     painter.drawRoundedRect(rect, 25, 25, Qt.RelativeSize)
                 elif self.shape == self.Ellipse:
                     painter.drawEllipse(rect)
                 elif self.shape == self.Arc:
                     painter.drawArc(rect, startAngle, arcLength)
                 elif self.shape == self.Chord:
                     painter.drawChord(rect, startAngle, arcLength)
                 elif self.shape == self.Pie:
                     painter.drawPie(rect, startAngle, arcLength)
                 elif self.shape == self.Path:
                     painter.drawPath(path)
                 elif self.shape == self.Text:
                     painter.drawText(rect, Qt.AlignCenter, "Qt by\nDigia")
                 elif self.shape == self.Pixmap:
                     painter.drawPixmap(10, 10, self.pixmap)
                 painter.restore()  # 画完一个之后，将画笔还原到初始设置，即原点（0,0）处的设置。好处是便于计算下一次的坐标变换

         painter.setPen(self.palette().dark().color())
         painter.setBrush(Qt.NoBrush)
         painter.setRenderHint(QPainter.Antialiasing, False)
         painter.drawRect(QRect(0, 0, self.width() - 1, self.height() - 1))
         painter.end()

     def sizeHint(self):
         return QSize(400, 200)

     def minimumSizeHint(self):
         return QSize(100, 100)

 class MyWindow(QWidget):

     def __init__(self):
         super(MyWindow, self).__init__()
         self.setUi()

         self.shapeChanged()
         self.penChanged()
         self.brushChanged()
         self.checkBox_antialiasing.setChecked(True)        

     def setUi(self):
         self.setWindowTitle("基础绘画例子")
         self.resize(400,300)
         self.renderArea = RenderArea()

         self.label_shape = QLabel("Shape:")
         self.label_penStyle = QLabel("Pen Style:")
         self.label_brushStyle = QLabel("Brush Style:")
         self.label_penWidth = QLabel("Pen Width:")
         self.label_penCap = QLabel("Pen Cap:")
         self.label_penJoin = QLabel("Pen Join:")

         self.comboBox_shape = QComboBox()
         self.comboBox_penStyle = QComboBox()
         self.comboBox_brushStyle = QComboBox()
         self.spinBox_penWidth = QSpinBox()
         self.comboBox_penCap = QComboBox()
         self.comboBox_penJoin = QComboBox()

         self.checkBox_antialiasing = QCheckBox("Antialiasing")
         self.checkBox_transformations = QCheckBox("Transformations")

         gridLayout = QGridLayout()

         gridLayout.setColumnStretch(0, 1)
         gridLayout.setColumnStretch(1, 4)
         gridLayout.setColumnStretch(2, 1)
         gridLayout.setColumnStretch(3, 1)
         gridLayout.setColumnStretch(4, 4)

         gridLayout.setColumnMinimumWidth(2, 15)
         gridLayout.setSpacing(15)
         #gridLayout.setMargin(10)

         gridLayout.addWidget(self.renderArea, 0, 0, 1, 5)
         gridLayout.addWidget(self.label_shape, 1, 0)
         gridLayout.addWidget(self.label_penStyle, 2, 0)
         gridLayout.addWidget(self.label_brushStyle, 3, 0)
         gridLayout.addWidget(self.checkBox_antialiasing, 4, 0, 1, 2)
         gridLayout.addWidget(self.comboBox_shape, 1, 1)
         gridLayout.addWidget(self.comboBox_penStyle, 2, 1)
         gridLayout.addWidget(self.comboBox_brushStyle, 3, 1)
         gridLayout.addWidget(self.label_penWidth, 1, 3)
         gridLayout.addWidget(self.label_penCap, 2, 3)
         gridLayout.addWidget(self.label_penJoin, 3, 3)
         gridLayout.addWidget(self.checkBox_transformations, 4, 3, 1, 2)
         gridLayout.addWidget(self.spinBox_penWidth, 1, 4)
         gridLayout.addWidget(self.comboBox_penCap, 2, 4)
         gridLayout.addWidget(self.comboBox_penJoin, 3, 4)

         self.setLayout(gridLayout)

         #self.checkBox_antialiasing.setChecked(True)
         #Line, Points, Polyline, Polygon, Rect, RoundedRect,
         #Ellipse, Arc, Chord, Pie, Path, Text, Pixmap
         self.comboBox_shape.addItem('Line')
         self.comboBox_shape.addItem('Points')
         self.comboBox_shape.addItem('Polyline')
         self.comboBox_shape.addItem('Polygon')
         self.comboBox_shape.addItem('Rect')
         self.comboBox_shape.addItem('RoundedRect')
         self.comboBox_shape.addItem('Ellipse')
         self.comboBox_shape.addItem('Arc')
         self.comboBox_shape.addItem('Chord')
         self.comboBox_shape.addItem('Pie')
         self.comboBox_shape.addItem('Path')
         self.comboBox_shape.addItem('Text')
         self.comboBox_shape.addItem('Pixmap')

         self.spinBox_penWidth.setRange(0, 20)
         #self.spinBox_penWidth.setSpecialValue('0 (cosmetic pen)')

         self.comboBox_penStyle.addItem('Solid',Qt.SolidLine)
         self.comboBox_penStyle.addItem('Dash',Qt.DashLine)
         self.comboBox_penStyle.addItem('Dot',Qt.DotLine)
         self.comboBox_penStyle.addItem('Dash Dot',Qt.DashDotLine)
         self.comboBox_penStyle.addItem('Dash Dot Dot',Qt.DashDotDotLine)
         self.comboBox_penStyle.addItem('None',Qt.NoPen)

         self.comboBox_penCap.addItem('Flat',Qt.FlatCap)
         self.comboBox_penCap.addItem('Square',Qt.SquareCap)
         self.comboBox_penCap.addItem('Round',Qt.RoundCap)

         self.comboBox_penJoin.addItem('Miter',Qt.MiterJoin)
         self.comboBox_penJoin.addItem('Bebel',Qt.BevelJoin)
         self.comboBox_penJoin.addItem('Round',Qt.RoundJoin)

         self.comboBox_brushStyle.addItem('Linear Gradient',Qt.LinearGradientPattern)
         self.comboBox_brushStyle.addItem('Radial Gradient',Qt.RadialGradientPattern)
         self.comboBox_brushStyle.addItem('Conical Gradient',Qt.ConicalGradientPattern)
         self.comboBox_brushStyle.addItem('Texture',Qt.TexturePattern)
         self.comboBox_brushStyle.addItem('Solid',Qt.SolidPattern)
         self.comboBox_brushStyle.addItem('Horizontal',Qt.HorPattern)
         self.comboBox_brushStyle.addItem('Vertical',Qt.VerPattern)
         self.comboBox_brushStyle.addItem('Cross',Qt.CrossPattern)
         self.comboBox_brushStyle.addItem('Backward Diagonal',Qt.BDiagPattern)
         self.comboBox_brushStyle.addItem('Forward Diagonal',Qt.FDiagPattern)
         self.comboBox_brushStyle.addItem('Diagonal Cross',Qt.DiagCrossPattern)
         self.comboBox_brushStyle.addItem('Dense 1',Qt.Dense1Pattern)
         self.comboBox_brushStyle.addItem('Dense 2',Qt.Dense2Pattern)
         self.comboBox_brushStyle.addItem('Dense 3',Qt.Dense3Pattern)
         self.comboBox_brushStyle.addItem('Dense 4',Qt.Dense4Pattern)
         self.comboBox_brushStyle.addItem('Dense 5',Qt.Dense5Pattern)
         self.comboBox_brushStyle.addItem('Dense 6',Qt.Dense6Pattern)
         self.comboBox_brushStyle.addItem('Dense 7',Qt.Dense7Pattern)
         self.comboBox_brushStyle.addItem('None',Qt.NoBrush)

         self.comboBox_shape.currentIndexChanged.connect(self.shapeChanged)
         self.comboBox_brushStyle.currentIndexChanged.connect(self.brushChanged)
         self.spinBox_penWidth.valueChanged.connect(self.penChanged)
         self.comboBox_penStyle.currentIndexChanged.connect(self.penChanged)
         self.comboBox_penCap.currentIndexChanged.connect(self.penChanged)
         self.comboBox_penJoin.currentIndexChanged.connect(self.penChanged)
         self.checkBox_antialiasing.clicked.connect(self.renderArea.setAntialiased)
         self.checkBox_transformations.clicked.connect(self.renderArea.setTransformed)

     def shapeChanged(self):
         index = self.comboBox_shape.currentIndex()
         shape = self.renderArea.Shape[index]
         self.renderArea.setShape(shape)

     def penChanged(self):
         width = self.spinBox_penWidth.value()
         style = Qt.PenStyle(self.comboBox_penStyle.itemData(self.comboBox_penStyle.currentIndex(),Qt.UserRole))
         cap = Qt.PenCapStyle(self.comboBox_penCap.itemData(self.comboBox_penCap.currentIndex(),Qt.UserRole))
         join = Qt.PenJoinStyle(self.comboBox_penJoin.itemData(self.comboBox_penJoin.currentIndex(),Qt.UserRole))
         self.renderArea.setPen(QPen(Qt.blue, width, style, cap, join))

     def brushChanged(self):
         style = Qt.BrushStyle(self.comboBox_brushStyle.itemData(self.comboBox_brushStyle.currentIndex(),Qt.UserRole))
         if style == Qt.LinearGradientPattern:
             linearGradient = QLinearGradient(0, 0, 100, 100)
             linearGradient.setColorAt(0.0, Qt.white)
             linearGradient.setColorAt(0.2, Qt.green)
             linearGradient.setColorAt(1.0, Qt.black)
             self.renderArea.setBrush(linearGradient)
         elif style == Qt.RadialGradientPattern:
             radialGradient = QRadialGradient(50, 50, 50, 70, 70);
             radialGradient.setColorAt(0.0, Qt.white)
             radialGradient.setColorAt(0.2, Qt.green)
             radialGradient.setColorAt(1.0, Qt.black)
             self.renderArea.setBrush(radialGradient)
         elif style == Qt.ConicalGradientPattern:
             conicalGradient = QConicalGradient(50, 50, 150)
             conicalGradient.setColorAt(0.0, Qt.white)
             conicalGradient.setColorAt(0.2, Qt.green)
             conicalGradient.setColorAt(1.0, Qt.black)
             self.renderArea.setBrush(conicalGradient)
         elif style == Qt.TexturePattern:
             self.renderArea.setBrush(QBrush(QPixmap("images/brick.png")))
         else:
             self.renderArea.setBrush(QBrush(Qt.green, style))

 if __name__ == "__main__":
     import sys
     app = QApplication(sys.argv)
     win = MyWindow()
     win.show()
     sys.exit(app.exec_())