PyQt5利用QPainter绘制各种图形

这个例子我做了好几天：

1）官网C++的源码，改写成PyQt5版本的代码，好多细节不会转化

2）网上的PyQt的例子根本运行不了

填了无数个坑，结合二者，终于能完成了一个关于绘图的东西。这个过程也掌握了很多新的知识点

【知识点】

1、关于多个点的使用

poitns = [QPoint(10, 80), QPoint(20, 10), QPoint(80, 30), QPoint(90, 70)]

请看：

# 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)

# ...

2、在QDialog窗体中显示QWidget部件

【效果图】





【资源】
http://doc.qt.io/qt-5/images/used-in-examples/painting/basicdrawing/images/brick.png http://doc.qt.io/qt-5/images/used-in-examples/painting/basicdrawing/images/qt-logo.png
【代码】

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_()

（罗兵 作于2015.02.05 01:58）