pyqt5绘画API_painter.setpen(qt.blue)

绘制正弦曲线

import sys,math
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import Qt
class DrawPoints(QWidget):
    def __init__(self):
        super(DrawPoints,self).__init__()
        self.resize(300,300)
        self.setWindowTitle('在窗口上用像素点绘制2个周期的正弦曲线')
    def paintEvent(self, event):
        painter = QPainter()
        painter.begin(self)
        painter.setPen(Qt.blue)
        size = self.size()
        for i in range(1000):
            x = 100 * (-1 + 2.0 * i/1000) + size.width()/2.0
            y = -50 * math.sin((x - size.width()/2.0) * math.pi/50) + size.height()/2.0
            painter.drawPoint(x,y)
        painter.end()
if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = DrawPoints()
    main.show()
    sys.exit(app.exec_())
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绘图API：绘制文本

import sys
from PyQt5.QtWidgets import QApplication,QWidget
from PyQt5.QtGui import QPainter,QColor,QFont
from PyQt5.QtCore import Qt
class DrawText(QWidget):
    def __init__(self):
        super(DrawText,self).__init__()
        self.setWindowTitle('在窗口上绘制文本')
        self.resize(300,200)
        self.text = "Python从菜鸟到高手"
    def paintEvent(self, event):
        painter = QPainter(self)
        painter.begin(self)
        painter.setPen(QColor(150,43,5))
        painter.setFont(QFont('SimSun',25))
        painter.drawText(event.rect(),Qt.AlignCenter,self.text)
        painter.end()
if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = DrawText()
    main.show()
    sys.exit(app.exec_())
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绘制不同类型的直线

import sys,math
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import Qt
class DrawMultiLine(QWidget):
    def __init__(self):
        super(DrawMultiLine,self).__init__()
        self.resize(300,300)
        self.setWindowTitle('设置Pen的样式')
    def paintEvent(self, event):
        painter = QPainter()
        painter.begin(self)
        pen = QPen(Qt.red,3,Qt.SolidLine)
        painter.setPen(pen)
        painter.drawLine(20,40,250,40)
        pen.setStyle(Qt.DashLine)
        painter.setPen(pen)
        painter.drawLine(20, 80, 250, 80)
        pen.setStyle(Qt.DashDotDotLine)
        painter.setPen(pen)
        painter.drawLine(20, 120, 250, 120)
        pen.setStyle(Qt.DotLine)
        painter.setPen(pen)
        painter.drawLine(20, 160, 250, 160)
        pen.setStyle(Qt.DashDotDotLine)
        painter.setPen(pen)
        painter.drawLine(20, 200, 250, 200)
        pen.setStyle(Qt.CustomDashLine)
        pen.setDashPattern([1,10,5,8])
        painter.setPen(pen)
        painter.drawLine(20, 240, 250, 240)
        painter.end()
if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = DrawMultiLine()
    main.show()
    sys.exit(app.exec_())
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绘制各种图形

import sys,math
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
class DrawAll(QWidget):
    def __init__(self):
        super(DrawAll,self).__init__()
        self.resize(300,600)
        self.setWindowTitle('绘制各种图形')
    def paintEvent(self, event):
        qp = QPainter()
        qp.begin(self)
        qp.setPen(Qt.blue)
        # 绘制弧
        rect = QRect(0,10,100,100)
        # alen: 1个alen等于1/16度   45 * 16
        qp.drawArc(rect,0, 50 * 16)
        # 通过弧绘制圆
        qp.setPen(Qt.red)
        qp.drawArc(120,10,100,100,0, 360 * 16)
        # 绘制带弦的弧
        qp.drawChord(10,120,100,100,12,130*16)
        # 绘制扇形
        qp.drawPie(10,240,100,100,12,130*16)
        # 椭圆
        qp.drawEllipse(120,120,150,100)
        # 绘制5边形
        point1 = QPoint(140,380)
        point2 = QPoint(270,420)
        point3 = QPoint(290,512)
        point4 = QPoint(290,588)
        point5 = QPoint(200,533)
        polygon = QPolygon([point1,point2,point3,point4,point5])
        qp.drawPolygon(polygon)
        # 绘制图像
        image = QImage('./images/book.png')
        rect = QRect(10, 400, image.width()/3, image.height()/3)
        qp.drawImage(rect,image)
        qp.end()
if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = DrawAll()
    main.show()
    sys.exit(app.exec_())
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