PyQT5之QPainter

参考https://www.cnblogs.com/jgg54335/p/14904853.html

实例一：

import sys
from PyQt5.QtWidgets import QApplication, QWidget
from PyQt5.QtGui import QPainter, QColor, QFont
from PyQt5.QtCore import Qt


class Drawing(QWidget):
    def __init__(self, parent=None):
        super(Drawing, self).__init__(parent)
        self.setWindowTitle('在窗口绘制文字')
        self.resize(300, 200)
        self.text = '欢迎学习 PyQt5'

    def paintEvent(self, event):
        painter = QPainter()
        painter.begin(self)
        # 自定义绘制方法
        self.drawText(event, painter)
        painter.end()

    def drawText(self, event, qp):
        # 设置画笔的颜色
        qp.setPen(QColor(168, 34, 3))
        # 设置字体
        qp.setFont(QFont('SimSun', 20))
        # 绘制文字
        qp.drawText(event.rect(), Qt.AlignCenter, self.text)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    demo = Drawing()
    demo.show()
    sys.exit(app.exec_())

实例二：

import sys, math
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *


class Drawing(QWidget):
    def __init__(self, parent=None):
        super(Drawing, self).__init__(parent)
        self.resize(300, 200)
        self.setWindowTitle('在窗口画点')

    def paintEvent(self, event):
        # 初始化绘图工具
        qp = QPainter()
        # 开始在窗口绘制
        qp.begin(self)
        # 自定义画点方法
        self.drawPoints(qp)
        # 结束在窗口的绘制
        qp.end()

    def drawPoints(self, qp):
        qp.setPen(Qt.red)
        size = self.size()

        for i in range(1000):
            # 绘制郑玄函数图像，它的周期是【-100,100】
            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

            qp.drawPoint(x, y)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    demo = Drawing()
    demo.show()
    sys.exit(app.exec_())

实例三：