生成一段基于Qt设计绘画板的python代码

以下是一个基于Qt设计的绘画板的Python代码示例：

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QAction, qApp
from PyQt5.QtGui import QIcon, QPainter, QPen
from PyQt5.QtCore import Qt


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        self.setWindowTitle("绘画板")
        self.setGeometry(100, 100, 800, 600)

        self.image = QImage(self.size(), QImage.Format_RGB32)
        self.image.fill(Qt.white)

        self.drawing = False
        self.brushSize = 2
        self.brushColor = Qt.black

        self.lastPoint = None

        self.createMenu()

    def createMenu(self):
        exitAction = QAction(QIcon("exit.png"), "退出", self)
        exitAction.setShortcut("Ctrl+Q")
        exitAction.setStatusTip("退出应用程序")
        exitAction.triggered.connect(qApp.quit)

        clearAction = QAction(QIcon("clear.png"), "清除", self)
        clearAction.setShortcut("Ctrl+C")
        clearAction.setStatusTip("清除画布")
        clearAction.triggered.connect(self.clearImage)

        menuBar = self.menuBar()
        fileMenu = menuBar.addMenu("文件")
        fileMenu.addAction(exitAction)

        editMenu = menuBar.addMenu("编辑")
        editMenu.addAction(clearAction)

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.drawImage(self.rect(), self.image, self.image.rect())

    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:
            self.drawing = True
            self.lastPoint = event.pos()

    def mouseMoveEvent(self, event):
        if (event.buttons() & Qt.LeftButton) and self.drawing:
            painter = QPainter(self.image)
            painter.setPen(QPen(self.brushColor, self.brushSize, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
            painter.drawLine(self.lastPoint, event.pos())
            self.lastPoint = event.pos()
            self.update()

    def mouseReleaseEvent(self, event):
        if event.button() == Qt.LeftButton and self.drawing:
            self.drawing = False
            painter = QPainter(self.image)
            painter.setPen(QPen(self.brushColor, self.brushSize, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
            painter.drawLine(self.lastPoint, event.pos())
            self.lastPoint = None
            self.update()

    def clearImage(self):
        self.image.fill(Qt.white)
        self.update()


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

这个绘画板基于Qt框架实现，使用了PyQt5库进行开发。在这个绘画板中，你可以使用鼠标进行自由绘画，并且支持清除画布和退出应用程序等功能。