python编写出写字板程序的代码

以下是一个使用 Python 和 PyQt5 模块编写的简单写字板程序代码：

from PyQt5.QtWidgets import QApplication, QMainWindow, QAction, QFileDialog, QColorDialog
from PyQt5.QtGui import QIcon, QImage, QPainter, QPen
from PyQt5.QtCore import Qt, QPoint
import sys

class PaintApp(QMainWindow):

    def __init__(self):
        super().__init__()
        self.title = "Python写字板"
        self.setGeometry(100, 100, 800, 600)
        self.image = QImage(self.size(), QImage.Format_RGB32)
        self.image.fill(Qt.white)
        self.last_point = QPoint()
        self.pen = QPen(Qt.black, 5, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin)
        self.initUI()

    def initUI(self):
        self.setWindowTitle(self.title)
        self.setWindowIcon(QIcon("icon.png"))

        main_menu = self.menuBar()
        file_menu = main_menu.addMenu("文件")
        color_menu = main_menu.addMenu("颜色")

        save_action = QAction(QIcon("save.png"), "保存", self)
        save_action.setShortcut("Ctrl+S")
        save_action.triggered.connect(self.save)

        clear_action = QAction(QIcon("clear.png"), "清空", self)
        clear_action.setShortcut("Ctrl+C")
        clear_action.triggered.connect(self.clear)

        exit_action = QAction(QIcon("exit.png"), "退出", self)
        exit_action.setShortcut("Ctrl+Q")
        exit_action.triggered.connect(self.close)

        file_menu.addAction(save_action)
        file_menu.addAction(clear_action)
        file_menu.addAction(exit_action)

        color_action = QAction(QIcon("color.png"), "选择颜色", self)
        color_action.triggered.connect(self.color_picker)

        color_menu.addAction(color_action)

        self.show()

    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.last_point = event.pos()

    def mouseMoveEvent(self, event):
        if event.buttons() and Qt.LeftButton:
            painter = QPainter(self.image)
            painter.setPen(self.pen)
            painter.drawLine(self.last_point, event.pos())
            self.last_point = event.pos()
            self.update()

    def save(self):
        file_path, _ = QFileDialog.getSaveFileName(self, "保存", "", "PNG(*.png);;JPEG(*.jpg *.jpeg);;All Files(*.*)")
        if file_path == "":
            return
        self.image.save(file_path)

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

    def color_picker(self):
        color = QColorDialog.getColor()
        if color.isValid():
            self.pen.setColor(color)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    paint_app = PaintApp()
    sys.exit(app.exec_())

这个程序创建了一个基本的 PyQt5 窗口，并在其中添加了一个画布对象。当鼠标在画布上按下并拖动时，程序会在画布上创建一条黑色的线条，模拟笔的效果。程序还提供了选择颜色、保存和清空画布等功能。