用python写一个有pyqt界面的画图程序

好的，我可以为您提供一个基于Python和PyQt的画图程序。以下是代码示例：

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QAction, QFileDialog, QGraphicsScene, QGraphicsView
from PyQt5.QtGui import QPixmap, QPainter, QPen, QColor
from PyQt5.QtCore import Qt, QPoint, QRectF

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

        self.setWindowTitle("画图程序")
        self.setGeometry(100, 100, 800, 600)

        self.scene = QGraphicsScene(self)
        self.view = QGraphicsView(self.scene, self)
        self.view.setGeometry(0, 0, 800, 600)

        self.pen = QPen(QColor(0, 0, 0), 2)
        self.drawing = False
        self.lastPoint = QPoint()

        self.create_actions()
        self.create_menus()

    def create_actions(self):
        self.new_action = QAction("新建", self)
        self.new_action.setShortcut("Ctrl+N")
        self.new_action.triggered.connect(self.new)

        self.open_action = QAction("打开", self)
        self.open_action.setShortcut("Ctrl+O")
        self.open_action.triggered.connect(self.open)

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

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

        self.pen_action = QAction("画笔", self)
        self.pen_action.setShortcut("Ctrl+P")
        self.pen_action.triggered.connect(self.set_pen)

        self.eraser_action = QAction("橡皮擦", self)
        self.eraser_action.setShortcut("Ctrl+E")
        self.eraser_action.triggered.connect(self.set_eraser)

    def create_menus(self):
        self.file_menu = self.menuBar().addMenu("文件")
        self.file_menu.addAction(self.new_action)
        self.file_menu.addAction(self.open_action)
        self.file_menu.addAction(self.save_action)
        self.file_menu.addAction(self.exit_action)

        self.tool_menu = self.menuBar().addMenu("工具")
        self.tool_menu.addAction(self.pen_action)
        self.tool_menu.addAction(self.eraser_action)

    def new(self):
        self.scene.clear()

    def open(self):
        file_name, _ = QFileDialog.getOpenFileName(self, "打开文件", "", "Images (*.png *.xpm *.jpg)")
        if file_name:
            pixmap = QPixmap(file_name)
            self.scene.clear()
            self.scene.addPixmap(pixmap)

    def save(self):
        file_name, _ = QFileDialog.getSaveFileName(self, "保存文件", "", "Images (*.png *.xpm *.jpg)")
        if file_name:
            pixmap = self.view.grab()
            pixmap.save(file_name)

    def set_pen(self):
        self.pen = QPen(QColor(0, 0, 0), 2)

    def set_eraser(self):
        self.pen = QPen(QColor(255, 255, 255), 10)

    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.scene)
            painter.setPen(self.pen)
            painter.drawLine(self.lastPoint, event.pos())
            self.lastPoint = event.pos()

    def mouseReleaseEvent(self, event):
        if event.button() == Qt.LeftButton and self.drawing:
            self.drawing = False

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

这个程序使用PyQt5库创建了一个窗口，其中包含一个QGraphicsView和一个QGraphicsScene，用于显示绘制的图形。程序提供了新建、打开、保存、画笔和橡皮擦等功能，可以通过菜单栏或快捷键进行操作。您可以在窗口中使用鼠标绘制图形，支持画笔和橡皮擦两种模式。