用qt实现labelme的代码

Labelme是一个用于图像标注的开源工具，使用Python和Qt开发。下面是一个简单的实现Labelme的代码示例：

import os
import json
from PyQt5.QtCore import Qt, QPoint, QRect
from PyQt5.QtGui import QImage, QPixmap, QPainter, QPen
from PyQt5.QtWidgets import QApplication, QMainWindow, QGraphicsScene, QGraphicsView, QGraphicsPixmapItem, QAction, QFileDialog

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.image_path = ''
        self.annotations = []
        self.current_annotation = None
        self.current_polygon = []
        self.scene = QGraphicsScene(self)
        self.view = QGraphicsView(self.scene)
        self.view.setDragMode(QGraphicsView.ScrollHandDrag)
        self.view.setRenderHint(QPainter.Antialiasing)
        self.setCentralWidget(self.view)
        self.create_actions()
        self.create_menus()
        self.setWindowTitle('Labelme')

    def create_actions(self):
        self.open_image_action = QAction('Open Image', self)
        self.open_image_action.setShortcut('Ctrl+O')
        self.open_image_action.triggered.connect(self.open_image)
        self.save_annotations_action = QAction('Save Annotations', self)
        self.save_annotations_action.setShortcut('Ctrl+S')
        self.save_annotations_action.triggered.connect(self.save_annotations)
        self.quit_action = QAction('Quit', self)
        self.quit_action.setShortcut('Ctrl+Q')
        self.quit_action.triggered.connect(self.close)

    def create_menus(self):
        self.file_menu = self.menuBar().addMenu('File')
        self.file_menu.addAction(self.open_image_action)
        self.file_menu.addAction(self.save_annotations_action)
        self.file_menu.addAction(self.quit_action)

    def open_image(self):
        options = QFileDialog.Options()
        options |= QFileDialog.DontUseNativeDialog
        file_path, _ = QFileDialog.getOpenFileName(self, 'Open Image', '', 'Images (*.png *.xpm *.jpg *.bmp *.gif)', options=options)
        if file_path:
            self.image_path = file_path
            self.scene.clear()
            self.current_annotation = None
            self.current_polygon = []
            pixmap = QPixmap(file_path)
            item = QGraphicsPixmapItem(pixmap)
            self.scene.addItem(item)
            self.view.fitInView(item, Qt.KeepAspectRatio)

    def save_annotations(self):
        if not self.image_path:
            return
        annotations_file = os.path.splitext(self.image_path)[0] + '.json'
        with open(annotations_file, 'w') as f:
            json.dump(self.annotations, f)

    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:
            if not self.current_annotation:
                self.current_annotation = {
                    'image_path': self.image_path,
                    'annotations': []
                }
                self.annotations.append(self.current_annotation)
            self.current_polygon.append(self.view.mapToScene(event.pos()))
            if len(self.current_polygon) > 1:
                self.scene.addLine(QLineF(self.current_polygon[-2], self.current_polygon[-1]), QPen(Qt.red))
    
    def keyPressEvent(self, event):
        if event.key() == Qt.Key_Return:
            if self.current_polygon:
                self.current_annotation['annotations'].append(self.current_polygon)
                self.current_polygon = []
                self.scene.clear()
                pixmap = QPixmap(self.image_path)
                item = QGraphicsPixmapItem(pixmap)
                self.scene.addItem(item)
                self.view.fitInView(item, Qt.KeepAspectRatio)

if __name__ == '__main__':
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()

这个示例代码实现了打开图片、绘制多边形标注、保存标注等功能。但是这只是一个简单的示例，实际使用中还需要考虑更多的细节和功能。