图像标注版本1-基本标注框

from PyQt5.QtWidgets import QWidget, QApplication, QLabel
from PyQt5.QtCore import QRect, Qt
from PyQt5.QtGui import QPixmap, QPainter, QPen
import sys

# 重定义QLabel，实现绘制事件和各类鼠标事件
class MyLabel(QLabel):
    def __init__(self, parent=None):
        '''
        :param parent:
        初始化基本参数
        '''
        super(MyLabel, self).__init__(parent)
        self.x0 = 0
        self.y0 = 0
        self.x1 = 0
        self.y1 = 0
        self.rect = QRect()
        self.flag = False

    # 单击鼠标触发事件
    # 获取鼠标事件的开始位置
    def mousePressEvent(self, event):
        # 将绘制标志设置为True
        self.flag = True
        self.x0 = event.pos().x()
        self.y0 = event.pos().y()

    # 鼠标移动事件
    # 绘制鼠标行进过程中的矩形框
    def mouseMoveEvent(self, event):
        if self.flag:
            self.x1 = event.pos().x()
            self.y1 = event.pos().y()
            self.update()

    # 鼠标释放事件
    def mouseReleaseEvent(self, event):
        # 将绘制标志设置为False
        self.flag = False

    # 绘制事件
    def paintEvent(self, event):
        super().paintEvent(event)
        # 构造矩形框的起始坐标和宽度、高度
        x0 = min(self.x0, self.x1)
        y0 = min(self.y0, self.y1)
        x1 = max(self.x0, self.x1)
        y1 = max(self.y0, self.y1)
        width = x1 - x0
        height = y1 - y0
        rect = QRect(x0, y0, width, height)
        # 构造QPainter，进行矩形框绘制
        painter = QPainter(self)
        painter.setPen(QPen(Qt.red, 2, Qt.SolidLine))
        painter.drawRect(rect)

# 窗口类
class LabelV1(QWidget):
    def __init__(self):
        super(LabelV1, self).__init__()
        self.initUI()

    def initUI(self):
        self.resize(960, 540)
        self.move(100, 50)
        self.setWindowTitle('Label标注框1.0版本')
        # 加载重定义的label
        self.lbl = MyLabel(self)
        # 构造QPixmap，加载待标注图片
        img = QPixmap('010.png')
        # 在自定义label中显示QImage
        self.lbl.setPixmap(img)
        self.lbl.setCursor(Qt.CrossCursor)
        self.show()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    labelwin = LabelV1()
    sys.exit(app.exec())