1、按鼠标左键任意画线

import sys
from PySide6.QtWidgets import QApplication, QLabel, QVBoxLayout, QWidget
from PySide6.QtGui import QPainter, QPixmap, QMouseEvent, QColor, QPen
from PySide6.QtCore import Qt, QPointclass PaintLabel(QLabel):def __init__(self, parent=None):super(PaintLabel, self).__init__(parent)self.setFixedSize(500, 500)self.pixmap = QPixmap(500, 500)  # 创建图像self.pixmap.fill(QColor('#000000'))  # 设为黑色self.setPixmap(self.pixmap)  # 设置图像self.drawing = Falseself.last_point = QPoint()def mousePressEvent(self, event: QMouseEvent):if event.button() == Qt.LeftButton:self.drawing = Trueself.last_point = event.position()def mouseMoveEvent(self, event: QMouseEvent):if event.buttons() & Qt.LeftButton and self.drawing:painter = QPainter(self.pixmap)pen = QPen(QColor('red'))pen.setWidth(3)painter.setPen(pen)painter.drawLine(self.last_point, event.position())self.last_point = event.position()self.setPixmap(self.pixmap)def mouseReleaseEvent(self, event: QMouseEvent):if event.button() == Qt.LeftButton:self.drawing = Falseclass MainWindow(QWidget):def __init__(self):super().__init__()self.label = PaintLabel()layout = QVBoxLayout()layout.addWidget(self.label)# layout.addWidget(save_button)self.setLayout(layout)if __name__ == "__main__":app = QApplication(sys.argv)main_window = MainWindow()main_window.show()sys.exit(app.exec())

2、画直线 

 

import sys
from PySide6.QtWidgets import QApplication, QLabel, QVBoxLayout, QWidget
from PySide6.QtGui import QPainter, QPixmap, QMouseEvent, QColor, QPen
from PySide6.QtCore import Qt, QPoint, QLineclass PaintLabel(QLabel):def __init__(self, parent=None):super(PaintLabel, self).__init__(parent)self.line = QLine()self.setFixedSize(500, 500)self.pixmap = QPixmap(500, 500)  # 创建图像self.pixmap.fill(QColor('#000000'))  # 设为黑色self.setPixmap(self.pixmap)  # 设置图像self.drawing = False         # 是否绘画中self.start_pos = QPoint()    # 起点self.end_pos = QPoint()      # 终点def mousePressEvent(self, event: QMouseEvent):if event.button() == Qt.LeftButton:self.drawing = Trueself.start_pos = event.position().toPoint()def mouseMoveEvent(self, event: QMouseEvent):if event.buttons() & Qt.LeftButton and self.drawing:self.end_pos = event.position().toPoint()self.line = QLine(self.start_pos, self.end_pos)self.update()def mouseReleaseEvent(self, event: QMouseEvent):if event.button() == Qt.LeftButton:self.drawing = Falseself.update()def paintEvent(self, event):super().paintEvent(event)  # 继承绘画事件if self.drawing:  # 如果正在绘画中painter = QPainter(self)  # 就不必刷新和写入，只是在当前的label上展示一下新增的线条而已pen = QPen(QColor(0, 255, 0), 2, Qt.CustomDashLine)   # 虚线pen.setDashPattern([1, 4, 5, 4])  # 设置自定义虚线模式painter.setPen(pen)painter.drawLine(self.line)painter.end()else:painter = QPainter(self.pixmap)  # 如果是松开鼠标的最后结果，就在图像上画painter.setPen(QPen(QColor(255, 0, 0, 255), 2, Qt.SolidLine))painter.drawLine(self.line)self.line = QLine()   # 画完后舍弃self.setPixmap(self.pixmap)    # 刷新显示class MainWindow(QWidget):def __init__(self):super().__init__()self.label = PaintLabel()layout = QVBoxLayout()layout.addWidget(self.label)self.setLayout(layout)if __name__ == "__main__":app = QApplication(sys.argv)main_window = MainWindow()main_window.show()sys.exit(app.exec())