如何在PyQt4中绘制一条带动画的线条

from PyQt4.QtGui import QPainter, QImage, QPainterPath, QTimeEdit
from PyQt4.QtCore import Qt, QTimer

# 创建一个QPainter对象
painter = QPainter(self.viewport())

# 创建一个QImage对象，用于保存绘制结果
image = QImage(self.viewport().size(), QImage.Format_RGB32)

# 创建一个QPainterPath对象，用于绘制线条
path = QPainterPath()
path.addLine(0, 0, 100, 100)

# 创建一个QTimeEdit对象，用于控制动画
timer = QTimer(self)
timer.timeout.connect(self.animate)
timer.start(1000)

# 动画函数
def animate(self):
    # 获取当前画笔的颜色和宽度
    color = painter.pen().color()
    width = painter.pen().width()

    # 设置画笔的颜色和宽度为线条的颜色和宽度
    painter.setPen(Qt.red)
    painter.setBrush(Qt.red)
    painter.setRenderHint(QPainter.Antialiasing)

    # 绘制线条
    painter.drawPath(path)

    # 将画笔的颜色和宽度还原为默认值
    painter.setPen(color)
    painter.setBrush(color)

    # 将绘制结果保存为图片
    image.save(self.viewport().mapToGlobal(QPoint(0, 0)))

# 运行程序
if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec())