如何让图像在kivy中移动

from kivy.app import App
from kivy.uix.image import Image
from kivy.uix.widget import Widget
from kivy.core.window import Window
from kivy.clock import Clock

class ImageWidget(Widget):
    def __init__(self, **kwargs):
        super(ImageWidget, self).__init__(**kwargs)
        self.image = Image(source='path_to_image.png')
        self.add_widget(self.image)
        self.velocity = 2  # 移动速度

    def update(self, dt):
        self.image.x += self.velocity  # 更新图像的位置
        if self.image.right > Window.width or self.image.x < 0:
            self.velocity *= -1  # 当图像到达窗口边缘时改变移动方向

class MyApp(App):
    def build(self):
        image_widget = ImageWidget()
        Clock.schedule_interval(image_widget.update, 1 / 60)  # 设置更新频率为60帧每秒
        return image_widget

if __name__ == '__main__':
    MyApp().run()