在Python Kivy中用鼠标右键或滚轮单击窗口会添加红色的可拖动圆圈

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.uix.scatter import Scatter
from kivy.uix.label import Label
from kivy.uix.floatlayout import FloatLayout
from kivy.graphics import Color, Ellipse

class MyWidget(Widget):
    def on_touch_down(self, touch):
        # 检查鼠标右键或滚轮单击事件
        if touch.button == 'right' or touch.is_mouse_scrolling:
            # 创建一个可拖动的圆圈
            scatter = Scatter(pos=(touch.x, touch.y), size=(100, 100))
            with scatter.canvas:
                Color(1, 0, 0)  # 设置圆圈颜色为红色
                Ellipse(pos=scatter.pos, size=scatter.size)
            self.add_widget(scatter)  # 将圆圈添加到窗口中

class MyApp(App):
    def build(self):
        return MyWidget()

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