如何在Kivy中获得RstDocument的大小？

from kivy.lang import Builder
from kivy.uix.rst import RstDocument
from kivy.metrics import dp

Builder.load_string('''
<MyLayout>:
    RstDocument:
        id: rst_doc
        text: 'Your RST content here'
''')

class MyLayout(FloatLayout):
    pass

layout = MyLayout()
rst_doc = layout.ids.rst_doc
rst_doc.bind(texture_size=lambda instance, size: setattr(rst_doc, 'size', size))
layout.add_widget(rst_doc)

# 获取RstDocument的宽度和高度
width = rst_doc.width
height = rst_doc.height

# 将像素值转换为dp
width_in_dp = dp(width)
height_in_dp = dp(height)