The format of .svg .pdf is ok, but the output of .pdf is empty

[qingchenbenpao]

Thanks for you code, the format of .svg .pdf is ok, but the output of .pdf file is empty, the storage of .pdf file is only 1kb, then open it, it is an empty image. my packages is as follow,

Package Version

---

cairocffi 1.3.0
CairoSVG 2.5.2
certifi 2022.6.15
cffi 1.15.1
cssselect2 0.6.0
defusedxml 0.7.1
mkl-fft 1.3.1
mkl-random 1.2.2
mkl-service 2.4.0
numpy 1.22.3
Pillow 9.0.1
pip 21.2.2
pycairo 1.21.0
pycparser 2.21
setuptools 61.2.0
six 1.16.0
tinycss2 1.1.1
tk 0.1.0
webencodings 0.5.1
wheel 0.37.1
wincertstore 0.2

the version of python is 3.8