doc ppt xls x5预览：lib_x5
pdf mupdf开源库预览：lib_mupdf
pdf pdfium开源库预览：lib_pdfium
mupdf-1.18.0
cygwin64 build: make generate
x5-43967
https://x5.tencent.com/tbs/sdk.html
mupdf-1.18.0
https://github.com/ArtifexSoftware/mupdf
pdfium-source-android11
https://github.com/chromium/pdfium
https://pdfium.googlesource.com/pdfium.git
https://github.com/barteksc/AndroidPdfViewer.git