I have solved the installed bug, it's wrong filename
Here is the snopshot for QEMU testing, it modified the original Plaintext plugin
The purpose is for Chinese Vertical Layout,
For Pango Layout,
a) set the base_Gravity to PANGO_GRAVITY_EAST
b) rotate 90
For Font data, it depends on Font face, (this part let me confuse)
I am not sure whether pango can do following things or not, especialy item (a).
a) unrotated the latin half glyphs
b) unrotated the Chinese full vertical scripts
c) hinting some punctuations
Others special cases are not considered, for example, time stamp, digital index, combinational hanzi,
later, I'll upload it.