[I am sorry i didn't serach before post. I find one. ]
[Answer is here:
http://www.cegui.org.uk/phpBB2/viewtopic.php?f=10&t=4131&p=18947&hilit=carat+position#p18947
I need to let an IME window follow the carat(caret) when i am typing Chinese in an edit box.
so i need to know where is the carat (in pixels) and put the IME window under it.
Thanks!
Here shows what i want:

