How to get the current text caret position(not mouse position) in Tauri?

[devinoue]

How can I get the text caret coordinates of the frontmost application?(not mouse position)

I have an application that wants to get caret position.

Context

I'm Japanese speaker and switching between Japanese and alphanumeric input sources on macOS.

Windows application "Google Japanese Input(Google 日本語入力)" shows "A" for alphanumeric input and "あ" for Japanese input under the caret to indicate which input source is currently being used when switching. I would like to implement a similar feature as an application on Tauri and macOS.
(Google Japanese Input for macOS does not have that feature.)

like this