Closes#15833
Related to [#12495
comment](https://github.com/zed-industries/zed/pull/12495#issuecomment-2328356125)
Destroying and recreating the Input context was the only way to reset
the IME but it's making the keyboard unresponsive sometimes due to a XIM
error.
The keyboard will still be unresponsive if you close your IME while
using zed, but I don't know how to fix this.
* Fixed preedit drawing for CJK
* Fixed unresponsive keyboard by properly implementing reset_ic in
`xim-rs`
Release Notes:
- N/A
This helps with the problem of keyboard input feeling laggy when the
event loop is under load.
What would previously happen is:
- N events from X11 arrive
- N events get forwarded to XIM
- N events are handled in N iterations of the event loop (sadly, yes: we
only seem to be getting back one `ClientMessage` per poll from XCB
connection)
- Each event is pushed into the channel
- N event loop iterations are needed to get the events off the channel
and handle them
With this change, we get rid of the last 2 steps: instead of pushing the
event onto a channel, we store it on the XIM handler itself, and then
work it off synchronously.
Usually one shouldn't block the event loop, but I think in this case -
user input! - it's better to handle the events directly instead of
re-enqueuing them again in a channel, where they can accumulate and need
multiple iterations of the loop to be worked off.
This does *not* fix the problem of input feeling choppy/slower when the
system is under load, but it makes the behavior now feel exactly the
same as when XIM is disabled.
I also think the code is easier to understand since it's more
straightforward.
Release Notes:
- N/A
This pull request adds XIM (X Input Method) support to x11 platform.
The implementation utilizes [xim-rs](https://crates.io/crates/xim), a
XIM library written entirely in Rust, to provide asynchronous XIM
communication.
Preedit and candidate positioning are fully supported in the editor
interface, yet notably absent in the terminal environment.
This work is sponsored by [Rainlab Inc.](https://rainlab.co.jp/en/)
Release Notes:
- N/A
---------
Signed-off-by: npmania <np@mkv.li>
