## Description
This PR implements basic support for Japanese Input Method Editors
(IMEs) in the Zed terminal on macOS, addressing issue #9900. Previously,
users had to switch input modes to confirm Japanese text, and pre-edit
(marked) text was not displayed.
With these changes:
- **Marked Text Display:** Pre-edit text (e.g., underlined characters
during Japanese composition) is now rendered directly in the terminal at
the cursor's current position.
- **Composition Confirmation:** Pressing Enter correctly finalizes the
IME composition, clears the marked text, and sends the confirmed string
to the underlying PTY process. This allows for a more natural input flow
similar to other macOS applications like iTerm2.
- **State Management:** IME state (marked text and its selected range
within the marked text) is now managed within the `TerminalView` struct.
- **Input Handling:** `TerminalInputHandler` has been updated to
correctly process IME callbacks (`replace_and_mark_text_in_range`,
`replace_text_in_range`, `unmark_text`, `marked_text_range`) by
interacting with `TerminalView`.
- **Painting Logic:** `TerminalElement::paint` now fetches the marked
text and its range from `TerminalView` and renders it with an underline.
The standard terminal cursor is hidden when marked text is present to
avoid visual clutter.
- **Candidate Window Positioning:**
`TerminalInputHandler::bounds_for_range` now attempts to provide more
accurate bounds for the IME candidate window by using the actual painted
bounds of the pre-edit text, falling back to a cursor-based
approximation if necessary.
This significantly improves the usability of the Zed terminal for users
who need to input Japanese characters, bringing the experience closer to
system-standard IME behavior.
## Movies
https://github.com/user-attachments/assets/be6c7597-7b65-49a6-b376-e1adff6da974
---
Closes#9900
Release Notes:
- **Terminal:** Implemented basic support for Japanese Input Method
Editors (IMEs) on macOS. Users can now see pre-edit (marked) text as
they type Japanese and confirm their input with the Enter key directly
in the terminal. This provides a more natural and efficient experience
for Japanese language input. (Fixes#9900)
---------
Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>
