winit: Both `_selected_range` and `_replacement_range` parameters are ignored in NSTextInputClient implementation.

Description

TypeAlias “ICB” = “Inline Composition Buffer” = “Inline PreEdit”

Both _selected_range and _replacement_range parameters are ignored in NSTextInputClient implementation. This causes an issue that these parameters sent from IME to IMKTextInput APIs are completely neglected:

https://github.com/rust-windowing/winit/blob/44aabdddcc9f720aec860c1f83c1041082c28560/src/platform_impl/macos/view.rs#L321

These parameters are crucial for some IMEs utilizing nested inline composition buffers (i.e. nested preedits). E.g. The Traditional Chinese Zhuyin IME shipped in macOS. In-ICB cursor is of vital necessity for these IMEs.

Note: These parameters are UTF16 ranges. Apple introduced these APIs in macOS 10.5 Leopard. See the IMKTextInput API header for more intelligence: https://github.com/phracker/MacOSX-SDKs/blob/041600eda65c6a668f66cb7d56b7d1da3e8bcc93/MacOSX10.5.sdk/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/Headers/IMKInputSession.h#L74-L85

I was about to send a PR to fix this issue. However, I have to figure out one thing:

In src/events.rs, search pub enum Ime and find Preedit(String, Option<(usize, usize)>),. I have doubts about this property: Are these cursor positions supposed to be utf8 or utf16? This has to be figured out prior to patching this issue.

macOS version

ProductName:		macOS
ProductVersion:		14.4.1
BuildVersion:		23E224

Winit version

Master Branch 44aabddd

About this issue

Original URL
State: open
Created 3 months ago
Comments: 16 (7 by maintainers)

Most upvoted comments

Yeah, selected range matches the start/end cursor APIs we have pretty much, as what I can say, so shouldn’t be that hard, I guess.

kchibisov on Apr 2, 2024

Yeah, so you need an API to indicate such range, and then delete send new text, that’s pretty much how it’s on Wayland. So this API could be left untouched for awhile until we have a separate Window::set_ime_surrounding_text or similar APIs. Though, I won’t stop you from drafting one.

kchibisov on Apr 2, 2024

Ah, I think I got what you mean. I’m pretty sure it works by indicating surrounding text around, so you can not really do that without adding a new API. Such API was discussed in the past, but that’s about it.

@ShikiSuen maybe you need a special key on macOS, but on linux I just have a binding to convert between　漢字 and kana. Though, I’m not sure there’s a way to trigger the convert just by starting selection, at least I’ve never seen how to.

kchibisov on Apr 2, 2024

It’s an offset into utf8’s byte string representation, because String is utf8.

kchibisov on Apr 1, 2024

Everything is utf8, it’s also documented like that.

kchibisov on Apr 1, 2024