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rust-windowing / winit

Window handling library in pure Rust
https://docs.rs/winit/
Apache License 2.0
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`set_ime_cursor_area` uses the top left corner of the rectangle as the composition/cursor point on X11 #3965

Open xorgy opened 1 week ago

xorgy commented 1 week ago

Description

On X11, unlike other platforms (windows, macOS), Window::set_ime_cursor_area behaves differently from how it is described in the documentation. In particular, it ignores the height of the rectangle, and submits the top left corner as the composition/insertion point: https://github.com/rust-windowing/winit/blob/c913cdab0b0b1ddecc6b7896d85da187f44b2393/src/platform_impl/linux/x11/window.rs#L2034-L2042

Whereas on Windows, the height is added to produce the equivalent: https://github.com/rust-windowing/winit/blob/c913cdab0b0b1ddecc6b7896d85da187f44b2393/src/platform_impl/windows/ime.rs#L123-L126

And on Mac, NSView gives a rectangle for this operation, which the system will avoid placing the candidate window over (still assuming the bottom left corner, typically)

https://github.com/rust-windowing/winit/blob/c913cdab0b0b1ddecc6b7896d85da187f44b2393/src/platform_impl/apple/appkit/view.rs#L370-L384

This results in the candidate window being reliably placed overtop the preedit text, without platform-specific workarounds.

OS and window mananger

Xorg 21

Winit version

0.30.5

kchibisov commented 1 week ago

I think the docs mention that it's not implemented on X11? The issue is mostly that I don't think there's an API for that, winit could try to e.g. put the thing below what was submitted, but it could break.

kchibisov commented 1 week ago

The APIs you see on other platforms require you to pass a rectangle to not obscure an area, so they are just different and compositor positions the window in a way to not obscure it.

xorgy commented 1 week ago

@kchibisov The problem is that if you use this API as documented, you will obscure your text 100% of the time with the most common X11 IME (iBus). If you ignore the documentation and send only a Position at the baseline with no size, you get usable behavior most of the time, but then you are misusing the API on every other platform.

The API being called in the X11 backend as far as I'm aware is meant to be given the equivalent of ptCurrentPos on Windows, as most implementations rarely place the candidate window anywhere but below the given point, but I may be wrong about that.

xorgy commented 1 week ago

Of course, you could also make a case for adding width to x in this case, because ibus on XIM will still obscure the line if it is near the bottom of the screen.

kchibisov commented 1 week ago

The thing is that none of that will happen with any of the other backend, though, it' x11 and i don't care that much.

xorgy commented 6 days ago

Alright so I've talked with Fcitx @wengxt and he's willing to accept an attribute on the XIM IC, I'll see if I can confirm with Mr. Fujiwara about a name for the attribute for adding this to iBus as well.