TextEdit autocompletion example

[crumblingstatue]

I'm opening this pull request for experimenting and getting early feedback on how to implement autocompletion for TextEdit.
It adds an autocomplete demo for easy experimentation.
This is very much a heavy work in progress, the only thing I managed to implement so far is setting the cursor to end in a crude way.

Main problems I identified with autocompletion:

• Need a way to set cursor position, or at least a way to set it to the end on demand (after the user applies the autocompletion)
• Need a way to ignore certain keyboard events (for example when the user is navigating the autocomplete list with Up/Down arrow keys)

I implemented the bare functionality I want for autocomplete to work properly, but I'm looking for feedback and guidance of how to integrate this into egui properly.

[crumblingstatue]

I implemented the bare features to showcase what I want to achieve. Here is a video of how it looks like, and it's available to try as a demo.
https://user-images.githubusercontent.com/1521976/136600706-df4b1156-fba9-4e33-b654-e9dc1599cd2b.mp4

I now welcome feedback on how to integrate this functionality into egui proper.

[Titaniumtown]

oop seems i've been accidentally spamming this PR from my fork of egui. my apologizes

[crumblingstatue]

As of this point, no modifications to egui are needed for at least basic autocomplete support, thanks to InputState::consume_key.
I updated the pull request to reflect this.

[emilk]

I finally got around to test this now - very nice work!

There are some issues though - when I press enter to select a word, the suggestion box lingers, and the focus is not returned to the TextEdit.

[crumblingstatue]

yeah, it's kind of messed up, since it went through multiple stages of egui updates. I'll try cleaning it up tomorrow if an autocompletion example is desirable.

[emilk]

I find it very desirable, and a good starting point for others to continue from. Sorry for taking so long before taking a look at this

[crumblingstatue]

I force pushed a more functional version, and removed the draft status of the PR.
Now it's ready for more serious review.

[emilk]

The functionality is nice, but the code is quite complicated imho. The purpose of most demos and examples is to show "This is how easy doing X is!" and this doesn't feel very simple to be honest :)

Perhaps it could be refactored into shorter and more reusable functions?

[crumblingstatue]

I'll try doing some refactoring tomorrow. If you have an idea of how to make it shorter and more reusable, feel free to give input.

[crumblingstatue]

I have decided to adopt a different strategy.

Originally, I opened this pull request because changes needed to be made to egui to make a functioning autocomplete popup.
However, since then, egui has acquired all the features required to implement such a thing.

This caused this pull request to instead try to add an example for autocompletion.
However, I don't think I can push here an autocompletion example that is both simple, and demonstrates all the features that I need.

So instead, I'm going to create an egui autocompletion library.
If the project is successful, I might submit a pull request for inclusion in egui_extras, along with an example.

Thank you for your patience!

[SerHanmer]

@crumblingstatue
Were you able to successfully create an autocompletion library?

[crumblingstatue]

@crumblingstatue Were you able to successfully create an autocompletion library?

Sorry, I haven't had the motivation to finish creating one.
I just use custom completion code in my application right now

[SerHanmer]

@crumblingstatue Were you able to successfully create an autocompletion library?

Sorry, I haven't had the motivation to finish creating one. I just use custom completion code in my application right now

No worries, Thanks for getting back to me.

[gabrieldechichi]

For anyone reading this in the future, I'm extracting the relevant part of the code for setting the cursor position to the end:

fn set_cursor_pos(ui: &mut Ui, te_id: Id, char_pos: usize) {
    let mut state = TextEdit::load_state(ui.ctx(), te_id).unwrap();
    let ccursor = text::CCursor::new(char_pos);
    state.set_ccursor_range(Some(text::CCursorRange::one(ccursor)));
    TextEdit::store_state(ui.ctx(), te_id, state);
}

Which can be used like

let input_id = ui.make_persistent_id("cmd_input_id");
TextEdit::singleline(&mut user_input)
                .id(input_id)
                .ui(ui);
//will set the cursor to the end of user_input
set_cursor_pos(ui, input_id, user_input.chars().count());