Which egui requirement permit virtual keyboard opening on smartphones ?

[buxx]

Hello !

First, A big thank you for this amazing lib. Egui is awesome for Rust world.

I have an issue with virtual keyboard opening on smartphones when use egui with its macroquad integration. Explainations :

Virtual keyboard opening on smartphones works well with egui when I try on my dev machine or online (tested version 0.17 and 0.16):

But, It fails to open virtual keyboard opening on smartphones when I use macroquad integration. There is the HowTo reproduction method :

1. Init a fresh rust project cargo init demo_smartphone_macroquad
2. Declare these dependencies in Cargo.toml:

[dependencies]
macroquad = "0.3"
egui = "0.16.1"
egui-macroquad = "0.8.0"

3. Write this main.rs :

use macroquad::prelude::*;
#[macroquad::main("egui with macroquad")]
async fn main() {
    let mut text = "input here 2".to_string();
    loop {
        clear_background(WHITE);
        egui_macroquad::ui(|egui_ctx| {
            egui::Window::new("egui ❤ macroquad").show(egui_ctx, |ui| {
                ui.text_edit_singleline(&mut text);
            });
        });
        egui_macroquad::draw();
        next_frame().await;
    }
}

To make macroquad builds able to work with wasm-bindgem, we must use this helper script : (wget https://gist.githubusercontent.com/olefasting/15ae263da4cf1ba308ce55c15c9b221b/raw/4ca4c8e23e19ae6e0040d68b0397cb0103066736/wasm-bindgen-macroquad.sh && chmod +x wasm-bindgen-macroquad.sh)

4. Build the wasm bin with ./wasm-bindgen-macroquad.sh demo_smartphone_macroquad --release (wasm-bindgen-cli is required: cargo install -f wasm-bindgen-cli)
5. Start http server cargo install basic-http-server && basic-http-server -a 0.0.0.0:4000 ./web
6. Open http://<you_computer_local_ip>:4000/ with a smartphone and try the text edit.

For information, egui macroquad integration code is visible here : https://github.com/optozorax/egui-macroquad/blob/master/src/lib.rs

My question : What in egui is permitting virtual keyboard opening ? Which seems to be missing in macroquad egui integration or wasm-bindgem compatibility hack. I would be happy to help make this work.

[KentaTheBugMaker]

egui_web attach dummy input element to body to capture KeyboardEvent,InputEvent,CompositionEvent but macroquad does not add input element .
this workaround introduced by @n2 in #253 .

[buxx]

Thank you a lot @t18b219k for these information. I will study them about making macroquad compatible !

[n2]

The dummy input element initial/enabling/moving logic is in this file, Composition events handle logic is here, hope that helps.

[buxx]

Hello @n2 ,

I'm trying to follow the steps which "activate" this install_text_agent feature. There is what I understand :

Starting from eframe_template

1. eframe_template indicate to wasm the start entrypoint. This function call eframe::start_web.

2. eframe::start_web call egui_web::start

3. egui_web::start call start_runner which call install_text_agent.

I suppose #[wasm_bindgen] on start in eframe_template is important too.

Am I right ?

I now have to explore egui-macroquad and egui-miniquad integrations ... :p

[n2]

Yes, that's the calling process, #[wasm_bindgen] is used to expose start(...) to JavaScript.
install_text_agent(...) uses web_sys to get Document on Html and creates HtmlInputElement on it. If web_sys is available on the macroquad, you can call this install_text_agent(...) directly in the initialization function, or you have to find a proper way to create/manipulate HtmlInputElement on the macroquad.