It might be lack of sleep, but I can’t figure this out.

I have a Label, and I want its text to be red when it represents an error, and I want it be green when it represent “good to go”.

I found search result for C and maybe a solution for Python, but nothing for Rust.

I tried manually setting the css-classes property and running queue_draw(); it didn’t work.

I can have a gtk::Box or a Frame that I place where the Label should go, then declare two Labels, and use set_child() to switch between them, but that seems like an ugly solution.

Do you have a solution?

  • d_k_bo@feddit.org
    3·
    3 hours ago

    Just use label.add_css_class(), label.remove_css_class() or label.set_css_classes() and make sure to properly load your CSS style sheets, this is usually done by including them as a resource alongside .ui files and icons. If you are using libadwaita, you can also use its predefined style classes.

    full example (requires nightly toolchain) 
    #!/usr/bin/env -S cargo +nightly -Zscript
---
[dependencies]
gtk = { package = "gtk4", version = "0.9.3", features = ["v4_12"] }
---

use gtk::{glib, prelude::*};

const STYLESHEET: &str = r#"
.green {
    color: green;
}
.red {
    color: red;
}
"#;

fn main() -> glib::ExitCode {
    let app = gtk::Application::builder()
        .application_id("org.example.HelloWorld")
        .build();

    app.connect_activate(|app| {
        let window = gtk::ApplicationWindow::builder()
            .application(app)
            .title("Hello, World!")
            .build();

        // Stylesheets are usually bundled with application resources
        // and automatically loaded
        let css_provider = gtk::CssProvider::new();
        css_provider.load_from_string(STYLESHEET);
        gtk::style_context_add_provider_for_display(
            &RootExt::display(&window),
            &css_provider,
            0
        );

        let box_ = gtk::Box::new(gtk::Orientation::Vertical, 6);

        let label = gtk::Label::builder()
            .label("Hello, World")
            .css_classes(["green"].as_slice())
            .build();
        box_.append(&label);


        let button = gtk::Button::builder()
            .label("Toggle Color")
            .build();
        box_.append(&button);

        button.connect_clicked(glib::clone!(#[weak] label, move |_| {
            if label.has_css_class("red") {
                label.add_css_class("green");
                label.remove_css_class("red");
            } else {
                label.add_css_class("red");
                label.remove_css_class("green");
            }
        }));

        window.set_child(Some(&box_));
        window.present();
    });

    app.run()
}
  • Doods@infosec.pubOP
    2·
    8 hours ago

    Before anyone suggests another library:

    • Iced and Egui both can’t handle Arabic, which is a deal breaker.
    • Iced takes forever to compile and iterate, maybe that’ll be fixed with dynamic linking.
    • Relm: I didn’t know it existed before I started this project.
    • Qt bindings: IDK I forgot Qt existed, I was always more of GNOME* guy.
    • I am already pretty deep into this project, and don’t want to learn something else for now.

    * GNU Network Object something Environment

    • BB_C@programming.dev
      11·
      7 hours ago

      Use libcosmic 😑

      No, but seriously… skip to the end.

      Iced and Egui both can’t handle Arabic, which is a deal breaker.

      Iced can handle Arabic shaping-wise when cosmic-text is used, but it can’t handle the direction (yet). If you only need it for the interface, a shit workaround would be to prefix all text with an RLM (RIGHT-TO-LEFT Mark). This would left-align all text of course.

      Iced takes forever to compile and iterate, maybe that’ll be fixed with dynamic linking.

      Fast iteration is already fixed by using cranelift in your release-dev profile (or whatever you want to call it), and mold as a linker. The binary will be slower, but iteration will be much much faster.

      Okay, something helpful instead: Did you try asking in the rust:gnome.org matrix room mentioned in the project page?