Globals

Declare a global singleton with global Name { /* .. properties or callbacks .. */ } to make properties and callbacks available throughout the entire project. Access them using Name.property.

For example, this can be useful for a common color palette:

global Palette  {
    in-out property<color> primary: blue;
    in-out property<color> secondary: green;
}

export component Example inherits Rectangle {
    background: Palette.primary;
    border-color: Palette.secondary;
    border-width: 2px;
}

slint

Export a global to make it accessible from other files. To reach a global from your business logic in Rust, C++, JavaScript, or Python — setting its properties and implementing its callbacks — re-export it from the file that also exports your main application component:

export global Logic  {
    in-out property <int> the-value;
    pure callback magic-operation(int) -> int;
}
// ...

slint

slint::slint!{
export global Logic {
    in-out property <int> the-value;
    pure callback magic-operation(int) -> int;
}

export component App inherits Window {
    // ...
}
}

fn main() {
    let app = App::new();
    app.global::<Logic>().on_magic_operation(|value| {
        eprintln!("magic operation input: {}", value);
        value * 2
    });
    app.global::<Logic>().set_the_value(42);
    // ...
}

rust

#include "app.h"

int main() {
    auto app = App::create();
    app->global<Logic>().on_magic_operation([](int value) -> int {
        return value * 2;
    });
    app->global<Logic>().set_the_value(42);
    // ...
}

C++

let slint = require("slint-ui");
let file = slint.loadFile("app.slint");
let app = new file.App();
app.Logic.magic_operation = (value) => {
    return value * 2;
};
app.Logic.the_value = 42;
// ...

import slint

class App(slint.loader.app.App):
    @slint.callback(global_name="Logic")
    def magic_operation(self, value: int) -> int:
        return value * 2

app = App()
app.Logic.the_value = 42

# ...

python

To re-expose global properties on a component with two-way bindings, see the Globals chapter of the language reference.