Choices and values

Slider for Slint

KitSlider · Slint Kit 0.3.0

Continuous slider projecting a domain value onto a normalized position.

Run preview

Try the component

Download the complete project, extract it and run cargo run --locked in its folder. Rust 1.92+; Slint Kit 0.3.0 from crates.io. You can also copy the four files below.

Click the track, then press Right: Rust increases the accepted volume in five-percentage-point steps.

ui/app.slint

export { KitFormValidation, HtmlInputKind, NumberInputFormat, KitInputConstraints, KitValidationResult, KitValidityState } from "@kit/kit.slint";
// SPDX-License-Identifier: GPL-3.0-or-later
import { KitSlider, RangeThumb, NavigationStep, KitTheme, KitThemes } from "@kit/kit.slint";
export component App inherits Window {
    title: "KitSlider example";
    preferred-width: 520px;
    preferred-height: 220px;
    max-width: 100000px;
    max-height: 100000px;
    background: root.theme.canvas;
    in-out property <KitTheme> theme: KitThemes.light;
    in property <int> lower;
    in property <int> upper;
    callback position(RangeThumb, float);
    callback navigate(RangeThumb, NavigationStep);
    callback begin();
    callback commit();
    callback cancel();
    VerticalLayout {
        padding: 24px;
        spacing: 16px;
        alignment: start;
        control := KitSlider { theme: root.theme; label: "Volume"; position: root.upper * 0.01; value-label: root.upper + "%";
            position-requested(value) => { root.position(RangeThumb.upper, value); }
            navigate(step) => { root.navigate(RangeThumb.upper, step); }
            gesture-started => { root.begin(); } committed => { root.commit(); } cancelled => { root.cancel(); }
        }
        result := Text { text: "Volume: " + root.upper + "%"; color: root.theme.text-primary; }
    }

}

src/main.rs

// SPDX-License-Identifier: GPL-3.0-or-later
use slint::ComponentHandle;
use slint_kit::{RangeController, RangeThumb, DecimalValue, DecimalStep, NumericBounds, OrderedRange, StepDirection};
use std::{cell::RefCell, rc::Rc};
mod ui { slint::include_modules!(); }
fn value(n: i64) -> DecimalValue { DecimalValue::from_integer(n) }
fn thumb(t: ui::RangeThumb) -> RangeThumb { match t { ui::RangeThumb::Lower => RangeThumb::Start, ui::RangeThumb::Upper => RangeThumb::End } }
fn publish(app: &ui::App, range: &RangeController) {
    app.set_lower(range.value().start().to_string().parse().expect("integral percent"));
    app.set_upper(range.value().end().to_string().parse().expect("integral percent"));
}
fn main() -> Result<(), slint::PlatformError> {
    let app = ui::App::new()?;
    slint_kit::init_form_validation!(ui, app);
    let range = Rc::new(RefCell::new(RangeController::new(NumericBounds::new(value(0), value(100)).unwrap(), OrderedRange::new(value(0), value(65)).unwrap(), DecimalStep::new(value(5)).unwrap()).unwrap()));
    publish(&app, &range.borrow());
    let state = range.clone(); let weak = app.as_weak();
    app.on_position(move |t, position| { if !position.is_finite() { return; }
        let quantized = value((position.clamp(0.0, 1.0) * 100.0).round() as i64);
        let _ = state.borrow_mut().set(thumb(t), quantized);
        if let Some(app) = weak.upgrade() { publish(&app, &state.borrow()); }
    });
    let state = range.clone(); let weak = app.as_weak();
    app.on_navigate(move |t, step| {
        let t = thumb(t);
        { let mut range = state.borrow_mut();
          let _ = match step {
            ui::NavigationStep::Next | ui::NavigationStep::PageNext => range.step(t, StepDirection::Increment),
            ui::NavigationStep::Previous | ui::NavigationStep::PagePrevious => range.step(t, StepDirection::Decrement),
            ui::NavigationStep::First => { let v = if t == RangeThumb::Start { value(0) } else { range.value().start() }; range.set(t, v) },
            ui::NavigationStep::Last => { let v = if t == RangeThumb::End { value(100) } else { range.value().end() }; range.set(t, v) },
          };
        }
        if let Some(app) = weak.upgrade() { publish(&app, &state.borrow()); }
    });
    let state = range.clone(); app.on_begin(move || state.borrow_mut().begin_drag());
    let state = range.clone(); app.on_commit(move || state.borrow_mut().commit_drag());
    let weak = app.as_weak(); app.on_cancel(move || { range.borrow_mut().cancel_drag(); if let Some(app) = weak.upgrade() { publish(&app, &range.borrow()); } });
    app.run()
}

[package]
name = "slint-kit-slider-example"
version = "0.1.0"
edition = "2024"
rust-version = "1.92"
license = "GPL-3.0-or-later"
publish = false

[dependencies]
slint-kit = "=0.3.0"
slint = { version = "=1.18.1", default-features = false, features = ["std", "compat-1-18", "backend-winit", "renderer-skia", "accessibility"] }

[build-dependencies]
slint-kit-build = "=0.3.0"

[workspace]

fn main() { slint_kit_build::compile("ui/app.slint").expect("compile component example"); }

Files: Cargo.toml · build.rs · ui/app.slint · src/main.rs

Supply position from 0 to 1 and a readable value-label. Convert position-requested(float) and navigate(NavigationStep) into requests on your domain type.

gesture-started, committed and cancelled delimit a reversible interaction. The view bounds rendering, while steps, rounding and accepted values belong to the controller.

View source ↗

Choose between built-in options and custom composition

Shared options

• label — built-in property; custom composition example

Visual composition

The file below produces the screenshot. For controller-driven components, it shows the displayed state without supplying the Rust wiring. Create a project.

Show the screenshot source

// SPDX-License-Identifier: GPL-3.0-or-later
import { KitSlider, KitTheme, KitThemes } from "@kit/kit.slint";

export component Example inherits Window {
    title: "KitSlider example";
    preferred-width: 420px;
    preferred-height: 180px;
    max-width: 100000px;
    max-height: 100000px;
    background: root.theme.canvas;
    in-out property <KitTheme> theme: KitThemes.light;
    in-out property <string> status;
    VerticalLayout {
        padding: 24px; spacing: 16px; alignment: start;
        Text { text: "Slider"; color: root.theme.text-primary; font-size: 20px * root.theme.text-scale; font-weight: 600; }
        Text { text: "Volume · 65%"; color: root.theme.text-primary; font-size: 14px * root.theme.text-scale; wrap: word-wrap; } KitSlider { theme: root.theme; label: "Volume"; position: 0.65; value-label: "65%"; position-requested(value) => { root.status = "Position requested"; } }
        if root.status != "": Text { text: root.status; color: root.theme.text-secondary; font-size: 12px * root.theme.text-scale; wrap: word-wrap; }
    }
}

Download this example

Public API

Inherits Rectangle.

Properties

Types and variants

Callbacks

• position-requested(float)
• navigate(NavigationStep)
• gesture-started()
• committed()
• cancelled()

Functions

• take-focus()

See also

• Range Slider
• Number Stepper