Struct druid::Key

pub struct Key<T> { /* fields omitted */ }

A typed Env key.

This lets you retrieve values of a given type. The parameter implements ValueType. For "expensive" types, this is a reference, so the type for a string is Key<&str>.

Examples

const IMPORTANT_LABEL_COLOR: Key<Color> = Key::new("my-app.important-label-color");

fn important_label() -> Label<()> {
    Label::new("Warning!").with_text_color(IMPORTANT_LABEL_COLOR)
}

fn main() {
    let main_window = WindowDesc::new(important_label);

    AppLauncher::with_window(main_window)
        .configure_env(|env, _state| {
            // The `Key` must be set before it is used.
            env.set(IMPORTANT_LABEL_COLOR, Color::rgb(1.0, 0.0, 0.0));
        });
}

Implementations

impl<T> Key<T>

pub const fn new(key: &'static str) -> Self

Create a new strongly typed Key with the given string value. The type of the key will be inferred.

Examples

use druid::Key;
use druid::piet::Color;

let float_key: Key<f64> = Key::new("a.very.good.float");
let color_key: Key<Color> = Key::new("a.very.nice.color");

impl Key<()>

pub const fn untyped(key: &'static str) -> Self

Create an untyped Key with the given string value.

WARNING: This is not for general usage - it's only useful for inspecting the contents of an Env - this is expected to be used for debugging, loading, and manipulating themes.

Trait Implementations

impl<T> From<Key<Color>> for BackgroundBrush<T>

fn from(src: Key<Color>) -> BackgroundBrush<T>

Performs the conversion.

impl<T> From<Key<T>> for String

fn from(src: Key<T>) -> String

Performs the conversion.

impl<'a, T: ValueType<'a>> From<Key<T>> for KeyOrValue<T>

fn from(key: Key<T>) -> KeyOrValue<T>

Performs the conversion.