Trait leechbar::Component [−] [src]

pub trait Component {
    fn update(&mut self) -> bool { ... }

    fn event(&mut self, _event: Event) -> bool { ... }

    fn redraw_timer(&mut self) -> Receiver<()> { ... }

    fn background(&self) -> Background { ... }

    fn foreground(&self) -> Foreground { ... }

    fn alignment(&self) -> Alignment { ... }

    fn width(&self) -> Width { ... }
}

Trait for creating custom components.

This trait is used for the Bar::add method. You can use it to implement custom components that change at runtime. Each method takes &mut self and is called whenever the component redraws, this allows mutating the struct of the component at runtime.

Examples

extern crate chan;

use leechbar::{Component, Background, Foreground, Alignment, Width};
use std::time::Duration;
use std::thread;

struct MyComponent;

// You can define your own custom components like this
impl Component for MyComponent {
    // No background image
    fn background(&self) -> Background {
        Background::new()
    }

    // Do not print any text
    fn foreground(&self) -> Foreground {
        Foreground::new()
    }

    // Put this element at the center of the bar
    fn alignment(&self) -> Alignment {
        Alignment::CENTER
    }

    // Redraw every 5 seconds
    fn redraw_timer(&mut self) -> chan::Receiver<()> {
        let (tx, rx) = chan::sync(0);

        // Start thread for sending update requests
        // Then send the updates every 5 seconds
        thread::spawn(move || loop {
            thread::sleep(Duration::from_secs(5));
            let _ = tx.send(());
        });

        rx
    }

    // No width restrictions
    fn width(&self) -> Width {
        Width::new()
    }

    // Always redraw component
    fn update(&mut self) -> bool {
        true
    }
}

fn main() {
    let component = MyComponent;
}

Provided Methods

This is the first thing called before redrawing a component. It can be used to modify the state of the struct implementing the Component trait.

This method's return value determines if the component should be redrawn in this cycle, returning false instead of redrawing the same content will save resources.

Default: true, component will always be redrawn.

This is called whenever an event occurs that is related to this component.

The return value is used to check if the component is supposed to be redrawn after the event has been processed.

Default: false, do nothing when an event is received.

This method controls the redraw-rate of the component. Every time the Receiver receives any message, the component is redrawn. This method is called only once when the component is added to the bar, dropping the Sender will stop the component from being redrawn without removing the current state from the bar.

Default: Sender dropped immediately, component is drawn only once.

The background of the component. Use None for no background.

Default: No background.

The text of the component.

Default: No foreground.

The alignment of the component.

Default: Alignment::CENTER

The width of the component.

Default: No width restrictions.

Implementors