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.

Examples

To create a component you only have to create a struct that implements the Component trait. This is how you create an empty component:

use leechbar::Component;

struct MyComponent;
impl Component for 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.

Examples

use leechbar::Component;

struct MyComponent;
impl Component for MyComponent {
    // This would never draw anything
    fn update(&mut self) -> bool {
        false
    }
}

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.

Examples

use leechbar::{Component, Event};

struct MyComponent;
impl Component for MyComponent {
    fn event(&mut self, event: Event) -> bool {
        if let Event::ClickEvent(_) = event {
            println!("Someone clicked on this component!");
        }
        false
    }
}

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.

Examples

extern crate chan;
use leechbar::Component;
use std::time::Duration;
use std::thread;

struct MyComponent;
impl Component for MyComponent {
    // Redraw this component every 5 seconds
    fn redraw_timer(&mut self) -> chan::Receiver<()> {
        let (tx, rx) = chan::sync(0);

        thread::spawn(move || loop {
            thread::sleep(Duration::from_secs(5));
            tx.send(());
        });

        rx
    }
}

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

Default: No background.

Examples

use leechbar::{Component, Color, Background};

struct MyComponent;
impl Component for MyComponent {
    // Fixed pink background color
    fn background(&self) -> Background {
        Color::new(255, 0, 255, 255).into()
    }
}

The text of the component.

Default: No foreground.

Examples

use leechbar::{Bar, Component, Foreground, Text};

struct MyComponent {
    bar: Bar,
}

impl Component for MyComponent {
    // Fixed "Hello, World!" text
    fn foreground(&self) -> Foreground {
        Text::new(&self.bar, "Hello, Word!", None, None).unwrap().into()
    }
}

The alignment of the component.

Default: Alignment::CENTER

Examples

use leechbar::{Component, Alignment};

struct MyComponent;
impl Component for MyComponent {
    // Put the component at the right of the bar
    fn alignment(&self) -> Alignment {
        Alignment::RIGHT
    }
}

The width of the component.

Default: No width restrictions.

Examples

use leechbar::{Component, Width};

struct MyComponent;
impl Component for MyComponent {
    // Fixed 300 pixel width
    fn width(&self) -> Width {
        Width::new().fixed(300)
    }
}

Implementors