//! Groupings of elements.
use crate::*;

/// A function or closure that emits renderables.
pub trait Collector<E: Engine>: Send + Sync + Fn(&mut dyn FnMut(&dyn Render<E>)) {}

/// Any function or closure that emits renderables for the given engine matches [CollectCallback].
impl<E, F> Collector<E> for F
where E: Engine, F: Send + Sync + Fn(&mut dyn FnMut(&dyn Render<E>)) {}

pub trait Render<E: Engine> {
    fn area (&self, to: E::Area) -> E::Area;
    fn render (&self, to: &mut E::Output);
}

impl<E: Engine, C: Content<E>> Render<E> for C {
    fn area (&self, to: E::Area) -> E::Area {
        Content::area(self, to)
    }
    fn render (&self, to: &mut E::Output) {
        Content::render(self, to)
    }
}