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use stretch::node;
use crate::{Number, Size, Style};
/// The visual requirements of a [`Widget`] and its children.
///
/// When there have been changes and the [`Layout`] needs to be recomputed, the
/// runtime obtains a [`Node`] by calling [`Widget::node`].
///
/// [`Style`]: struct.Style.html
/// [`Widget`]: widget/trait.Widget.html
/// [`Node`]: struct.Node.html
/// [`Widget::node`]: widget/trait.Widget.html#tymethod.node
/// [`Layout`]: struct.Layout.html
#[derive(Debug)]
pub struct Node(pub(crate) node::Node);
impl Node {
/// Creates a new [`Node`] with the given [`Style`].
///
/// [`Node`]: struct.Node.html
/// [`Style`]: struct.Style.html
pub fn new(style: Style) -> Node {
Self::with_children(style, Vec::new())
}
/// Creates a new [`Node`] with the given [`Style`] and a measure function.
///
/// This type of node cannot have any children.
///
/// You should use this when your [`Widget`] can adapt its contents to the
/// size of its container. The measure function will receive the container
/// size as a parameter and must compute the size of the [`Node`] inside
/// the given bounds (if the `Number` for a dimension is `Undefined` it
/// means that it has no boundary).
///
/// [`Node`]: struct.Node.html
/// [`Style`]: struct.Style.html
/// [`Widget`]: widget/trait.Widget.html
pub fn with_measure<F>(style: Style, measure: F) -> Node
where
F: 'static + Fn(Size<Number>) -> Size<f32>,
{
Node(node::Node::new_leaf(
style.0,
Box::new(move |size| Ok(measure(size))),
))
}
/// Creates a new [`Node`] with the given [`Style`] and children.
///
/// [`Node`]: struct.Node.html
/// [`Style`]: struct.Style.html
pub fn with_children(style: Style, children: Vec<Node>) -> Node {
Node(node::Node::new(
style.0,
children.iter().map(|c| &c.0).collect(),
))
}
}
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