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//! Layout nodes.
use std::any::Any;
use std::fmt::{self, Debug, Formatter};
use super::*;
/// A self-contained, styled layout node.
#[derive(Clone, PartialEq)]
pub enum LayoutNode {
/// A spacing node.
Spacing(Spacing),
/// A text node.
Text(Text),
/// A dynamic that can implement custom layouting behaviour.
Dyn(Dynamic),
}
impl LayoutNode {
/// Create a new dynamic node.
pub fn dynamic<T>(inner: T) -> Self
where
T: Layout + Debug + Clone + PartialEq + 'static,
{
Self::Dyn(Dynamic::new(inner))
}
}
impl Layout for LayoutNode {
fn layout(&self, ctx: &mut LayoutContext, areas: &Areas) -> Layouted {
match self {
Self::Spacing(spacing) => spacing.layout(ctx, areas),
Self::Text(text) => text.layout(ctx, areas),
Self::Dyn(dynamic) => dynamic.layout(ctx, areas),
}
}
}
impl Debug for LayoutNode {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
match self {
Self::Spacing(spacing) => spacing.fmt(f),
Self::Text(text) => text.fmt(f),
Self::Dyn(dynamic) => dynamic.fmt(f),
}
}
}
/// A wrapper around a dynamic layouting node.
pub struct Dynamic(Box<dyn Bounds>);
impl Dynamic {
/// Create a new instance from any node that satisifies the required bounds.
pub fn new<T>(inner: T) -> Self
where
T: Layout + Debug + Clone + PartialEq + 'static,
{
Self(Box::new(inner))
}
}
impl Layout for Dynamic {
fn layout(&self, ctx: &mut LayoutContext, areas: &Areas) -> Layouted {
self.0.layout(ctx, areas)
}
}
impl Clone for Dynamic {
fn clone(&self) -> Self {
Self(self.0.dyn_clone())
}
}
impl PartialEq for Dynamic {
fn eq(&self, other: &Self) -> bool {
self.0.dyn_eq(other.0.as_ref())
}
}
impl Debug for Dynamic {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
self.0.fmt(f)
}
}
impl From<Dynamic> for LayoutNode {
fn from(dynamic: Dynamic) -> Self {
Self::Dyn(dynamic)
}
}
trait Bounds: Layout + Debug + 'static {
fn as_any(&self) -> &dyn Any;
fn dyn_eq(&self, other: &dyn Bounds) -> bool;
fn dyn_clone(&self) -> Box<dyn Bounds>;
}
impl<T> Bounds for T
where
T: Layout + Debug + PartialEq + Clone + 'static,
{
fn as_any(&self) -> &dyn Any {
self
}
fn dyn_eq(&self, other: &dyn Bounds) -> bool {
if let Some(other) = other.as_any().downcast_ref::<Self>() {
self == other
} else {
false
}
}
fn dyn_clone(&self) -> Box<dyn Bounds> {
Box::new(self.clone())
}
}
|
