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use crate::core::{Rectangle, Size};
use crate::pane_grid::{Axis, Pane, Split};
use std::collections::BTreeMap;
/// A layout node of a [`PaneGrid`].
///
/// [`PaneGrid`]: super::PaneGrid
#[derive(Debug, Clone)]
pub enum Node {
/// The region of this [`Node`] is split into two.
Split {
/// The [`Split`] of this [`Node`].
id: Split,
/// The direction of the split.
axis: Axis,
/// The ratio of the split in [0.0, 1.0].
ratio: f32,
/// The left/top [`Node`] of the split.
a: Box<Node>,
/// The right/bottom [`Node`] of the split.
b: Box<Node>,
},
/// The region of this [`Node`] is taken by a [`Pane`].
Pane(Pane),
}
impl Node {
/// Returns an iterator over each [`Split`] in this [`Node`].
pub fn splits(&self) -> impl Iterator<Item = &Split> {
let mut unvisited_nodes = vec![self];
std::iter::from_fn(move || {
while let Some(node) = unvisited_nodes.pop() {
if let Node::Split { id, a, b, .. } = node {
unvisited_nodes.push(a);
unvisited_nodes.push(b);
return Some(id);
}
}
None
})
}
/// Returns the rectangular region for each [`Pane`] in the [`Node`] given
/// the spacing between panes and the total available space.
pub fn pane_regions(
&self,
spacing: f32,
size: Size,
) -> BTreeMap<Pane, Rectangle> {
let mut regions = BTreeMap::new();
self.compute_regions(
spacing,
&Rectangle {
x: 0.0,
y: 0.0,
width: size.width,
height: size.height,
},
&mut regions,
);
regions
}
/// Returns the axis, rectangular region, and ratio for each [`Split`] in
/// the [`Node`] given the spacing between panes and the total available
/// space.
pub fn split_regions(
&self,
spacing: f32,
size: Size,
) -> BTreeMap<Split, (Axis, Rectangle, f32)> {
let mut splits = BTreeMap::new();
self.compute_splits(
spacing,
&Rectangle {
x: 0.0,
y: 0.0,
width: size.width,
height: size.height,
},
&mut splits,
);
splits
}
pub(crate) fn find(&mut self, pane: Pane) -> Option<&mut Node> {
match self {
Node::Split { a, b, .. } => {
a.find(pane).or_else(move || b.find(pane))
}
Node::Pane(p) => {
if *p == pane {
Some(self)
} else {
None
}
}
}
}
pub(crate) fn split(&mut self, id: Split, axis: Axis, new_pane: Pane) {
*self = Node::Split {
id,
axis,
ratio: 0.5,
a: Box::new(self.clone()),
b: Box::new(Node::Pane(new_pane)),
};
}
pub(crate) fn split_inverse(&mut self, id: Split, axis: Axis, pane: Pane) {
*self = Node::Split {
id,
axis,
ratio: 0.5,
a: Box::new(Node::Pane(pane)),
b: Box::new(self.clone()),
};
}
pub(crate) fn update(&mut self, f: &impl Fn(&mut Node)) {
if let Node::Split { a, b, .. } = self {
a.update(f);
b.update(f);
}
f(self);
}
pub(crate) fn resize(&mut self, split: Split, percentage: f32) -> bool {
match self {
Node::Split {
id, ratio, a, b, ..
} => {
if *id == split {
*ratio = percentage;
true
} else if a.resize(split, percentage) {
true
} else {
b.resize(split, percentage)
}
}
Node::Pane(_) => false,
}
}
pub(crate) fn remove(&mut self, pane: Pane) -> Option<Pane> {
match self {
Node::Split { a, b, .. } => {
if a.pane() == Some(pane) {
*self = *b.clone();
Some(self.first_pane())
} else if b.pane() == Some(pane) {
*self = *a.clone();
Some(self.first_pane())
} else {
a.remove(pane).or_else(|| b.remove(pane))
}
}
Node::Pane(_) => None,
}
}
fn pane(&self) -> Option<Pane> {
match self {
Node::Split { .. } => None,
Node::Pane(pane) => Some(*pane),
}
}
fn first_pane(&self) -> Pane {
match self {
Node::Split { a, .. } => a.first_pane(),
Node::Pane(pane) => *pane,
}
}
fn compute_regions(
&self,
spacing: f32,
current: &Rectangle,
regions: &mut BTreeMap<Pane, Rectangle>,
) {
match self {
Node::Split {
axis, ratio, a, b, ..
} => {
let (region_a, region_b) = axis.split(current, *ratio, spacing);
a.compute_regions(spacing, ®ion_a, regions);
b.compute_regions(spacing, ®ion_b, regions);
}
Node::Pane(pane) => {
let _ = regions.insert(*pane, *current);
}
}
}
fn compute_splits(
&self,
spacing: f32,
current: &Rectangle,
splits: &mut BTreeMap<Split, (Axis, Rectangle, f32)>,
) {
match self {
Node::Split {
axis,
ratio,
a,
b,
id,
} => {
let (region_a, region_b) = axis.split(current, *ratio, spacing);
let _ = splits.insert(*id, (*axis, *current, *ratio));
a.compute_splits(spacing, ®ion_a, splits);
b.compute_splits(spacing, ®ion_b, splits);
}
Node::Pane(_) => {}
}
}
}
impl std::hash::Hash for Node {
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
match self {
Node::Split {
id,
axis,
ratio,
a,
b,
} => {
id.hash(state);
axis.hash(state);
((ratio * 100_000.0) as u32).hash(state);
a.hash(state);
b.hash(state);
}
Node::Pane(pane) => {
pane.hash(state);
}
}
}
}