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helix/helix-view/src/tree.rs

648 lines
21 KiB
Rust

use crate::{graphics::Rect, View, ViewId};
use slotmap::HopSlotMap;
// the dimensions are recomputed on window resize/tree change.
//
#[derive(Debug)]
pub struct Tree {
root: ViewId,
// (container, index inside the container)
pub focus: ViewId,
// fullscreen: bool,
area: Rect,
nodes: HopSlotMap<ViewId, Node>,
// used for traversals
stack: Vec<(ViewId, Rect)>,
}
#[derive(Debug)]
pub struct Node {
parent: ViewId,
content: Content,
}
#[derive(Debug)]
pub enum Content {
View(Box<View>),
Container(Box<Container>),
}
impl Node {
pub fn container(layout: Layout) -> Self {
Self {
parent: ViewId::default(),
content: Content::Container(Box::new(Container::new(layout))),
}
}
pub fn view(view: View) -> Self {
Self {
parent: ViewId::default(),
content: Content::View(Box::new(view)),
}
}
}
// TODO: screen coord to container + container coordinate helpers
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Layout {
Horizontal,
Vertical,
// could explore stacked/tabbed
}
#[derive(Debug, Clone, Copy)]
pub enum Direction {
Up,
Down,
Left,
Right,
}
#[derive(Debug)]
pub struct Container {
layout: Layout,
children: Vec<ViewId>,
area: Rect,
}
impl Container {
pub fn new(layout: Layout) -> Self {
Self {
layout,
children: Vec::new(),
area: Rect::default(),
}
}
}
impl Default for Container {
fn default() -> Self {
Self::new(Layout::Vertical)
}
}
impl Tree {
pub fn new(area: Rect) -> Self {
let root = Node::container(Layout::Vertical);
let mut nodes = HopSlotMap::with_key();
let root = nodes.insert(root);
// root is it's own parent
nodes[root].parent = root;
Self {
root,
focus: root,
// fullscreen: false,
area,
nodes,
stack: Vec::new(),
}
}
pub fn insert(&mut self, view: View) -> ViewId {
let focus = self.focus;
let parent = self.nodes[focus].parent;
let mut node = Node::view(view);
node.parent = parent;
let node = self.nodes.insert(node);
self.get_mut(node).id = node;
let container = match &mut self.nodes[parent] {
Node {
content: Content::Container(container),
..
} => container,
_ => unreachable!(),
};
// insert node after the current item if there is children already
let pos = if container.children.is_empty() {
0
} else {
let pos = container
.children
.iter()
.position(|&child| child == focus)
.unwrap();
pos + 1
};
container.children.insert(pos, node);
// focus the new node
self.focus = node;
// recalculate all the sizes
self.recalculate();
node
}
pub fn split(&mut self, view: View, layout: Layout) -> ViewId {
let focus = self.focus;
let parent = self.nodes[focus].parent;
let node = Node::view(view);
let node = self.nodes.insert(node);
self.get_mut(node).id = node;
let container = match &mut self.nodes[parent] {
Node {
content: Content::Container(container),
..
} => container,
_ => unreachable!(),
};
if container.layout == layout {
// insert node after the current item if there is children already
let pos = if container.children.is_empty() {
0
} else {
let pos = container
.children
.iter()
.position(|&child| child == focus)
.unwrap();
pos + 1
};
container.children.insert(pos, node);
self.nodes[node].parent = parent;
} else {
let mut split = Node::container(layout);
split.parent = parent;
let split = self.nodes.insert(split);
let container = match &mut self.nodes[split] {
Node {
content: Content::Container(container),
..
} => container,
_ => unreachable!(),
};
container.children.push(focus);
container.children.push(node);
self.nodes[focus].parent = split;
self.nodes[node].parent = split;
let container = match &mut self.nodes[parent] {
Node {
content: Content::Container(container),
..
} => container,
_ => unreachable!(),
};
let pos = container
.children
.iter()
.position(|&child| child == focus)
.unwrap();
// replace focus on parent with split
container.children[pos] = split;
}
// focus the new node
self.focus = node;
// recalculate all the sizes
self.recalculate();
node
}
pub fn remove(&mut self, index: ViewId) {
let mut stack = Vec::new();
if self.focus == index {
// focus on something else
self.focus_next();
}
stack.push(index);
while let Some(index) = stack.pop() {
let parent_id = self.nodes[index].parent;
if let Node {
content: Content::Container(container),
..
} = &mut self.nodes[parent_id]
{
if let Some(pos) = container.children.iter().position(|&child| child == index) {
container.children.remove(pos);
// TODO: if container now only has one child, remove it and place child in parent
if container.children.is_empty() && parent_id != self.root {
// if container now empty, remove it
stack.push(parent_id);
}
}
}
self.nodes.remove(index);
}
self.recalculate()
}
pub fn views(&self) -> impl Iterator<Item = (&View, bool)> {
let focus = self.focus;
self.nodes.iter().filter_map(move |(key, node)| match node {
Node {
content: Content::View(view),
..
} => Some((view.as_ref(), focus == key)),
_ => None,
})
}
pub fn views_mut(&mut self) -> impl Iterator<Item = (&mut View, bool)> {
let focus = self.focus;
self.nodes
.iter_mut()
.filter_map(move |(key, node)| match node {
Node {
content: Content::View(view),
..
} => Some((view.as_mut(), focus == key)),
_ => None,
})
}
pub fn get(&self, index: ViewId) -> &View {
match &self.nodes[index] {
Node {
content: Content::View(view),
..
} => view,
_ => unreachable!(),
}
}
pub fn get_mut(&mut self, index: ViewId) -> &mut View {
match &mut self.nodes[index] {
Node {
content: Content::View(view),
..
} => view,
_ => unreachable!(),
}
}
pub fn is_empty(&self) -> bool {
match &self.nodes[self.root] {
Node {
content: Content::Container(container),
..
} => container.children.is_empty(),
_ => unreachable!(),
}
}
pub fn resize(&mut self, area: Rect) -> bool {
if self.area != area {
self.area = area;
self.recalculate();
return true;
}
false
}
pub fn recalculate(&mut self) {
if self.is_empty() {
return;
}
self.stack.push((self.root, self.area));
// take the area
// fetch the node
// a) node is view, give it whole area
// b) node is container, calculate areas for each child and push them on the stack
while let Some((key, area)) = self.stack.pop() {
let node = &mut self.nodes[key];
match &mut node.content {
Content::View(view) => {
// debug!!("setting view area {:?}", area);
view.area = area;
} // TODO: call f()
Content::Container(container) => {
// debug!!("setting container area {:?}", area);
container.area = area;
match container.layout {
Layout::Horizontal => {
let len = container.children.len();
let height = area.height / len as u16;
let mut child_y = area.y;
for (i, child) in container.children.iter().enumerate() {
let mut area = Rect::new(
container.area.x,
child_y,
container.area.width,
height,
);
child_y += height;
// last child takes the remaining width because we can get uneven
// space from rounding
if i == len - 1 {
area.height = container.area.y + container.area.height - area.y;
}
self.stack.push((*child, area));
}
}
Layout::Vertical => {
let len = container.children.len();
let width = area.width / len as u16;
let inner_gap = 1u16;
// let total_gap = inner_gap * (len as u16 - 1);
let mut child_x = area.x;
for (i, child) in container.children.iter().enumerate() {
let mut area = Rect::new(
child_x,
container.area.y,
width,
container.area.height,
);
child_x += width + inner_gap;
// last child takes the remaining width because we can get uneven
// space from rounding
if i == len - 1 {
area.width = container.area.x + container.area.width - area.x;
}
self.stack.push((*child, area));
}
}
}
}
}
}
}
pub fn traverse(&self) -> Traverse {
Traverse::new(self)
}
// Finds the split in the given direction if it exists
pub fn find_split_in_direction(&self, id: ViewId, direction: Direction) -> Option<ViewId> {
let parent = self.nodes[id].parent;
// Base case, we found the root of the tree
if parent == id {
return None;
}
// Parent must always be a container
let parent_container = match &self.nodes[parent].content {
Content::Container(container) => container,
Content::View(_) => unreachable!(),
};
match (direction, parent_container.layout) {
(Direction::Up, Layout::Vertical)
| (Direction::Left, Layout::Horizontal)
| (Direction::Right, Layout::Horizontal)
| (Direction::Down, Layout::Vertical) => {
// The desired direction of movement is not possible within
// the parent container so the search must continue closer to
// the root of the split tree.
self.find_split_in_direction(parent, direction)
}
(Direction::Up, Layout::Horizontal)
| (Direction::Down, Layout::Horizontal)
| (Direction::Left, Layout::Vertical)
| (Direction::Right, Layout::Vertical) => {
// It's possible to move in the desired direction within
// the parent container so an attempt is made to find the
// correct child.
match self.find_child(id, &parent_container.children, direction) {
// Child is found, search is ended
Some(id) => Some(id),
// A child is not found. This could be because of either two scenarios
// 1. Its not possible to move in the desired direction, and search should end
// 2. A layout like the following with focus at X and desired direction Right
// | _ | x | |
// | _ _ _ | |
// | _ _ _ | |
// The container containing X ends at X so no rightward movement is possible
// however there still exists another view/container to the right that hasn't
// been explored. Thus another search is done here in the parent container
// before concluding it's not possible to move in the desired direction.
None => self.find_split_in_direction(parent, direction),
}
}
}
}
fn find_child(&self, id: ViewId, children: &[ViewId], direction: Direction) -> Option<ViewId> {
let mut child_id = match direction {
// index wise in the child list the Up and Left represents a -1
// thus reversed iterator.
Direction::Up | Direction::Left => children
.iter()
.rev()
.skip_while(|i| **i != id)
.copied()
.nth(1)?,
// Down and Right => +1 index wise in the child list
Direction::Down | Direction::Right => {
children.iter().skip_while(|i| **i != id).copied().nth(1)?
}
};
let (current_x, current_y) = match &self.nodes[self.focus].content {
Content::View(current_view) => (current_view.area.left(), current_view.area.top()),
Content::Container(_) => unreachable!(),
};
// If the child is a container the search finds the closest container child
// visually based on screen location.
while let Content::Container(container) = &self.nodes[child_id].content {
match (direction, container.layout) {
(_, Layout::Vertical) => {
// find closest split based on x because y is irrelevant
// in a vertical container (and already correct based on previous search)
child_id = *container.children.iter().min_by_key(|id| {
let x = match &self.nodes[**id].content {
Content::View(view) => view.inner_area().left(),
Content::Container(container) => container.area.left(),
};
(current_x as i16 - x as i16).abs()
})?;
}
(_, Layout::Horizontal) => {
// find closest split based on y because x is irrelevant
// in a horizontal container (and already correct based on previous search)
child_id = *container.children.iter().min_by_key(|id| {
let y = match &self.nodes[**id].content {
Content::View(view) => view.inner_area().top(),
Content::Container(container) => container.area.top(),
};
(current_y as i16 - y as i16).abs()
})?;
}
}
}
Some(child_id)
}
pub fn focus_direction(&mut self, direction: Direction) {
if let Some(id) = self.find_split_in_direction(self.focus, direction) {
self.focus = id;
}
}
pub fn focus_next(&mut self) {
// This function is very dumb, but that's because we don't store any parent links.
// (we'd be able to go parent.next_sibling() recursively until we find something)
// For now that's okay though, since it's unlikely you'll be able to open a large enough
// number of splits to notice.
// current = focus
// let found = loop do {
// node = focus.parent;
// let found = node.next_sibling_of(current)
// if some {
// break found;
// }
// // else
// if node == root {
// return first child of root;
// };
// current = parent;
// }
// }
//
// use found next sibling
// loop do {
// if found = view -> focus = found, return
// if found = container -> found = first child
// }
let mut views = self
.traverse()
.skip_while(|&(id, _view)| id != self.focus)
.skip(1); // Skip focused value
if let Some((id, _)) = views.next() {
self.focus = id;
} else {
// extremely crude, take the first item again
let (key, _) = self.traverse().next().unwrap();
self.focus = key;
}
}
pub fn area(&self) -> Rect {
self.area
}
}
#[derive(Debug)]
pub struct Traverse<'a> {
tree: &'a Tree,
stack: Vec<ViewId>, // TODO: reuse the one we use on update
}
impl<'a> Traverse<'a> {
fn new(tree: &'a Tree) -> Self {
Self {
tree,
stack: vec![tree.root],
}
}
}
impl<'a> Iterator for Traverse<'a> {
type Item = (ViewId, &'a View);
fn next(&mut self) -> Option<Self::Item> {
loop {
let key = self.stack.pop()?;
let node = &self.tree.nodes[key];
match &node.content {
Content::View(view) => return Some((key, view)),
Content::Container(container) => {
self.stack.extend(container.children.iter().rev());
}
}
}
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::DocumentId;
#[test]
fn find_split_in_direction() {
let mut tree = Tree::new(Rect {
x: 0,
y: 0,
width: 180,
height: 80,
});
let mut view = View::new(DocumentId::default());
view.area = Rect::new(0, 0, 180, 80);
tree.insert(view);
let l0 = tree.focus;
let view = View::new(DocumentId::default());
tree.split(view, Layout::Vertical);
let r0 = tree.focus;
tree.focus = l0;
let view = View::new(DocumentId::default());
tree.split(view, Layout::Horizontal);
let l1 = tree.focus;
tree.focus = l0;
let view = View::new(DocumentId::default());
tree.split(view, Layout::Vertical);
let l2 = tree.focus;
// Tree in test
// | L0 | L2 | |
// | L1 | R0 |
tree.focus = l2;
assert_eq!(Some(l0), tree.find_split_in_direction(l2, Direction::Left));
assert_eq!(Some(l1), tree.find_split_in_direction(l2, Direction::Down));
assert_eq!(Some(r0), tree.find_split_in_direction(l2, Direction::Right));
assert_eq!(None, tree.find_split_in_direction(l2, Direction::Up));
tree.focus = l1;
assert_eq!(None, tree.find_split_in_direction(l1, Direction::Left));
assert_eq!(None, tree.find_split_in_direction(l1, Direction::Down));
assert_eq!(Some(r0), tree.find_split_in_direction(l1, Direction::Right));
assert_eq!(Some(l0), tree.find_split_in_direction(l1, Direction::Up));
tree.focus = l0;
assert_eq!(None, tree.find_split_in_direction(l0, Direction::Left));
assert_eq!(Some(l1), tree.find_split_in_direction(l0, Direction::Down));
assert_eq!(Some(l2), tree.find_split_in_direction(l0, Direction::Right));
assert_eq!(None, tree.find_split_in_direction(l0, Direction::Up));
tree.focus = r0;
assert_eq!(Some(l2), tree.find_split_in_direction(r0, Direction::Left));
assert_eq!(None, tree.find_split_in_direction(r0, Direction::Down));
assert_eq!(None, tree.find_split_in_direction(r0, Direction::Right));
assert_eq!(None, tree.find_split_in_direction(r0, Direction::Up));
}
}