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|
use crate::{panes::PaneId, tab::Pane};
use cassowary::{
strength::{REQUIRED, STRONG},
Expression, Solver, Variable,
WeightedRelation::EQ,
};
use std::cell::RefCell;
use std::collections::{HashMap, HashSet};
use std::rc::Rc;
use zellij_utils::{
input::layout::Direction,
pane_size::{Constraint, Dimension, PaneGeom},
};
pub struct PaneResizer<'a> {
panes: Rc<RefCell<HashMap<PaneId, &'a mut Box<dyn Pane>>>>,
vars: HashMap<PaneId, Variable>,
solver: Solver,
}
// FIXME: Just hold a mutable Pane reference instead of the PaneId, fixed, pos, and size?
// Do this after panes are no longer trait-objects!
#[derive(Debug, Clone, Copy)]
struct Span {
pid: PaneId,
direction: Direction,
pos: usize,
size: Dimension,
size_var: Variable,
}
type Grid = Vec<Vec<Span>>;
impl<'a> PaneResizer<'a> {
pub fn new(panes: Rc<RefCell<HashMap<PaneId, &'a mut Box<dyn Pane>>>>) -> Self {
let mut vars = HashMap::new();
for &k in panes.borrow().keys() {
vars.insert(k, Variable::new());
}
PaneResizer {
panes,
vars,
solver: Solver::new(),
}
}
pub fn layout(&mut self, direction: Direction, space: usize) -> Result<(), String> {
self.solver.reset();
let grid = self.solve(direction, space)?;
let spans = self.discretize_spans(grid, space)?;
self.apply_spans(spans);
Ok(())
}
fn solve(&mut self, direction: Direction, space: usize) -> Result<Grid, String> {
let grid: Grid = self
.grid_boundaries(direction)
.into_iter()
.map(|b| self.spans_in_boundary(direction, b))
.collect();
let constraints: HashSet<_> = grid
.iter()
.flat_map(|s| constrain_spans(space, s))
.collect();
self.solver
.add_constraints(&constraints)
.map_err(|e| format!("{:?}", e))?;
Ok(grid)
}
fn discretize_spans(&mut self, mut grid: Grid, space: usize) -> Result<Vec<Span>, String> {
let mut rounded_sizes: HashMap<_, _> = grid
.iter()
.flatten()
.map(|s| {
(
s.size_var,
stable_round(self.solver.get_value(s.size_var)) as isize,
)
})
.collect();
// Round f64 pane sizes to usize without gaps or overlap
let mut finalised = Vec::new();
for spans in &mut grid {
let rounded_size: isize = spans.iter().map(|s| rounded_sizes[&s.size_var]).sum();
let mut error = space as isize - rounded_size;
let mut flex_spans: Vec<_> = spans
.iter_mut()
.filter(|s| !s.size.is_fixed() && !finalised.contains(&s.pid))
.collect();
flex_spans.sort_by_key(|s| rounded_sizes[&s.size_var]);
if error < 0 {
flex_spans.reverse();
}
for span in flex_spans {
rounded_sizes
.entry(span.size_var)
.and_modify(|s| *s += error.signum());
error -= error.signum();
}
finalised.extend(spans.iter().map(|s| s.pid));
}
// Update span positions based on their rounded sizes
for spans in &mut grid {
let mut offset = 0;
for span in spans {
span.pos = offset;
let sz = rounded_sizes[&span.size_var];
if sz < 1 {
return Err("Ran out of room for spans".into());
}
span.size.set_inner(sz as usize);
offset += span.size.as_usize();
}
}
Ok(grid.into_iter().flatten().collect())
}
fn apply_spans(&mut self, spans: Vec<Span>) {
let mut panes = self.panes.borrow_mut();
for span in spans {
let pane = panes.get_mut(&span.pid).unwrap();
let new_geom = match span.direction {
Direction::Horizontal => PaneGeom {
x: span.pos,
cols: span.size,
..pane.current_geom()
},
Direction::Vertical => PaneGeom {
y: span.pos,
rows: span.size,
..pane.current_geom()
},
};
if pane.geom_override().is_some() {
pane.set_geom_override(new_geom);
} else {
pane.set_geom(new_geom);
}
}
}
// FIXME: Functions like this should have unit tests!
fn grid_boundaries(&self, direction: Direction) -> Vec<(usize, usize)> {
// Select the spans running *perpendicular* to the direction of resize
let spans: Vec<Span> = self
.panes
.borrow()
.values()
.map(|p| self.get_span(!direction, p.as_ref()))
.collect();
let mut last_edge = 0;
let mut bounds =
|
