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use std::{collections::HashMap, ops::Deref};
use super::*;
/// Caches layouting artifacts.
#[derive(Default, Debug, Clone)]
pub struct LayoutCache {
/// Maps from node hashes to the resulting frames and regions in which the
/// frames are valid.
pub frames: HashMap<u64, FramesEntry>,
}
impl LayoutCache {
/// Create a new, empty layout cache.
pub fn new() -> Self {
Self { frames: HashMap::new() }
}
/// Clear the cache.
pub fn clear(&mut self) {
self.frames.clear();
}
/// Retains all elements for which the closure on the level returns `true`.
pub fn retain<F>(&mut self, mut f: F)
where
F: FnMut(usize) -> bool,
{
self.frames.retain(|_, entry| f(entry.level));
}
/// Amount of items in the cache.
pub fn len(&self) -> usize {
self.frames.len()
}
}
#[derive(Debug, Clone)]
/// Cached frames from past layouting.
pub struct FramesEntry {
/// The cached frames for a node.
pub frames: Vec<Constrained<Rc<Frame>>>,
/// How nested the frame was in the context is was originally appearing in.
pub level: usize,
}
impl FramesEntry {
/// Checks if the cached [`Frame`] is valid for the given regions.
pub fn check(&self, mut regions: Regions) -> Option<Vec<Constrained<Rc<Frame>>>> {
for (i, frame) in self.frames.iter().enumerate() {
if (i != 0 && !regions.next()) || !frame.constraints.check(®ions) {
return None;
}
}
Some(self.frames.clone())
}
}
#[derive(Debug, Copy, Clone, PartialEq)]
pub struct Constraints {
/// The minimum available length in the region.
pub min: Spec<Option<Length>>,
/// The maximum available length in the region.
pub max: Spec<Option<Length>>,
/// The available length in the region.
pub exact: Spec<Option<Length>>,
/// The base length of the region used for relative length resolution.
pub base: Spec<Option<Length>>,
/// The expand settings of the region.
pub expand: Spec<bool>,
}
impl Constraints {
/// Create a new region constraint.
pub fn new(expand: Spec<bool>) -> Self {
Self {
min: Spec::default(),
max: Spec::default(),
exact: Spec::default(),
base: Spec::default(),
expand,
}
}
/// Set the appropriate base constraints for (relative) width and height
/// metrics, respectively.
pub fn set_base_using_linears(
&mut self,
size: Spec<Option<Linear>>,
regions: &Regions,
) {
// The full sizes need to be equal if there is a relative component in the sizes.
if size.horizontal.map_or(false, |l| l.is_relative()) {
self.base.horizontal = Some(regions.base.width);
}
if size.vertical.map_or(false, |l| l.is_relative()) {
self.base.vertical = Some(regions.base.height);
}
}
fn check(&self, regions: &Regions) -> bool {
if self.expand != regions.expand {
return false;
}
let base = regions.base.to_spec();
let current = regions.current.to_spec();
current.eq_by(&self.min, |x, y| y.map_or(true, |y| x >= &y))
&& current.eq_by(&self.max, |x, y| y.map_or(true, |y| x < &y))
&& current.eq_by(&self.exact, |x, y| y.map_or(true, |y| x == &y))
&& base.eq_by(&self.base, |x, y| y.map_or(true, |y| x == &y))
}
/// Changes all constraints by adding the argument to them if they are set.
pub fn mutate(&mut self, size: Size) {
for x in &mut [self.min, self.max, self.exact, self.base] {
if let Some(horizontal) = x.horizontal.as_mut() {
*horizontal += size.width;
}
if let Some(vertical) = x.vertical.as_mut() {
*vertical += size.height;
}
}
}
}
#[derive(Debug, Copy, Clone, PartialEq)]
pub struct Constrained<T> {
pub item: T,
pub constraints: Constraints,
}
impl<T> Deref for Constrained<T> {
type Target = T;
fn deref(&self) -> &Self::Target {
&self.item
}
}
pub trait OptionExt {
fn set_min(&mut self, other: Length);
fn set_max(&mut self, other: Length);
}
impl OptionExt for Option<Length> {
fn set_min(&mut self, other: Length) {
match self {
Some(x) => x.set_min(other),
None => *self = Some(other),
}
}
fn set_max(&mut self, other: Length) {
match self {
Some(x) => x.set_max(other),
None => *self = Some(other),
}
}
}
|
