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623 lines
16 KiB
Rust
623 lines
16 KiB
Rust
use std::cell::RefCell;
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use std::cmp::{max, min};
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use std::collections::HashMap;
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use cassowary::strength::{REQUIRED, WEAK};
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use cassowary::WeightedRelation::*;
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use cassowary::{Constraint as CassowaryConstraint, Expression, Solver, Variable};
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#[derive(Debug, Hash, Clone, Copy, PartialEq, Eq)]
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pub enum Corner {
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TopLeft,
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TopRight,
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BottomRight,
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BottomLeft,
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}
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#[derive(Debug, Hash, Clone, PartialEq, Eq)]
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pub enum Direction {
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Horizontal,
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Vertical,
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}
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#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
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pub enum Unit {
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Length(u16),
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Percentage(u16),
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Ratio(u32, u32),
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}
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impl From<u16> for Unit {
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fn from(v: u16) -> Unit {
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Unit::Length(v)
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}
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}
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impl Unit {
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pub(crate) fn apply(&self, length: u16) -> u16 {
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match *self {
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Unit::Percentage(p) => length * p / 100,
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Unit::Ratio(num, den) => {
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let r = num * u32::from(length) / den;
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r as u16
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}
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Unit::Length(l) => length.min(l),
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}
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}
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fn check(&self) {
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match *self {
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Unit::Percentage(p) => {
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assert!(
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p <= 100,
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"Percentages should be between 0 and 100 inclusively."
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);
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}
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Unit::Ratio(num, den) => {
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assert!(
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num <= den,
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"Ratio numerator should be less than or equalt to denominator."
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);
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}
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_ => {}
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}
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}
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}
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#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
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enum Operator {
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Equal,
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GreaterThanOrEqual,
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LessThanOrEqual,
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}
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#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
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pub struct Constraint {
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operator: Operator,
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unit: Unit,
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weight: u8,
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}
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impl Constraint {
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pub fn gte<T>(u: T) -> Constraint
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where
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T: Into<Unit>,
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{
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let u = u.into();
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u.check();
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Constraint {
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operator: Operator::GreaterThanOrEqual,
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unit: u,
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weight: 0,
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}
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}
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pub fn lte<T>(u: T) -> Constraint
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where
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T: Into<Unit>,
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{
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let u = u.into();
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u.check();
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Constraint {
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operator: Operator::LessThanOrEqual,
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unit: u,
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weight: 0,
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}
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}
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pub fn eq<T>(u: T) -> Constraint
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where
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T: Into<Unit>,
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{
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let u = u.into();
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u.check();
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Constraint {
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operator: Operator::Equal,
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unit: u,
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weight: 0,
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}
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}
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pub fn weight(mut self, weight: u8) -> Constraint {
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self.weight = weight;
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self
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}
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}
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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pub struct Constraints(Vec<Constraint>);
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impl From<Constraint> for Constraints {
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fn from(c: Constraint) -> Constraints {
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Constraints(vec![c])
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}
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}
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impl<T> std::iter::FromIterator<T> for Constraints
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where
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T: Into<Constraint>,
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{
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fn from_iter<I>(iter: I) -> Constraints
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where
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I: IntoIterator<Item = T>,
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{
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Constraints(iter.into_iter().map(|c| c.into()).collect())
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}
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}
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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pub struct Margin {
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pub vertical: u16,
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pub horizontal: u16,
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}
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#[derive(Debug, Clone, Copy, PartialEq)]
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pub enum Alignment {
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Left,
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Center,
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Right,
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}
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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pub struct Layout {
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direction: Direction,
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margin: Margin,
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constraints: Vec<Constraints>,
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}
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thread_local! {
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static LAYOUT_CACHE: RefCell<HashMap<(Rect, Layout), Vec<Rect>>> = RefCell::new(HashMap::new());
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}
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impl Default for Layout {
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fn default() -> Layout {
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Layout {
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direction: Direction::Vertical,
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margin: Margin {
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horizontal: 0,
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vertical: 0,
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},
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constraints: Vec::new(),
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}
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}
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}
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impl Layout {
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pub fn constraints<I>(mut self, constraints: I) -> Layout
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where
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I: IntoIterator,
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I::Item: Into<Constraints>,
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{
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self.constraints = constraints.into_iter().map(|c| c.into()).collect();
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self
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}
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pub fn margin(mut self, margin: u16) -> Layout {
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self.margin = Margin {
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horizontal: margin,
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vertical: margin,
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};
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self
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}
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pub fn horizontal_margin(mut self, horizontal: u16) -> Layout {
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self.margin.horizontal = horizontal;
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self
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}
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pub fn vertical_margin(mut self, vertical: u16) -> Layout {
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self.margin.vertical = vertical;
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self
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}
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pub fn direction(mut self, direction: Direction) -> Layout {
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self.direction = direction;
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self
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}
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/// Wrapper function around the cassowary-rs solver to be able to split a given
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/// area into smaller ones based on the preferred widths or heights and the direction.
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///
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/// # Examples
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/// ```
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/// # use tui::layout::{Rect, Constraint, Direction, Layout, Unit};
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/// let chunks = Layout::default()
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/// .direction(Direction::Vertical)
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/// .constraints([
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/// Constraint::eq(5).weight(10),
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/// Constraint::eq(Unit::Percentage(100)).weight(5)
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/// ])
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/// .split(Rect {
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/// x: 2,
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/// y: 2,
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/// width: 10,
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/// height: 10,
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/// });
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/// assert_eq!(
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/// chunks,
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/// vec![
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/// Rect {
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/// x: 2,
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/// y: 2,
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/// width: 10,
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/// height: 5
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/// },
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/// Rect {
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/// x: 2,
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/// y: 7,
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/// width: 10,
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/// height: 5
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/// }
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/// ]
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/// );
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///
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/// let chunks = Layout::default()
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/// .direction(Direction::Horizontal)
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/// .constraints([Constraint::eq(Unit::Ratio(1, 3)), Constraint::eq(Unit::Ratio(2, 3))])
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/// .split(Rect {
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/// x: 0,
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/// y: 0,
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/// width: 9,
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/// height: 2,
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/// });
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/// assert_eq!(
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/// chunks,
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/// vec![
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/// Rect {
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/// x: 0,
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/// y: 0,
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/// width: 3,
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/// height: 2
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/// },
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/// Rect {
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/// x: 3,
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/// y: 0,
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/// width: 6,
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/// height: 2
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/// }
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/// ]
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/// );
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/// ```
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pub fn split(&self, area: Rect) -> Vec<Rect> {
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// TODO: Maybe use a fixed size cache ?
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LAYOUT_CACHE.with(|c| {
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c.borrow_mut()
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.entry((area, self.clone()))
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.or_insert_with(|| split(area, self))
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.clone()
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})
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}
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}
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fn split(area: Rect, layout: &Layout) -> Vec<Rect> {
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let mut solver = Solver::new();
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let mut vars: HashMap<Variable, (usize, usize)> = HashMap::new();
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let elements = layout
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.constraints
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.iter()
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.map(|_| Element::new())
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.collect::<Vec<Element>>();
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let mut results = layout
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.constraints
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.iter()
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.map(|_| Rect::default())
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.collect::<Vec<Rect>>();
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let dest_area = area.inner(&layout.margin);
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for (i, e) in elements.iter().enumerate() {
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vars.insert(e.x, (i, 0));
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vars.insert(e.y, (i, 1));
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vars.insert(e.width, (i, 2));
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vars.insert(e.height, (i, 3));
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}
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let mut ccs: Vec<CassowaryConstraint> =
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Vec::with_capacity(elements.len() * 4 + layout.constraints.len() * 6);
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for elt in &elements {
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ccs.push(elt.width | GE(REQUIRED) | 0f64);
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ccs.push(elt.height | GE(REQUIRED) | 0f64);
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ccs.push(elt.left() | GE(REQUIRED) | f64::from(dest_area.left()));
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ccs.push(elt.top() | GE(REQUIRED) | f64::from(dest_area.top()));
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ccs.push(elt.right() | LE(REQUIRED) | f64::from(dest_area.right()));
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ccs.push(elt.bottom() | LE(REQUIRED) | f64::from(dest_area.bottom()));
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}
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if let Some(first) = elements.first() {
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ccs.push(match layout.direction {
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Direction::Horizontal => first.left() | EQ(REQUIRED) | f64::from(dest_area.left()),
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Direction::Vertical => first.top() | EQ(REQUIRED) | f64::from(dest_area.top()),
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});
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}
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match layout.direction {
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Direction::Horizontal => {
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for pair in elements.windows(2) {
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ccs.push((pair[0].x + pair[0].width) | EQ(REQUIRED) | pair[1].x);
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}
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for (i, c) in layout.constraints.iter().enumerate() {
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ccs.push(elements[i].y | EQ(REQUIRED) | f64::from(dest_area.y));
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ccs.push(elements[i].height | EQ(REQUIRED) | f64::from(dest_area.height));
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apply_constraints(&mut ccs, c, elements[i].width, dest_area.width);
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}
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}
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Direction::Vertical => {
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for pair in elements.windows(2) {
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ccs.push((pair[0].y + pair[0].height) | EQ(REQUIRED) | pair[1].y);
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}
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for (i, c) in layout.constraints.iter().enumerate() {
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ccs.push(elements[i].x | EQ(REQUIRED) | f64::from(dest_area.x));
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ccs.push(elements[i].width | EQ(REQUIRED) | f64::from(dest_area.width));
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apply_constraints(&mut ccs, c, elements[i].height, dest_area.height);
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}
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}
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}
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solver.add_constraints(&ccs).unwrap();
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for &(var, value) in solver.fetch_changes() {
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let (index, attr) = vars[&var];
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let value = if value.is_sign_negative() {
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0
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} else {
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value as u16
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};
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match attr {
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0 => {
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results[index].x = value;
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}
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1 => {
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results[index].y = value;
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}
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2 => {
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results[index].width = value;
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}
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3 => {
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results[index].height = value;
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}
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_ => {}
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}
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}
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results
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}
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fn apply_constraints(
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ccs: &mut Vec<CassowaryConstraint>,
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constraints: &Constraints,
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var: Variable,
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total_length: u16,
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) {
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for c in &constraints.0 {
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let weight = WEAK + f64::from(c.weight);
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let value = match c.unit {
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Unit::Length(v) => f64::from(v),
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Unit::Percentage(v) => f64::from(v * total_length) / 100.0,
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Unit::Ratio(n, d) => f64::from(total_length) * f64::from(n) / f64::from(d),
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};
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let operator = match c.operator {
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Operator::GreaterThanOrEqual => GE(weight),
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Operator::Equal => EQ(weight),
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Operator::LessThanOrEqual => LE(weight),
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};
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ccs.push(var | operator | value);
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}
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}
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/// A container used by the solver inside split
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struct Element {
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x: Variable,
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y: Variable,
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width: Variable,
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height: Variable,
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}
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impl Element {
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fn new() -> Element {
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Element {
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x: Variable::new(),
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y: Variable::new(),
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width: Variable::new(),
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height: Variable::new(),
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}
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}
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fn left(&self) -> Variable {
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self.x
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}
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fn top(&self) -> Variable {
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self.y
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}
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fn right(&self) -> Expression {
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self.x + self.width
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}
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fn bottom(&self) -> Expression {
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self.y + self.height
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}
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}
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/// A simple rectangle used in the computation of the layout and to give widgets an hint about the
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/// area they are supposed to render to.
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#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
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pub struct Rect {
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pub x: u16,
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pub y: u16,
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pub width: u16,
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pub height: u16,
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}
|
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impl Default for Rect {
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fn default() -> Rect {
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Rect {
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x: 0,
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y: 0,
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width: 0,
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height: 0,
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}
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}
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}
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impl Rect {
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/// Creates a new rect, with width and height limited to keep the area under max u16.
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/// If clipped, aspect ratio will be preserved.
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pub fn new(x: u16, y: u16, width: u16, height: u16) -> Rect {
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let max_area = u16::max_value();
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let (clipped_width, clipped_height) =
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if u32::from(width) * u32::from(height) > u32::from(max_area) {
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let aspect_ratio = f64::from(width) / f64::from(height);
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let max_area_f = f64::from(max_area);
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let height_f = (max_area_f / aspect_ratio).sqrt();
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let width_f = height_f * aspect_ratio;
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(width_f as u16, height_f as u16)
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} else {
|
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(width, height)
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};
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Rect {
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x,
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y,
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width: clipped_width,
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height: clipped_height,
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}
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}
|
|
|
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pub fn area(self) -> u16 {
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self.width * self.height
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}
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pub fn left(self) -> u16 {
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self.x
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}
|
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pub fn right(self) -> u16 {
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self.x.saturating_add(self.width)
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}
|
|
|
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pub fn top(self) -> u16 {
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self.y
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}
|
|
|
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pub fn bottom(self) -> u16 {
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self.y.saturating_add(self.height)
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}
|
|
|
|
pub fn inner(self, margin: &Margin) -> Rect {
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if self.width < 2 * margin.horizontal || self.height < 2 * margin.vertical {
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Rect::default()
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|
} else {
|
|
Rect {
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|
x: self.x + margin.horizontal,
|
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y: self.y + margin.vertical,
|
|
width: self.width - 2 * margin.horizontal,
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height: self.height - 2 * margin.vertical,
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}
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}
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}
|
|
|
|
pub fn union(self, other: Rect) -> Rect {
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let x1 = min(self.x, other.x);
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let y1 = min(self.y, other.y);
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let x2 = max(self.x + self.width, other.x + other.width);
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let y2 = max(self.y + self.height, other.y + other.height);
|
|
Rect {
|
|
x: x1,
|
|
y: y1,
|
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width: x2 - x1,
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|
height: y2 - y1,
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|
}
|
|
}
|
|
|
|
pub fn intersection(self, other: Rect) -> Rect {
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let x1 = max(self.x, other.x);
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let y1 = max(self.y, other.y);
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let x2 = min(self.x + self.width, other.x + other.width);
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let y2 = min(self.y + self.height, other.y + other.height);
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Rect {
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x: x1,
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y: y1,
|
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width: x2 - x1,
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height: y2 - y1,
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}
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}
|
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|
|
pub fn intersects(self, other: Rect) -> bool {
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self.x < other.x + other.width
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&& self.x + self.width > other.x
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&& self.y < other.y + other.height
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&& self.y + self.height > other.y
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}
|
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}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
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|
use super::*;
|
|
|
|
#[test]
|
|
#[should_panic]
|
|
fn constraint_invalid_percentages() {
|
|
Constraint::eq(Unit::Percentage(110));
|
|
}
|
|
|
|
#[test]
|
|
fn test_vertical_split_by_height() {
|
|
let target = Rect {
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x: 2,
|
|
y: 2,
|
|
width: 10,
|
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height: 10,
|
|
};
|
|
|
|
let chunks = Layout::default()
|
|
.direction(Direction::Vertical)
|
|
.constraints([
|
|
Constraint::eq(10),
|
|
Constraint::eq(10),
|
|
Constraint::lte(5),
|
|
Constraint::gte(1),
|
|
])
|
|
.split(target);
|
|
|
|
assert_eq!(target.height, chunks.iter().map(|r| r.height).sum::<u16>());
|
|
chunks.windows(2).for_each(|w| assert!(w[0].y <= w[1].y));
|
|
}
|
|
|
|
#[test]
|
|
fn test_rect_size_truncation() {
|
|
for width in 256u16..300u16 {
|
|
for height in 256u16..300u16 {
|
|
let rect = Rect::new(0, 0, width, height);
|
|
rect.area(); // Should not panic.
|
|
assert!(rect.width < width || rect.height < height);
|
|
// The target dimensions are rounded down so the math will not be too precise
|
|
// but let's make sure the ratios don't diverge crazily.
|
|
assert!(
|
|
(f64::from(rect.width) / f64::from(rect.height)
|
|
- f64::from(width) / f64::from(height))
|
|
.abs()
|
|
< 1.0
|
|
)
|
|
}
|
|
}
|
|
|
|
// One dimension below 255, one above. Area above max u16.
|
|
let width = 900;
|
|
let height = 100;
|
|
let rect = Rect::new(0, 0, width, height);
|
|
assert_ne!(rect.width, 900);
|
|
assert_ne!(rect.height, 100);
|
|
assert!(rect.width < width || rect.height < height);
|
|
}
|
|
|
|
#[test]
|
|
fn test_rect_size_preservation() {
|
|
for width in 0..256u16 {
|
|
for height in 0..256u16 {
|
|
let rect = Rect::new(0, 0, width, height);
|
|
rect.area(); // Should not panic.
|
|
assert_eq!(rect.width, width);
|
|
assert_eq!(rect.height, height);
|
|
}
|
|
}
|
|
|
|
// One dimension below 255, one above. Area below max u16.
|
|
let rect = Rect::new(0, 0, 300, 100);
|
|
assert_eq!(rect.width, 300);
|
|
assert_eq!(rect.height, 100);
|
|
}
|
|
}
|