third_party/rust_crates/vendor/cassowary/tests/quadrilateral.rs

extern crate cassowary;
use cassowary::{ Solver, Variable };
use cassowary::WeightedRelation::*;

mod common;
use common::new_values;

#[test]
fn test_quadrilateral() {
    use cassowary::strength::{WEAK, STRONG, REQUIRED};
    struct Point {
        x: Variable,
        y: Variable
    }
    impl Point {
        fn new() -> Point {
            Point {
                x: Variable::new(),
                y: Variable::new()
            }
        }
    }
    let (value_of, update_values) = new_values();

    let points = [Point::new(),
                  Point::new(),
                  Point::new(),
                  Point::new()];
    let point_starts = [(10.0, 10.0), (10.0, 200.0), (200.0, 200.0), (200.0, 10.0)];
    let midpoints = [Point::new(),
                     Point::new(),
                     Point::new(),
                     Point::new()];
    let mut solver = Solver::new();
    let mut weight = 1.0;
    let multiplier = 2.0;
    for i in 0..4 {
        solver.add_constraints(&[points[i].x |EQ(WEAK * weight)| point_starts[i].0,
                                 points[i].y |EQ(WEAK * weight)| point_starts[i].1])
            .unwrap();
        weight *= multiplier;
    }

    for (start, end) in vec![(0, 1), (1, 2), (2, 3), (3, 0)] {
        solver.add_constraints(&[midpoints[start].x |EQ(REQUIRED)| (points[start].x + points[end].x) / 2.0,
                                 midpoints[start].y |EQ(REQUIRED)| (points[start].y + points[end].y) / 2.0])
            .unwrap();
    }

    solver.add_constraints(&[points[0].x + 20.0 |LE(STRONG)| points[2].x,
                             points[0].x + 20.0 |LE(STRONG)| points[3].x,

                             points[1].x + 20.0 |LE(STRONG)| points[2].x,
                             points[1].x + 20.0 |LE(STRONG)| points[3].x,

                             points[0].y + 20.0 |LE(STRONG)| points[1].y,
                             points[0].y + 20.0 |LE(STRONG)| points[2].y,

                             points[3].y + 20.0 |LE(STRONG)| points[1].y,
                             points[3].y + 20.0 |LE(STRONG)| points[2].y])
        .unwrap();

    for point in &points {
        solver.add_constraints(&[point.x |GE(REQUIRED)| 0.0,
                                 point.y |GE(REQUIRED)| 0.0,

                                 point.x |LE(REQUIRED)| 500.0,
                                 point.y |LE(REQUIRED)| 500.0]).unwrap()
    }

    update_values(solver.fetch_changes());

    assert_eq!([(value_of(midpoints[0].x), value_of(midpoints[0].y)),
                (value_of(midpoints[1].x), value_of(midpoints[1].y)),
                (value_of(midpoints[2].x), value_of(midpoints[2].y)),
                (value_of(midpoints[3].x), value_of(midpoints[3].y))],
               [(10.0, 105.0),
                (105.0, 200.0),
                (200.0, 105.0),
                (105.0, 10.0)]);

    solver.add_edit_variable(points[2].x, STRONG).unwrap();
    solver.add_edit_variable(points[2].y, STRONG).unwrap();
    solver.suggest_value(points[2].x, 300.0).unwrap();
    solver.suggest_value(points[2].y, 400.0).unwrap();

    update_values(solver.fetch_changes());

    assert_eq!([(value_of(points[0].x), value_of(points[0].y)),
                (value_of(points[1].x), value_of(points[1].y)),
                (value_of(points[2].x), value_of(points[2].y)),
                (value_of(points[3].x), value_of(points[3].y))],
               [(10.0, 10.0),
                (10.0, 200.0),
                (300.0, 400.0),
                (200.0, 10.0)]);

    assert_eq!([(value_of(midpoints[0].x), value_of(midpoints[0].y)),
                (value_of(midpoints[1].x), value_of(midpoints[1].y)),
                (value_of(midpoints[2].x), value_of(midpoints[2].y)),
                (value_of(midpoints[3].x), value_of(midpoints[3].y))],
               [(10.0, 105.0),
                (155.0, 300.0),
                (250.0, 205.0),
                (105.0, 10.0)]);
}