iris/tests/cases/unsettled.rs

//! The smallest trees that laid out differently warm than cold, each shrunk
//! by `tests/shrink.rs` from hundreds of widgets. The first two are a cold
//! frame that had not settled: a wrapping text shaped at a width it was
//! measured in rather than the one it was given. The rest are a widget
//! measured again in a box its own answer had decided, where the old answer
//! is a fixed point whatever the content now says. The last is neither: one
//! box length, composed two ways, landing either side of the boundary that
//! decided whether a child was drawn at all.

use iris::harness::Harness;
use iris::prelude::*;

/// Six widgets, shrunk from a 402-widget tree the fuzzer found. Nothing about
/// the tree changes -- every widget is marked for redraw and the frame is
/// taken again -- so no box may move, and a warm frame has to land where a
/// cold one does.
fn plant(h: &mut Harness) -> Vec<WidgetId> {
    let plain = wtext("Wrapping").size(16).wrap(false).add(&mut h.rsc);
    let wrapped = wtext("Wrapping shapes").size(16).wrap(true).add(&mut h.rsc);
    let sized = wrapped.width(76).add(&mut h.rsc);
    let aligned = sized;
    h.rsc
        .widgets_mut()
        .set_alignment(sized, Axis::X, AxisAlign::POS);
    h.rsc
        .widgets_mut()
        .set_alignment(sized, Axis::Y, AxisAlign::POS);
    let stack = Stack {
        children: vec![plain.add_strong(&mut h.rsc), aligned.add_strong(&mut h.rsc)],
        size: StackSize::Child(0),
    }
    .add(&mut h.rsc);
    let root = (stack,).span(Dir::RIGHT).add(&mut h.rsc);
    h.set_root(root);
    vec![
        plain.id(),
        wrapped.id(),
        sized.id(),
        aligned.id(),
        stack.id(),
        root.id(),
    ]
}

/// The first frame does not reach the layout a second one does, so "cold" is
/// not a fixed point and comparing against it compares against a tree that
/// has not settled.
#[test]
fn one_frame_is_enough() {
    let mut h = Harness::new((640, 900));
    let ids = plant(&mut h);
    let first = h.region(&ids[1]).unwrap();
    for _ in 0..3 {
        for &id in &ids {
            h.rsc.widgets_mut().get_dyn_mut(id);
        }
        h.frame();
    }
    let settled = h.region(&ids[1]).unwrap();
    println!(
        "first frame {} tall, settled {} tall",
        first.bot_right.y - first.top_left.y,
        settled.bot_right.y - settled.top_left.y
    );
    assert_eq!(
        first.bot_right.y - first.top_left.y,
        settled.bot_right.y - settled.top_left.y,
        "the first frame had not finished laying out"
    );
}

#[test]
fn repainting_everything_moves_nothing() {
    let mut warm = Harness::new((640, 900));
    let ids = plant(&mut warm);
    for &id in &ids {
        warm.rsc.widgets_mut().get_dyn_mut(id);
    }
    warm.frame();

    let mut cold = Harness::new((640, 900));
    let cold_ids = plant(&mut cold);

    let mut wrong = Vec::new();
    for (i, (&w, &c)) in ids.iter().zip(&cold_ids).enumerate() {
        let (got, want) = (warm.region(&w), cold.region(&c));
        if got != want {
            wrong.push(format!("widget {i}: warm {got:?} cold {want:?}"));
        }
    }
    assert!(wrong.is_empty(), "{}", wrong.join("\n"));
}

/// Six widgets, shrunk from 905. Everything inside the declared 189x176 box
/// is the same size whatever the output is, so a resize may not change any of
/// it -- but the text comes out 3.92px narrower warm than cold.
fn plant_fixed(h: &mut Harness) -> Vec<WidgetId> {
    let words = "Wrapping shapes one source into as many lines as the box leaves";
    let text = wtext(words).size(16).wrap(true).add(&mut h.rsc);
    let aligned = text;
    h.rsc
        .widgets_mut()
        .set_alignment(text, Axis::X, AxisAlign::NEG);
    let inner = (aligned,).span(Dir::RIGHT).add(&mut h.rsc);
    let sized = inner.sized((189, 176)).add(&mut h.rsc);
    let filler = rect(Color::RED).add(&mut h.rsc);
    let root = (filler, sized).span(Dir::RIGHT).add(&mut h.rsc);
    h.state.root = Some(root.add_strong(&mut h.rsc));
    vec![
        text.id(),
        aligned.id(),
        inner.id(),
        sized.id(),
        filler.id(),
        root.id(),
    ]
}

#[test]
fn a_resize_does_not_reach_inside_a_box_of_declared_pixels() {
    let mut warm = Harness::new((1920, 1200));
    let ids = plant_fixed(&mut warm);
    warm.frame();
    warm.resize((640, 900));
    warm.frame();

    let mut cold = Harness::new((640, 900));
    let cold_ids = plant_fixed(&mut cold);
    cold.frame();

    let mut wrong = Vec::new();
    for (i, (&w, &c)) in ids.iter().zip(&cold_ids).enumerate() {
        let (got, want) = (warm.region(&w), cold.region(&c));
        if got != want {
            wrong.push(format!("widget {i}: warm {got:?} cold {want:?}"));
        }
    }
    assert!(wrong.is_empty(), "{}", wrong.join("\n"));
}

/// Four widgets, shrunk from 486. A span's two children are swapped: warm by
/// moving them, cold by growing them that way. Same widgets, same sizes, one
/// ends up 29.9px from where the other does.
fn plant_pair(h: &mut Harness, swapped: bool) -> (Vec<WidgetId>, WeakWidget<Span>) {
    let wrapped = wtext("Wrapping shapes one source into as many lines")
        .size(16)
        .wrap(true)
        .add(&mut h.rsc);
    let plain = wtext("one line, overflowing whatever it is given")
        .size(16)
        .wrap(false)
        .add(&mut h.rsc);
    let first: StrongWidget = wrapped.add_strong(&mut h.rsc);
    let second: StrongWidget = plain.add_strong(&mut h.rsc);
    let children = match swapped {
        true => vec![second, first],
        false => vec![first, second],
    };
    let span = Span {
        children,
        dir: Dir::RIGHT,
        gap: Px::ZERO,
    }
    .add(&mut h.rsc);
    let span_handle = span;
    let aligned = span;
    h.rsc
        .widgets_mut()
        .set_alignment(span, Axis::X, AxisAlign::CENTER);
    h.state.root = Some(aligned.add_strong(&mut h.rsc));
    (
        vec![wrapped.id(), plain.id(), span.id(), aligned.id()],
        span_handle,
    )
}

#[test]
fn swapping_two_children_lands_where_growing_them_that_way_does() {
    let mut warm = Harness::new((640, 900));
    let (ids, span) = plant_pair(&mut warm, false);
    warm.frame();
    warm.rsc[span].children.rotate_left(1);
    warm.frame();

    let mut cold = Harness::new((640, 900));
    let (cold_ids, _) = plant_pair(&mut cold, true);
    cold.frame();

    let mut wrong = Vec::new();
    for (i, (&w, &c)) in ids.iter().zip(&cold_ids).enumerate() {
        let (got, want) = (warm.region(&w), cold.region(&c));
        if got != want {
            wrong.push(format!("widget {i}: warm {got:?} cold {want:?}"));
        }
    }
    assert!(wrong.is_empty(), "{}", wrong.join("\n"));
}

/// Eight widgets, shrunk from 80. The scroll decides how wide to make its
/// content from what the content says, and hands that box down through a
/// pass-through; the span under it was given that box once, so nothing at its
/// own edge says the box was its own answer.
fn plant_scrolled(h: &mut Harness, swapped: bool) -> (Vec<WidgetId>, [WeakWidget<Span>; 2]) {
    let words = "Wrapping shapes one source into as many lines as the box leaves room for,";
    let text = wtext(words).size(16).wrap(true).add(&mut h.rsc);
    let filler = rect(Color::RED).add(&mut h.rsc);
    let mut inner_children: Vec<StrongWidget> =
        vec![text.add_strong(&mut h.rsc), filler.add_strong(&mut h.rsc)];
    if swapped {
        inner_children.rotate_left(1);
    }
    let inner = Span {
        children: inner_children,
        dir: Dir::RIGHT,
        gap: Px::ZERO,
    }
    .add(&mut h.rsc);
    let block = rect(Color::RED).add(&mut h.rsc);
    let fixed = block.width(87).add(&mut h.rsc);
    let mut outer_children: Vec<StrongWidget> =
        vec![fixed.add_strong(&mut h.rsc), inner.add_strong(&mut h.rsc)];
    if swapped {
        outer_children.rotate_left(1);
    }
    let outer = Span {
        children: outer_children,
        dir: Dir::RIGHT,
        gap: Px::ZERO,
    }
    .add(&mut h.rsc);
    // Carried no rule even before rules were a property: it is here to be a
    // widget between the span and the scroll, not to declare anything.
    let through = (outer,).span(Dir::RIGHT).add(&mut h.rsc);
    let scroll = Scroll::new(through.add_strong(&mut h.rsc), Axis::X).add(&mut h.rsc);
    h.state.root = Some(scroll.add_strong(&mut h.rsc));
    (
        vec![
            text.id(),
            filler.id(),
            inner.id(),
            block.id(),
            fixed.id(),
            outer.id(),
            through.id(),
            scroll.id(),
        ],
        [inner, outer],
    )
}

#[test]
fn a_span_given_the_box_its_answer_decided_matches_a_cold_layout() {
    let mut warm = Harness::new((640, 900));
    let (ids, spans) = plant_scrolled(&mut warm, false);
    warm.frame();
    for span in spans {
        warm.rsc[span].children.rotate_left(1);
    }
    warm.frame();

    let mut cold = Harness::new((640, 900));
    let (cold_ids, _) = plant_scrolled(&mut cold, true);
    cold.frame();

    let mut wrong = Vec::new();
    for (i, (&w, &c)) in ids.iter().zip(&cold_ids).enumerate() {
        let (got, want) = (warm.region(&w), cold.region(&c));
        if got != want {
            wrong.push(format!("widget {i}: warm {got:?} cold {want:?}"));
        }
    }
    assert!(wrong.is_empty(), "{}", wrong.join("\n"));
}

/// Reports a width derived from the box it is asked in. Reading through the
/// painter is its declaration that the answer holds for that width only.
struct Wider {
    extra: f32,
}

impl Widget for Wider {
    fn draw(&mut self, painter: &mut Painter) -> Size {
        Size {
            x: Len {
                px: painter.px_len(Axis::X) + Px::from_f32(self.extra),
                ..Len::ZERO
            },
            y: Len::LEFTOVER,
        }
    }
}

fn plant_wider(h: &mut Harness, extra: f32) -> (WeakWidget<Wider>, WidgetId) {
    let content = Wider { extra }.add(&mut h.rsc);
    let scroll = Scroll::new(content.add_strong(&mut h.rsc), Axis::X).add(&mut h.rsc);
    let root = scroll;
    h.rsc
        .widgets_mut()
        .set_alignment(scroll, Axis::X, AxisAlign::NEG);
    h.set_root(root);
    (content, scroll.id())
}

#[test]
fn a_scrolls_retained_answer_is_the_one_a_cold_layout_asks_for() {
    let mut warm = Harness::new((100, 100));
    let (content, scroll) = plant_wider(&mut warm, 50.0);
    warm.rsc[content].extra = 70.0;
    warm.frame();

    let mut cold = Harness::new((100, 100));
    let (_, cold_scroll) = plant_wider(&mut cold, 70.0);

    assert_eq!(warm.region(&scroll), cold.region(&cold_scroll));
}

/// Six widgets, shrunk from 266. `measured`'s box is exactly the height of its
/// one fixed child, which is the box a parent sizing itself from that answer
/// hands back -- so whether its leftover-only child was drawn at all came down
/// to the 0.00003 px the composed length differs by, one way warm and the
/// other cold.
fn plant_boundary(h: &mut Harness, swapped: bool) -> (Vec<WidgetId>, [WeakWidget<Span>; 2]) {
    let filler = rect(Color::RED).add(&mut h.rsc);
    let plain = wtext("one line, overflowing whatever it is given")
        .size(16)
        .wrap(false)
        .add(&mut h.rsc);
    let mut pair: Vec<StrongWidget> =
        vec![filler.add_strong(&mut h.rsc), plain.add_strong(&mut h.rsc)];
    if swapped {
        pair.rotate_left(1);
    }
    let measured = Span {
        children: pair,
        dir: Dir::DOWN,
        gap: Px::ZERO,
    }
    .add(&mut h.rsc);
    // Takes the whole box on its own, so the span above has nothing left to
    // divide and `measured` is given exactly the text's height.
    let whole = rect(Color::RED).add(&mut h.rsc);
    h.rsc
        .widgets_mut()
        .set_size_rules(whole, None, Some(Len::rel(1.0)));
    let mut inner_children: Vec<StrongWidget> = vec![
        measured.add_strong(&mut h.rsc),
        whole.add_strong(&mut h.rsc),
    ];
    if swapped {
        inner_children.rotate_left(1);
    }
    let inner = Span {
        children: inner_children,
        dir: Dir::DOWN,
        gap: Px::ZERO,
    }
    .add(&mut h.rsc);
    h.rsc
        .widgets_mut()
        .set_size_rules(inner, None, Some(Len::px(198.0)));
    // One more span above it: without a box composed through it, both trees
    // round the same way and the boundary is never crossed.
    let outer = (inner,).span(Dir::DOWN).add(&mut h.rsc);
    h.set_root(outer);
    (
        vec![
            filler.id(),
            plain.id(),
            measured.id(),
            whole.id(),
            inner.id(),
            outer.id(),
        ],
        [measured, inner],
    )
}

#[test]
fn a_box_that_only_rounds_past_its_fixed_children_leaves_nothing_over() {
    let mut warm = Harness::new((640, 900));
    let (ids, spans) = plant_boundary(&mut warm, false);
    warm.frame();
    for span in spans {
        warm.rsc[span].children.rotate_left(1);
    }
    warm.frame();

    let mut cold = Harness::new((640, 900));
    let (cold_ids, _) = plant_boundary(&mut cold, true);
    cold.frame();

    let mut wrong = Vec::new();
    for (i, (&w, &c)) in ids.iter().zip(&cold_ids).enumerate() {
        let (got, want) = (warm.region(&w), cold.region(&c));
        if got != want {
            wrong.push(format!("widget {i}: warm {got:?} cold {want:?}"));
        }
    }
    assert!(wrong.is_empty(), "{}", wrong.join("\n"));
}