//! Baking live geometry effects for export.
//!
//! SVG, PDF and the clipboard have no notion of Illustrator's live effects, so exporters receive a
//! copy of the document in which every geometry effect — object level, per fill/stroke and
//! Effect → Pathfinder, and those on type, images, symbol instances and live objects (through their
//! outlines, [`reshape`]) — is evaluated exactly like the renderer does, and so are the own fills,
//! strokes and geometry effects of groups and layers ([`evaluate_container`]). Raster effects
//! (shadows, glows, blur) stay on the objects for the exporter to translate (e.g. SVG filters).
//! Colour adjustments recolour the objects ([`adjust_in_document`]; recoloured embedded images
//! become images of their own).
//!
//! Type that Transform effects on it, or on its group or layer, only move and copy stays type in
//! each place when its characters are in solid colors and the copies do not overlap ([`moved_type`]
//! and [`container_keeping_type`] list the other conditions). The renderer still draws its outlines.
//!
//! Object → Expand Appearance goes further ([`expand_leaf`]): every fill and stroke becomes an
//! object of its own, strokes turned into filled art by the caller (their outlines or brush art).

use std::collections::HashMap;
use std::sync::Arc;

use vectorcraft_doc::color::Paint;
use vectorcraft_doc::{Appearance, AppearanceItem, Document, Effect, FillLayer, Knockout, Node, NodeKind, StrokeLayer};
use vectorcraft_geom::{Affine, FillRule, PathData, Rect, Vec2};

use crate::distort::{transform_move, transform_offsets};
use crate::group::{has_own_paint, paints};
use crate::reshape::{as_art, geometry_effects, glyph_outlines, outline_nested_text, reshape_leaves};
use crate::{
    GeomContext, adjust_in_document, apply_geometry_with, crop_marks_art, evaluate_container, has_adjustment, has_crop_marks, has_geometry,
    has_item_geometry, has_pathfinder, is_geometry, is_pathfinder, merged_params, needs_outline, outline_text, reshape,
};

fn item_effects(item: &AppearanceItem) -> &[vectorcraft_doc::Effect] {
    match item {
        AppearanceItem::Fill(f) => &f.effects,
        AppearanceItem::Stroke(s) => &s.effects,
    }
}

fn clear_item_effects(item: &mut AppearanceItem) {
    match item {
        AppearanceItem::Fill(f) => f.effects.retain(|e| !is_geometry(&e.id)),
        AppearanceItem::Stroke(s) => s.effects.retain(|e| !is_geometry(&e.id)),
    }
}

/// Does anything in `n`'s subtree need baking?
pub fn needs_bake(n: &Node) -> bool {
    crate::has_revolve(n)
        || crate::has_solid(n)
        || has_adjustment(n)
        || has_crop_marks(n)
        || has_pathfinder(n)
        || has_own_paint(n)
        || has_geometry(&n.appearance.effects)
        || n.projection().is_some()
        || n.appearance.items.iter().any(|i| has_geometry(item_effects(i)))
        || n.children().is_some_and(|ch| ch.iter().any(|c| needs_bake(c)))
}

fn geometry(n: &Node) -> Option<(PathData, FillRule)> {
    match &n.kind {
        NodeKind::Path { path, rule, guide: false, .. } => Some((path.clone(), *rule)),
        NodeKind::Compound { children, rule } => {
            Some((PathData::new(children.iter().filter_map(|c| c.path_data()).flat_map(|p| p.subpaths.iter().cloned()).collect()), *rule))
        }
        _ => None,
    }
}

fn apply(effects: &[vectorcraft_doc::Effect], path: &PathData, ctx: &GeomContext) -> PathData {
    if !has_geometry(effects) || path.is_empty() {
        return path.clone();
    }
    let b = vectorcraft_geom::Shape::bounding_box(&path.to_bezpath());
    apply_geometry_with(effects, path, b, ctx)
}

/// A path node of `kind`'s flavour (compound when the result has several subpaths).
fn path_kind(d: &mut Document, path: PathData, rule: FillRule) -> NodeKind {
    if path.subpaths.len() > 1 {
        let children = path.subpaths.into_iter().map(|sp| Arc::new(Node::path(d.alloc_id(), PathData::single(sp), Appearance::default()))).collect();
        NodeKind::Compound { children, rule }
    } else {
        NodeKind::Path { path, rule, live: None, clipping: false, guide: false }
    }
}

/// `n` with its geometry effects evaluated (`None` = unchanged).
fn bake_node(d: &mut Document, n: &Node) -> Option<Node> {
    // A cancelled export leaves the rest of the document as it is: the caller drops the result.
    if !needs_bake(n) || vectorcraft_doc::cancel::is_cancelled() {
        return None;
    }
    // Colour adjustments: the object recoloured (inside it too), then baked as it is.
    if has_adjustment(n)
        && let Some(m) = adjust_in_document(d, n)
    {
        return Some(bake_node(d, &m).unwrap_or(m));
    }
    // Crop marks: the object and its marks.
    if let Some(m) = crop_marks_art(n) {
        return Some(bake_pieces(d, m));
    }
    if let Some(m) = crate::revolve_art(n).or_else(|| crate::solid_art(n)) {
        let m = evaluate_container(&m).unwrap_or(m);
        return Some(bake_pieces(d, m));
    }
    // Type, images, symbol instances and live objects: reshaped through their outlines, and so are
    // type whose own fills or strokes have geometry effects and images whose own fills or strokes
    // paint a shape ([`has_item_geometry`]). Type that Transform effects only move and copy stays
    // type, moved to each place.
    if needs_outline(n) && (has_geometry(&n.appearance.effects) || n.projection().is_some() || has_item_geometry(n)) {
        if let Some(m) = moved_type_group(n) {
            return Some(bake_pieces(d, m));
        }
        let symbol = match &n.kind {
            NodeKind::SymbolInstance { symbol, .. } => d.symbols.iter().find(|s| s.name == *symbol).map(|s| s.art.clone()),
            _ => None,
        };
        let m = reshape(n, symbol.as_deref())?;
        return Some(bake_node(d, &m).unwrap_or(m));
    }
    // A path whose Transform effect copies it with a gradient, or scales its strokes or moves its
    // patterns: each copy an object of its own, so its gradient fits it rather than spanning
    // every copy and its strokes and patterns can differ from the others'.
    if crate::has_transform_art(n)
        && let Some(m) = reshape(n, None)
    {
        return Some(bake_pieces(d, m));
    }
    // Groups and layers: Pathfinder, geometry effects and their own fills and strokes (type that
    // Transform effects only move stays type). The new pieces (results, outlines, copies, the
    // fills' and strokes' art) get ids of their own.
    if let Some(m) = container_keeping_type(n).or_else(|| evaluate_container(n)) {
        return Some(bake_pieces(d, m));
    }
    if let Some(ch) = n.children() {
        if matches!(n.kind, NodeKind::Compound { .. })
            && (has_geometry(&n.appearance.effects) || n.appearance.items.iter().any(|i| has_geometry(item_effects(i))))
        {
            return bake_leaf(d, n);
        }
        let mut m = n.clone();
        let baked: Vec<Arc<Node>> = ch.iter().map(|c| bake_node(d, c).map(Arc::new).unwrap_or_else(|| c.clone())).collect();
        if let Some(ch) = m.children_mut() {
            *ch = baked;
        }
        return Some(m);
    }
    bake_leaf(d, n)
}

/// `m`, art evaluated from an object, with its children baked and then given ids of their own (the
/// pieces copied from the source keep the source's ids until then). The pieces are baked with the
/// ids the renderer draws them with: Random in a Transform effect takes its seed from the id.
fn bake_pieces(d: &mut Document, mut m: Node) -> Node {
    let mut seen = std::collections::HashSet::from([m.id]);
    let children = m.children().cloned().unwrap_or_default();
    let children = children
        .into_iter()
        .map(|c| {
            let c = Arc::unwrap_or_clone(c);
            let mut c = bake_node(d, &c).unwrap_or(c);
            fresh_ids(d, &mut c, &mut seen);
            Arc::new(c)
        })
        .collect();
    if let Some(ch) = m.children_mut() {
        *ch = children;
    }
    m
}

/// Give `n` and its descendants a new id wherever one was already `seen` (the pieces evaluated art
/// copies from its source keep ids of their own).
pub fn fresh_ids(d: &mut Document, n: &mut Node, seen: &mut std::collections::HashSet<vectorcraft_doc::NodeId>) {
    if !seen.insert(n.id) {
        n.id = d.alloc_id();
        seen.insert(n.id);
    }
    for c in n.children_mut().into_iter().flatten() {
        fresh_ids(d, Arc::make_mut(c), seen);
    }
}

/// Most copies of one type object that stay type, the original included ([`moved_type`]).
const MAX_TYPE_COPIES: usize = 10_000;
/// Most bytes that the copies of one type object that stay type take together in the document's
/// JSON form, the original included ([`moved_type`]): its text, frame or path, wrap shapes and the
/// rest of the object, once per copy.
const MAX_TYPE_COPY_BYTES: usize = 20_000_000;

/// The params of geometry effects `fx` when there are some and they are all Transform effects that
/// only move ([`transform_move`]), in order; `None` otherwise.
fn transform_moves(fx: &[&Effect]) -> Option<Vec<serde_json::Value>> {
    if fx.is_empty() {
        return None;
    }
    fx.iter().map(|e| (e.id == "distort.transform").then(|| merged_params(&e.id, &e.params)).filter(|p| transform_move(p).is_some())).collect()
}

/// Type `n` in each place that Transform effects that only move ([`transform_moves`]) copy its
/// glyph outlines to: `n` moved there, the original's place first. `None` for other objects; for
/// type that is hidden, in perspective, has effects, transparency, an opacity mask or fills and
/// strokes of its own (beyond its characters'), has characters painted with a gradient or pattern,
/// underlined or struck through, has character strokes and is scaled or sheared, holds inline
/// graphics or has no glyphs; when the effects would stop copies of its outlines early
/// ([`transform_offsets`]); when the copies would pass [`MAX_TYPE_COPIES`] or
/// [`MAX_TYPE_COPY_BYTES`]; and when the copies overlap: what one copy paints (its
/// character strokes included) reaches into another's box.
fn moved_type(n: &Node, moves: &[serde_json::Value]) -> Option<Vec<Node>> {
    let NodeKind::Text(t) = &n.kind else { return None };
    let flat = |p: &Paint| matches!(p, Paint::None | Paint::Solid { .. });
    let [a, b, c, d, _, _] = t.xf.as_coeffs();
    let rigid = (a * a + b * b - 1.0).abs() < 1e-9 && (c * c + d * d - 1.0).abs() < 1e-9 && (a * c + b * d).abs() < 1e-9;
    let stroked = t.runs.iter().any(|r| r.style.has_stroke());
    if !n.visible
        || (stroked && !rigid)
        || n.projection().is_some()
        || !n.has_default_transparency()
        || !n.appearance.effects.is_empty()
        || n.appearance.items.iter().any(|i| paints(i) || !item_effects(i).is_empty())
        || t.runs.iter().any(|r| r.inline.is_some() || r.style.underline || r.style.strikethrough || !flat(&r.style.fill) || !flat(&r.style.stroke))
    {
        return None;
    }
    let (_, all) = glyph_outlines(t);
    let outline = PathData::from_bezpath(&all).transformed(t.xf);
    let ink = outline.bounds()?;
    let offsets = transform_offsets(moves, &outline)?;
    if offsets.len() > MAX_TYPE_COPIES {
        return None;
    }
    let size = serde_json::to_vec(n).ok()?.len();
    if size.saturating_mul(offsets.len()) > MAX_TYPE_COPY_BYTES {
        return None;
    }
    let strokes = t.runs.iter().map(|r| r.style.appearance().outset()).fold(0.0, f64::max);
    if !apart(&offsets, ink.inflate(strokes, strokes)) {
        return None;
    }
    Some(
        offsets
            .into_iter()
            .map(|o| {
                let mut c = n.clone();
                c.transform(Affine::translate(o), false);
                c
            })
            .collect(),
    )
}

/// Do the copies of box `b` moved by each of `offsets` stay clear of each other? Copies may touch.
/// False as well when an offset is 10^15 or more times the box's width or height.
fn apart(offsets: &[Vec2], b: Rect) -> bool {
    let (w, h) = (b.width(), b.height());
    if offsets.len() < 2 {
        return true;
    }
    if !(w > 0.0 && h > 0.0 && w.is_finite() && h.is_finite()) {
        return false;
    }
    // Copies closer than `w` across and `h` down lie in the same or a neighboring cell.
    let cell = |o: Vec2| {
        let (x, y) = ((o.x / w).floor(), (o.y / h).floor());
        (x.abs() < 1e15 && y.abs() < 1e15).then_some((x as i64, y as i64))
    };
    let mut cells: HashMap<(i64, i64), Vec2> = HashMap::new();
    for &o in offsets {
        let Some((x, y)) = cell(o) else { return false };
        for dx in -1..=1 {
            for dy in -1..=1 {
                if let Some(p) = cells.get(&(x + dx, y + dy))
                    && (p.x - o.x).abs() < w
                    && (p.y - o.y).abs() < h
                {
                    return false;
                }
            }
        }
        cells.insert((x, y), o);
    }
    true
}

/// Type `n` whose own geometry effects only move it ([`transform_moves`]) as a group of the moved
/// type ([`moved_type`]). The group keeps `n`'s id, name, visibility, transparency, opacity mask and
/// remaining (raster) effects, and the type in it has none of them. `None` otherwise.
fn moved_type_group(n: &Node) -> Option<Node> {
    if !matches!(n.kind, NodeKind::Text(_)) {
        return None;
    }
    let moves = transform_moves(&geometry_effects(n))?;
    let mut plain = n.clone();
    plain.visible = true;
    plain.opacity = 1.0;
    plain.blend = Default::default();
    plain.isolate = false;
    plain.knockout_shape = false;
    plain.extras_mut().mask = None;
    plain.appearance.effects.clear();
    let copies = moved_type(&plain, &moves)?;
    let mut g = Node::group(n.id, copies.into_iter().map(Arc::new).collect());
    g.name = n.name.clone();
    g.visible = n.visible;
    g.opacity = n.opacity;
    g.blend = n.blend;
    g.isolate = n.isolate;
    // One element: its pieces never knock each other out.
    g.knockout = Knockout::Off;
    g.knockout_shape = n.knockout_shape;
    g.extras_mut().mask = n.extras().mask.clone();
    g.appearance.effects = n.appearance.effects.iter().filter(|e| !is_geometry(&e.id)).cloned().collect();
    Some(g)
}

/// `n`, a group or layer without Pathfinder effects or fills and strokes that paint, whose geometry
/// effects only move its members ([`transform_moves`]), as plain art in which the type it holds
/// stays type: each type object moved, or replaced by a group of its copies ([`moved_type`]).
/// Type in a clipping path, other type that [`moved_type`] doesn't copy, and type inside live
/// objects or inside groups with Pathfinder or geometry effects or fills and strokes that paint, is
/// outlined as [`evaluate_container`] outlines it, and the other members become what it makes of
/// them. `None` when no type stays type.
fn container_keeping_type(n: &Node) -> Option<Node> {
    fn keep(n: &mut Node, moves: &[serde_json::Value], clipping: bool, kept: &mut bool) {
        let clips = n.clips();
        let Some(ch) = n.children_mut() else { return };
        for (i, c) in ch.iter_mut().enumerate() {
            let clipping = clipping || (clips && i == 0);
            if !matches!(c.kind, NodeKind::Text(_)) {
                if has_pathfinder(c) || has_own_paint(c) || !geometry_effects(c).is_empty() {
                    outline_nested_text(Arc::make_mut(c), clipping);
                } else if c.children().is_some() {
                    keep(Arc::make_mut(c), moves, clipping, kept);
                }
                continue;
            }
            // Type that isn't copied is outlined as `outline_nested_text` outlines it.
            let copies = if clipping { None } else { moved_type(c, moves) };
            let art = match copies {
                Some(mut copies) => {
                    *kept = true;
                    match copies.pop() {
                        Some(only) if copies.is_empty() => Some(only),
                        last => Some(Node::group(c.id, copies.into_iter().chain(last).map(Arc::new).collect())),
                    }
                }
                None if clipping => outline_text(c).map(|o| Node { visible: c.visible, ..o }),
                None => as_art(c, None),
            };
            if let Some(o) = art {
                *c = Arc::new(o);
            }
        }
    }
    if !matches!(n.kind, NodeKind::Group { .. } | NodeKind::Layer { .. }) || has_pathfinder(n) || has_own_paint(n) {
        return None;
    }
    let fx = geometry_effects(n);
    let moves = transform_moves(&fx)?;
    let mut text = false;
    n.walk(&mut |c| text |= matches!(c.kind, NodeKind::Text(_)));
    if !text {
        return None;
    }
    let hook: &dyn Fn(&Node) -> Option<Node> = &outline_text;
    let mut m = vectorcraft_doc::live::expand_deep(n, Some(hook));
    let mut kept = false;
    keep(&mut m, &moves, false, &mut kept);
    if !kept {
        return None;
    }
    reshape_leaves(&mut m, &fx);
    m.appearance.effects.retain(|e| !is_pathfinder(&e.id) && !is_geometry(&e.id));
    m.appearance.items.clear();
    m.appearance.contents_index = None;
    Some(m)
}

/// A new path of `n`'s (its geometry `path`, filled under `rule`) painted by `item` alone, with
/// none of `n`'s transparency.
fn piece(d: &mut Document, n: &Node, path: PathData, rule: FillRule, item: AppearanceItem) -> Node {
    let id = d.alloc_id();
    let kind = path_kind(d, path, rule);
    let mut out = n.clone();
    out.id = id;
    out.name = None;
    out.appearance = Appearance { items: vec![item], ..Default::default() }.into();
    out.opacity = 1.0;
    out.blend = Default::default();
    out.isolate = false;
    out.knockout = Default::default();
    out.knockout_shape = false;
    out.kind = kind;
    let mut extras = out.extras_mut();
    extras.mask = None;
    extras.trace = None;
    extras.wrap = None;
    extras.graph = None;
    // The group keeps the URL (one link around the pieces).
    extras.attrs = None;
    drop(extras);
    out
}

/// `n`'s geometry with its object-level geometry effects applied, its fill rule, the context of
/// its effects, and `n` without those effects.
fn leaf_base(n: &Node) -> Option<(PathData, FillRule, GeomContext<'_>, Node)> {
    let (base, rule) = geometry(n)?;
    let ctx = GeomContext::of(n);
    let g = apply(&n.appearance.effects, &base, &ctx);
    let mut m = n.clone();
    m.appearance.effects.retain(|e| !is_geometry(&e.id));
    Some((g, rule, ctx, m))
}

fn bake_leaf(d: &mut Document, n: &Node) -> Option<Node> {
    let (g, rule, ctx, mut m) = leaf_base(n)?;
    if !n.appearance.items.iter().any(|i| has_geometry(item_effects(i))) {
        m.kind = path_kind(d, g, rule);
        return Some(m);
    }
    // Per-item geometry: one path per fill/stroke, grouped under the object's transparency and
    // raster effects.
    let children = n
        .appearance
        .items
        .iter()
        .map(|item| {
            let ig = apply(item_effects(item), &g, &ctx.item(item));
            let mut it = item.clone();
            clear_item_effects(&mut it);
            Arc::new(piece(d, n, ig, rule, it))
        })
        .collect();
    m.appearance.items.clear();
    m.kind = NodeKind::Group { children, clip: false };
    Some(m)
}

/// Turns one stroke of a path (the path after its geometry effects, its fill rule, the stroke
/// without geometry effects) into filled art for [`expand_leaf`]: its outline filled with its
/// paint, or its brush art. `None` when it paints nothing.
pub type StrokeArt<'a> = &'a mut dyn FnMut(&mut Document, &PathData, FillRule, &StrokeLayer) -> Option<Node>;

/// Object → Expand Appearance of a path or compound path `n`: its geometry effects applied, every
/// visible fill becomes a copy of the path painted by that fill alone and every visible stroke the
/// filled art `stroke_art` makes of it (each with its fill's or stroke's opacity and blend mode as
/// its own), in paint order, as the members of a group that keeps
/// `n`'s id, name, transparency, opacity mask and remaining (raster) effects. A single piece
/// without transparency or effects of its own takes `n`'s place itself. Hidden fills, strokes and
/// effects are dropped. `None` for other kinds of objects.
pub fn expand_leaf(d: &mut Document, n: &Node, stroke_art: StrokeArt) -> Option<Node> {
    if let Some(m) = crate::revolve::expand_revolve_art(n).or_else(|| crate::solid_art(n)) {
        let m = evaluate_container(&m).unwrap_or(m);
        return Some(bake_pieces(d, m));
    }
    let (g, rule, ctx, mut m) = leaf_base(n)?;
    m.appearance.effects.retain(|e| e.visible);
    let mut pieces = vec![];
    for item in n.appearance.items.iter().filter(|i| paints(i)) {
        let ig = apply(item.effects(), &g, &ctx.item(item));
        let mut it = item.clone();
        clear_item_effects(&mut it);
        it.effects_mut().retain(|e| e.visible);
        let p = match &it {
            AppearanceItem::Stroke(st) => stroke_art(d, &ig, rule, st),
            AppearanceItem::Fill(_) => Some(piece(d, n, ig, rule, it)),
        };
        pieces.extend(p.map(hoist_transparency));
    }
    m.appearance.items.clear();
    m.appearance.contents_index = None;
    match pieces.as_slice() {
        [one] if m.appearance.effects.is_empty() && one.has_default_transparency() && one.appearance.effects.is_empty() => {
            m.kind = one.kind.clone();
            m.appearance = one.appearance.clone();
        }
        _ => m.kind = NodeKind::Group { children: pieces.into_iter().map(Arc::new).collect(), clip: false },
    }
    Some(m)
}

/// `p` with the opacity and blend mode of its only fill or stroke as its own (the same look, and a
/// basic appearance).
fn hoist_transparency(mut p: Node) -> Node {
    if p.has_default_transparency()
        && let [item] = p.appearance.items.as_mut_slice()
    {
        let (opacity, blend) = match item {
            AppearanceItem::Fill(f) => (&mut f.opacity, &mut f.blend),
            AppearanceItem::Stroke(s) => (&mut s.opacity, &mut s.blend),
        };
        p.opacity = std::mem::replace(opacity, 1.0);
        p.blend = std::mem::take(blend);
    }
    p
}

/// [`expand_leaf`] every path and compound path in `n` (art made for Expand Appearance, such as a
/// group's own fills and strokes or outlined type), in place.
pub fn expand_art(d: &mut Document, n: &mut Node, stroke_art: StrokeArt) {
    if matches!(n.kind, NodeKind::Path { clipping: false, guide: false, .. } | NodeKind::Compound { .. }) {
        if let Some(m) = expand_leaf(d, n, stroke_art) {
            *n = m;
        }
        return;
    }
    for c in n.children_mut().into_iter().flatten() {
        expand_art(d, Arc::make_mut(c), stroke_art);
    }
}

/// Envelope Options → Distort Appearance: path or compound path `n` as plain filled art that an
/// envelope bends as a whole: its geometry effects applied, every visible fill a copy of the path
/// painted by that fill and every visible stroke without a brush its filled outline in the
/// stroke's paint, opacity, blend mode and raster effects (a gradient along or across the stroke:
/// its gradient meshes clipped to the outline; a brushed stroke stays a stroke), in paint order, as
/// the members of a group keeping `n`'s id, transparency, opacity mask and raster effects. `None`
/// when it has neither a stroke to outline nor a geometry effect, so bending first changes nothing.
pub fn bake_appearance(n: &Node) -> Option<Node> {
    if let Some(m) = crate::revolve_art(n).or_else(|| crate::solid_art(n)) {
        return Some(m);
    }
    if !matches!(n.kind, NodeKind::Path { clipping: false, guide: false, .. } | NodeKind::Compound { .. }) {
        return None;
    }
    let outlined = |i: &AppearanceItem| paints(i) && matches!(i, AppearanceItem::Stroke(s) if s.brush.is_none());
    let geometric = has_geometry(&n.appearance.effects) || n.appearance.items.iter().any(|i| has_geometry(item_effects(i)));
    if !geometric && !n.appearance.items.iter().any(outlined) {
        return None;
    }
    let (g, rule, ctx, mut m) = leaf_base(n)?;
    let piece = |path: PathData, rule: FillRule, item: AppearanceItem| {
        let mut p = Node::path(n.id, path, Appearance { items: vec![item], ..Default::default() });
        if let NodeKind::Path { rule: r, .. } = &mut p.kind {
            *r = rule;
        }
        Arc::new(p)
    };
    let mut pieces = vec![];
    for item in n.appearance.items.iter().filter(|i| paints(i)) {
        let ig = apply(item_effects(item), &g, &ctx.item(item));
        let mut it = item.clone();
        clear_item_effects(&mut it);
        pieces.push(match &it {
            AppearanceItem::Stroke(st) if st.brush.is_none() => {
                let outline = crate::stroke::outline_region(&ig, rule, st);
                match st.path_gradient() {
                    // A gradient along or across the stroke: its gradient meshes clipped to the outline.
                    Some(g) => {
                        let mut clip = Node::path(n.id, outline, Appearance::default());
                        if let NodeKind::Path { clipping, .. } = &mut clip.kind {
                            *clipping = true;
                        }
                        let meshes = crate::stroke::gradient_meshes(&ig.to_bezpath(), rule, st, &g.gradient);
                        let meshes = meshes.into_iter().map(|m| Node::new(n.id, NodeKind::Mesh(m)));
                        let children = std::iter::once(clip).chain(meshes).map(Arc::new).collect();
                        let mut group = Node::new(n.id, NodeKind::Group { children, clip: true });
                        (group.opacity, group.blend) = (st.opacity, st.blend);
                        group.appearance.effects = st.effects.clone();
                        Arc::new(group)
                    }
                    None => {
                        let effects = st.effects.clone();
                        let fill = FillLayer { opacity: st.opacity, blend: st.blend, effects, ..FillLayer::new(st.paint.stroke_as_fill()) };
                        piece(outline, FillRule::NonZero, AppearanceItem::Fill(fill))
                    }
                }
            }
            _ => piece(ig, rule, it),
        });
    }
    m.appearance.items.clear();
    m.appearance.contents_index = None;
    m.kind = NodeKind::Group { children: pieces, clip: false };
    Some(m)
}

/// A copy of `doc` ready to export: every live geometry effect baked into plain paths, and the
/// resources of its placed documents' art added ([`Document::with_placed_art`]); `None` when
/// there is nothing to do (export it as is).
pub fn bake_document(doc: &Document) -> Option<Document> {
    let placed = doc.with_placed_art();
    if !placed.layers.iter().any(|l| needs_bake(l)) {
        return match placed {
            std::borrow::Cow::Owned(d) => Some(d),
            std::borrow::Cow::Borrowed(_) => None,
        };
    }
    let mut d = placed.into_owned();
    let layers = d.layers.clone();
    d.layers = layers.iter().map(|l| bake_node(&mut d, l).map(Arc::new).unwrap_or_else(|| l.clone())).collect();
    Some(d)
}

#[cfg(test)]
mod tests {
    use super::*;
    use serde_json::json;
    use vectorcraft_color::{Color, Paint};
    use vectorcraft_doc::{CharStyle, Effect, NodeId, TextObject};
    use vectorcraft_geom::{Point, Rect, shapes};

    /// Type tests need glyph outlines, which only the optional craft-fonts build input provides.
    fn skip_without_craft_fonts() -> bool {
        let skip = vectorcraft_text::CRAFT_FONTS.is_empty();
        if skip {
            eprintln!("skipped: built without craft-fonts (set CRAFT_FONTS_DIR to a craft-fonts checkout to run it)");
        }
        skip
    }

    fn fx(id: &str, params: serde_json::Value) -> Effect {
        Effect { id: id.into(), params, visible: true }
    }

    fn doc_with(n: Node) -> Document {
        let mut d = Document::new(400.0, 400.0);
        let l = d.layers[0].id;
        d.insert(Some(l), 0, n).unwrap();
        d
    }

    #[test]
    fn plain_documents_are_not_copied() {
        let mut d = Document::new(100.0, 100.0);
        let id = d.alloc_id();
        let d = doc_with(Node::path(id, shapes::rectangle(Rect::new(0.0, 0.0, 10.0, 10.0)), Appearance::default_art()));
        assert!(bake_document(&d).is_none());
    }

    #[test]
    fn object_effects_become_geometry_and_raster_effects_stay() {
        let mut n = Node::path(NodeId(50), shapes::rectangle(Rect::new(0.0, 0.0, 100.0, 100.0)), Appearance::default_art());
        n.appearance.effects.push(fx("path.offsetPath", json!({"offset": 10.0})));
        n.appearance.effects.push(fx("stylize.dropShadow", json!({})));
        let d = bake_document(&doc_with(n)).unwrap();
        let m = d.node(NodeId(50)).unwrap();
        let b = m.geometric_bounds().unwrap();
        assert!((b.width() - 120.0).abs() < 0.5, "{b:?}");
        assert_eq!(m.appearance.effects.len(), 1);
        assert_eq!(m.appearance.effects[0].id, "stylize.dropShadow");
    }

    #[test]
    fn item_effects_split_into_one_path_per_item() {
        let mut n = Node::path(NodeId(50), shapes::rectangle(Rect::new(0.0, 0.0, 100.0, 100.0)), Appearance::default_art());
        if let AppearanceItem::Stroke(s) = &mut n.appearance.items[1] {
            s.effects.push(fx("path.offsetPath", json!({"offset": 5.0})));
        }
        let d = bake_document(&doc_with(n)).unwrap();
        let m = d.node(NodeId(50)).unwrap();
        let ch = m.children().unwrap();
        assert_eq!(ch.len(), 2);
        assert!((ch[0].geometric_bounds().unwrap().width() - 100.0).abs() < 1e-6);
        assert!((ch[1].geometric_bounds().unwrap().width() - 110.0).abs() < 0.5);
        assert!(ch[0].id != ch[1].id && ch[0].id != NodeId(50));
    }

    #[test]
    fn a_baked_stroke_keeps_its_raster_effects() {
        let mut n = Node::path(NodeId(50), shapes::rectangle(Rect::new(0.0, 0.0, 100.0, 100.0)), Appearance::default_art());
        if let AppearanceItem::Stroke(s) = &mut n.appearance.items[1] {
            s.effects.push(fx("path.offsetPath", json!({"offset": 5.0})));
            s.effects.push(fx("stylize.dropShadow", json!({})));
        }
        let m = bake_appearance(&n).unwrap();
        let ch = m.children().unwrap();
        let Some(AppearanceItem::Fill(f)) = ch[1].appearance.items.first() else { panic!("the outline is filled") };
        assert_eq!(f.effects.iter().map(|e| e.id.as_str()).collect::<Vec<_>>(), ["stylize.dropShadow"]);
    }

    #[test]
    fn a_baked_stroke_leaves_dither_behind() {
        // Strokes ignore dither, so the filled outline goes without it and looks as the stroke did.
        let mut n = Node::path(NodeId(50), shapes::rectangle(Rect::new(0.0, 0.0, 100.0, 100.0)), Appearance::default_art());
        if let AppearanceItem::Stroke(s) = &mut n.appearance.items[1] {
            let mut g = vectorcraft_color::GradientPaint::new(Default::default());
            g.gradient.dither = true;
            s.paint = Paint::Gradient(Box::new(g));
        }
        let m = bake_appearance(&n).unwrap();
        let ch = m.children().unwrap();
        let Some(AppearanceItem::Fill(f)) = ch[1].appearance.items.first() else { panic!("the outline is filled") };
        let Paint::Gradient(g) = &f.paint else { panic!("a gradient fill") };
        assert!(!g.gradient.dither);
    }

    #[test]
    fn a_baked_stroke_with_a_gradient_along_it_becomes_meshes_clipped_to_its_outline() {
        let mut n = Node::path(NodeId(50), shapes::rectangle(Rect::new(0.0, 0.0, 100.0, 100.0)), Appearance::default_art());
        if let AppearanceItem::Stroke(s) = &mut n.appearance.items[1] {
            s.width = 10.0;
            s.paint = Paint::Gradient(Box::new(vectorcraft_color::GradientPaint::new(Default::default())));
            s.gradient_mode = vectorcraft_doc::StrokeGradientMode::Along;
            s.opacity = 0.5;
        }
        let m = bake_appearance(&n).unwrap();
        let ch = m.children().unwrap();
        let NodeKind::Group { children, clip: true } = &ch[1].kind else { panic!("a clip group: {:?}", ch[1].kind) };
        assert!(matches!(children[0].kind, NodeKind::Path { clipping: true, .. }));
        assert!(children.len() > 1 && children[1..].iter().all(|c| matches!(c.kind, NodeKind::Mesh(_))), "gradient meshes");
        assert_eq!(ch[1].opacity, 0.5);
    }

    /// Black 24 pt "Type" with its baseline at (20, 60).
    fn type_node(id: u64) -> Node {
        let style = CharStyle { size: 24.0, fill: Paint::solid(Color::BLACK), ..Default::default() };
        Node::new(NodeId(id), NodeKind::Text(Box::new(TextObject::point(Point::new(20.0, 60.0), "Type", style))))
    }

    /// The origins of the type objects in `d`, in paint order.
    fn type_origins(d: &Document) -> Vec<(f64, f64)> {
        let mut out = vec![];
        d.walk(|n| {
            if let NodeKind::Text(t) = &n.kind {
                let c = t.xf.as_coeffs();
                out.push((c[4], c[5]));
            }
        });
        out
    }

    /// A group of the type and a 10 pt square with `effects`.
    fn type_group(effects: Vec<Effect>) -> Node {
        let square = Node::path(NodeId(51), shapes::rectangle(Rect::new(0.0, 0.0, 10.0, 10.0)), Appearance::default_art());
        let mut g = Node::group(NodeId(52), vec![Arc::new(type_node(50)), Arc::new(square)]);
        g.appearance.effects = effects;
        g
    }

    #[test]
    fn type_moved_or_copied_by_a_groups_transform_effect_stays_type() {
        if skip_without_craft_fonts() {
            return;
        }
        for (params, origins, square) in [
            (json!({"moveH": 30}), vec![(50.0, 60.0)], Rect::new(30.0, 0.0, 40.0, 10.0)),
            (json!({"moveH": 200, "copies": 1}), vec![(20.0, 60.0), (220.0, 60.0)], Rect::new(0.0, 0.0, 210.0, 10.0)),
            (json!({"moveV": 50, "copies": 2}), vec![(20.0, 60.0), (20.0, 110.0), (20.0, 160.0)], Rect::new(0.0, 0.0, 10.0, 110.0)),
        ] {
            let g = type_group(vec![fx("distort.transform", params.clone()), fx("stylize.dropShadow", json!({}))]);
            let d = bake_document(&doc_with(g.clone())).unwrap();
            assert_eq!(type_origins(&d), origins, "{params}");
            let baked = d.node(NodeId(52)).unwrap();
            assert_eq!(baked.appearance.effects.iter().map(|e| e.id.as_str()).collect::<Vec<_>>(), ["stylize.dropShadow"]);
            // The square moves with the type, as one path holding its copies.
            let b = baked.children().unwrap().last().and_then(|s| s.geometric_bounds()).unwrap();
            assert!([b.x0 - square.x0, b.y0 - square.y0, b.x1 - square.x1, b.y1 - square.y1].iter().all(|v| v.abs() < 1e-9), "{params}: {b:?}");
            let mut ids = std::collections::HashSet::new();
            baked.walk(&mut |n| assert!(ids.insert(n.id), "{params}: duplicate id {}", n.id));
            // The renderer and Expand Appearance still draw it as outlines.
            let mut text = 0;
            evaluate_container(&g).unwrap().walk(&mut |n| text += usize::from(matches!(n.kind, NodeKind::Text(_))));
            assert_eq!(text, 0, "{params}");
        }
        // Stacked effects that only move: every copy of a copy.
        let d = bake_document(&doc_with(type_group(vec![
            fx("distort.transform", json!({"moveH": 100, "copies": 1})),
            fx("distort.transform", json!({"moveV": 100, "copies": 1})),
        ])))
        .unwrap();
        assert_eq!(type_origins(&d), [(20.0, 60.0), (120.0, 60.0), (20.0, 160.0), (120.0, 160.0)]);
    }

    #[test]
    fn hidden_type_in_a_group_that_keeps_its_type_stays_hidden() {
        if skip_without_craft_fonts() {
            return;
        }
        let mut g = type_group(vec![fx("distort.transform", json!({"moveH": 200, "copies": 1}))]);
        let mut hidden = type_node(55);
        hidden.visible = false;
        g.children_mut().unwrap().push(Arc::new(hidden));
        let d = bake_document(&doc_with(g)).unwrap();
        assert_eq!(type_origins(&d), [(20.0, 60.0), (220.0, 60.0)]);
        assert!(!d.node(NodeId(55)).unwrap().visible);
    }

    #[test]
    fn type_outlined_next_to_type_that_stays_type_keeps_its_look() {
        if skip_without_craft_fonts() {
            return;
        }
        let mut g = type_group(vec![fx("distort.transform", json!({"moveH": 200, "copies": 1}))]);
        let mut shadowed = type_node(55);
        shadowed.opacity = 0.5;
        shadowed.appearance.effects.push(fx("stylize.dropShadow", json!({})));
        // Type that clips a group is outlined as the plain outlines it clips by.
        let square = Node::path(NodeId(57), shapes::rectangle(Rect::new(0.0, 0.0, 100.0, 100.0)), Appearance::default_art());
        let clip = Node::new(NodeId(58), NodeKind::Group { children: vec![Arc::new(type_node(56)), Arc::new(square)], clip: true });
        g.children_mut().unwrap().extend([Arc::new(shadowed), Arc::new(clip)]);
        let d = bake_document(&doc_with(g)).unwrap();
        assert_eq!(type_origins(&d), [(20.0, 60.0), (220.0, 60.0)]);
        let o = d.node(NodeId(55)).unwrap();
        assert!(matches!(o.kind, NodeKind::Group { .. }) && o.opacity == 0.5, "{o:?}");
        assert_eq!(o.appearance.effects.iter().map(|e| e.id.as_str()).collect::<Vec<_>>(), ["stylize.dropShadow"]);
        // The outlines are copied with the type.
        let b = o.geometric_bounds().unwrap();
        assert!(b.x0 < 30.0 && b.x1 > 220.0, "{b:?}");
        let clipped = d.node(NodeId(58)).and_then(|n| n.children()).and_then(|c| c.first()).unwrap();
        assert!(matches!(clipped.kind, NodeKind::Group { .. }) && clipped.opacity == 1.0, "{clipped:?}");
    }

    #[test]
    fn type_in_a_clipping_group_with_a_fill_of_its_own_is_outlined_plain() {
        if skip_without_craft_fonts() {
            return;
        }
        let mut g = type_group(vec![fx("distort.transform", json!({"moveH": 200, "copies": 1}))]);
        // The clipping path is a group with a fill of its own, holding type with an effect of its own.
        let mut moved = type_node(60);
        moved.appearance.effects.push(fx("distort.transform", json!({"moveV": 300})));
        let mut path = Node::group(NodeId(59), vec![Arc::new(moved)]);
        path.appearance.items.push(AppearanceItem::Fill(FillLayer::new(Paint::solid(Color::BLACK))));
        let square = Node::path(NodeId(57), shapes::rectangle(Rect::new(0.0, 0.0, 100.0, 100.0)), Appearance::default_art());
        let clip = Node::new(NodeId(58), NodeKind::Group { children: vec![Arc::new(path), Arc::new(square)], clip: true });
        g.children_mut().unwrap().push(Arc::new(clip));
        let d = bake_document(&doc_with(g)).unwrap();
        assert_eq!(type_origins(&d), [(20.0, 60.0), (220.0, 60.0)]);
        // The type clips by its plain outlines, as the canvas clips by them: its own effect is left out.
        let b = d.node(NodeId(59)).and_then(|n| n.geometric_bounds()).unwrap();
        assert!(b.y0 > 30.0 && b.y1 < 70.0, "{b:?}");
    }

    #[test]
    fn type_with_its_own_transform_effect_copies_stays_type() {
        if skip_without_craft_fonts() {
            return;
        }
        let mut n = type_node(50);
        n.opacity = 0.5;
        n.appearance.effects = vec![fx("distort.transform", json!({"moveV": 50, "copies": 2})), fx("stylize.dropShadow", json!({}))];
        let d = bake_document(&doc_with(n)).unwrap();
        assert_eq!(type_origins(&d), [(20.0, 60.0), (20.0, 110.0), (20.0, 160.0)]);
        // One group keeps the object's transparency and its other effects; the copies are plain.
        let g = d.node(NodeId(50)).unwrap();
        assert!(matches!(g.kind, NodeKind::Group { .. }) && g.opacity == 0.5);
        assert_eq!(g.appearance.effects.iter().map(|e| e.id.as_str()).collect::<Vec<_>>(), ["stylize.dropShadow"]);
        for c in g.children().unwrap() {
            assert!(c.opacity == 1.0 && c.appearance.effects.is_empty() && c.id != g.id, "{c:?}");
        }
        // Hidden type stays hidden.
        let mut n = type_node(50);
        n.visible = false;
        n.appearance.effects = vec![fx("distort.transform", json!({"moveV": 50, "copies": 1}))];
        let d = bake_document(&doc_with(n)).unwrap();
        assert_eq!(type_origins(&d).len(), 2);
        assert!(!d.node(NodeId(50)).unwrap().visible);
    }

    #[test]
    fn type_under_other_geometry_effects_is_still_outlined() {
        for effects in [
            vec![fx("distort.transform", json!({"moveH": 30, "random": true}))],
            vec![fx("distort.transform", json!({"moveH": 30, "scaleH": 50}))],
            vec![fx("distort.transform", json!({"moveH": 30, "rotate": 10, "copies": 1}))],
            vec![fx("distort.transform", json!({"moveH": 30, "reflectX": true}))],
            vec![fx("distort.transform", json!({"moveH": 30})), fx("distort.roughen", json!({"size": 4}))],
            // Copies that would reach past the effect's limit, which stops them early.
            vec![fx("distort.transform", json!({"moveH": 1.0e7, "copies": 1000}))],
            // Copies that overlap, or land on each other.
            vec![fx("distort.transform", json!({"moveH": 5, "copies": 1}))],
            vec![fx("distort.transform", json!({"moveH": 100, "copies": 1})), fx("distort.transform", json!({"moveH": -100, "copies": 1}))],
        ] {
            let mut own = type_node(50);
            own.appearance.effects = effects.clone();
            for n in [type_group(effects.clone()), own] {
                let d = bake_document(&doc_with(n)).unwrap();
                assert!(type_origins(&d).is_empty(), "{effects:?}");
            }
        }
    }

    #[test]
    fn type_whose_copies_paint_over_each_other_is_still_outlined() {
        if skip_without_craft_fonts() {
            return;
        }
        let moves = vec![fx("distort.transform", json!({"moveV": 40, "copies": 1}))];
        assert_eq!(type_origins(&bake_document(&doc_with(type_group(moves.clone()))).unwrap()).len(), 2);
        // A 20 pt stroke on the characters reaches the copy below.
        let mut stroked = type_node(50);
        if let NodeKind::Text(t) = &mut stroked.kind {
            t.runs[0].style.stroke = Paint::solid(Color::BLACK);
            t.runs[0].style.stroke_width = 20.0;
        }
        let mut g = type_group(moves);
        g.children_mut().unwrap()[0] = Arc::new(stroked);
        assert!(type_origins(&bake_document(&doc_with(g)).unwrap()).is_empty());
    }

    #[test]
    fn type_with_a_look_of_its_own_in_a_moved_group_is_still_outlined() {
        if skip_without_craft_fonts() {
            return;
        }
        let moves = vec![fx("distort.transform", json!({"moveV": 40, "copies": 1}))];
        let mut translucent = type_node(50);
        translucent.opacity = 0.5;
        let mut underlined = type_node(50);
        if let NodeKind::Text(t) = &mut underlined.kind {
            t.runs[0].style.underline = true;
        }
        let mut shadowed = type_node(50);
        shadowed.appearance.effects.push(fx("stylize.dropShadow", json!({})));
        let mut gradient = type_node(50);
        if let NodeKind::Text(t) = &mut gradient.kind {
            t.runs[0].style.fill = Paint::Gradient(Box::new(vectorcraft_color::GradientPaint::new(vectorcraft_color::Gradient::default())));
        }
        let mut reshaped = type_node(50);
        let mut fill = FillLayer::new(Paint::solid(Color::BLACK));
        fill.effects.push(fx("path.offsetPath", json!({"offset": 2})));
        reshaped.appearance.items.push(AppearanceItem::Fill(fill));
        // A stroke of the type object's own (beyond its characters').
        let mut stroked = type_node(50);
        stroked.appearance.items.push(AppearanceItem::Stroke(StrokeLayer::new(Paint::solid(Color::BLACK), 1.0)));
        // Character strokes scale with type scaled by its transform, where the outlines keep theirs.
        let mut scaled = type_node(50);
        if let NodeKind::Text(t) = &mut scaled.kind {
            t.runs[0].style.stroke = Paint::solid(Color::BLACK);
            t.runs[0].style.stroke_width = 1.0;
            t.xf *= Affine::scale(2.0);
        }
        let mut turned = scaled.clone();
        if let NodeKind::Text(t) = &mut turned.kind {
            t.xf = Affine::translate((20.0, 60.0)) * Affine::rotate(0.5);
        }
        let far = vec![fx("distort.transform", json!({"moveH": 300, "copies": 1}))];
        for (t, kept) in [(turned, 2), (scaled, 0)] {
            let mut g = type_group(far.clone());
            g.children_mut().unwrap()[0] = Arc::new(t);
            assert_eq!(type_origins(&bake_document(&doc_with(g)).unwrap()).len(), kept);
        }
        for t in [translucent, underlined, shadowed, gradient, reshaped, stroked] {
            let mut g = type_group(moves.clone());
            g.children_mut().unwrap()[0] = Arc::new(t);
            assert!(type_origins(&bake_document(&doc_with(g)).unwrap()).is_empty());
        }
    }

    #[test]
    fn type_in_a_moved_group_with_a_fill_of_its_own_is_still_outlined() {
        let moves = vec![fx("distort.transform", json!({"moveV": 100, "copies": 1}))];
        let fill = AppearanceItem::Fill(FillLayer::new(Paint::solid(Color::BLACK)));
        let mut g = type_group(moves.clone());
        g.appearance.items.push(fill.clone());
        assert!(type_origins(&bake_document(&doc_with(g)).unwrap()).is_empty());
        // A group with a fill of its own inside the moved group.
        let mut inner = type_group(vec![]);
        inner.id = NodeId(53);
        inner.appearance.items.push(fill);
        let mut outer = Node::group(NodeId(54), vec![Arc::new(inner)]);
        outer.appearance.effects = moves;
        assert!(type_origins(&bake_document(&doc_with(outer)).unwrap()).is_empty());
    }

    #[test]
    fn type_in_a_moved_group_inside_a_moved_group_is_still_outlined() {
        // The inner copy lands back on the original.
        let mut inner = type_group(vec![fx("distort.transform", json!({"moveH": -200, "copies": 1}))]);
        inner.id = NodeId(53);
        let mut outer = Node::group(NodeId(54), vec![Arc::new(inner)]);
        outer.appearance.effects.push(fx("distort.transform", json!({"moveH": 200, "copies": 1})));
        assert!(type_origins(&bake_document(&doc_with(outer)).unwrap()).is_empty());
    }

    #[test]
    fn type_whose_copies_hold_too_much_is_still_outlined() {
        if skip_without_craft_fonts() {
            return;
        }
        let spaced = |spaces: usize| {
            let mut n = type_node(50);
            if let NodeKind::Text(t) = &mut n.kind {
                t.runs[0].text = format!("a{}", " ".repeat(spaces));
            }
            Arc::new(n)
        };
        // 1001 copies of about 2,000 bytes stay type; of about 21,000 bytes each, past 20,000,000
        // bytes together, they are outlined.
        let copies = vec![fx("distort.transform", json!({"moveH": 100, "copies": 1000}))];
        for (spaces, kept) in [(1000, 1001), (20_000, 0)] {
            let mut g = type_group(copies.clone());
            g.children_mut().unwrap()[0] = spaced(spaces);
            assert_eq!(type_origins(&bake_document(&doc_with(g)).unwrap()).len(), kept, "{spaces} spaces");
        }
        // 1001 × 21 copies, past 10,000.
        let mut g = type_group(vec![
            fx("distort.transform", json!({"moveH": 100, "copies": 1000})),
            fx("distort.transform", json!({"moveV": 100, "copies": 20})),
        ]);
        g.children_mut().unwrap()[0] = spaced(0);
        assert!(type_origins(&bake_document(&doc_with(g)).unwrap()).is_empty());
    }

    #[test]
    fn copies_are_apart_when_their_boxes_only_touch() {
        let b = Rect::new(0.0, 0.0, 10.0, 5.0);
        assert!(apart(&[Vec2::ZERO, Vec2::new(10.0, 0.0), Vec2::new(0.0, 5.0), Vec2::new(-10.0, -5.0)], b));
        assert!(!apart(&[Vec2::ZERO, Vec2::new(9.0, 4.0)], b));
        assert!(!apart(&[Vec2::new(100.0, 0.0), Vec2::new(30.0, 0.0), Vec2::new(100.0, 0.0)], b));
        assert!(!apart(&[Vec2::new(-1.0, -1.0), Vec2::new(8.5, 3.5)], b));
        // Offsets too far for the cells' range count as overlapping.
        assert!(!apart(&[Vec2::ZERO, Vec2::new(1.0e9, 0.0)], Rect::new(0.0, 0.0, 1.0e-9, 1.0)));
    }

    #[test]
    fn type_in_a_pathfinder_group_inside_a_moved_group_is_still_outlined() {
        if skip_without_craft_fonts() {
            return;
        }
        let mut inner = type_group(vec![fx("pathfinder.add", json!({}))]);
        inner.id = NodeId(53);
        let mut outer = Node::group(NodeId(54), vec![Arc::new(inner)]);
        outer.appearance.effects.push(fx("distort.transform", json!({"moveV": 100, "copies": 1})));
        let d = bake_document(&doc_with(outer)).unwrap();
        assert!(type_origins(&d).is_empty());
        // The glyphs take part in Add: the result reaches past the 10 pt square.
        let b = d.node(NodeId(54)).and_then(|n| n.geometric_bounds()).unwrap();
        assert!(b.width() > 30.0, "{b:?}");
    }

    #[test]
    fn type_is_copied_only_when_the_effect_makes_every_copy() {
        // A 10 pt line with `n` anchors.
        let line = |n: usize| {
            let pts: Vec<Point> = (0..n).map(|i| Point::new(i as f64 * 10.0 / n as f64, 0.0)).collect();
            PathData::new(vec![vectorcraft_geom::SubPath::polyline(&pts, false)])
        };
        let right = json!({"moveH": 10, "copies": 1000});
        let down = json!({"moveV": 10, "copies": 1});
        // 1000 copies of a path stay within 2,000,000 anchors up to 1998 anchors.
        assert_eq!(transform_offsets(std::slice::from_ref(&right), &line(1998)).map(|o| o.len()), Some(1001));
        assert!(transform_offsets(std::slice::from_ref(&right), &line(1999)).is_none());
        // A second effect copies every copy.
        assert_eq!(transform_offsets(&[right.clone(), down.clone()], &line(999)).map(|o| o.len()), Some(2002));
        assert!(transform_offsets(&[right, down], &line(1000)).is_none());
        // Copies stop before one reaches 1,000,000,000 pt from the origin.
        let square = shapes::rectangle(Rect::new(0.0, 0.0, 10.0, 10.0));
        assert_eq!(transform_offsets(&[json!({"moveH": 1.0e7, "copies": 99})], &square).map(|o| o.len()), Some(100));
        assert!(transform_offsets(&[json!({"moveH": 1.0e7, "copies": 100})], &square).is_none());
        // An effect that also scales.
        assert!(transform_offsets(&[json!({"moveH": 10, "scaleH": 50})], &square).is_none());
    }
    /// A 10 pt square painted with a red to blue gradient and a Transform effect with 2 copies.
    fn gradient_copies(id: u64) -> Node {
        use vectorcraft_color::{Gradient, GradientKind, GradientPaint, GradientStop};
        let stops = vec![GradientStop::new(0.0, Color::rgb(1.0, 0.0, 0.0)), GradientStop::new(1.0, Color::rgb(0.0, 0.0, 1.0))];
        let paint = Paint::Gradient(Box::new(GradientPaint::new(Gradient::new(GradientKind::Linear, stops))));
        let mut n = Node::path(NodeId(id), shapes::rectangle(Rect::new(0.0, 0.0, 10.0, 10.0)), Appearance::basic(paint, Paint::None, 0.0));
        n.appearance.effects.push(fx("distort.transform", json!({"moveH": 30, "copies": 2})));
        n
    }

    /// The paths under `n` that paint a gradient fitted to their own 10 pt box, left to right.
    fn gradient_pieces(n: &Node) -> Vec<f64> {
        let mut out = vec![];
        let mut walk = vec![n];
        while let Some(n) = walk.pop() {
            match n.children() {
                Some(ch) if !matches!(n.kind, NodeKind::Compound { .. }) => walk.extend(ch.iter().map(|c| &**c)),
                _ => {
                    assert!(matches!(n.appearance.fill_paint(), Paint::Gradient(_)), "{n:?}");
                    out.extend(n.geometric_bounds().map(|b| b.width()));
                }
            }
        }
        out
    }

    #[test]
    fn exporting_a_path_with_a_transform_gives_each_copy_its_own_gradient() {
        let d = bake_document(&doc_with(gradient_copies(50))).unwrap();
        // Three squares of their own, not one path spanning all three.
        assert_eq!(gradient_pieces(d.node(NodeId(50)).unwrap()), vec![10.0; 3]);
    }
}