refactor: split complex input, explode, sweep, cache and options code into helpers

Pure extraction, no behaviour change: same order of side effects, same
early returns and error values. Clears cognitive-complexity findings on
AreaM::input, explode_kind, hatch sweep, the COMPARE overlay paint and
the Files options tab (S3776).

crates/engine/src/cmd/inquiry.rs

@@ -963,6 +963,57 @@ impl AreaM {
             AreaMode::Subtract => self.total - v,
         }
     }
+    /// Input while a height is pending: typed, or given by two points (their distance).
+    fn height_input(&mut self, s: &mut Session, i: Input) -> Step {
+        match (i, self.height_from) {
+            (Input::Point(p), None) => self.height_from = Some(p),
+            (Input::Point(p), Some(from)) => {
+                self.height_from = None;
+                return self.height(s, p.dist(from));
+            }
+            (Input::Text(t), None) => match crate::units::parse_distance(&t).filter(|v| v.is_finite()) {
+                Some(h) => return self.height(s, h),
+                None => s.echo("Requires a distance."),
+            },
+            (Input::Enter, None) => s.echo("Requires a height."),
+            (Input::Enter, Some(_)) => s.echo("Requires a second point."),
+            (Input::Text(_), Some(_)) => s.echo("Requires a point."),
+            _ => {}
+        }
+        Step::Continue
+    }
+
+    /// Input while the objects to measure are picked.
+    fn object_input(&mut self, s: &mut Session, i: Input) -> Step {
+        match i {
+            Input::Pick(hs) => {
+                for h in hs {
+                    match object_area(s, h) {
+                        Ok((a, per)) => {
+                            if self.measured(s, a, per) == Step::Done {
+                                return Step::Done;
+                            }
+                            // A single volume takes the first object with an area.
+                            if self.volume && self.mode == AreaMode::Single {
+                                break;
+                            }
+                        }
+                        Err(_) => s.echo("The selected object has no area."),
+                    }
+                }
+            }
+            Input::Enter => {
+                self.object = false;
+                if self.mode == AreaMode::Single {
+                    return Step::Done;
+                }
+            }
+            Input::Text(_) | Input::Keyword(_) => s.echo("*Invalid selection*"),
+            _ => {}
+        }
+        Step::Continue
+    }
+
     /// Measure the oldest pending area's volume with height `h`.
     fn height(&mut self, s: &mut Session, h: f64) -> Step {
         match self.pending.first().map(|a| a * h.abs()) {
@@ -1042,52 +1093,10 @@ impl Interactive for AreaM {
     }
     fn input(&mut self, s: &mut Session, i: Input) -> Result<Step> {
         if !self.pending.is_empty() {
-            // A height is typed, or given by two points (their distance).
-            match (i, self.height_from) {
-                (Input::Point(p), None) => self.height_from = Some(p),
-                (Input::Point(p), Some(from)) => {
-                    self.height_from = None;
-                    return Ok(self.height(s, p.dist(from)));
-                }
-                (Input::Text(t), None) => match crate::units::parse_distance(&t).filter(|v| v.is_finite()) {
-                    Some(h) => return Ok(self.height(s, h)),
-                    None => s.echo("Requires a distance."),
-                },
-                (Input::Enter, None) => s.echo("Requires a height."),
-                (Input::Enter, Some(_)) => s.echo("Requires a second point."),
-                (Input::Text(_), Some(_)) => s.echo("Requires a point."),
-                _ => {}
-            }
-            return Ok(Step::Continue);
+            return Ok(self.height_input(s, i));
         }
         if self.object {
-            match i {
-                Input::Pick(hs) => {
-                    for h in hs {
-                        match object_area(s, h) {
-                            Ok((a, per)) => {
-                                if self.measured(s, a, per) == Step::Done {
-                                    return Ok(Step::Done);
-                                }
-                                // A single volume takes the first object with an area.
-                                if self.volume && self.mode == AreaMode::Single {
-                                    break;
-                                }
-                            }
-                            Err(_) => s.echo("The selected object has no area."),
-                        }
-                    }
-                }
-                Input::Enter => {
-                    self.object = false;
-                    if self.mode == AreaMode::Single {
-                        return Ok(Step::Done);
-                    }
-                }
-                Input::Text(_) | Input::Keyword(_) => s.echo("*Invalid selection*"),
-                _ => {}
-            }
-            return Ok(Step::Continue);
+            return Ok(self.object_input(s, i));
         }
         if self.length {
             if let Some(p) = length_input(&self.pts, i)? {

crates/engine/src/cmd/modify.rs

@@ -1296,6 +1296,128 @@ fn run_chamfer(s: &mut Session, p: &Value) -> Result<Value> {
 
 // ---------------- explode / array / order / break / join ----------------
 
+fn explode_block_ref(d: &cadcraft_doc::Drawing, e: &Entity, ins: &cadcraft_doc::Insert) -> Option<Vec<Entity>> {
+    if let Some(items) = super::array::explode_array(d, e) {
+        return Some(items);
+    }
+    let blk = d.block(&ins.block)?;
+    let m = ins.transform(blk.base.xy());
+    Some(
+        blk.entities
+            .iter()
+            .map(|be| {
+                let mut ne = (**be).clone();
+                ne.kind.transform(&m);
+                if ne.common.layer == "0" {
+                    ne.common.layer = e.common.layer.clone();
+                }
+                if ne.common.color == cadcraft_color::Color::ByBlock {
+                    ne.common.color = e.common.color;
+                }
+                ne
+            })
+            .collect(),
+    )
+}
+
+fn explode_mtext(e: &Entity, m: &cadcraft_doc::MText) -> Vec<Entity> {
+    cadcraft_fonts::plain_mtext(&m.contents)
+        .split('\n')
+        .enumerate()
+        .map(|(i, l)| {
+            let at = m.insert.xy() + Vec2::from_angle(m.rotation - std::f64::consts::FRAC_PI_2) * (m.height * (1.0 + 5.0 / 3.0 * i as f64));
+            Entity {
+                handle: Handle(0),
+                common: e.common.clone(),
+                kind: EntityKind::Text(cadcraft_doc::Text {
+                    insert: v3(at),
+                    align_pt: None,
+                    height: m.height,
+                    value: l.into(),
+                    rotation: m.rotation,
+                    width_factor: 1.0,
+                    oblique: 0.0,
+                    style: m.style.clone(),
+                    halign: Default::default(),
+                    valign: Default::default(),
+                }),
+            }
+        })
+        .collect()
+}
+
+/// The entities of a boundary's lines and arcs, on the object's layer and style.
+fn segment_entities(e: &Entity, segs: impl IntoIterator<Item = Segment>) -> Vec<Entity> {
+    segs.into_iter()
+        .map(|s| {
+            let k = match s {
+                Segment::Line(l) => line(l.a, l.b),
+                Segment::Arc { arc: a, .. } => arc(&a),
+            };
+            Entity { handle: Handle(0), common: e.common.clone(), kind: k }
+        })
+        .collect()
+}
+
+fn explode_dimension(d: &cadcraft_doc::Drawing, e: &Entity, dm: &cadcraft_doc::Dimension) -> Vec<Entity> {
+    // The dimension as drawn: its overrides, DIMSCALE (0 = the drawing's) and text font.
+    let style = d.dim_style(&dm.style).cloned().unwrap_or_default().with_overrides(&dm.overrides);
+    let g = cadcraft_render::dimension_in(d, dm);
+    let line_entity = |l: &Vec<Vec2>| {
+        if l.len() == 2 {
+            Some(Entity { handle: Handle(0), common: e.common.clone(), kind: line(*l.first()?, *l.get(1)?) })
+        } else {
+            Some(Entity { handle: Handle(0), common: e.common.clone(), kind: lwpoly(l.iter().map(|p| PolyVertex::new(*p)).collect(), false) })
+        }
+    };
+    // The text's marks (arc length symbol, DIMINSPECT frame) go after the text background.
+    let text_marks = &g.text_marks;
+    let marks = |want: bool| g.lines.iter().enumerate().filter(move |(i, _)| text_marks.contains(i) == want).map(|(_, l)| l);
+    let mut v: Vec<Entity> = marks(false).filter_map(&line_entity).collect();
+    for t in &g.fills {
+        if let [a, b, c] = t.as_slice() {
+            v.push(Entity {
+                handle: Handle(0),
+                common: e.common.clone(),
+                kind: EntityKind::Solid(cadcraft_doc::Solid { corners: [v3(*a), v3(*b), v3(*c), v3(*c)] }),
+            });
+        }
+    }
+    // DIMTFILL 2: the text background as a SOLID in DIMTFILLCLR, over the lines and
+    // arrowheads, under the text and its marks (SOLID corners go 1, 2, 4, 3).
+    if style.text_fill == 2
+        && let [p0, p1, p2, p3] = g.text_fill.as_slice()
+    {
+        let fill = style.text_fill_color;
+        let color = if fill == cadcraft_doc::color::Color::ByBlock { e.common.color } else { fill };
+        v.push(Entity {
+            handle: Handle(0),
+            common: cadcraft_doc::Common { color, ..e.common.clone() },
+            kind: EntityKind::Solid(cadcraft_doc::Solid { corners: [v3(*p0), v3(*p1), v3(*p3), v3(*p2)] }),
+        });
+    }
+    v.extend(marks(true).filter_map(&line_entity));
+    if !g.value.is_empty() {
+        v.push(Entity {
+            handle: Handle(0),
+            common: e.common.clone(),
+            kind: EntityKind::MText(cadcraft_doc::MText {
+                insert: v3(g.text_pos),
+                height: g.text_height,
+                width: 0.0,
+                attach: 5,
+                rotation: g.text_angle,
+                style: style.text_style.clone(),
+                contents: g.mtext_contents(),
+                line_spacing: 1.0,
+                line_spacing_exact: false,
+                columns: None,
+            }),
+        });
+    }
+    v
+}
+
 pub(crate) fn explode_kind(d: &cadcraft_doc::Drawing, e: &Entity) -> Option<Vec<Entity>> {
     // An annotative object explodes into plain objects as it draws at the current annotation scale.
     if cadcraft_doc::is_annotative(e) {
@@ -1309,42 +1431,9 @@ pub(crate) fn explode_kind(d: &cadcraft_doc::Drawing, e: &Entity) -> Option<Vec<
     match &e.kind {
         EntityKind::LwPolyline(p) => {
             let pl = Polyline { vertices: p.vertices.clone(), closed: p.closed };
-            Some(
-                pl.segments()
-                    .into_iter()
-                    .map(|s| {
-                        let k = match s {
-                            Segment::Line(l) => line(l.a, l.b),
-                            Segment::Arc { arc: a, .. } => arc(&a),
-                        };
-                        Entity { handle: Handle(0), common: e.common.clone(), kind: k }
-                    })
-                    .collect(),
-            )
-        }
-        EntityKind::Insert(ins) => {
-            if let Some(items) = super::array::explode_array(d, e) {
-                return Some(items);
-            }
-            let blk = d.block(&ins.block)?;
-            let m = ins.transform(blk.base.xy());
-            Some(
-                blk.entities
-                    .iter()
-                    .map(|be| {
-                        let mut ne = (**be).clone();
-                        ne.kind.transform(&m);
-                        if ne.common.layer == "0" {
-                            ne.common.layer = e.common.layer.clone();
-                        }
-                        if ne.common.color == cadcraft_color::Color::ByBlock {
-                            ne.common.color = e.common.color;
-                        }
-                        ne
-                    })
-                    .collect(),
-            )
+            Some(segment_entities(e, pl.segments()))
         }
+        EntityKind::Insert(ins) => explode_block_ref(d, e, ins),
         // A helix explodes into its spline (seen from above).
         EntityKind::Helix(h) => Some(vec![Entity { handle: Handle(0), common: e.common.clone(), kind: EntityKind::Spline(h.spline()) }]),
         EntityKind::Polyline3d(p) => Some(
@@ -1357,102 +1446,10 @@ pub(crate) fn explode_kind(d: &cadcraft_doc::Drawing, e: &Entity) -> Option<Vec<
                 .collect(),
         ),
         EntityKind::MLine(m) => Some(super::draw2::mline::explode(e, m)),
-        EntityKind::MText(m) => Some(
-            cadcraft_fonts::plain_mtext(&m.contents)
-                .split('\n')
-                .enumerate()
-                .map(|(i, l)| {
-                    let at = m.insert.xy() + Vec2::from_angle(m.rotation - std::f64::consts::FRAC_PI_2) * (m.height * (1.0 + 5.0 / 3.0 * i as f64));
-                    Entity {
-                        handle: Handle(0),
-                        common: e.common.clone(),
-                        kind: EntityKind::Text(cadcraft_doc::Text {
-                            insert: v3(at),
-                            align_pt: None,
-                            height: m.height,
-                            value: l.into(),
-                            rotation: m.rotation,
-                            width_factor: 1.0,
-                            oblique: 0.0,
-                            style: m.style.clone(),
-                            halign: Default::default(),
-                            valign: Default::default(),
-                        }),
-                    }
-                })
-                .collect(),
-        ),
+        EntityKind::MText(m) => Some(explode_mtext(e, m)),
         // A region explodes into its boundary's lines and arcs.
-        EntityKind::Region(r) => Some(
-            r.segments()
-                .into_iter()
-                .map(|s| {
-                    let k = match s {
-                        Segment::Line(l) => line(l.a, l.b),
-                        Segment::Arc { arc: a, .. } => arc(&a),
-                    };
-                    Entity { handle: Handle(0), common: e.common.clone(), kind: k }
-                })
-                .collect(),
-        ),
-        EntityKind::Dimension(dm) => {
-            // The dimension as drawn: its overrides, DIMSCALE (0 = the drawing's) and text font.
-            let style = d.dim_style(&dm.style).cloned().unwrap_or_default().with_overrides(&dm.overrides);
-            let g = cadcraft_render::dimension_in(d, dm);
-            let line_entity = |l: &Vec<Vec2>| {
-                if l.len() == 2 {
-                    Some(Entity { handle: Handle(0), common: e.common.clone(), kind: line(*l.first()?, *l.get(1)?) })
-                } else {
-                    Some(Entity { handle: Handle(0), common: e.common.clone(), kind: lwpoly(l.iter().map(|p| PolyVertex::new(*p)).collect(), false) })
-                }
-            };
-            // The text's marks (arc length symbol, DIMINSPECT frame) go after the text background.
-            let text_marks = &g.text_marks;
-            let marks = |want: bool| g.lines.iter().enumerate().filter(move |(i, _)| text_marks.contains(i) == want).map(|(_, l)| l);
-            let mut v: Vec<Entity> = marks(false).filter_map(&line_entity).collect();
-            for t in &g.fills {
-                if let [a, b, c] = t.as_slice() {
-                    v.push(Entity {
-                        handle: Handle(0),
-                        common: e.common.clone(),
-                        kind: EntityKind::Solid(cadcraft_doc::Solid { corners: [v3(*a), v3(*b), v3(*c), v3(*c)] }),
-                    });
-                }
-            }
-            // DIMTFILL 2: the text background as a SOLID in DIMTFILLCLR, over the lines and
-            // arrowheads, under the text and its marks (SOLID corners go 1, 2, 4, 3).
-            if style.text_fill == 2
-                && let [p0, p1, p2, p3] = g.text_fill.as_slice()
-            {
-                let fill = style.text_fill_color;
-                let color = if fill == cadcraft_doc::color::Color::ByBlock { e.common.color } else { fill };
-                v.push(Entity {
-                    handle: Handle(0),
-                    common: cadcraft_doc::Common { color, ..e.common.clone() },
-                    kind: EntityKind::Solid(cadcraft_doc::Solid { corners: [v3(*p0), v3(*p1), v3(*p3), v3(*p2)] }),
-                });
-            }
-            v.extend(marks(true).filter_map(&line_entity));
-            if !g.value.is_empty() {
-                v.push(Entity {
-                    handle: Handle(0),
-                    common: e.common.clone(),
-                    kind: EntityKind::MText(cadcraft_doc::MText {
-                        insert: v3(g.text_pos),
-                        height: g.text_height,
-                        width: 0.0,
-                        attach: 5,
-                        rotation: g.text_angle,
-                        style: style.text_style.clone(),
-                        contents: g.mtext_contents(),
-                        line_spacing: 1.0,
-                        line_spacing_exact: false,
-                        columns: None,
-                    }),
-                });
-            }
-            Some(v)
-        }
+        EntityKind::Region(r) => Some(segment_entities(e, r.segments())),
+        EntityKind::Dimension(dm) => Some(explode_dimension(d, e, dm)),
         EntityKind::Tolerance(t) => Some(super::tolerance::explode(d, e, t)),
         _ => None,
     }

crates/io/src/dxf_read.rs

@@ -249,130 +249,6 @@ fn entity(kind: &str, tags: &[Tag]) -> Option<(Common, EntityKind)> {
 }
 
 /// Parse one entity while charging materialized table cells to the caller's shared import budget.
-/// An ARC, with its angles run the other way in a mirrored OCS.
-fn arc(c: &Common, t: &T) -> Arc {
-    let mut a = Arc { center: ocs(c, t.p(10)), radius: t.fd(40, 1.0).abs(), start: t.fd(50, 0.0).to_radians(), end: t.fd(51, 360.0).to_radians() };
-    if c.extrusion.z < 0.0 {
-        // Mirrored OCS: angles run the other way.
-        let (s, e) = (std::f64::consts::PI - a.end, std::f64::consts::PI - a.start);
-        a.start = cadcraft_geom::norm_angle(s);
-        a.end = cadcraft_geom::norm_angle(e);
-    }
-    a
-}
-
-fn ellipse(c: &Common, t: &T) -> Ellipse {
-    let mut e = Ellipse {
-        center: t.p(10),
-        major: t.p(11),
-        ratio: t.fd(40, 1.0).clamp(1e-9, 1.0),
-        start: t.fd(41, 0.0),
-        end: t.fd(42, std::f64::consts::TAU),
-    };
-    if c.extrusion.z < 0.0 && (cadcraft_geom::ccw_sweep(e.start, e.end) - std::f64::consts::TAU).abs() > 1e-9 {
-        // Centre and major axis are WCS, but the minor axis is extrusion × major: with (0,0,-1)
-        // it points the other way, so parameter t lands where -t does in the XY plane. A full
-        // ellipse is symmetric and stays as it is.
-        let (s, e2) = (-e.end, -e.start);
-        e.start = cadcraft_geom::norm_angle(s);
-        e.end = cadcraft_geom::norm_angle(e2);
-    }
-    e
-}
-
-/// A LWPOLYLINE, or the region CADCraft wrote as one.
-fn lwpolyline(tags: &[Tag], c: &Common, t: &T) -> Option<EntityKind> {
-    let mut verts = Vec::new();
-    let mut cur: Option<PolyVertex> = None;
-    for tg in tags {
-        match tg.code {
-            10 => {
-                if let Some(v) = cur.take() {
-                    verts.push(v);
-                }
-                cur = Some(PolyVertex { p: Vec2::new(tg.f64(), 0.0), ..Default::default() });
-            }
-            20 => {
-                if let Some(v) = cur.as_mut() {
-                    v.p.y = tg.f64();
-                }
-            }
-            40 => {
-                if let Some(v) = cur.as_mut() {
-                    v.start_width = tg.f64();
-                }
-            }
-            41 => {
-                if let Some(v) = cur.as_mut() {
-                    v.end_width = tg.f64();
-                }
-            }
-            42 => {
-                if let Some(v) = cur.as_mut() {
-                    v.bulge = tg.f64();
-                }
-            }
-            _ => {}
-        }
-    }
-    verts.extend(cur);
-    let flags = t.i(70).unwrap_or(0);
-    if c.extrusion.z < 0.0 {
-        for v in &mut verts {
-            v.p.x = -v.p.x;
-            v.bulge = -v.bulge;
-        }
-    }
-    let pl = LwPolyline { vertices: verts, closed: flags & 1 != 0, const_width: t.fd(43, 0.0), elevation: t.fd(38, 0.0), plinegen: flags & 128 != 0 };
-    // A region CADCraft wrote as polylines (`dxf_region`).
-    crate::dxf_region::from_polyline(tags, pl)
-}
-
-fn spline(t: &T) -> Spline {
-    let degree = t.i(71).unwrap_or(3).clamp(1, 10) as usize;
-    let knots = t.all_f(40);
-    let control = t.pts(10);
-    let weights = t.all_f(41);
-    let fit = t.pts(11);
-    let tangent = |c: i32| t.f(c).map(|_| t.p(c).xy());
-    let fit_opts =
-        cadcraft_geom::FitOptions { knots: Default::default(), start_tangent: tangent(12), end_tangent: tangent(13), tolerance: t.fd(44, 0.0) }
-            .sanitized();
-    let closed = t.i(70).unwrap_or(0) & 1 != 0;
-    let mut sp = Spline { degree, knots, control, weights, fit: fit.clone(), closed, fit_opts };
-    if !sp.is_valid() && fit.len() >= 2 {
-        sp = Spline::fit_with(&fit, sp.closed, fit_opts);
-    } else if !sp.is_valid() && sp.control.len() >= 2 {
-        sp = Spline::from_control(sp.control.clone(), degree);
-    } else if fit.len() >= 3 {
-        // DXF keeps the knots, not how they were spaced: recover it for later refits.
-        sp.fit_opts.knots = sp.infer_knot_param();
-    }
-    sp
-}
-
-/// An ATTDEF, whose multiline text is embedded MTEXT after its own groups.
-fn attdef(tags: &[Tag], c: &Common) -> Attrib {
-    // A multiline definition has its text as embedded MTEXT after its own groups.
-    let (own, embedded) = split_embedded(tags);
-    let multiline = multiline_attrib(embedded, c);
-    let own = T(own);
-    let mut text = text_from(&own);
-    if let Some(m) = &multiline {
-        text.value.clone_from(&m.read_as);
-    }
-    Attrib {
-        tag: own.s(2).unwrap_or_default(),
-        text,
-        invisible: own.i(70).unwrap_or(0) & 1 != 0,
-        constant: own.i(70).unwrap_or(0) & 2 != 0,
-        prompt: own.s(3).unwrap_or_default(),
-        props: Default::default(),
-        multiline,
-        modes: attrib_modes(own.0),
-    }
-}
-
 fn entity_with_table_budget(kind: &str, tags: &[Tag], table_cells_left: &mut usize) -> Option<(Common, EntityKind)> {
     // The paper-space viewport our writer adds (dxf_write::paper_view) stays implicit.
     if kind == "VIEWPORT" && crate::dxf_ext::is_paper_view(tags) {
@@ -384,16 +260,138 @@ fn entity_with_table_budget(kind: &str, tags: &[Tag], table_cells_left: &mut usi
         "LINE" => EntityKind::Line(Line { a: t.p(10), b: t.p(11) }),
         "POINT" => EntityKind::Point(Point { p: t.p(10), angle: t.fd(50, 0.0).to_radians() }),
         "CIRCLE" => EntityKind::Circle(Circle { center: ocs(&c, t.p(10)), radius: t.fd(40, 1.0).abs() }),
-        "ARC" => EntityKind::Arc(arc(&c, &t)),
-        "ELLIPSE" => EntityKind::Ellipse(ellipse(&c, &t)),
-        "LWPOLYLINE" => lwpolyline(tags, &c, &t)?,
-        "SPLINE" => EntityKind::Spline(spline(&t)),
+        "ARC" => {
+            let mut a =
+                Arc { center: ocs(&c, t.p(10)), radius: t.fd(40, 1.0).abs(), start: t.fd(50, 0.0).to_radians(), end: t.fd(51, 360.0).to_radians() };
+            if c.extrusion.z < 0.0 {
+                // Mirrored OCS: angles run the other way.
+                let (s, e) = (std::f64::consts::PI - a.end, std::f64::consts::PI - a.start);
+                a.start = cadcraft_geom::norm_angle(s);
+                a.end = cadcraft_geom::norm_angle(e);
+            }
+            EntityKind::Arc(a)
+        }
+        "ELLIPSE" => {
+            let mut e = Ellipse {
+                center: t.p(10),
+                major: t.p(11),
+                ratio: t.fd(40, 1.0).clamp(1e-9, 1.0),
+                start: t.fd(41, 0.0),
+                end: t.fd(42, std::f64::consts::TAU),
+            };
+            if c.extrusion.z < 0.0 && (cadcraft_geom::ccw_sweep(e.start, e.end) - std::f64::consts::TAU).abs() > 1e-9 {
+                // Centre and major axis are WCS, but the minor axis is extrusion × major: with (0,0,-1)
+                // it points the other way, so parameter t lands where -t does in the XY plane. A full
+                // ellipse is symmetric and stays as it is.
+                let (s, e2) = (-e.end, -e.start);
+                e.start = cadcraft_geom::norm_angle(s);
+                e.end = cadcraft_geom::norm_angle(e2);
+            }
+            EntityKind::Ellipse(e)
+        }
+        "LWPOLYLINE" => {
+            let mut verts = Vec::new();
+            let mut cur: Option<PolyVertex> = None;
+            for tg in tags {
+                match tg.code {
+                    10 => {
+                        if let Some(v) = cur.take() {
+                            verts.push(v);
+                        }
+                        cur = Some(PolyVertex { p: Vec2::new(tg.f64(), 0.0), ..Default::default() });
+                    }
+                    20 => {
+                        if let Some(v) = cur.as_mut() {
+                            v.p.y = tg.f64();
+                        }
+                    }
+                    40 => {
+                        if let Some(v) = cur.as_mut() {
+                            v.start_width = tg.f64();
+                        }
+                    }
+                    41 => {
+                        if let Some(v) = cur.as_mut() {
+                            v.end_width = tg.f64();
+                        }
+                    }
+                    42 => {
+                        if let Some(v) = cur.as_mut() {
+                            v.bulge = tg.f64();
+                        }
+                    }
+                    _ => {}
+                }
+            }
+            verts.extend(cur);
+            let flags = t.i(70).unwrap_or(0);
+            if c.extrusion.z < 0.0 {
+                for v in &mut verts {
+                    v.p.x = -v.p.x;
+                    v.bulge = -v.bulge;
+                }
+            }
+            let pl = LwPolyline {
+                vertices: verts,
+                closed: flags & 1 != 0,
+                const_width: t.fd(43, 0.0),
+                elevation: t.fd(38, 0.0),
+                plinegen: flags & 128 != 0,
+            };
+            // A region CADCraft wrote as polylines (`dxf_region`).
+            crate::dxf_region::from_polyline(tags, pl)?
+        }
+        "SPLINE" => {
+            let degree = t.i(71).unwrap_or(3).clamp(1, 10) as usize;
+            let knots = t.all_f(40);
+            let control = t.pts(10);
+            let weights = t.all_f(41);
+            let fit = t.pts(11);
+            let tangent = |c: i32| t.f(c).map(|_| t.p(c).xy());
+            let fit_opts = cadcraft_geom::FitOptions {
+                knots: Default::default(),
+                start_tangent: tangent(12),
+                end_tangent: tangent(13),
+                tolerance: t.fd(44, 0.0),
+            }
+            .sanitized();
+            let closed = t.i(70).unwrap_or(0) & 1 != 0;
+            let mut sp = Spline { degree, knots, control, weights, fit: fit.clone(), closed, fit_opts };
+            if !sp.is_valid() && fit.len() >= 2 {
+                sp = Spline::fit_with(&fit, sp.closed, fit_opts);
+            } else if !sp.is_valid() && sp.control.len() >= 2 {
+                sp = Spline::from_control(sp.control.clone(), degree);
+            } else if fit.len() >= 3 {
+                // DXF keeps the knots, not how they were spaced: recover it for later refits.
+                sp.fit_opts.knots = sp.infer_knot_param();
+            }
+            EntityKind::Spline(sp)
+        }
         "HELIX" => EntityKind::Helix(helix(tags)),
         "RAY" => EntityKind::Ray(RayLine { base: t.p(10), dir: t.p(11) }),
         "XLINE" => EntityKind::XLine(RayLine { base: t.p(10), dir: t.p(11) }),
         "TEXT" => EntityKind::Text(text_from(&t)),
         "MTEXT" => EntityKind::MText(mtext_from(tags, &c)),
-        "ATTDEF" => EntityKind::AttDef(attdef(tags, &c)),
+        "ATTDEF" => {
+            // A multiline definition has its text as embedded MTEXT after its own groups.
+            let (own, embedded) = split_embedded(tags);
+            let multiline = multiline_attrib(embedded, &c);
+            let own = T(own);
+            let mut text = text_from(&own);
+            if let Some(m) = &multiline {
+                text.value.clone_from(&m.read_as);
+            }
+            EntityKind::AttDef(Attrib {
+                tag: own.s(2).unwrap_or_default(),
+                text,
+                invisible: own.i(70).unwrap_or(0) & 1 != 0,
+                constant: own.i(70).unwrap_or(0) & 2 != 0,
+                prompt: own.s(3).unwrap_or_default(),
+                props: Default::default(),
+                multiline,
+                modes: attrib_modes(own.0),
+            })
+        }
         "INSERT" => {
             // A mirrored block reference comes with extrusion (0,0,-1): its insertion point, scale,
             // rotation and column spacing are in that OCS, where x runs the other way. In the WCS that
@@ -1111,91 +1109,6 @@ fn entity_extras(kind: &str, tags: &[Tag], h: Handle, k: &mut EntityKind, rx: &m
 
 /// Parse a run of entity records (ENTITIES section or a block's body) into entities. Records that
 /// can't be placed are counted in `skipped`.
-/// The entity of a POLYLINE, with its mesh faces (advancing `i` past its VERTEX records). `None`
-/// for a mesh without faces.
-fn polyline_entity(recs: &[(String, Vec<Tag>)], i: &mut usize, t: &T) -> Option<(Common, EntityKind, Vec<EntityKind>)> {
-    let flags = t.i(70).unwrap_or(0);
-    let mut pts: Vec<(Vec3, f64, f64, f64)> = Vec::new();
-    // Polyface face records (VERTEX 70 bit 128 without 64): vertex indices 71–74.
-    let mut faces: Vec<[i64; 4]> = Vec::new();
-    while let Some((k2, t2)) = recs.get(*i) {
-        if k2 == "VERTEX" {
-            let tt = T(t2);
-            let vflags = tt.i(70).unwrap_or(0);
-            if vflags & 128 != 0 && vflags & 64 == 0 {
-                faces.push([71, 72, 73, 74].map(|c| tt.i(c).unwrap_or(0)));
-            } else if vflags & 16 == 0 {
-                pts.push((tt.p(10), tt.fd(42, 0.0), tt.fd(40, 0.0), tt.fd(41, 0.0)));
-            }
-            *i += 1;
-        } else {
-            if k2 == "SEQEND" {
-                *i += 1;
-            }
-            break;
-        }
-    }
-    let c = common(t);
-    let mut extra: Vec<EntityKind> = Vec::new();
-    let k = if flags & (16 | 64) != 0 {
-        // Polyface (64) and polygon (16) meshes become 3D faces; the first takes the
-        // polyline's place.
-        let verts: Vec<Vec3> = pts.iter().map(|p| p.0).collect();
-        let mut fs = if flags & 64 != 0 { polyface_faces(&verts, &faces) } else { mesh_faces(&verts, t, flags) }.into_iter().map(EntityKind::Face3d);
-        let first = fs.next()?;
-        extra.extend(fs);
-        first
-    } else if flags & 8 != 0 {
-        EntityKind::Polyline3d(Polyline3d { points: pts.iter().map(|p| p.0).collect(), closed: flags & 1 != 0 })
-    } else {
-        // A 2D polyline's vertices are in its OCS: mirrored like LWPOLYLINE.
-        let m = if c.extrusion.z < 0.0 { -1.0 } else { 1.0 };
-        EntityKind::LwPolyline(LwPolyline {
-            vertices: pts.iter().map(|p| PolyVertex { p: Vec2::new(m * p.0.x, p.0.y), bulge: m * p.1, start_width: p.2, end_width: p.3 }).collect(),
-            closed: flags & 1 != 0,
-            const_width: t.fd(40, 0.0).min(t.fd(41, 0.0)).max(0.0),
-            elevation: t.p(10).z,
-            plinegen: flags & 128 != 0,
-        })
-    };
-    Some((c, k, extra))
-}
-
-/// The ATTRIB records after an INSERT, advancing `i` past them and their SEQEND.
-fn insert_attribs(recs: &[(String, Vec<Tag>)], i: &mut usize, ins_layer: &str) -> Vec<Attrib> {
-    let mut attribs = Vec::new();
-    while let Some((k2, t2)) = recs.get(*i) {
-        if k2 == "ATTRIB" {
-            let tt = T(t2);
-            // A multiline attribute has its text as embedded MTEXT after its own groups.
-            let (own, embedded) = split_embedded(t2);
-            let multiline = multiline_attrib(embedded, &common(&tt));
-            let own = T(own);
-            let mut text = text_from(&own);
-            if let Some(m) = &multiline {
-                text.value.clone_from(&m.read_as);
-            }
-            attribs.push(Attrib {
-                tag: own.s(2).unwrap_or_default(),
-                text,
-                invisible: own.i(70).unwrap_or(0) & 1 != 0,
-                constant: false,
-                prompt: String::new(),
-                props: attrib_props(&tt, ins_layer),
-                multiline,
-                modes: attrib_modes(own.0),
-            });
-            *i += 1;
-        } else {
-            if k2 == "SEQEND" {
-                *i += 1;
-            }
-            break;
-        }
-    }
-    attribs
-}
-
 fn parse_entities(
     recs: &[(String, Vec<Tag>)],
     d: &mut Drawing,
@@ -1221,17 +1134,92 @@ fn parse_entities(
         i += 1;
         match kind.as_str() {
             "POLYLINE" => {
-                let Some((c, k, more)) = polyline_entity(recs, &mut i, &t) else {
-                    *skipped = skipped.saturating_add(1);
-                    continue;
+                let flags = t.i(70).unwrap_or(0);
+                let mut pts: Vec<(Vec3, f64, f64, f64)> = Vec::new();
+                // Polyface face records (VERTEX 70 bit 128 without 64): vertex indices 71–74.
+                let mut faces: Vec<[i64; 4]> = Vec::new();
+                while let Some((k2, t2)) = recs.get(i) {
+                    if k2 == "VERTEX" {
+                        let tt = T(t2);
+                        let vflags = tt.i(70).unwrap_or(0);
+                        if vflags & 128 != 0 && vflags & 64 == 0 {
+                            faces.push([71, 72, 73, 74].map(|c| tt.i(c).unwrap_or(0)));
+                        } else if vflags & 16 == 0 {
+                            pts.push((tt.p(10), tt.fd(42, 0.0), tt.fd(40, 0.0), tt.fd(41, 0.0)));
+                        }
+                        i += 1;
+                    } else {
+                        if k2 == "SEQEND" {
+                            i += 1;
+                        }
+                        break;
+                    }
+                }
+                let c = common(&t);
+                let k = if flags & (16 | 64) != 0 {
+                    // Polyface (64) and polygon (16) meshes become 3D faces; the first takes the
+                    // polyline's place.
+                    let verts: Vec<Vec3> = pts.iter().map(|p| p.0).collect();
+                    let mut fs = if flags & 64 != 0 { polyface_faces(&verts, &faces) } else { mesh_faces(&verts, &t, flags) }
+                        .into_iter()
+                        .map(EntityKind::Face3d);
+                    let Some(first) = fs.next() else {
+                        *skipped = skipped.saturating_add(1);
+                        continue;
+                    };
+                    extra.extend(fs);
+                    first
+                } else if flags & 8 != 0 {
+                    EntityKind::Polyline3d(Polyline3d { points: pts.iter().map(|p| p.0).collect(), closed: flags & 1 != 0 })
+                } else {
+                    // A 2D polyline's vertices are in its OCS: mirrored like LWPOLYLINE.
+                    let m = if c.extrusion.z < 0.0 { -1.0 } else { 1.0 };
+                    EntityKind::LwPolyline(LwPolyline {
+                        vertices: pts
+                            .iter()
+                            .map(|p| PolyVertex { p: Vec2::new(m * p.0.x, p.0.y), bulge: m * p.1, start_width: p.2, end_width: p.3 })
+                            .collect(),
+                        closed: flags & 1 != 0,
+                        const_width: t.fd(40, 0.0).min(t.fd(41, 0.0)).max(0.0),
+                        elevation: t.p(10).z,
+                        plinegen: flags & 128 != 0,
+                    })
                 };
-                extra = more;
                 kindent = Some((c, k));
             }
             "INSERT" => {
                 if t.i(66) == Some(1) {
+                    let mut attribs = Vec::new();
                     let ins_layer = kindent.as_ref().map(|(c, _)| c.layer.clone()).unwrap_or_default();
-                    let attribs = insert_attribs(recs, &mut i, &ins_layer);
+                    while let Some((k2, t2)) = recs.get(i) {
+                        if k2 == "ATTRIB" {
+                            let tt = T(t2);
+                            // A multiline attribute has its text as embedded MTEXT after its own groups.
+                            let (own, embedded) = split_embedded(t2);
+                            let multiline = multiline_attrib(embedded, &common(&tt));
+                            let own = T(own);
+                            let mut text = text_from(&own);
+                            if let Some(m) = &multiline {
+                                text.value.clone_from(&m.read_as);
+                            }
+                            attribs.push(Attrib {
+                                tag: own.s(2).unwrap_or_default(),
+                                text,
+                                invisible: own.i(70).unwrap_or(0) & 1 != 0,
+                                constant: false,
+                                prompt: String::new(),
+                                props: attrib_props(&tt, &ins_layer),
+                                multiline,
+                                modes: attrib_modes(own.0),
+                            });
+                            i += 1;
+                        } else {
+                            if k2 == "SEQEND" {
+                                i += 1;
+                            }
+                            break;
+                        }
+                    }
                     if let Some((_, EntityKind::Insert(ins))) = kindent.as_mut() {
                         ins.attribs = attribs;
                     }
@@ -1700,13 +1688,6 @@ pub fn read(bytes: &[u8]) -> Result<Drawing> {
     read_budgeted(bytes, 4_000_000)
 }
 
-/// A block definition read from BLOCKS: name, base point, description, entities (owner, paper
-/// flag, entity) and block flags.
-type BlockDef = (String, Vec3, String, Vec<(Option<String>, bool, Entity)>, i64);
-
-/// A layout read from OBJECTS: name, tab order, paper block handle and page setup.
-type LayoutDef = (String, u32, String, PageSetup);
-
 /// Import DXF sections while sharing one materialized-table-cell budget across blocks and entity sections.
 fn read_budgeted(bytes: &[u8], mut table_cells_left: usize) -> Result<Drawing> {
     let tags = cadcraft_dxf::parse(bytes).map_err(|e| IoError::Format(e.to_string()))?;
@@ -1719,8 +1700,8 @@ fn read_budgeted(bytes: &[u8], mut table_cells_left: usize) -> Result<Drawing> {
     // A file without $INSUNITS declares no units (#1209); only new drawings take the template's.
     d.header.set_i64("INSUNITS", 0);
     let mut rx = Rx { pstyles: plot_style_names(&secs), ..Rx::default() };
-    let mut blocks: Vec<BlockDef> = Vec::new();
-    let mut layout_objs: Vec<LayoutDef> = Vec::new();
+    let mut blocks: Vec<(String, Vec3, String, Vec<(Option<String>, bool, Entity)>, i64)> = Vec::new();
+    let mut layout_objs: Vec<(String, u32, String, PageSetup)> = Vec::new();
     let mut entities = Vec::new();
     let mut objs = Objects::default();
     // Every handle another program's file already uses is taken before anything gets a new one:
@@ -1740,109 +1721,73 @@ fn read_budgeted(bytes: &[u8], mut table_cells_left: usize) -> Result<Drawing> {
         match s.name.as_str() {
             "HEADER" => header(&s.tags, &mut d),
             "TABLES" => tables(&s.tags, &mut d, &mut rx),
-            "BLOCKS" => blocks.extend(read_blocks(&s.tags, &mut d, &mut rx, &mut table_cells_left, &mut skipped)),
+            "BLOCKS" => {
+                let recs = records(&s.tags);
+                for (k, tg) in &recs {
+                    let t = T(tg);
+                    if k == "BLOCK" && t.i(70).unwrap_or(0) & 4 != 0 {
+                        rx.xref_paths.insert(t.s(2).unwrap_or_default().to_ascii_uppercase(), t.s(1).unwrap_or_default());
+                    }
+                }
+                let mut n = 0;
+                let mut i = 0;
+                while let Some((k, tg)) = recs.get(i) {
+                    if k == "BLOCK" {
+                        let t = T(tg);
+                        let name = t.s(2).unwrap_or_default();
+                        let base = t.p(10);
+                        let description = t.s(4).unwrap_or_default();
+                        // Block flags: 4 xref, 8 overlay.
+                        let xref = t.i(70).unwrap_or(0) & 12;
+                        let mut j = i + 1;
+                        while recs.get(j).is_some_and(|(k, _)| k != "ENDBLK") {
+                            j += 1;
+                        }
+                        let body = recs.get(i + 1..j).unwrap_or(&[]);
+                        let ents = parse_entities(body, &mut d, &mut rx, &mut n, &mut table_cells_left);
+                        blocks.push((name, base, description, ents, xref));
+                        i = j + 1;
+                    } else {
+                        // A record outside any BLOCK ... ENDBLK pair.
+                        if k != "ENDBLK" {
+                            n = n.saturating_add(1);
+                        }
+                        i += 1;
+                    }
+                }
+                count_skipped(&mut skipped, "BLOCKS", n);
+            }
             // A damaged file may split its entities over several ENTITIES sections (#865).
             "ENTITIES" => {
                 let mut n = 0;
                 entities.extend(parse_entities(&records(&s.tags), &mut d, &mut rx, &mut n, &mut table_cells_left));
                 count_skipped(&mut skipped, "ENTITIES", n);
             }
-            "OBJECTS" => read_objects(&s.tags, &mut objs, &mut layout_objs),
+            "OBJECTS" => {
+                for (k, tg) in records(&s.tags) {
+                    objs.add(&k, &tg);
+                    if k == "LAYOUT" {
+                        // Fields after the AcDbLayout marker (AcDbPlotSettings also has a code 1).
+                        let start = tg.iter().position(|x| x.code == 100 && x.str() == "AcDbLayout").unwrap_or(0);
+                        let tail = tg.get(start..).unwrap_or(&[]);
+                        let t = T(tail);
+                        // LAYOUT has two 330s: owner dict and the block record; take the last.
+                        let br = tg.iter().rfind(|x| x.code == 330).map(Tag::str).unwrap_or_default();
+                        let plot = T(tg.get(..start).unwrap_or(&[]));
+                        layout_objs.push((t.s(1).unwrap_or_default(), t.i(71).unwrap_or(0) as u32, br.to_ascii_uppercase(), page_setup(&plot)));
+                    }
+                }
+            }
             _ => {}
         }
     }
     // A file CADCraft wrote names its own next handle (#495): its table records and objects
     // are numbered above it and rebuilt on save, so following $HANDSEED would drift every save.
     let own_seed = objs.xrecord_text(crate::dxf_ext::HANDSEED_KEY).and_then(|t| Handle::parse_hex(t.trim()));
-    let (paper_block_for, first_layout) = setup_layouts(&mut d, &mut layout_objs, &rx);
-    place_blocks(&mut d, blocks, &mut rx, &paper_block_for, &first_layout);
-    place_entities(&mut d, entities, &rx, &paper_block_for, &first_layout);
-    apply_sortents(&mut d, &objs.sortents, &rx.brs, &paper_block_for, &first_layout);
-    objs.apply(&mut d, &rx);
-    crate::dxf_image::resolve(&secs, &mut d);
-    crate::dxf_mline::resolve(&secs, &mut d);
-    // Keep handles unique against the header's seed.
-    let seed = d.header.str("HANDSEED", "");
-    if let Some(h) = own_seed.or_else(|| Handle::parse_hex(&seed)) {
-        d.bump_handseed(Handle(h.0.saturating_sub(1)));
-    }
-    if d.layer("0").is_none() {
-        d.layers.insert(0, Layer::default());
-    }
-    crate::dxf_raw::read(&secs, &mut d);
-    d.skipped_records = skipped;
-    Ok(d)
-}
-
-/// Read the BLOCKS section: the xref paths of external blocks, then each block's entities.
-fn read_blocks(
-    tags: &[Tag],
-    d: &mut Drawing,
-    rx: &mut Rx,
-    table_cells_left: &mut usize,
-    skipped: &mut std::collections::BTreeMap<String, usize>,
-) -> Vec<BlockDef> {
-    let recs = records(tags);
-    for (k, tg) in &recs {
-        let t = T(tg);
-        if k == "BLOCK" && t.i(70).unwrap_or(0) & 4 != 0 {
-            rx.xref_paths.insert(t.s(2).unwrap_or_default().to_ascii_uppercase(), t.s(1).unwrap_or_default());
-        }
-    }
-    let mut blocks = Vec::new();
-    let mut n = 0;
-    let mut i = 0;
-    while let Some((k, tg)) = recs.get(i) {
-        if k == "BLOCK" {
-            let t = T(tg);
-            let name = t.s(2).unwrap_or_default();
-            let base = t.p(10);
-            let description = t.s(4).unwrap_or_default();
-            // Block flags: 4 xref, 8 overlay.
-            let xref = t.i(70).unwrap_or(0) & 12;
-            let mut j = i + 1;
-            while recs.get(j).is_some_and(|(k, _)| k != "ENDBLK") {
-                j += 1;
-            }
-            let body = recs.get(i + 1..j).unwrap_or(&[]);
-            let ents = parse_entities(body, d, rx, &mut n, table_cells_left);
-            blocks.push((name, base, description, ents, xref));
-            i = j + 1;
-        } else {
-            // A record outside any BLOCK ... ENDBLK pair.
-            if k != "ENDBLK" {
-                n = n.saturating_add(1);
-            }
-            i += 1;
-        }
-    }
-    count_skipped(skipped, "BLOCKS", n);
-    blocks
-}
-
-/// Read the OBJECTS section into `objs`, and each LAYOUT into `layout_objs`.
-fn read_objects(tags: &[Tag], objs: &mut Objects, layout_objs: &mut Vec<LayoutDef>) {
-    for (k, tg) in records(tags) {
-        objs.add(&k, &tg);
-        if k == "LAYOUT" {
-            // Fields after the AcDbLayout marker (AcDbPlotSettings also has a code 1).
-            let start = tg.iter().position(|x| x.code == 100 && x.str() == "AcDbLayout").unwrap_or(0);
-            let tail = tg.get(start..).unwrap_or(&[]);
-            let t = T(tail);
-            // LAYOUT has two 330s: owner dict and the block record; take the last.
-            let br = tg.iter().rfind(|x| x.code == 330).map(Tag::str).unwrap_or_default();
-            let plot = T(tg.get(..start).unwrap_or(&[]));
-            layout_objs.push((t.s(1).unwrap_or_default(), t.i(71).unwrap_or(0) as u32, br.to_ascii_uppercase(), page_setup(&plot)));
-        }
-    }
-}
-
-/// Add the drawing's layouts, and return the layout each paper-space block belongs to, and the
-/// layout that takes paper-space entities without an owner.
-fn setup_layouts(d: &mut Drawing, layout_objs: &mut [LayoutDef], rx: &Rx) -> (HashMap<String, String>, String) {
+    // Layouts.
     let mut paper_block_for: HashMap<String, String> = HashMap::new();
     layout_objs.sort_by_key(|l| l.1);
-    for (name, order, br, page) in layout_objs.iter() {
+    for (name, order, br, page) in &layout_objs {
         if name.eq_ignore_ascii_case("Model") {
             continue;
         }
@@ -1861,12 +1806,7 @@ fn setup_layouts(d: &mut Drawing, layout_objs: &mut [LayoutDef], rx: &Rx) -> (Ha
     let first_tab = d.layouts.iter().min_by_key(|l| l.tab_order).map(|l| l.name.clone());
     d.active_layout = active.clone().filter(|a| Some(a) != first_tab.as_ref());
     let first_layout = active.or_else(|| d.layouts.first().map(|l| l.name.clone())).unwrap_or_else(|| "Layout1".into());
-    (paper_block_for, first_layout)
-}
-
-/// Place the BLOCKS entities: model and paper space blocks go to their space, the rest become
-/// block definitions.
-fn place_blocks(d: &mut Drawing, blocks: Vec<BlockDef>, rx: &mut Rx, paper_block_for: &HashMap<String, String>, first_layout: &str) {
+    // Blocks: model/paper space blocks hold entities in newer files.
     for (name, base, description, ents, xref) in blocks {
         let up = name.to_ascii_uppercase();
         if up == "*MODEL_SPACE" {
@@ -1877,7 +1817,7 @@ fn place_blocks(d: &mut Drawing, blocks: Vec<BlockDef>, rx: &mut Rx, paper_block
             continue;
         }
         if up.starts_with("*PAPER_SPACE") {
-            let lname = paper_block_for.get(&up).cloned().unwrap_or_else(|| first_layout.to_string());
+            let lname = paper_block_for.get(&up).cloned().unwrap_or_else(|| first_layout.clone());
             if let Some(l) = d.layouts.iter_mut().find(|l| l.name == lname) {
                 for (_, _, e) in ents {
                     l.entities.push(e);
@@ -1917,22 +1857,13 @@ fn place_blocks(d: &mut Drawing, blocks: Vec<BlockDef>, rx: &mut Rx, paper_block
         }
         d.blocks.insert(name, std::sync::Arc::new(b));
     }
-}
-
-/// Place the ENTITIES section: model space, or paper space when flagged (67=1).
-fn place_entities(
-    d: &mut Drawing,
-    entities: Vec<(Option<String>, bool, Entity)>,
-    rx: &Rx,
-    paper_block_for: &HashMap<String, String>,
-    first_layout: &str,
-) {
+    // ENTITIES section: model space, or paper space when flagged (67=1).
     for (owner, paper, e) in entities {
         d.ensure_layer(&e.common.layer);
         let owner_name = owner.and_then(|o| rx.brs.get(&o.trim().to_ascii_uppercase()).cloned()).map(|n| n.to_ascii_uppercase());
         let to_paper = paper || owner_name.as_deref().is_some_and(|n| n.starts_with("*PAPER_SPACE"));
         if to_paper {
-            let lname = owner_name.and_then(|n| paper_block_for.get(&n).cloned()).unwrap_or_else(|| first_layout.to_string());
+            let lname = owner_name.and_then(|n| paper_block_for.get(&n).cloned()).unwrap_or_else(|| first_layout.clone());
             if let Some(l) = d.layouts.iter_mut().find(|l| l.name == lname) {
                 l.entities.push(e);
             }
@@ -1940,6 +1871,21 @@ fn place_entities(
             d.model.push(e);
         }
     }
+    apply_sortents(&mut d, &objs.sortents, &rx.brs, &paper_block_for, &first_layout);
+    objs.apply(&mut d, &rx);
+    crate::dxf_image::resolve(&secs, &mut d);
+    crate::dxf_mline::resolve(&secs, &mut d);
+    // Keep handles unique against the header's seed.
+    let seed = d.header.str("HANDSEED", "");
+    if let Some(h) = own_seed.or_else(|| Handle::parse_hex(&seed)) {
+        d.bump_handseed(Handle(h.0.saturating_sub(1)));
+    }
+    if d.layer("0").is_none() {
+        d.layers.insert(0, Layer::default());
+    }
+    crate::dxf_raw::read(&secs, &mut d);
+    d.skipped_records = skipped;
+    Ok(d)
 }
 
 fn count_skipped(skipped: &mut std::collections::BTreeMap<String, usize>, section: &str, n: usize) {
@@ -2108,7 +2054,13 @@ impl Objects {
         Some(text)
     }
 
-    fn apply_table_styles(&self, d: &mut Drawing) {
+    fn apply(self, d: &mut Drawing, rx: &Rx) {
+        if let Some(v) = self.wipeout_frame {
+            d.header.set_i64("WIPEOUTFRAME", v);
+        }
+        if let Some(style) = self.xrecord_text(crate::dxf_ext::MLEADER_STYLE_KEY).filter(|s| !s.trim().is_empty()) {
+            d.header.set_str("CMLEADERSTYLE", &style);
+        }
         // Table styles (named by their ACAD_TABLESTYLE dictionary entries).
         for (h, tags) in &self.table_styles {
             let Some(name) = self.names.get(h).filter(|n| !n.is_empty()) else { continue };
@@ -2118,9 +2070,6 @@ impl Objects {
                 None => d.table_styles.push(st),
             }
         }
-    }
-
-    fn apply_table_style_fixes(&self, d: &mut Drawing, rx: &Rx) {
         for (h, sh) in &rx.table_style_fix {
             let name = self.names.get(sh).cloned();
             // A table from another writer has no scale of its own: its text height is its
@@ -2141,61 +2090,6 @@ impl Objects {
                 }
             });
         }
-    }
-
-    fn apply_mleader_styles(&self, d: &mut Drawing, rx: &Rx) {
-        // Multileader styles (named by their ACAD_MLEADERSTYLE dictionary entries).
-        for (h, tags) in &self.mleader_styles {
-            let Some(name) = self.names.get(h).filter(|n| !n.is_empty()) else { continue };
-            let t = T(tags);
-            let def = MLeaderStyle::default();
-            let num = |code: i32, d: f64, min: f64| t.f(code).filter(|v| v.is_finite() && *v >= min).unwrap_or(d);
-            let text_style = t.s(342).and_then(|sh| rx.styles.get(&sh.trim().to_ascii_uppercase()).cloned()).filter(|n| !n.is_empty());
-            let st = MLeaderStyle {
-                name: name.clone(),
-                arrow_size: num(44, def.arrow_size, 0.0),
-                text_height: t.f(45).filter(|v| v.is_finite() && *v > 0.0).unwrap_or(def.text_height),
-                landing_gap: num(42, def.landing_gap, 0.0),
-                dogleg: num(43, def.dogleg, 0.0),
-                text_style: text_style.unwrap_or(def.text_style),
-                annotative: t.i(296).unwrap_or(0) != 0,
-            };
-            match d.mleader_styles.iter_mut().find(|s| s.name.eq_ignore_ascii_case(name)) {
-                Some(x) => *x = st,
-                None => d.mleader_styles.push(st),
-            }
-        }
-    }
-
-    fn apply_groups(&self, d: &mut Drawing) {
-        // Groups (named by their ACAD_GROUP dictionary entries); members that exist.
-        for (h, tags) in &self.groups {
-            let Some(name) = self.names.get(h).filter(|n| !n.is_empty()) else { continue };
-            let t = T(tags);
-            let members: Vec<Handle> = tags
-                .iter()
-                .filter(|x| x.code == 340)
-                .filter_map(|x| Handle::parse_hex(&x.str()))
-                .filter(|m| d.entity(*m).is_some())
-                .take(MAX_OBJECTS)
-                .collect();
-            let g = Group { name: name.clone(), description: t.s(300).unwrap_or_default(), selectable: t.i(71).unwrap_or(1) != 0, members };
-            match d.groups.iter_mut().find(|x| x.name.eq_ignore_ascii_case(name)) {
-                Some(x) => *x = g,
-                None => d.groups.push(g),
-            }
-        }
-    }
-
-    fn apply(self, d: &mut Drawing, rx: &Rx) {
-        if let Some(v) = self.wipeout_frame {
-            d.header.set_i64("WIPEOUTFRAME", v);
-        }
-        if let Some(style) = self.xrecord_text(crate::dxf_ext::MLEADER_STYLE_KEY).filter(|s| !s.trim().is_empty()) {
-            d.header.set_str("CMLEADERSTYLE", &style);
-        }
-        self.apply_table_styles(d);
-        self.apply_table_style_fixes(d, rx);
         // Parametric constraints and parameters.
         if let Some((c, p)) = self.xrecord_text(crate::dxf_ext::CONSTRAINTS_KEY).and_then(|t| crate::dxf_ext::parse_constraints(&t)) {
             d.constraints = c;
@@ -2219,14 +2113,50 @@ impl Objects {
         if let Some(tables) = self.xrecord_text(crate::dxf_ext::PLOT_STYLES_KEY).and_then(|t| crate::dxf_ext::parse_plot_styles(&t)) {
             d.plot_style_tables = tables;
         }
-        self.apply_mleader_styles(d, rx);
+        // Multileader styles (named by their ACAD_MLEADERSTYLE dictionary entries).
+        for (h, tags) in &self.mleader_styles {
+            let Some(name) = self.names.get(h).filter(|n| !n.is_empty()) else { continue };
+            let t = T(tags);
+            let def = MLeaderStyle::default();
+            let num = |code: i32, d: f64, min: f64| t.f(code).filter(|v| v.is_finite() && *v >= min).unwrap_or(d);
+            let text_style = t.s(342).and_then(|sh| rx.styles.get(&sh.trim().to_ascii_uppercase()).cloned()).filter(|n| !n.is_empty());
+            let st = MLeaderStyle {
+                name: name.clone(),
+                arrow_size: num(44, def.arrow_size, 0.0),
+                text_height: t.f(45).filter(|v| v.is_finite() && *v > 0.0).unwrap_or(def.text_height),
+                landing_gap: num(42, def.landing_gap, 0.0),
+                dogleg: num(43, def.dogleg, 0.0),
+                text_style: text_style.unwrap_or(def.text_style),
+                annotative: t.i(296).unwrap_or(0) != 0,
+            };
+            match d.mleader_styles.iter_mut().find(|s| s.name.eq_ignore_ascii_case(name)) {
+                Some(x) => *x = st,
+                None => d.mleader_styles.push(st),
+            }
+        }
         crate::dxf_mleader::apply(d, &rx.mleader_fix, &self.names);
         for (name, view) in &self.layout_views {
             if let Some(l) = d.layouts.iter_mut().find(|l| l.name == *name) {
                 l.view = Some(*view);
             }
         }
-        self.apply_groups(d);
+        // Groups (named by their ACAD_GROUP dictionary entries); members that exist.
+        for (h, tags) in &self.groups {
+            let Some(name) = self.names.get(h).filter(|n| !n.is_empty()) else { continue };
+            let t = T(tags);
+            let members: Vec<Handle> = tags
+                .iter()
+                .filter(|x| x.code == 340)
+                .filter_map(|x| Handle::parse_hex(&x.str()))
+                .filter(|m| d.entity(*m).is_some())
+                .take(MAX_OBJECTS)
+                .collect();
+            let g = Group { name: name.clone(), description: t.s(300).unwrap_or_default(), selectable: t.i(71).unwrap_or(1) != 0, members };
+            match d.groups.iter_mut().find(|x| x.name.eq_ignore_ascii_case(name)) {
+                Some(x) => *x = g,
+                None => d.groups.push(g),
+            }
+        }
         // Standard associativity, for dimensions without CADCraft's exact links.
         for tags in &self.dimassocs {
             dimassoc(d, tags);

crates/io/src/pdf.rs

@@ -17,7 +17,7 @@ use std::fmt::Write as _;
 use cadcraft_color::Rgb;
 use cadcraft_doc::{Drawing, Handle, PageSetup, Space};
 use cadcraft_geom::{Bounds2, Vec2};
-use cadcraft_render::{DPrim, Kind, Sheet, clip, paper};
+use cadcraft_render::{Kind, Sheet, clip, paper};
 use serde_json::Value;
 
 use craft_pdf::write::backend as kr;
@@ -808,7 +808,7 @@ fn krilla_failure(e: KrillaError) -> Failure {
 /// as text instead: the glyph at font size 1 under its glyph matrix (the matrix axes are one
 /// em).
 fn marks(s: &mut Surface<'_>, p: &SheetPage, groups: &Groups, fonts: &mut fonts::Fonts) -> std::result::Result<(), Failure> {
-    let list = &p.list;
+    let (list, map) = (&p.list, &p.map);
     let texts = fonts::texts(list);
     let white = Rgb(255, 255, 255);
     let mut batch: Option<(StrokeStyle, PathBuilder)> = None;
@@ -829,126 +829,100 @@ fn marks(s: &mut Surface<'_>, p: &SheetPage, groups: &Groups, fonts: &mut fonts:
         let t = if prim.kind == Kind::Mask { 0 } else { prim.transparency.min(cadcraft_render::MAX_TRANSPARENCY) };
         let w = f64::from(prim.lw) * PT_PER_MM;
         let w = if w.is_finite() && w > 0.0 { w.min(100.0) } else { 0.0 };
-        let m = Mark { rgb, t, w };
         match prim.kind {
-            Kind::Polyline | Kind::Infinite { .. } => polyline(s, &mut batch, p, prim, raw, m),
+            Kind::Polyline | Kind::Infinite { .. } => {
+                let pts: Vec<Vec2> = match prim.kind {
+                    Kind::Infinite { ray } => match (raw.first(), raw.get(1)) {
+                        (Some(base), Some(dir)) => {
+                            let a = map.pt(*base);
+                            let dir_pt = map.pt(*base + *dir) - a;
+                            match clip::clip_infinite(a, dir_pt, ray, &p.clip_pt) {
+                                Some((x, y)) => vec![x, y],
+                                None => continue,
+                            }
+                        }
+                        _ => continue,
+                    },
+                    _ => raw.iter().map(|q| map.pt(*q)).collect(),
+                };
+                if pts.len() < 2 {
+                    continue;
+                }
+                // With a vertex out of range, keep the pieces inside the plot area, widened so
+                // a wide stroke just outside it still shows its edge.
+                let runs = if pts.iter().all(|q| coord(*q).is_some()) { vec![pts] } else { clip::clip_polyline(&pts, &p.clip_pt.expand(w + 1.0)) };
+                let style = StrokeStyle { rgb, width: w as f32, transparency: t };
+                if t > 0 || batch.as_ref().is_some_and(|(b, _)| *b != style) {
+                    flush(s, &mut batch);
+                }
+                for run in runs {
+                    let Some(pts) = run.iter().map(|q| coord(*q)).collect::<Option<Vec<_>>>() else { continue };
+                    // The writer leaves out a path without extent, so a zero-length line is
+                    // painted as the round-cap dot its stroke would make.
+                    if let Some(&(x, y)) = pts.first()
+                        && pts.iter().all(|q| *q == (x, y))
+                    {
+                        flush(s, &mut batch);
+                        let d = if w > 0.0 { w as f32 } else { HAIRLINE_DOT_PT };
+                        if let Some(path) = circle_path(x, y, d / 2.0) {
+                            fill_path(s, &path, rgb, t);
+                        }
+                        continue;
+                    }
+                    let (_, pb) = batch.get_or_insert_with(|| (style, PathBuilder::new()));
+                    for (j, (x, y)) in pts.iter().enumerate() {
+                        if j == 0 {
+                            pb.move_to(*x, *y);
+                        } else {
+                            pb.line_to(*x, *y);
+                        }
+                    }
+                }
+            }
             Kind::Tris | Kind::Mask => {
                 flush(s, &mut batch);
                 // A wipeout's mask is paper white.
-                let m = if prim.kind == Kind::Mask { Mark { rgb: white, ..m } } else { m };
-                let text_font =
-                    u32::try_from(i).ok().and_then(|i| texts.get(&i).copied()).and_then(|text| fonts.font(&text.glyph.face).map(|font| (text, font)));
-                match text_font {
-                    Some((text, font)) => glyph(s, font, text, &p.map, m.rgb, m.t),
-                    None => fill_tris(s, p, raw, m.rgb, m.t),
+                let rgb = if prim.kind == Kind::Mask { white } else { rgb };
+                if let Some(text) = u32::try_from(i).ok().and_then(|i| texts.get(&i))
+                    && let Some(font) = fonts.font(&text.glyph.face)
+                {
+                    glyph(s, font, text, map, rgb, t);
+                    continue;
+                }
+                let mapped: Vec<Vec2> = raw.iter().map(|q| map.pt(*q)).collect();
+                // With a vertex out of range, keep the parts inside the plot area.
+                let tris = if mapped.iter().all(|q| coord(*q).is_some()) { mapped } else { clip::clip_triangles(&mapped, &p.clip_pt) };
+                let mut pb = PathBuilder::new();
+                for tri in tris.as_chunks::<3>().0 {
+                    let Some(v) = tri.iter().map(|q| coord(*q)).collect::<Option<Vec<_>>>() else { continue };
+                    for (j, (x, y)) in v.iter().enumerate() {
+                        if j == 0 {
+                            pb.move_to(*x, *y);
+                        } else {
+                            pb.line_to(*x, *y);
+                        }
+                    }
+                    pb.close();
+                }
+                if let Some(path) = pb.finish() {
+                    fill_path(s, &path, rgb, t);
+                }
+            }
+            Kind::Point => {
+                let Some(q) = raw.first() else { continue };
+                flush(s, &mut batch);
+                let half = (w.max(0.5)) / 2.0;
+                let c = map.pt(*q);
+                if let Some(path) = rect_path(c - Vec2::new(half, half), c + Vec2::new(half, half)) {
+                    fill_path(s, &path, rgb, t);
                 }
             }
-            Kind::Point => point(s, &mut batch, &p.map, raw, m),
         }
     }
     flush(s, &mut batch);
     layer_changed(s, layer, None)
 }
 
-/// How a primitive is painted: colour, transparency (percent) and lineweight (points).
-#[derive(Clone, Copy)]
-struct Mark {
-    rgb: Rgb,
-    t: u8,
-    w: f64,
-}
-
-/// Stroke a polyline or infinite line, clipped to the plot area, into the open batch.
-fn polyline(s: &mut Surface<'_>, batch: &mut Option<(StrokeStyle, PathBuilder)>, p: &SheetPage, prim: &DPrim, raw: &[Vec2], m: Mark) {
-    let Some(pts) = polyline_points(prim, raw, &p.map, &p.clip_pt) else { return };
-    if pts.len() < 2 {
-        return;
-    }
-    // With a vertex out of range, keep the pieces inside the plot area, widened so
-    // a wide stroke just outside it still shows its edge.
-    let runs = if pts.iter().all(|q| coord(*q).is_some()) { vec![pts] } else { clip::clip_polyline(&pts, &p.clip_pt.expand(m.w + 1.0)) };
-    let style = StrokeStyle { rgb: m.rgb, width: m.w as f32, transparency: m.t };
-    if m.t > 0 || batch.as_ref().is_some_and(|(b, _)| *b != style) {
-        flush(s, batch);
-    }
-    for run in runs {
-        stroke_run(s, batch, &run, style, m);
-    }
-}
-
-/// The page points of a polyline, or of an infinite line clipped to the plot area; `None` when
-/// there is nothing to draw.
-fn polyline_points(prim: &DPrim, raw: &[Vec2], map: &Map, clip_pt: &Bounds2) -> Option<Vec<Vec2>> {
-    match prim.kind {
-        Kind::Infinite { ray } => {
-            let (Some(base), Some(dir)) = (raw.first(), raw.get(1)) else { return None };
-            let a = map.pt(*base);
-            let dir_pt = map.pt(*base + *dir) - a;
-            let (x, y) = clip::clip_infinite(a, dir_pt, ray, clip_pt)?;
-            Some(vec![x, y])
-        }
-        _ => Some(raw.iter().map(|q| map.pt(*q)).collect()),
-    }
-}
-
-/// Add one run of a polyline to the batch, or paint it as a dot when it has no extent.
-fn stroke_run(s: &mut Surface<'_>, batch: &mut Option<(StrokeStyle, PathBuilder)>, run: &[Vec2], style: StrokeStyle, m: Mark) {
-    let Some(pts) = run.iter().map(|q| coord(*q)).collect::<Option<Vec<_>>>() else { return };
-    // The writer leaves out a path without extent, so a zero-length line is
-    // painted as the round-cap dot its stroke would make.
-    if let Some(&(x, y)) = pts.first()
-        && pts.iter().all(|q| *q == (x, y))
-    {
-        flush(s, batch);
-        let d = if m.w > 0.0 { m.w as f32 } else { HAIRLINE_DOT_PT };
-        if let Some(path) = circle_path(x, y, d / 2.0) {
-            fill_path(s, &path, m.rgb, m.t);
-        }
-        return;
-    }
-    let (_, pb) = batch.get_or_insert_with(|| (style, PathBuilder::new()));
-    for (j, (x, y)) in pts.iter().enumerate() {
-        if j == 0 {
-            pb.move_to(*x, *y);
-        } else {
-            pb.line_to(*x, *y);
-        }
-    }
-}
-
-/// Fill a set of triangles, clipped to the plot area.
-fn fill_tris(s: &mut Surface<'_>, p: &SheetPage, raw: &[Vec2], rgb: Rgb, t: u8) {
-    let mapped: Vec<Vec2> = raw.iter().map(|q| p.map.pt(*q)).collect();
-    // With a vertex out of range, keep the parts inside the plot area.
-    let tris = if mapped.iter().all(|q| coord(*q).is_some()) { mapped } else { clip::clip_triangles(&mapped, &p.clip_pt) };
-    let mut pb = PathBuilder::new();
-    for tri in tris.as_chunks::<3>().0 {
-        let Some(v) = tri.iter().map(|q| coord(*q)).collect::<Option<Vec<_>>>() else { continue };
-        for (j, (x, y)) in v.iter().enumerate() {
-            if j == 0 {
-                pb.move_to(*x, *y);
-            } else {
-                pb.line_to(*x, *y);
-            }
-        }
-        pb.close();
-    }
-    if let Some(path) = pb.finish() {
-        fill_path(s, &path, rgb, t);
-    }
-}
-
-/// Paint a point marker: a small square at the point.
-fn point(s: &mut Surface<'_>, batch: &mut Option<(StrokeStyle, PathBuilder)>, map: &Map, raw: &[Vec2], m: Mark) {
-    let Some(q) = raw.first() else { return };
-    flush(s, batch);
-    let half = (m.w.max(0.5)) / 2.0;
-    let c = map.pt(*q);
-    if let Some(path) = rect_path(c - Vec2::new(half, half), c + Vec2::new(half, half)) {
-        fill_path(s, &path, m.rgb, m.t);
-    }
-}
-
 /// Write one glyph as text in its embedded font: font size 1, placed by the glyph's matrix (one
 /// em along each axis). A glyph whose matrix is out of range or collapses is left out.
 fn glyph(s: &mut Surface<'_>, font: kr::text::Font, t: &cadcraft_render::PlotText, map: &Map, rgb: Rgb, transparency: u8) {

crates/render/src/hatch.rs

@@ -465,6 +465,26 @@ impl Family<'_> {
         self.origin + p.rotate(self.ang)
     }
 
+    /// The range of the lines swept, in this frame: the boundary's extent, cut to the view's
+    /// when there is one, and the view's x extent that spans are cut to. Spans are cut to the
+    /// view's extent only: they already lie within the boundary, and cutting them to its extent
+    /// too would move an end that sits on a boundary corner by a rounding error, so a view
+    /// covering the hatch would change its lines. `None` when the view misses the boundary.
+    fn lines_range(&self, bb: &Bounds2, view: Option<&Bounds2>) -> Option<(Vec2, Vec2, Option<(f64, f64)>)> {
+        let (mut lo, mut hi) = (bb.min, bb.max);
+        let mut span_cut = None;
+        if let Some(v) = view {
+            let vb = Bounds2::from_points(v.corners().iter().map(|p| self.to_local(*p)));
+            if vb.is_empty() || !vb.intersects(bb) {
+                return None;
+            }
+            lo = Vec2::new(lo.x.max(vb.min.x), lo.y.max(vb.min.y));
+            hi = Vec2::new(hi.x.min(vb.max.x), hi.y.min(vb.max.y));
+            span_cut = Some((vb.min.x, vb.max.x));
+        }
+        Some((lo, hi, span_cut))
+    }
+
     /// Intersect a pattern family with boundary loops, respecting view, output, cancellation, and shared dash-work limits.
     fn sweep(&self, loops: &[Vec<Vec2>], px: f64, view: Option<&Bounds2>, cancel: Option<&AtomicBool>, out: &mut Vec<Vec<Vec2>>, work: &mut u64) {
         let local: Vec<Vec<Vec2>> = loops.iter().map(|l| l.iter().map(|p| self.to_local(*p)).collect()).collect();
@@ -472,21 +492,7 @@ impl Family<'_> {
         if bb.is_empty() {
             return;
         }
-        // The lines swept: the boundary's extent, cut to the view's (its corners in this frame)
-        // when there is one. Spans are cut to the view's extent only: they already lie within the
-        // boundary, and cutting them to its extent too would move an end that sits on a boundary
-        // corner by a rounding error, so a view covering the hatch would change its lines.
-        let (mut lo, mut hi) = (bb.min, bb.max);
-        let mut span_cut = None;
-        if let Some(v) = view {
-            let vb = Bounds2::from_points(v.corners().iter().map(|p| self.to_local(*p)));
-            if vb.is_empty() || !vb.intersects(&bb) {
-                return;
-            }
-            lo = Vec2::new(lo.x.max(vb.min.x), lo.y.max(vb.min.y));
-            hi = Vec2::new(hi.x.min(vb.max.x), hi.y.min(vb.max.y));
-            span_cut = Some((vb.min.x, vb.max.x));
-        }
+        let Some((lo, hi, span_cut)) = self.lines_range(&bb, view) else { return };
         let shift_per_line = self.delta.rotate(-self.ang).x;
         let k0 = (lo.y / self.spacing).floor() as i64;
         let k1 = (hi.y / self.spacing).ceil() as i64;
@@ -504,17 +510,7 @@ impl Family<'_> {
                 return;
             }
             let y = k as f64 * self.spacing;
-            let mut xs: Vec<f64> = Vec::new();
-            for l in &local {
-                let n = l.len();
-                for i in 0..n {
-                    let (Some(a), Some(b)) = (l.get(i), l.get((i + 1) % n)) else { continue };
-                    if (a.y > y) != (b.y > y) {
-                        xs.push(a.x + (b.x - a.x) * (y - a.y) / (b.y - a.y));
-                    }
-                }
-            }
-            xs.sort_by(f64::total_cmp);
+            let xs = crossings(&local, y);
             let offset = shift_per_line * k as f64;
             for span in xs.chunks(2) {
                 let [x0, x1] = span else { continue };
@@ -565,6 +561,22 @@ impl Family<'_> {
     }
 }
 
+/// The x positions where the boundary loops cross the horizontal line at `y`, in order.
+fn crossings(local: &[Vec<Vec2>], y: f64) -> Vec<f64> {
+    let mut xs: Vec<f64> = Vec::new();
+    for l in local {
+        let n = l.len();
+        for i in 0..n {
+            let (Some(a), Some(b)) = (l.get(i), l.get((i + 1) % n)) else { continue };
+            if (a.y > y) != (b.y > y) {
+                xs.push(a.x + (b.x - a.x) * (y - a.y) / (b.y - a.y));
+            }
+        }
+    }
+    xs.sort_by(f64::total_cmp);
+    xs
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

crates/ui-egui/src/canvas/compare.rs

@@ -4,7 +4,8 @@
 
 use std::sync::Arc;
 
-use cadcraft_engine::doc::Handle;
+use cadcraft_engine::cmd::file::compare::Comparison;
+use cadcraft_engine::doc::{Drawing, Handle};
 use cadcraft_render::DisplayList;
 use egui::{Rect, RichText, Stroke, vec2};
 use serde_json::json;
@@ -29,6 +30,23 @@ fn id() -> egui::Id {
     egui::Id::unique("cadcraft-compare-overlay")
 }
 
+/// The display lists of the differences for this frame: the stored ones when they still match
+/// `key`, otherwise rebuilt at zoom `scale` and stored.
+fn cache_for(ctx: &egui::Context, key: (u64, u64, usize, usize, i64), doc: &Drawing, c: &Comparison, scale: f64) -> Cache {
+    let mut cache: Cache = ctx.data_mut(|d| d.get_temp(id())).unwrap_or_default();
+    if cache.key != key || cache.ours.is_none() {
+        let opts = cadcraft_render::Options { tolerance: 0.5 / scale.max(1e-12), ..Default::default() };
+        let ours: Vec<Handle> = c.added.iter().copied().chain(c.changed.iter().map(|(a, _)| *a)).take(MAX_DRAWN).collect();
+        let theirs: Vec<Handle> = c.removed.iter().copied().chain(c.changed.iter().map(|(_, b)| *b)).take(MAX_DRAWN).collect();
+        let list = |d: &Drawing, hs: &[Handle]| {
+            Arc::new(cadcraft_render::build_entities(d, hs.iter().filter_map(|h| d.entity(*h)).map(|e| e.as_ref()), &opts))
+        };
+        cache = Cache { key, ours: Some(list(doc, &ours)), theirs: Some(list(&c.other, &theirs)) };
+        ctx.data_mut(|d| d.insert_temp(id(), cache.clone()));
+    }
+    cache
+}
+
 /// Draw the comparison over the canvas when it was made for the drawing and tab shown.
 pub(super) fn paint(app: &mut CadApp, ctx: &egui::Context, p: &egui::Painter, xf: &Xf, rect: Rect) {
     let t = Tokens::get();
@@ -38,17 +56,7 @@ pub(super) fn paint(app: &mut CadApp, ctx: &egui::Context, p: &egui::Painter, xf
     p.rect_filled(rect, 0.0, t.canvas.gamma_multiply(0.75));
     let band = xf.scale.max(1e-300).log2().round() as i64;
     let key = (st.uid, st.revision, Arc::as_ptr(&c.other) as usize, c.differences(), band);
-    let mut cache: Cache = ctx.data_mut(|d| d.get_temp(id())).unwrap_or_default();
-    if cache.key != key || cache.ours.is_none() {
-        let opts = cadcraft_render::Options { tolerance: 0.5 / xf.scale.max(1e-12), ..Default::default() };
-        let ours: Vec<Handle> = c.added.iter().copied().chain(c.changed.iter().map(|(a, _)| *a)).take(MAX_DRAWN).collect();
-        let theirs: Vec<Handle> = c.removed.iter().copied().chain(c.changed.iter().map(|(_, b)| *b)).take(MAX_DRAWN).collect();
-        let list = |d: &cadcraft_engine::doc::Drawing, hs: &[Handle]| {
-            Arc::new(cadcraft_render::build_entities(d, hs.iter().filter_map(|h| d.entity(*h)).map(|e| e.as_ref()), &opts))
-        };
-        cache = Cache { key, ours: Some(list(&st.doc, &ours)), theirs: Some(list(&c.other, &theirs)) };
-        ctx.data_mut(|d| d.insert_temp(id(), cache.clone()));
-    }
+    let cache = cache_for(ctx, key, &st.doc, c, xf.scale);
     for (list, color) in [(&cache.theirs, t.compare_other), (&cache.ours, t.compare_this)] {
         if let Some(l) = list {
             let all: Vec<usize> = (0..l.prims.len()).collect();

crates/ui-egui/src/options/dialog.rs

@@ -217,73 +217,15 @@ fn display(app: &CadApp, ui: &mut egui::Ui, changes: &mut Map<String, Value>) {
 /// Files tab: save format and default version, new-drawing units, autosave interval and autosave file location; edits accumulate in `changes`.
 fn files(app: &CadApp, ui: &mut egui::Ui, changes: &mut Map<String, Value>) {
     grid(ui, "options_files", |ui| {
-        ui.label(crate::tl!("Save new drawings as"));
-        ui.horizontal(|ui| {
-            for f in crate::SaveFormat::ALL {
-                let label = match f {
-                    crate::SaveFormat::Dxf => crate::tl!("DXF"),
-                    crate::SaveFormat::Dwg => crate::tl!("DWG"),
-                };
-                if ui.radio(app.ui.save_format == f, label).clicked() && app.ui.save_format != f {
-                    changes.insert("saveFormat".into(), json!(f.as_str()));
-                }
-            }
-        });
+        save_format_row(ui, app, changes);
         ui.end_row();
-
-        let version_caption = ui.label(crate::tl!("Default save version"));
-        let current = crate::SaveVersion::parse(&app.ui.save_version).unwrap_or_default();
-        let mut version = current;
-        let version_combo = egui::ComboBox::from_id_salt("options_save_version").selected_text(version.year()).show_ui(ui, |ui| {
-            for v in crate::SaveVersion::ALL {
-                ui.selectable_value(&mut version, v, v.year());
-            }
-        });
-        version_combo.response.labelled_by(version_caption.id);
-        if version != current {
-            changes.insert("saveVersion".into(), json!(version.year()));
-        }
+        save_version_row(ui, app, changes);
         ui.end_row();
-
-        ui.label(crate::tl!("Units of new drawings"));
-        ui.horizontal(|ui| {
-            let metric = app.session.settings.measureinit;
-            if ui.radio(!metric, crate::tl!("Imperial (inches)")).clicked() && metric {
-                changes.insert("MEASUREINIT".into(), json!(0));
-            }
-            if ui.radio(metric, crate::tl!("Metric (millimetres)")).clicked() && !metric {
-                changes.insert("MEASUREINIT".into(), json!(1));
-            }
-        });
+        units_row(ui, app, changes);
         ui.end_row();
-
-        let minutes_caption = ui.label(crate::tl!("Automatic save every"));
-        let mut minutes = cadcraft_engine::autosave::savetime();
-        let max = cadcraft_engine::autosave::MAX_SAVETIME;
-        if ui
-            .add(egui::DragValue::new(&mut minutes).range(0..=max).suffix(format!(" {}", crate::tl!("min"))))
-            .labelled_by(minutes_caption.id)
-            .changed()
-        {
-            changes.insert("SAVETIME".into(), json!(minutes));
-        }
+        autosave_row(ui, changes);
         ui.end_row();
-
-        let savefile_label = ui.label(crate::tl!("Automatic save file location"));
-        // Edited as text; the folder changes when the field loses focus.
-        let id = egui::Id::unique("cc_options_savefilepath");
-        let current = cadcraft_engine::autosave::savefilepath();
-        let mut path = ui.data(|d| d.get_temp::<String>(id)).unwrap_or_else(|| current.clone());
-        let r = ui.add(egui::TextEdit::singleline(&mut path).desired_width(330.0)).labelled_by(savefile_label.id);
-        if r.changed() {
-            ui.data_mut(|d| d.insert_temp(id, path.clone()));
-        }
-        if r.lost_focus() {
-            ui.data_mut(|d| d.remove::<String>(id));
-            if path.trim() != current {
-                changes.insert("SAVEFILEPATH".into(), json!(path.trim()));
-            }
-        }
+        savefile_row(ui, changes);
         ui.end_row();
     });
     hint(ui, crate::tl!("New and the first drawing at startup use these units unless a default template is set (QNEWTEMPLATE)."));
@@ -291,6 +233,76 @@ fn files(app: &CadApp, ui: &mut egui::Ui, changes: &mut Map<String, Value>) {
     hint(ui, crate::tl!("Drawings with no file yet are saved in the default version. 0 minutes turns automatic save off."));
 }
 
+fn save_format_row(ui: &mut egui::Ui, app: &CadApp, changes: &mut Map<String, Value>) {
+    ui.label(crate::tl!("Save new drawings as"));
+    ui.horizontal(|ui| {
+        for f in crate::SaveFormat::ALL {
+            let label = match f {
+                crate::SaveFormat::Dxf => crate::tl!("DXF"),
+                crate::SaveFormat::Dwg => crate::tl!("DWG"),
+            };
+            if ui.radio(app.ui.save_format == f, label).clicked() && app.ui.save_format != f {
+                changes.insert("saveFormat".into(), json!(f.as_str()));
+            }
+        }
+    });
+}
+
+fn save_version_row(ui: &mut egui::Ui, app: &CadApp, changes: &mut Map<String, Value>) {
+    let version_caption = ui.label(crate::tl!("Default save version"));
+    let current = crate::SaveVersion::parse(&app.ui.save_version).unwrap_or_default();
+    let mut version = current;
+    let version_combo = egui::ComboBox::from_id_salt("options_save_version").selected_text(version.year()).show_ui(ui, |ui| {
+        for v in crate::SaveVersion::ALL {
+            ui.selectable_value(&mut version, v, v.year());
+        }
+    });
+    version_combo.response.labelled_by(version_caption.id);
+    if version != current {
+        changes.insert("saveVersion".into(), json!(version.year()));
+    }
+}
+
+fn units_row(ui: &mut egui::Ui, app: &CadApp, changes: &mut Map<String, Value>) {
+    ui.label(crate::tl!("Units of new drawings"));
+    ui.horizontal(|ui| {
+        let metric = app.session.settings.measureinit;
+        if ui.radio(!metric, crate::tl!("Imperial (inches)")).clicked() && metric {
+            changes.insert("MEASUREINIT".into(), json!(0));
+        }
+        if ui.radio(metric, crate::tl!("Metric (millimetres)")).clicked() && !metric {
+            changes.insert("MEASUREINIT".into(), json!(1));
+        }
+    });
+}
+
+fn autosave_row(ui: &mut egui::Ui, changes: &mut Map<String, Value>) {
+    let minutes_caption = ui.label(crate::tl!("Automatic save every"));
+    let mut minutes = cadcraft_engine::autosave::savetime();
+    let max = cadcraft_engine::autosave::MAX_SAVETIME;
+    if ui.add(egui::DragValue::new(&mut minutes).range(0..=max).suffix(format!(" {}", crate::tl!("min")))).labelled_by(minutes_caption.id).changed() {
+        changes.insert("SAVETIME".into(), json!(minutes));
+    }
+}
+
+fn savefile_row(ui: &mut egui::Ui, changes: &mut Map<String, Value>) {
+    let savefile_label = ui.label(crate::tl!("Automatic save file location"));
+    // Edited as text; the folder changes when the field loses focus.
+    let id = egui::Id::unique("cc_options_savefilepath");
+    let current = cadcraft_engine::autosave::savefilepath();
+    let mut path = ui.data(|d| d.get_temp::<String>(id)).unwrap_or_else(|| current.clone());
+    let r = ui.add(egui::TextEdit::singleline(&mut path).desired_width(330.0)).labelled_by(savefile_label.id);
+    if r.changed() {
+        ui.data_mut(|d| d.insert_temp(id, path.clone()));
+    }
+    if r.lost_focus() {
+        ui.data_mut(|d| d.remove::<String>(id));
+        if path.trim() != current {
+            changes.insert("SAVEFILEPATH".into(), json!(path.trim()));
+        }
+    }
+}
+
 /// Drafting tab: object-snap marker size and aperture previews plus the Drafting Settings entry; edits accumulate in `changes` and the entry may request a command through `start`.
 fn drafting(app: &CadApp, ui: &mut egui::Ui, changes: &mut Map<String, Value>, start: &mut Option<&'static str>) {
     let t = Tokens::get();