Merge pull request #4543 from storytold/feat/path-smooth

Path: Object › Path › Smooth with a slider and Auto-Smooth (#4115)

crates/engine/src/cmd/pathops.rs

@@ -14,7 +14,10 @@ use vectorcraft_pathops as po;
 use vectorcraft_pathops::{BoolOp, PathfinderOp};
 
 use super::edit::selected_roots;
-use super::{CommandSpec, EngineError, Result, Session, always, bad, bool_or, cmd, has_doc, has_multi, has_selection, str_param};
+use super::{
+    CommandSpec, EngineError, Result, Session, always, bad, bool_or, checked_ids_or_selection, cmd, has_doc, has_multi, has_selection, number_or,
+    str_param, switch_or,
+};
 
 pub fn specs() -> Vec<CommandSpec> {
     vec![
@@ -153,6 +156,15 @@ pub fn specs() -> Vec<CommandSpec> {
             has_selection,
             simplify
         ),
+        cmd!(
+            "object.path.smooth",
+            "Smooth…",
+            ["Object", "Path"],
+            None,
+            "{level?: 0..100 (50; the Smooth slider: 0 minimum smoothing, the path staying within 0.1% of its longer side, 100 maximum: refitted with curves within up to 2.5% of it, corners kept only where the path turns back, never with more anchor points), auto?: bool (Auto-Smooth: level 50), ids?: [id…] (default: the selection)} smooth each path under the objects, compound path members included, as one undo step → {ids, before, after} anchor counts, and the level used",
+            has_selection,
+            smooth
+        ),
         cmd!("object.path.addAnchorPoints", "Add Anchor Points", ["Object", "Path"], None, "{} → {ids}", has_selection, add_anchor_points),
         cmd!(
             "object.path.divideObjectsBelow",
@@ -957,20 +969,20 @@ fn path_ids(d: &Document, roots: &[NodeId]) -> Vec<NodeId> {
 /// selected segments when they were picked as segments). `None` selects the path whole.
 type PartSelection = Option<(BTreeSet<AnchorRef>, Option<BTreeSet<SegmentRef>>)>;
 
-/// Replace each path under the selection ([`path_ids`]) by what `f` makes of it, given its
+/// Replace each path under `roots` ([`path_ids`]) by what `f` makes of it, given its
 /// direct-selected anchors and picked segments (none when it is selected whole): → (their ids, how
 /// many anchors they have before and after). A path that `f` would empty or returns unchanged is
 /// left as it is, with its live shape and its direct selection; a replaced path loses its live
 /// shape and has the direct selection `f` gives it.
 fn edit_paths(
     s: &mut Session,
+    roots: &[NodeId],
     label: &str,
     f: impl Fn(&PathData, Option<&BTreeSet<AnchorRef>>, Option<&BTreeSet<SegmentRef>>) -> (PathData, PartSelection),
 ) -> Result<(Vec<NodeId>, usize, usize)> {
-    let roots = selected_roots(s)?;
     let st = s.doc()?;
     let (d, sel) = (&st.doc, &st.selection);
-    let ids = path_ids(d, &roots);
+    let ids = path_ids(d, roots);
     if ids.is_empty() {
         return Err(EngineError::Other(format!("{label}: select paths")));
     }
@@ -1064,7 +1076,8 @@ fn simplify(s: &mut Session, p: &Value) -> Result<Value> {
     let whole = bool_or(p, "wholePaths", false);
     // A path with segments direct-selected simplifies only their runs, and keeps those runs (and the
     // other anchors it had selected) direct-selected.
-    let (ids, before, after) = edit_paths(s, "Simplify", |path, anchors, segments| {
+    let roots = selected_roots(s)?;
+    let (ids, before, after) = edit_paths(s, &roots, "Simplify", |path, anchors, segments| {
         let Some(picked) = selected_segments(path, anchors, segments).filter(|_| !whole) else {
             return (po::simplify_with(path, &opts), None);
         };
@@ -1084,8 +1097,20 @@ fn simplify(s: &mut Session, p: &Value) -> Result<Value> {
     Ok(out)
 }
 
+/// Object › Path › Smooth (`object.path.smooth`): [`po::smooth_level`] on each path under the
+/// objects given or selected, as one undo step; Auto-Smooth (`auto`) uses [`po::SMOOTH_AUTO_LEVEL`].
+fn smooth(s: &mut Session, p: &Value) -> Result<Value> {
+    const C: &str = "object.path.smooth";
+    let level = number_or(p, "level", po::SMOOTH_AUTO_LEVEL, C)?.round().clamp(0.0, 100.0);
+    let level = if switch_or(p, "auto", false, C)? { po::SMOOTH_AUTO_LEVEL } else { level };
+    let roots = checked_ids_or_selection(s, p, C)?;
+    let (ids, before, after) = edit_paths(s, &roots, "Smooth", |path, _, _| (po::smooth_level(path, level), None))?;
+    Ok(json!({ "ids": ids.iter().map(|i| i.0).collect::<Vec<_>>(), "before": before, "after": after, "level": level }))
+}
+
 fn add_anchor_points(s: &mut Session, _: &Value) -> Result<Value> {
-    let (ids, before, after) = edit_paths(s, "Add Anchor Points", |path, _, _| (po::add_anchor_points(path), None))?;
+    let roots = selected_roots(s)?;
+    let (ids, before, after) = edit_paths(s, &roots, "Add Anchor Points", |path, _, _| (po::add_anchor_points(path), None))?;
     Ok(json!({ "ids": ids.iter().map(|i| i.0).collect::<Vec<_>>(), "before": before, "after": after }))
 }
 

crates/engine/src/lib.rs

@@ -37,7 +37,7 @@ pub use journal::Journal;
 pub use tooling::{UiRequest, ViewInfo};
 pub use vectorcraft_doc as doc;
 pub use vectorcraft_doc::cancel;
-pub use vectorcraft_pathops::{SIMPLIFY_LEVEL, simplify_level_tolerance};
+pub use vectorcraft_pathops::{SIMPLIFY_LEVEL, SMOOTH_AUTO_LEVEL, simplify_level_tolerance};
 pub use vectorcraft_tools as tools;
 
 /// Coordinates beyond this (points) are rejected: ~1,400 m, far past Illustrator's large canvas.

crates/engine/src/tests.rs

@@ -140,6 +140,7 @@ mod shortcutset;
 mod simplify_part;
 mod slices;
 mod smartguides;
+mod smooth_path;
 mod store;
 mod strokegeom;
 mod strokegradient;

crates/engine/src/tests/smooth_path.rs

@@ -0,0 +1,163 @@
+//! Object › Path › Smooth (`object.path.smooth`): the slider from minimum to maximum smoothing and
+//! Auto-Smooth, as the Smooth slider help page describes
+//! (https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/refine-path-segments-with-the-smooth-slider.html).
+
+use serde_json::{Value, json};
+use vectorcraft_doc::NodeKind;
+use vectorcraft_geom::kurbo::ParamCurveNearest;
+use vectorcraft_geom::{ParamCurve, PathData, Point};
+
+use crate::*;
+
+fn session() -> Session {
+    let mut s = Session::new();
+    s.execute("file.new", &json!({"width": 800, "height": 600})).unwrap();
+    s
+}
+
+fn path_of(s: &Session, id: NodeId) -> PathData {
+    match &s.doc().unwrap().doc.node(id).unwrap().kind {
+        NodeKind::Path { path, .. } => path.clone(),
+        _ => panic!("not a path"),
+    }
+}
+
+/// A path through `points`, selected: its id.
+fn polyline(s: &mut Session, points: &[(f64, f64)], closed: bool) -> NodeId {
+    let anchors: Vec<Value> = points.iter().map(|&(x, y)| json!({"x": x, "y": y})).collect();
+    NodeId(s.execute("path.create", &json!({"anchors": anchors, "closed": closed})).unwrap()["id"].as_u64().unwrap())
+}
+
+/// A sine wave 300 pt long with an anchor every 3 pt, its anchors 1.5 pt above and below it in turn.
+fn jagged_wave(s: &mut Session) -> NodeId {
+    let pts: Vec<(f64, f64)> = (0..=100u32)
+        .map(|i| (f64::from(i) * 3.0, 200.0 + 40.0 * (f64::from(i) * 3.0 / 50.0).sin() + if i.is_multiple_of(2) { 1.5 } else { -1.5 }))
+        .collect();
+    polyline(s, &pts, false)
+}
+
+/// A closed ring of radius `r` around (`cx`, 300) with 120 anchors, `jag` pt in and out in turn.
+fn jagged_ring(s: &mut Session, cx: f64, r: f64, jag: f64) -> NodeId {
+    let pts: Vec<(f64, f64)> = (0..120u32)
+        .map(|i| {
+            let a = f64::from(i) * std::f64::consts::TAU / 120.0;
+            let rr = r + if i.is_multiple_of(2) { jag } else { -jag };
+            (cx + rr * a.cos(), 300.0 + rr * a.sin())
+        })
+        .collect();
+    polyline(s, &pts, true)
+}
+
+/// The farthest that 11 points on each segment of `from` lie from the nearest point of `to`.
+fn farthest(from: &PathData, to: &PathData) -> f64 {
+    let off = |p: Point| {
+        to.subpaths
+            .iter()
+            .flat_map(|sp| (0..sp.segment_count()).map(move |i| sp.segment(i).nearest(p, 1e-9).distance_sq.sqrt()))
+            .fold(f64::INFINITY, f64::min)
+    };
+    from.subpaths
+        .iter()
+        .flat_map(|sp| (0..sp.segment_count()).flat_map(move |i| (0..=10).map(move |k| sp.segment(i).eval(f64::from(k) / 10.0))))
+        .map(off)
+        .fold(0.0, f64::max)
+}
+
+fn undo_len(s: &Session) -> usize {
+    s.doc().unwrap().history.undo.len()
+}
+
+#[test]
+fn minimum_smoothing_leaves_the_path_where_it_was() {
+    let mut s = session();
+    let id = jagged_wave(&mut s);
+    let before = path_of(&s, id);
+    let out = s.execute("object.path.smooth", &json!({"level": 0})).unwrap();
+    assert_eq!(out["level"], json!(0.0));
+    let after = path_of(&s, id);
+    // 0.1 % of the longer side (300 pt), both ways.
+    assert!(farthest(&before, &after) <= 0.3 + 1e-6 && farthest(&after, &before) <= 0.3 + 1e-6);
+}
+
+#[test]
+fn more_smoothing_removes_the_jags_and_keeps_the_shape() {
+    let mut s = session();
+    let id = jagged_wave(&mut s);
+    let before = path_of(&s, id);
+    let mut counts = vec![];
+    for level in [25, 50, 100] {
+        let out = s.execute("object.path.smooth", &json!({ "level": level })).unwrap();
+        let after = path_of(&s, id);
+        assert_eq!(out["after"].as_u64().unwrap() as usize, after.anchor_count());
+        counts.push(after.anchor_count());
+        // Within the tolerance (2.5 % of 300 pt at most) plus the jag the refit smooths away.
+        assert!(farthest(&before, &after) <= 7.5 + 1.5, "level {level}: {}", farthest(&before, &after));
+        // The end points of an open path stay put.
+        let (a, b) = (&before.subpaths[0].anchors, &after.subpaths[0].anchors);
+        assert_eq!((a[0].p, a[a.len() - 1].p), (b[0].p, b[b.len() - 1].p));
+        assert!(!after.subpaths[0].closed);
+        s.execute("edit.undo", &json!({})).unwrap();
+    }
+    assert!(counts[0] < 101 / 2 && counts[2] <= 10, "{counts:?}");
+    assert!(counts.windows(2).all(|w| w[0] >= w[1]), "{counts:?}");
+}
+
+#[test]
+fn auto_smooth_uses_the_middle_level() {
+    let mut s = session();
+    let id = jagged_wave(&mut s);
+    let out = s.execute("object.path.smooth", &json!({"auto": true, "level": 0})).unwrap();
+    assert_eq!(out["level"], json!(50.0));
+    let auto = path_of(&s, id);
+    s.execute("edit.undo", &json!({})).unwrap();
+    s.execute("object.path.smooth", &json!({"level": 50})).unwrap();
+    assert_eq!(path_of(&s, id), auto);
+}
+
+#[test]
+fn closed_paths_and_compound_path_members_smooth_in_one_undo_step() {
+    let mut s = session();
+    let outer = jagged_ring(&mut s, 300.0, 100.0, 2.0);
+    let inner = jagged_ring(&mut s, 300.0, 40.0, 1.0);
+    s.execute("select.set", &json!({"ids": [outer.0, inner.0]})).unwrap();
+    s.execute("object.compoundPath.make", &json!({})).unwrap();
+    let (o, i) = (path_of(&s, outer), path_of(&s, inner));
+    let steps = undo_len(&s);
+    let out = s.execute("object.path.smooth", &json!({"level": 100})).unwrap();
+    assert_eq!(out["ids"].as_array().unwrap().len(), 2);
+    assert_eq!(undo_len(&s), steps + 1);
+    for id in [outer, inner] {
+        let now = path_of(&s, id);
+        assert!(now.subpaths[0].closed);
+        assert!(now.anchor_count() < 120 / 4, "{}", now.anchor_count());
+    }
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!((path_of(&s, outer), path_of(&s, inner)), (o, i));
+}
+
+#[test]
+fn smooths_the_objects_given() {
+    let mut s = session();
+    let a = jagged_wave(&mut s);
+    let b = jagged_ring(&mut s, 300.0, 50.0, 1.0);
+    let ring = path_of(&s, b);
+    // `b` is selected; `ids` names `a` instead.
+    let out = s.execute("object.path.smooth", &json!({"ids": [a.0], "level": 100})).unwrap();
+    assert_eq!(out["ids"], json!([a.0]));
+    assert_eq!(path_of(&s, b), ring);
+}
+
+#[test]
+fn bad_params_are_refused_and_change_nothing() {
+    let mut s = session();
+    let id = jagged_wave(&mut s);
+    let before = path_of(&s, id);
+    let steps = undo_len(&s);
+    for p in [json!({"level": "50"}), json!({"auto": true, "level": "max"}), json!({"auto": "yes"}), json!({"ids": "all"}), json!({"ids": [999_999]})]
+    {
+        assert!(s.execute("object.path.smooth", &p).is_err(), "{p}");
+    }
+    assert_eq!((path_of(&s, id), undo_len(&s)), (before, steps));
+    // Levels past the ends count as the ends.
+    assert_eq!(s.execute("object.path.smooth", &json!({"level": 250})).unwrap()["level"], json!(100.0));
+}

crates/pathops/src/edit.rs

@@ -314,6 +314,55 @@ pub fn smooth(path: &PathData, amount: f64) -> PathData {
     out
 }
 
+/// The Smooth slider's level Auto-Smooth picks, halfway between minimum and maximum smoothing.
+/// VectorCraft's own rule: the help page says only that Auto-Smooth smooths the path automatically
+/// (https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/refine-path-segments-with-the-smooth-slider.html).
+/// [`smooth_level`] already scales with each path's size, so one level suits every path.
+pub const SMOOTH_AUTO_LEVEL: f64 = 50.0;
+
+/// Object › Path › Smooth at slider level `level`, from 0 (minimum smoothing: the path stays within
+/// 0.1 % of its longer side of where it was) to 100 (maximum). The help page names only the two
+/// ends; the rest is VectorCraft's own rule. Each subpath is refitted with curves as Simplify does,
+/// but keeping a corner only where the path turns back on itself (so jags and kinks become curves),
+/// within a tolerance from 0.1 % of the path's longer side at level 0 to 2.5 % at level 100. A refit
+/// never has more anchor points than the subpath had: a shape whose corners the tolerance can't
+/// round, such as a rectangle, stays as it is. Closed subpaths stay closed, with no kink left where
+/// they start, and open ones keep their end points. A level outside 0..=100 counts as the nearer end, and one that is not a number as
+/// [`SMOOTH_AUTO_LEVEL`].
+pub fn smooth_level(path: &PathData, level: f64) -> PathData {
+    let level = if level.is_finite() { level.clamp(0.0, 100.0) } else { SMOOTH_AUTO_LEVEL };
+    let size = path.bounds().map_or(0.0, |b| b.width().max(b.height()));
+    if !size.is_finite() {
+        return path.clone();
+    }
+    let opts = SimplifyOptions { tolerance: size * (0.001 + 0.024 * level / 100.0), corner_angle_deg: SMOOTH_CORNER_DEG, straight_lines: false };
+    let smoothed = |sp: &SubPath| {
+        let Some(mut fit) = simplify_subpath(sp, &opts).filter(|f| f != sp) else { return sp.clone() };
+        smooth_seam(&mut fit);
+        fit
+    };
+    PathData::new(path.subpaths.iter().map(smoothed).collect())
+}
+
+/// [`smooth_level`] keeps a corner only where the path turns by more than this (turns back).
+const SMOOTH_CORNER_DEG: f64 = 179.0;
+
+/// A closed subpath's refit leaves its start anchor with the tangents of the original segments on
+/// either side of it, a kink when the path had one there: turn it into a smooth anchor with the same
+/// handle lengths, unless the path turns back there.
+fn smooth_seam(sp: &mut SubPath) {
+    if !sp.closed {
+        return;
+    }
+    let Some(a) = sp.anchors.first_mut() else { return };
+    let (Some(i), Some(o)) = (crate::fit::unit(a.p - a.h_in), crate::fit::unit(a.h_out - a.p)) else { return };
+    if i.dot(o) < SMOOTH_CORNER_DEG.to_radians().cos() {
+        return;
+    }
+    let Some(dir) = crate::fit::unit(i + o) else { return };
+    *a = Anchor::with_handles(a.p, a.p - dir * a.h_in.distance(a.p), a.p + dir * a.h_out.distance(a.p));
+}
+
 /// Remove anchors that can be deleted without changing the shape by more than `tolerance`
 /// (collinear corner points, duplicate points, and curve joints that one cubic can replace).
 pub fn remove_redundant_points(path: &PathData, tolerance: f64) -> PathData {

crates/pathops/src/lib.rs

@@ -20,8 +20,8 @@ pub use boolean::{
     try_unite_all_with, unite_all, unite_all_with,
 };
 pub use edit::{
-    AverageAxis, SIMPLIFY_LEVEL, SimplifiedPart, SimplifyOptions, add_anchor_points, auto_simplify_level, average, join, remove_anchor,
-    remove_redundant_points, simplify, simplify_level_tolerance, simplify_part, simplify_with, smooth, split_into_grid,
+    AverageAxis, SIMPLIFY_LEVEL, SMOOTH_AUTO_LEVEL, SimplifiedPart, SimplifyOptions, add_anchor_points, auto_simplify_level, average, join,
+    remove_anchor, remove_redundant_points, simplify, simplify_level_tolerance, simplify_part, simplify_with, smooth, smooth_level, split_into_grid,
 };
 pub use offset::{Cap, Join, offset_path, outline_stroke, stroke_region};
 pub use pathfinder::{FaceMerger, PathfinderOp, Region, Shape, merge_regions, pathfinder, pathfinder_with, region_at, regions};

crates/pathops/tests/it/ops.rs

@@ -1,7 +1,7 @@
 use std::f64::consts::PI;
 
 use kurbo::{ParamCurve, Point, Rect, Shape as _};
-use vectorcraft_geom::{FillRule, PathData, SubPath};
+use vectorcraft_geom::{AnchorKind, FillRule, PathData, SubPath};
 use vectorcraft_pathops::*;
 
 const NZ: FillRule = FillRule::NonZero;
@@ -430,6 +430,21 @@ fn smooth_rounds_corners() {
     assert_eq!(same, rect(0.0, 0.0, 10.0, 10.0));
 }
 
+/// Object › Path › Smooth: a rectangle, whose corners no curve rounds within the tolerance, stays as
+/// it is even at maximum smoothing; a polygon of 16 sides becomes a closed curve of fewer anchors once the tolerance
+/// passes its 0.96 pt sagitta, smooth all round.
+#[test]
+fn smooth_level_keeps_corners_it_cannot_round_and_curves_polygons() {
+    let r = rect(0.0, 0.0, 100.0, 50.0);
+    assert_eq!(smooth_level(&r, 100.0), r);
+    let pts: Vec<Point> = (0..16).map(|i| Point::new(50.0 * (f64::from(i) * PI / 8.0).cos(), 50.0 * (f64::from(i) * PI / 8.0).sin())).collect();
+    let polygon = PathData::single(SubPath::polyline(&pts, true));
+    let s = smooth_level(&polygon, SMOOTH_AUTO_LEVEL);
+    assert!(s.subpaths.len() == 1 && s.subpaths[0].closed && s.anchor_count() < 8, "{}", s.anchor_count());
+    assert!(s.subpaths[0].anchors.iter().all(|a| a.kind == AnchorKind::Smooth), "no kink, its start included: {s:?}");
+    assert_eq!(smooth_level(&polygon, 0.0), polygon, "0.1 pt is less than the sagitta");
+}
+
 #[test]
 fn remove_redundant_collinear_and_curve() {
     let p = PathData::single(SubPath::polyline(

crates/ui-egui/src/canvas.rs

@@ -327,8 +327,9 @@ pub fn show(app: &mut VectorcraftApp, ui: &mut Ui) {
     if app.ui.view.rulers && app.ui.screen_mode < 3 {
         ruler_bands(app, ui, &xf, (full, rect), origin_preview, &t);
     }
-    // The task bar is not drawn while the Simplify slider shows.
-    if app.ui.task_bar && !revolve_edit && !app.session.tool_busy() && app.ui.screen_mode < 3 && !crate::dialogs::simplify_slider::showing(app) {
+    // The task bar is not drawn while the Simplify or Smooth slider shows.
+    let strip = crate::dialogs::simplify_slider::showing(app) || crate::dialogs::smooth_slider::showing(app);
+    if app.ui.task_bar && !revolve_edit && !app.session.tool_busy() && app.ui.screen_mode < 3 && !strip {
         task_bar(app, ui, &xf);
     }
     if app.ui.screen_mode < 3 {

crates/ui-egui/src/dialogs.rs

@@ -99,6 +99,7 @@ pub(crate) mod shapes;
 pub mod shortcut_import;
 pub(crate) mod simplify_slider;
 pub mod slices;
+pub(crate) mod smooth_slider;
 pub mod spot_colors;
 pub(crate) mod svg_options;
 pub mod swatch_conflict;
@@ -352,6 +353,7 @@ registry! {
     ScriptCheck: [script_check::KIND] => script_check::SPEC,
     VectorHalftone: [halftone::KIND] => halftone::SPEC,
     SimplifySlider: [simplify_slider::KIND] => simplify_slider::SPEC,
+    SmoothSlider: [smooth_slider::KIND] => smooth_slider::SPEC,
     PerspectiveGrid: [perspective_grid::KIND] => perspective_grid::SPEC,
     Envelope: [envelope::WARP, envelope::MESH, envelope::OPTIONS] => envelope::SPEC,
     LiquifyOptions: [liquify::KIND] => liquify::SPEC,

crates/ui-egui/src/dialogs/simplify_slider.rs

@@ -8,6 +8,8 @@
 //! (https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/manually-simplify-paths.html).
 //! `vectorcraft_pathops::simplify_level_tolerance` maps levels to tolerances.
 //!
+//! The strip itself ([`Strip`]) is shared with Object › Path › Smooth's slider (`smooth_slider`).
+//!
 //! Fields: `level` (0..=100, the command's parameter).
 
 use egui::{Color32, CornerRadius, Order, Pos2, Sense, Stroke, vec2};
@@ -25,9 +27,122 @@ pub(crate) const KIND: &str = "simplifySlider";
 
 pub(super) const SPEC: DialogSpec = DialogSpec { window: Some(show), confirm, preview: true, ..DialogSpec::FORM };
 
-/// The command the slider previews, and its undo label.
-const CMD: &str = "object.path.simplify";
-const LABEL: &str = "Simplify";
+/// What the Simplify slider previews, and its buttons.
+const STRIP: Strip = Strip {
+    kind: KIND,
+    cmd: "object.path.simplify",
+    label: "Simplify",
+    default_level: SIMPLIFY_LEVEL,
+    auto: ("Auto-Simplify", auto),
+    more_options: Some(more_options),
+};
+
+/// A UI command a button of a strip runs.
+type Button = fn(&mut VectorcraftApp) -> Result<Value, String>;
+
+/// A slider strip under the selection that previews `cmd {level}` while it is open: its first
+/// button picks the level `cmd {auto: true}` does, and an optional last one, More Options, opens a
+/// dialog in its place. Enter or a click outside the strip keeps the result as one undo step, and
+/// Escape puts the paths back.
+pub(super) struct Strip {
+    /// The dialog kind.
+    pub kind: &'static str,
+    /// The command previewed.
+    pub cmd: &'static str,
+    /// The undo step's name, and the slider's.
+    pub label: &'static str,
+    /// The level when the field holds no number.
+    pub default_level: f64,
+    /// The auto button's tip, and what it runs.
+    pub auto: (&'static str, Button),
+    /// What More Options runs, when the strip has it.
+    pub more_options: Option<Button>,
+}
+
+impl Strip {
+    /// Whether this strip is open.
+    pub fn showing(&self, app: &VectorcraftApp) -> bool {
+        app.ui.dialog.as_ref().is_some_and(|d| d.kind == self.kind)
+    }
+
+    /// The open strip, if it is this one.
+    pub fn open(&self, app: &VectorcraftApp) -> Option<Dialog> {
+        app.ui.dialog.clone().filter(|d| d.kind == self.kind)
+    }
+
+    /// The slider's level, a whole number from 0 to 100.
+    fn level(&self, d: &Dialog) -> f64 {
+        let l = d.f64("level", self.default_level);
+        if l.is_finite() { l.round().clamp(0.0, 100.0) } else { self.default_level }
+    }
+
+    fn params(&self, d: &Dialog) -> Value {
+        json!({ "level": self.level(d) })
+    }
+
+    pub fn confirm(&self, app: &mut VectorcraftApp, d: &Dialog) -> DialogResult {
+        form::commit_preview(app, self.cmd, self.params(d))
+    }
+
+    /// The open strip `d` moves to the level `cmd {auto: true}` picks for the selection, and the
+    /// canvas previews it → {level}.
+    pub fn auto(&self, app: &mut VectorcraftApp, mut d: Dialog) -> Result<Value, String> {
+        let _ = app.session.begin_interaction(self.label);
+        let r = app.session.preview(self.cmd, &json!({ "auto": true })).map_err(|e| e.to_string())?;
+        let level = r["level"].as_f64().unwrap_or(self.default_level);
+        d.fields.insert("level".into(), json!(level));
+        d.fields.insert(form::PREVIEWED.into(), self.params(&d));
+        app.ui.dialog = Some(d);
+        Ok(json!({ "level": level }))
+    }
+
+    pub fn show(&self, app: &mut VectorcraftApp, ctx: &egui::Context) {
+        let Some(mut d) = app.ui.dialog.clone() else { return };
+        let t = Tokens::get(ctx);
+        let id = egui::Id::unique(("dialog", self.kind));
+        let b = bounds(app, &mut d);
+        let pos = place(app, ctx, id, b);
+        // A click anywhere else keeps the result, and the rest of the app doesn't take it.
+        let dim = modal::backdrop();
+        let outside =
+            egui::Area::new(dim.id).order(dim.order).fixed_pos(Pos2::ZERO).show(ctx, |ui| ui.allocate_rect(ctx.content_rect(), Sense::click())).inner;
+        let mut action: Option<Button> = None;
+        egui::Area::new(id).order(Order::Foreground).fixed_pos(pos).show(ctx, |ui| {
+            egui::Frame::NONE
+                .fill(t.panel)
+                .stroke(Stroke::new(1.0, t.tool_active))
+                .corner_radius(CornerRadius::same(5))
+                .inner_margin(egui::Margin::symmetric(8, 6))
+                .shadow(egui::epaint::Shadow { offset: [0, 3], blur: 10, spread: 0, color: Color32::from_black_alpha(70) })
+                .show(ui, |ui| {
+                    ui.horizontal(|ui| {
+                        ui.spacing_mut().item_spacing.x = 6.0;
+                        if widgets::icon_button(ui, "wand-sparkles", tl!(self.auto.0), false, 28.0).clicked() {
+                            action = Some(self.auto.1);
+                        }
+                        let rail = t.input_border;
+                        form::slider_rail_named(ui, &mut d, "level", tl!(self.label), 0.0..=100.0, &|_| rail);
+                        if let Some(more) = self.more_options
+                            && widgets::icon_button(ui, "ellipsis", tl!("More Options"), false, 28.0).clicked()
+                        {
+                            action = Some(more);
+                        }
+                    });
+                });
+        });
+        let p = self.params(&d);
+        let _ = form::preview_now(app, &mut d, self.label, self.cmd, p);
+        app.ui.dialog = Some(d);
+        let r = match action {
+            Some(run) => run(app),
+            None if outside.clicked() || ctx.input(|i| i.key_pressed(egui::Key::Enter)) => super::confirm(app),
+            None => Ok(Value::Null),
+        };
+        if let Err(e) = r {
+            app.status(e);
+        }
+    }
+}
 
 /// The fields the slider opens with: Auto-Simplify's level for the selection, or
 /// [`SIMPLIFY_LEVEL`] without a document.
@@ -37,46 +152,29 @@ pub(crate) fn fields(app: &VectorcraftApp) -> Value {
 
 /// Whether the Simplify slider is open.
 pub(crate) fn showing(app: &VectorcraftApp) -> bool {
-    app.ui.dialog.as_ref().is_some_and(|d| d.kind == KIND)
-}
-
-/// The slider's level, a whole number from 0 to 100.
-fn level(d: &Dialog) -> f64 {
-    let l = d.f64("level", SIMPLIFY_LEVEL);
-    if l.is_finite() { l.round().clamp(0.0, 100.0) } else { SIMPLIFY_LEVEL }
-}
-
-fn params(d: &Dialog) -> Value {
-    json!({ "level": level(d) })
+    STRIP.showing(app)
 }
 
 fn confirm(app: &mut VectorcraftApp, d: &Dialog) -> DialogResult {
-    form::commit_preview(app, CMD, params(d))
+    STRIP.confirm(app, d)
 }
 
-/// The open slider, or an error when it isn't open.
-fn open_slider(app: &VectorcraftApp) -> Result<Dialog, String> {
-    app.ui.dialog.clone().filter(|d| d.kind == KIND).ok_or_else(|| "the Simplify slider is not open".to_string())
+fn show(app: &mut VectorcraftApp, ctx: &egui::Context) {
+    STRIP.show(app, ctx);
 }
 
 /// Auto-Simplify (`ui.simplifyAuto`): the open slider moves to the level `object.path.simplify
 /// {auto: true}` picks for the selection, and the canvas previews it → {level}.
 pub(crate) fn auto(app: &mut VectorcraftApp) -> Result<Value, String> {
-    let mut d = open_slider(app)?;
-    let _ = app.session.begin_interaction(LABEL);
-    let r = app.session.preview(CMD, &json!({ "auto": true })).map_err(|e| e.to_string())?;
-    let level = r["level"].as_f64().unwrap_or(SIMPLIFY_LEVEL);
-    d.fields.insert("level".into(), json!(level));
-    d.fields.insert(form::PREVIEWED.into(), params(&d));
-    app.ui.dialog = Some(d);
-    Ok(json!({ "level": level }))
+    let d = STRIP.open(app).ok_or_else(|| "the Simplify slider is not open".to_string())?;
+    STRIP.auto(app, d)
 }
 
 /// More Options (`ui.simplifyMoreOptions`): the Simplify dialog takes the slider's place, at the
 /// slider's tolerance → {tolerance}.
 pub(crate) fn more_options(app: &mut VectorcraftApp) -> Result<Value, String> {
-    let d = open_slider(app)?;
-    let tolerance = simplify_level_tolerance(level(&d));
+    let d = STRIP.open(app).ok_or_else(|| "the Simplify slider is not open".to_string())?;
+    let tolerance = simplify_level_tolerance(STRIP.level(&d));
     app.ui.dialog = Some(Dialog::new("simplify", super::path_ops::simplify_dialog(tolerance)));
     Ok(json!({ "tolerance": tolerance }))
 }
@@ -115,55 +213,3 @@ fn place(app: &mut VectorcraftApp, ctx: &egui::Context, id: egui::Id, bounds: Op
     let bounds = rect.shrink(8.0);
     under.clamp(bounds.min, (bounds.max - size).max(bounds.min))
 }
-
-/// What a button of the strip asked for.
-enum Action {
-    Auto,
-    MoreOptions,
-}
-
-fn show(app: &mut VectorcraftApp, ctx: &egui::Context) {
-    let Some(mut d) = app.ui.dialog.clone() else { return };
-    let t = Tokens::get(ctx);
-    let id = egui::Id::unique(("dialog", KIND));
-    let b = bounds(app, &mut d);
-    let pos = place(app, ctx, id, b);
-    // A click anywhere else keeps the result, and the rest of the app doesn't take it.
-    let dim = modal::backdrop();
-    let outside =
-        egui::Area::new(dim.id).order(dim.order).fixed_pos(Pos2::ZERO).show(ctx, |ui| ui.allocate_rect(ctx.content_rect(), Sense::click())).inner;
-    let mut action = None;
-    egui::Area::new(id).order(Order::Foreground).fixed_pos(pos).show(ctx, |ui| {
-        egui::Frame::NONE
-            .fill(t.panel)
-            .stroke(Stroke::new(1.0, t.tool_active))
-            .corner_radius(CornerRadius::same(5))
-            .inner_margin(egui::Margin::symmetric(8, 6))
-            .shadow(egui::epaint::Shadow { offset: [0, 3], blur: 10, spread: 0, color: Color32::from_black_alpha(70) })
-            .show(ui, |ui| {
-                ui.horizontal(|ui| {
-                    ui.spacing_mut().item_spacing.x = 6.0;
-                    if widgets::icon_button(ui, "wand-sparkles", tl!("Auto-Simplify"), false, 28.0).clicked() {
-                        action = Some(Action::Auto);
-                    }
-                    let rail = t.input_border;
-                    form::slider_rail_named(ui, &mut d, "level", tl!("Simplify"), 0.0..=100.0, &|_| rail);
-                    if widgets::icon_button(ui, "ellipsis", tl!("More Options"), false, 28.0).clicked() {
-                        action = Some(Action::MoreOptions);
-                    }
-                });
-            });
-    });
-    let p = params(&d);
-    let _ = form::preview_now(app, &mut d, LABEL, CMD, p);
-    app.ui.dialog = Some(d);
-    let r = match action {
-        Some(Action::Auto) => auto(app),
-        Some(Action::MoreOptions) => more_options(app),
-        None if outside.clicked() || ctx.input(|i| i.key_pressed(egui::Key::Enter)) => super::confirm(app),
-        None => Ok(Value::Null),
-    };
-    if let Err(e) = r {
-        app.status(e);
-    }
-}

crates/ui-egui/src/dialogs/smooth_slider.rs

@@ -0,0 +1,57 @@
+//! Object › Path › Smooth's slider, as the Smooth slider help page describes
+//! (https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/refine-path-segments-with-the-smooth-slider.html):
+//! the strip of Simplify's slider (`simplify_slider::Strip`) with Auto-Smooth and a slider from
+//! minimum smoothing (left) to maximum smoothing (right). While it is open the canvas previews
+//! `object.path.smooth {level}`; Enter or a click outside the strip keeps the result as one undo
+//! step, and Escape puts the paths back. It opens at Auto-Smooth's level, as Simplify's slider
+//! opens at Auto-Simplify's (VectorCraft's choice: the page doesn't say where it starts).
+//!
+//! Fields: `level` (0..=100, the command's parameter).
+
+use serde_json::{Value, json};
+use vectorcraft_engine::SMOOTH_AUTO_LEVEL;
+
+use super::simplify_slider::Strip;
+use super::{DialogResult, DialogSpec};
+use crate::VectorcraftApp;
+use crate::state::Dialog;
+
+/// The dialog kind of the Smooth slider.
+pub(crate) const KIND: &str = "smoothSlider";
+
+pub(super) const SPEC: DialogSpec = DialogSpec { window: Some(show), confirm, preview: true, ..DialogSpec::FORM };
+
+/// What the Smooth slider previews, and its button.
+const STRIP: Strip = Strip {
+    kind: KIND,
+    cmd: "object.path.smooth",
+    label: "Smooth",
+    default_level: SMOOTH_AUTO_LEVEL,
+    auto: ("Auto-Smooth", auto),
+    more_options: None,
+};
+
+/// The fields the slider opens with: Auto-Smooth's level.
+pub(crate) fn fields() -> Value {
+    json!({ "level": SMOOTH_AUTO_LEVEL })
+}
+
+/// Whether the Smooth slider is open.
+pub(crate) fn showing(app: &VectorcraftApp) -> bool {
+    STRIP.showing(app)
+}
+
+fn confirm(app: &mut VectorcraftApp, d: &Dialog) -> DialogResult {
+    STRIP.confirm(app, d)
+}
+
+fn show(app: &mut VectorcraftApp, ctx: &egui::Context) {
+    STRIP.show(app, ctx);
+}
+
+/// Auto-Smooth (`ui.smoothAuto`): the open slider moves to the level `object.path.smooth {auto:
+/// true}` picks, and the canvas previews it → {level}.
+pub(crate) fn auto(app: &mut VectorcraftApp) -> Result<Value, String> {
+    let d = STRIP.open(app).ok_or_else(|| "the Smooth slider is not open".to_string())?;
+    STRIP.auto(app, d)
+}

crates/ui-egui/src/dialogs/tests_modal.rs

@@ -513,6 +513,38 @@ fn simplify_slider_and_dialog_simplify_only_the_direct_selected_part_of_a_path()
     kept(&app, "the dialog");
 }
 
+/// Object › Path › Smooth opens its slider (#4115) at the Auto-Smooth level, previewing that
+/// result; moving it previews the level, Auto-Smooth (the strip's only button) moves it back, and a
+/// click outside keeps the result as one undo step.
+#[test]
+fn smooth_slider_previews_auto_smooth_and_keeps_the_result() {
+    let ctx = ctx();
+    let mut app = VectorcraftApp::new(Session::new(), Default::default());
+    app.run("file.new", json!({"width": 400, "height": 300})).unwrap();
+    let anchors: Vec<_> =
+        (0..=60).map(|i| json!({"x": 20 + i * 5, "y": 150.0 + 40.0 * (f64::from(i) / 10.0).sin() + f64::from(i % 2) * 3.0})).collect();
+    app.run("path.create", json!({"anchors": anchors})).unwrap();
+    let before = app.session.doc().unwrap().doc.clone();
+    let undo_len = app.session.doc().unwrap().history.undo.len();
+    assert!(app.run("ui.smoothAuto", json!({})).is_err(), "the slider is not open");
+    crate::menus::invoke(&mut app, "object.path.smooth", json!({}));
+    assert_eq!(app.ui.dialog.as_ref().map(|d| (d.kind.as_str(), d.f64("level", -1.0))), Some((smooth_slider::KIND, 50.0)));
+    settle(&ctx, &mut app);
+    assert_eq!(simplify_preview(&app), json!({"level": 50.0}));
+    assert!(anchor_count(&app) < 61 / 4, "the preview smooths the jags: {}", anchor_count(&app));
+    app.ui.dialog.as_mut().unwrap().fields.insert("level".into(), json!(0));
+    settle(&ctx, &mut app);
+    assert_eq!(simplify_preview(&app), json!({"level": 0.0}));
+    let strip = rect_of(&ctx, egui::Id::unique(("dialog", smooth_slider::KIND)));
+    click(&ctx, &mut app, Pos2::new(strip.left() + 8.0 + 14.0, strip.center().y));
+    assert_eq!(app.ui.dialog.as_ref().unwrap().f64("level", 0.0), 50.0);
+    assert_eq!(simplify_preview(&app), json!({"auto": true}));
+    click(&ctx, &mut app, Pos2::new(20.0, 20.0));
+    assert!(app.ui.dialog.is_none() && !app.session.in_interaction());
+    assert_eq!(app.session.doc().unwrap().history.undo.len(), undo_len + 1);
+    assert_ne!(app.session.doc().unwrap().doc, before);
+}
+
 /// More Options opens the Simplify dialog at the slider's tolerance. With "Open this dialog with
 /// these settings next time" ticked, OK makes the menu item open the dialog on its settings; with
 /// it unticked, the slider again.

crates/ui-egui/src/i18n/bg.tsv

@@ -2950,6 +2950,7 @@ font-technology	Variable	Променливи
 	Show Original Path	Показване на оригиналния път
 	Open this dialog with these settings next time	Отваряне на този прозорец с тези настройки следващия път
 	Auto-Simplify	Автоматично опростяване
+	Auto-Smooth	Автоматично изглаждане
 	Show Package	Показване на пакет
 	Show Panel	Показване на панел
 	Show Pattern Swatches	Показване на образци за мостра
@@ -2984,6 +2985,7 @@ font-technology	Variable	Променливи
 	Simplify	Опростяване
 	Simplify:	Опростяване:
 	Simplify…	Опростяване…
+	Smooth…	Изглаждане…
 	Simulate Colored Paper	Симулиране на цветна хартия
 	Simulate Paper	Симулиране на хартия
 	Double Column	Две колони

crates/ui-egui/src/i18n/cs.tsv

@@ -224,6 +224,7 @@
 	Offset Path…	Odsadit cestu…
 	Reverse Path Direction	Obrátit směr cesty
 	Simplify…	Zjednodušit…
+	Smooth…	Vyhladit…
 	Add Anchor Points	Přidat kotevní body
 	Remove Anchor Points	Odstranit kotevní body
 	Divide Objects Below	Rozdělit objekty pod
@@ -1755,6 +1756,7 @@ lighting	Light	Světlo
 	Show Original Path	Zobrazit původní cestu
 	Open this dialog with these settings next time	Příště otevřít toto dialogové okno s tímto nastavením
 	Auto-Simplify	Automaticky zjednodušit
+	Auto-Smooth	Automaticky vyhladit
 	Transparency Options	Možnosti průhlednosti
 	Color Mixer (Shift-click the chip)	Míchání barev (Shift+kliknutí na políčko)
 	Fill: click for swatches, Shift-click for the color mixer	Výplň: kliknutím otevřete vzorník, Shift+kliknutím míchání barev
@@ -4307,6 +4309,7 @@ imageTrace	Outline	Obrys
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio musí být číslo od 0,1 do 10
 @msg	the Color Picker is not open	Výběr barvy není otevřený
 @msg	the Simplify slider is not open	Posuvník Zjednodušit není otevřený
+@msg	the Smooth slider is not open	Posuvník Vyhladit není otevřený
 @msg	the screen color sampler is already open	nástroj pro nabírání barvy z obrazovky už je otevřený
 @msg	this system has no screen color sampler	tento systém nemá nástroj pro nabírání barvy z obrazovky
 @msg	bad colour `{hex}` (#rrggbb)	chybná barva `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/da.tsv

@@ -208,6 +208,7 @@
 	Offset Path…	Forskyd kurve…
 	Reverse Path Direction	Omvend kurveretning
 	Simplify…	Forenkl…
+	Smooth…	Udglat…
 	Add Anchor Points	Tilføj ankerpunkter
 	Remove Anchor Points	Fjern ankerpunkter
 	Divide Objects Below	Opdel objekter nedenunder
@@ -5196,6 +5197,7 @@ swatch	Bright Violet	Kraftig violet
 	Show Original Path	Vis oprindelig kurve
 	Open this dialog with these settings next time	Åbn denne dialogboks med disse indstillinger næste gang
 	Auto-Simplify	Forenkl automatisk
+	Auto-Smooth	Udglat automatisk
 @msg	check a layer to export	markér et lag, der skal eksporteres
 @msg	select the art to export first	markér først grafikken, der skal eksporteres
 @msg	no saved selection recalled	ingen gemt markering hentet

crates/ui-egui/src/i18n/de.tsv

@@ -2981,6 +2981,7 @@ mark-style	Japanese	Japanisch
 	Show Original Path	Originalpfad einblenden
 	Open this dialog with these settings next time	Dieses Dialogfeld nächstes Mal mit diesen Einstellungen öffnen
 	Auto-Simplify	Automatisch vereinfachen
+	Auto-Smooth	Automatisch glätten
 	Color Panel Options	Optionen für das Farbbedienfeld
 	Show Package	Paket anzeigen
 	Show Panel	Bedienfeld einblenden
@@ -3017,6 +3018,7 @@ mark-style	Japanese	Japanisch
 	Simplify	Vereinfachen
 	Simplify:	Vereinfachen:
 	Simplify…	Vereinfachen…
+	Smooth…	Glätten…
 	Simulate Colored Paper	Farbiges Papier simulieren
 	Simulate Paper	Papier simulieren
 	Double Column	Zweispaltig
@@ -3924,6 +3926,7 @@ theme	Appearance	Erscheinungsbild
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio muss eine Zahl von 0,1 bis 10 sein
 @msg	the Color Picker is not open	der Farbwähler ist nicht geöffnet
 @msg	the Simplify slider is not open	der Regler „Vereinfachen“ ist nicht geöffnet
+@msg	the Smooth slider is not open	der Regler „Glätten“ ist nicht geöffnet
 @msg	the screen color sampler is already open	die Farbaufnahme vom Bildschirm ist bereits geöffnet
 @msg	this system has no screen color sampler	dieses System hat keine Farbaufnahme vom Bildschirm
 @msg	bad colour `{hex}` (#rrggbb)	ungültige Farbe `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/el.tsv

@@ -1866,6 +1866,7 @@ font-technology	Variable	Μεταβλητές
 	Simplify	Απλοποίηση
 	Simplify:	Απλοποίηση:
 	Simplify…	Απλοποίηση…
+	Smooth…	Εξομάλυνση…
 	Size	Μέγεθος
 	Size:	Μέγεθος:
 	Skew	Λοξότητα
@@ -3424,6 +3425,7 @@ theme	Appearance	Εμφάνιση
 	Show Original Path	Εμφάνιση αρχικής διαδρομής
 	Open this dialog with these settings next time	Άνοιγμα αυτού του παραθύρου με αυτές τις ρυθμίσεις την επόμενη φορά
 	Auto-Simplify	Αυτόματη απλοποίηση
+	Auto-Smooth	Αυτόματη εξομάλυνση
 	Show Package	Εμφάνιση συσκευασίας
 	Show Panel	Εμφάνιση πίνακα
 	Show Pattern Swatches	Εμφάνιση δειγμάτων μοτίβου
@@ -5300,6 +5302,7 @@ effect	Points	Σημεία
 @msg	span: "selection" places the gradient itself: leave out `start` and `end` (they already place it in document coordinates)	span: το "selection" τοποθετεί το ίδιο το ντεγκραντέ: παραλείψτε τα `start` και `end` (το τοποθετούν ήδη σε συντεταγμένες εγγράφου)
 @msg	the Color Picker is not open	ο επιλογέας χρώματος δεν είναι ανοιχτός
 @msg	the Simplify slider is not open	ο ρυθμιστής Απλοποίησης δεν είναι ανοιχτός
+@msg	the Smooth slider is not open	ο ρυθμιστής Εξομάλυνσης δεν είναι ανοιχτός
 @msg	the action has no steps	η ενέργεια δεν έχει βήματα
 @msg	the file's layers weren't read ({_1}): it comes in as its page, in one layer	τα επίπεδα του αρχείου δεν διαβάστηκαν ({_1}): εισάγεται ως η σελίδα του, σε ένα επίπεδο
 @msg	the file's layers weren't read from its editing data ({_1}): they come from its PDF part	τα επίπεδα του αρχείου δεν διαβάστηκαν από τα δεδομένα επεξεργασίας του ({_1}): προέρχονται από το τμήμα PDF του

crates/ui-egui/src/i18n/es.tsv

@@ -3016,6 +3016,7 @@ font-technology	Variable	Variables
 	Show Original Path	Mostrar trazado original
 	Open this dialog with these settings next time	Abrir este cuadro de diálogo con estos ajustes la próxima vez
 	Auto-Simplify	Simplificar automáticamente
+	Auto-Smooth	Suavizar automáticamente
 	Color Panel Options	Opciones del panel Color
 	Show Package	Mostrar paquete
 	Show Panel	Mostrar panel
@@ -3052,6 +3053,7 @@ font-technology	Variable	Variables
 	Simplify	Simplificar
 	Simplify:	Simplificar:
 	Simplify…	Simplificar…
+	Smooth…	Suavizar…
 	Simulate Colored Paper	Simular papel de color
 	Simulate Paper	Simular papel
 	Double Column	Columna doble
@@ -4004,6 +4006,7 @@ axis	Both	Ambos
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio debe ser un número de 0,1 a 10
 @msg	the Color Picker is not open	el Selector de color no está abierto
 @msg	the Simplify slider is not open	el regulador de Simplificar no está abierto
+@msg	the Smooth slider is not open	el regulador de Suavizar no está abierto
 @msg	the screen color sampler is already open	el muestreador de color de la pantalla ya está abierto
 @msg	this system has no screen color sampler	este sistema no tiene muestreador de color de la pantalla
 @msg	bad colour `{hex}` (#rrggbb)	color no válido `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/fi.tsv

@@ -231,6 +231,7 @@
 	Offset Path…	Siirrä polkua…
 	Reverse Path Direction	Käännä polun suunta
 	Simplify…	Yksinkertaista…
+	Smooth…	Tasoita…
 	Add Anchor Points	Lisää ankkuripisteitä
 	Remove Anchor Points	Poista ankkuripisteitä
 	Divide Objects Below	Jaa alla olevat objektit
@@ -1718,6 +1719,7 @@ lighting	Light	Valo
 	Show Original Path	Näytä alkuperäinen polku
 	Open this dialog with these settings next time	Avaa tämä valintaikkuna näillä asetuksilla ensi kerralla
 	Auto-Simplify	Yksinkertaista automaattisesti
+	Auto-Smooth	Tasoita automaattisesti
 	Transparency Options	Läpinäkyvyysasetukset
 	Color Mixer (Shift-click the chip)	Värisekoitin (Vaihto-napsauta värilaattaa)
 	Fill: click for swatches, Shift-click for the color mixer	Täyttö: napsauta avataksesi värimallit, Vaihto-napsauta avataksesi värisekoittimen
@@ -5312,6 +5314,7 @@ mark-style	Japanese	Japanilainen
 @msg	span: "selection" places the gradient itself: leave out `start` and `end` (they already place it in document coordinates)	span: "selection" sijoittaa itse liukuvärin: jätä pois `start` ja `end` (ne sijoittavat sen jo asiakirjan koordinaatteihin)
 @msg	the Color Picker is not open	värinvalitsin ei ole auki
 @msg	the Simplify slider is not open	Yksinkertaista-liukusäädin ei ole auki
+@msg	the Smooth slider is not open	Tasoita-liukusäädin ei ole auki
 @msg	the action has no steps	toiminnossa ei ole vaiheita
 @msg	the file's layers weren't read ({_1}): it comes in as its page, in one layer	tiedoston tasoja ei luettu ({_1}): se tuodaan sivunaan yhdelle tasolle
 @msg	the file's layers weren't read from its editing data ({_1}): they come from its PDF part	tiedoston tasoja ei luettu sen muokkaustiedoista ({_1}): ne tulevat sen PDF-osasta

crates/ui-egui/src/i18n/fr.tsv

@@ -3013,6 +3013,7 @@ font-technology	Variable	Variables
 	Show Original Path	Afficher le tracé d’origine
 	Open this dialog with these settings next time	Ouvrir cette boîte de dialogue avec ces réglages la prochaine fois
 	Auto-Simplify	Simplifier automatiquement
+	Auto-Smooth	Lisser automatiquement
 	Color Panel Options	Options du panneau Couleur
 	Show Package	Afficher le dossier d’assemblage
 	Show Panel	Afficher le panneau
@@ -3049,6 +3050,7 @@ font-technology	Variable	Variables
 	Simplify	Simplifier
 	Simplify:	Simplifier :
 	Simplify…	Simplifier…
+	Smooth…	Lisser…
 	Simulate Colored Paper	Simuler un papier de couleur
 	Simulate Paper	Simuler le papier
 	Double Column	Deux colonnes
@@ -4001,6 +4003,7 @@ axis	Both	Les deux
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio doit être un nombre de 0,1 à 10
 @msg	the Color Picker is not open	le Sélecteur de couleurs n’est pas ouvert
 @msg	the Simplify slider is not open	le curseur Simplifier n’est pas ouvert
+@msg	the Smooth slider is not open	le curseur Lisser n’est pas ouvert
 @msg	the screen color sampler is already open	l’outil de prélèvement de couleur à l’écran est déjà ouvert
 @msg	this system has no screen color sampler	ce système n’a pas d’outil de prélèvement de couleur à l’écran
 @msg	bad colour `{hex}` (#rrggbb)	couleur non valide `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/hu.tsv

@@ -3640,6 +3640,7 @@ mark-style	Japanese	Japán
 	Show Original Path	Eredeti útvonal megjelenítése
 	Open this dialog with these settings next time	Legközelebb ez a párbeszédablak nyíljon meg ezekkel a beállításokkal
 	Auto-Simplify	Automatikus egyszerűsítés
+	Auto-Smooth	Automatikus simítás
 	Color Panel Options	Szín panel beállításai
 	Show Package	Csomag megjelenítése
 	Show Panel	Panel megjelenítése
@@ -3683,6 +3684,7 @@ mark-style	Japanese	Japán
 	Simplify	Egyszerűsítés
 	Simplify:	Egyszerűsítés:
 	Simplify…	Egyszerűsítés…
+	Smooth…	Simítás…
 	Simulate	Szimulálás
 	Simulate Colored Paper	Színes papír szimulálása
 	Simulate Paper	Papír szimulálása
@@ -4560,6 +4562,7 @@ imageTrace	Outline	Körvonal
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio: 0,1 és 10 közötti szám kell
 @msg	the Color Picker is not open	a Színválasztó nincs megnyitva
 @msg	the Simplify slider is not open	az Egyszerűsítés csúszka nincs megnyitva
+@msg	the Smooth slider is not open	a Simítás csúszka nincs megnyitva
 @msg	the screen color sampler is already open	a képernyős színmintavevő már nyitva van
 @msg	this system has no screen color sampler	ezen a rendszeren nincs képernyős színmintavevő
 @msg	bad colour `{hex}` (#rrggbb)	hibás szín: `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/id.tsv

@@ -208,6 +208,7 @@
 	Offset Path…	Jalur ofset…
 	Reverse Path Direction	Balikkan arah jalur
 	Simplify…	Sederhanakan…
+	Smooth…	Haluskan…
 	Add Anchor Points	Tambahkan titik jangkar
 	Remove Anchor Points	Hapus titik jangkar
 	Divide Objects Below	Bagi objek di bawah
@@ -5196,6 +5197,7 @@ swatch	Bright Violet	Violet cerah
 	Show Original Path	Tampilkan jalur asli
 	Open this dialog with these settings next time	Buka dialog ini dengan pengaturan ini lain kali
 	Auto-Simplify	Sederhanakan otomatis
+	Auto-Smooth	Haluskan otomatis
 @msg	check a layer to export	centang lapisan yang akan diekspor
 @msg	select the art to export first	pilih dulu karya yang akan diekspor
 @msg	no saved selection recalled	tidak ada seleksi tersimpan yang dipanggil

crates/ui-egui/src/i18n/it.tsv

@@ -3050,6 +3050,7 @@ mark-style	Japanese	Giapponese
 	Show Original Path	Mostra tracciato originale
 	Open this dialog with these settings next time	Apri questa finestra di dialogo con queste impostazioni la prossima volta
 	Auto-Simplify	Semplifica automaticamente
+	Auto-Smooth	Smussa automaticamente
 	Color Panel Options	Opzioni pannello Colore
 	Show Package	Mostra pacchetto
 	Show Panel	Mostra pannello
@@ -3086,6 +3087,7 @@ mark-style	Japanese	Giapponese
 	Simplify	Semplifica
 	Simplify:	Semplifica:
 	Simplify…	Semplifica…
+	Smooth…	Smussa…
 	Simulate Colored Paper	Simula carta colorata
 	Simulate Paper	Simula carta
 	Double Column	Colonna doppia
@@ -4044,6 +4046,7 @@ axis	Both	Entrambi
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio deve essere un numero da 0,1 a 10
 @msg	the Color Picker is not open	il Selettore colore non è aperto
 @msg	the Simplify slider is not open	il cursore Semplifica non è aperto
+@msg	the Smooth slider is not open	il cursore Smussa non è aperto
 @msg	the screen color sampler is already open	il campionatore di colore dello schermo è già aperto
 @msg	this system has no screen color sampler	questo sistema non ha un campionatore di colore dello schermo
 @msg	bad colour `{hex}` (#rrggbb)	colore non valido `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/ja.tsv

@@ -228,6 +228,7 @@ font-technology	Variable	バリアブル
 	Offset Path…	パスのオフセット…
 	Reverse Path Direction	パスの方向反転
 	Simplify…	単純化…
+	Smooth…	スムーズ…
 	Add Anchor Points	アンカーポイントの追加
 	Remove Anchor Points	アンカーポイントの削除
 	Divide Objects Below	背面のオブジェクトで型抜き
@@ -2850,6 +2851,7 @@ mark-style	Japanese	日本式
 	Show Original Path	元のパスを表示
 	Open this dialog with these settings next time	次回はこの設定でこのダイアログを開く
 	Auto-Simplify	自動単純化
+	Auto-Smooth	自動スムーズ
 	Color Panel Options	カラーパネルオプション
 	Show Package	パッケージを表示
 	Show Panel	パネルを表示
@@ -4367,6 +4369,7 @@ swatch	Bright Violet	ビビッドバイオレット
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio には 0.1 〜 10 の数値を指定してください
 @msg	the Color Picker is not open	カラーピッカーが開いていません
 @msg	the Simplify slider is not open	単純化スライダーが開いていません
+@msg	the Smooth slider is not open	スムーズスライダーが開いていません
 @msg	the screen color sampler is already open	画面のカラーサンプラーはすでに開いています
 @msg	this system has no screen color sampler	このシステムには画面のカラーサンプラーがありません
 @msg	Corners edits the corners of a path	「コーナー」で編集できるのはパスの角だけです

crates/ui-egui/src/i18n/ka.tsv

@@ -173,6 +173,7 @@
 	Offset Path…	ტრაექტორიის წანაცვლება…
 	Reverse Path Direction	ტრაექტორიის მიმართულების შებრუნება
 	Simplify…	გამარტივება…
+	Smooth…	გაგლუვება…
 	Add Anchor Points	საყრდენი წერტილების დამატება
 	Remove Anchor Points	საყრდენი წერტილების მოცილება
 	Divide Objects Below	ქვედა ობიექტების დაყოფა
@@ -4910,6 +4911,7 @@ imageTrace	Outline	კონტური
 @msg	the file's layers weren't read from its editing data ({_1}): they come from its PDF part	ფაილის შრეები რედაქტირების მონაცემებიდან ვერ წაიკითხა ({_1}): ისინი მისი PDF ნაწილიდან აიღება
 @msg	the Color Picker is not open	ფერის ამრჩევი გახსნილი არ არის
 @msg	the Simplify slider is not open	გამარტივების სლაიდერი გახსნილი არ არის
+@msg	the Smooth slider is not open	გაგლუვების სლაიდერი გახსნილი არ არის
 @msg	the screen color sampler is already open	ეკრანიდან ფერის აღება უკვე გახსნილია
 @msg	this system has no screen color sampler	ამ სისტემას ეკრანიდან ფერის აღების საშუალება არ აქვს
 # Dimension tool and Object › Dimensions. A drafting dimension is ზომა (ზომის დასმა), like a dimension on a technical drawing.
@@ -5070,6 +5072,7 @@ imageTrace	Outline	კონტური
 	Show Original Path	საწყისი ტრაექტორიის ჩვენება
 	Open this dialog with these settings next time	შემდეგ ჯერზე ამ დიალოგის ამ პარამეტრებით გახსნა
 	Auto-Simplify	ავტომატური გამარტივება
+	Auto-Smooth	ავტომატური გაგლუვება
 	Texture Image	ტექსტურის გამოსახულება
 @msg	check a layer to export	მონიშნეთ საექსპორტო შრე
 @msg	select the art to export first	ჯერ მონიშნეთ საექსპორტო ნახატი

crates/ui-egui/src/i18n/ko.tsv

@@ -224,6 +224,7 @@ font-technology	Variable	가변
 	Offset Path…	패스 오프셋…
 	Reverse Path Direction	패스 방향 반전
 	Simplify…	단순화…
+	Smooth…	매끄럽게…
 	Add Anchor Points	앵커 포인트 추가
 	Remove Anchor Points	앵커 포인트 제거
 	Divide Objects Below	아래 개체 나누기
@@ -2844,6 +2845,7 @@ mark-style	Japanese	일본식
 	Show Original Path	원래 패스 표시
 	Open this dialog with these settings next time	다음에 이 설정으로 이 대화상자 열기
 	Auto-Simplify	자동 단순화
+	Auto-Smooth	자동 매끄럽게
 	Color Panel Options	색상 패널 옵션
 	Show Package	패키지 표시
 	Show Panel	패널 표시
@@ -4299,6 +4301,7 @@ theme	Appearance	외관
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio은(는) 0.1에서 10 사이의 숫자여야 합니다
 @msg	the Color Picker is not open	색상 피커가 열려 있지 않습니다
 @msg	the Simplify slider is not open	단순화 슬라이더가 열려 있지 않습니다
+@msg	the Smooth slider is not open	매끄럽게 슬라이더가 열려 있지 않습니다
 @msg	the screen color sampler is already open	화면 색상 추출기가 이미 열려 있습니다
 @msg	this system has no screen color sampler	이 시스템에는 화면 색상 추출기가 없습니다
 @msg	Corners edits the corners of a path	모퉁이는 패스의 모퉁이를 편집합니다

crates/ui-egui/src/i18n/nl.tsv

@@ -222,6 +222,7 @@
 	Offset Path…	Pad verschuiven…
 	Reverse Path Direction	Padrichting omkeren
 	Simplify…	Vereenvoudigen…
+	Smooth…	Gladmaken…
 	Add Anchor Points	Ankerpunten toevoegen
 	Remove Anchor Points	Ankerpunten verwijderen
 	Divide Objects Below	Objecten eronder verdelen
@@ -5207,6 +5208,7 @@ swatch	Bright Violet	Felviolet
 	Show Original Path	Oorspronkelijk pad tonen
 	Open this dialog with these settings next time	Dit dialoogvenster de volgende keer met deze instellingen openen
 	Auto-Simplify	Automatisch vereenvoudigen
+	Auto-Smooth	Automatisch gladmaken
 @msg	check a layer to export	vink een laag aan om te exporteren
 @msg	select the art to export first	selecteer eerst de illustratie die je wilt exporteren
 @msg	no saved selection recalled	geen opgeslagen selectie opgeroepen

crates/ui-egui/src/i18n/pl.tsv

@@ -189,6 +189,7 @@
 	Offset Path…	Odsuń ścieżkę…
 	Reverse Path Direction	Odwróć kierunek ścieżki
 	Simplify…	Uprość…
+	Smooth…	Wygładź…
 	Add Anchor Points	Dodaj punkty kontrolne
 	Remove Anchor Points	Usuń punkty kontrolne
 	Divide Objects Below	Podziel obiekty poniżej
@@ -1675,6 +1676,7 @@ lighting	Light	Światło
 	Show Original Path	Pokaż oryginalną ścieżkę
 	Open this dialog with these settings next time	Następnym razem otwórz to okno dialogowe z tymi ustawieniami
 	Auto-Simplify	Uprość automatycznie
+	Auto-Smooth	Wygładź automatycznie
 	Transparency Options	Opcje przezroczystości
 	Color Mixer (Shift-click the chip)	Mikser kolorów (kliknij próbkę z Shift)
 	Fill: click for swatches, Shift-click for the color mixer	Wypełnienie: kliknij, aby wybrać próbkę, z Shift — mikser kolorów
@@ -4131,6 +4133,7 @@ imageTrace	Outline	Kontur
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio musi być liczbą od 0,1 do 10
 @msg	the Color Picker is not open	Próbnik kolorów nie jest otwarty
 @msg	the Simplify slider is not open	Suwak Uprość nie jest otwarty
+@msg	the Smooth slider is not open	Suwak Wygładź nie jest otwarty
 @msg	the screen color sampler is already open	narzędzie do pobierania koloru z ekranu jest już otwarte
 @msg	this system has no screen color sampler	ten system nie ma narzędzia do pobierania koloru z ekranu
 @msg	bad colour `{hex}` (#rrggbb)	nieprawidłowy kolor `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/pt-br.tsv

@@ -2498,6 +2498,7 @@
 	Show Original Path	Mostrar Caminho Original
 	Open this dialog with these settings next time	Abrir este diálogo com estas configurações na próxima vez
 	Auto-Simplify	Simplificar Automaticamente
+	Auto-Smooth	Suavizar Automaticamente
 	Show Package	Mostrar Pacote
 	Show Panel	Mostrar Painel
 	Show Perspective Grid	Mostrar Grade de Perspectiva
@@ -2535,6 +2536,7 @@
 	Simplify	Simplificar
 	Simplify:	Simplificar:
 	Simplify…	Simplificar…
+	Smooth…	Suavizar…
 	Simulate Colored Paper	Simular Papel Colorido
 	Simulate Paper	Simular Papel
 	Double Column	Coluna Dupla
@@ -5255,6 +5257,7 @@ mark-style	Japanese	Japonesas
 @msg	Unknown dimension option {k}	Opção de cota desconhecida {k}
 @msg	the Color Picker is not open	o Seletor de Cores não está aberto
 @msg	the Simplify slider is not open	o controle deslizante Simplificar não está aberto
+@msg	the Smooth slider is not open	o controle deslizante Suavizar não está aberto
 @msg	the screen color sampler is already open	o coletor de cores da tela já está aberto
 @msg	this system has no screen color sampler	este sistema não tem coletor de cores da tela
 	Darkness	Escuridão

crates/ui-egui/src/i18n/ru.tsv

@@ -3046,6 +3046,7 @@ mark-style	Japanese	Японский
 	Show Original Path	Показать исходный контур
 	Open this dialog with these settings next time	Открывать это диалоговое окно с этими параметрами в следующий раз
 	Auto-Simplify	Автоматическое упрощение
+	Auto-Smooth	Автоматическое сглаживание
 	Color Panel Options	Параметры панели «Цвет»
 	Show Package	Показать пакет
 	Show Panel	Показать панель
@@ -3082,6 +3083,7 @@ mark-style	Japanese	Японский
 	Simplify	Упростить
 	Simplify:	Упростить:
 	Simplify…	Упростить…
+	Smooth…	Сгладить…
 	Simulate Colored Paper	Имитировать цветную бумагу
 	Simulate Paper	Имитировать бумагу
 	Double Column	Двойной столбец
@@ -4040,6 +4042,7 @@ axis	Both	Оба
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio должно быть числом от 0,1 до 10
 @msg	the Color Picker is not open	палитра цветов не открыта
 @msg	the Simplify slider is not open	ползунок «Упростить» не открыт
+@msg	the Smooth slider is not open	ползунок «Сгладить» не открыт
 @msg	the screen color sampler is already open	средство выбора цвета с экрана уже открыто
 @msg	this system has no screen color sampler	в этой системе нет средства выбора цвета с экрана
 @msg	bad colour `{hex}` (#rrggbb)	недопустимый цвет `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/sv.tsv

@@ -2950,6 +2950,7 @@ font-technology	Variable	Variabla
 	Show Original Path	Visa ursprunglig bana
 	Open this dialog with these settings next time	Öppna den här dialogrutan med de här inställningarna nästa gång
 	Auto-Simplify	Förenkla automatiskt
+	Auto-Smooth	Jämna ut automatiskt
 	Show Package	Visa paket
 	Show Panel	Visa panel
 	Show Pattern Swatches	Visa mönsterprover
@@ -2984,6 +2985,7 @@ font-technology	Variable	Variabla
 	Simplify	Förenkla
 	Simplify:	Förenkla:
 	Simplify…	Förenkla…
+	Smooth…	Jämna ut…
 	Simulate Colored Paper	Simulera färgat papper
 	Simulate Paper	Simulera papper
 	Double Column	Dubbel kolumn
@@ -5304,6 +5306,7 @@ theme	Appearance	Utseende
 @msg	span: "selection" places the gradient itself: leave out `start` and `end` (they already place it in document coordinates)	span: "selection" placerar själva gradienten: utelämna `start` och `end` (de placerar den redan i dokumentkoordinater)
 @msg	the Color Picker is not open	färgväljaren är inte öppen
 @msg	the Simplify slider is not open	Förenkla-reglaget är inte öppet
+@msg	the Smooth slider is not open	Jämna ut-reglaget är inte öppet
 @msg	the action has no steps	åtgärden har inga steg
 @msg	the file's layers weren't read ({_1}): it comes in as its page, in one layer	filens lager lästes inte ({_1}): den hämtas in som en sida, i ett enda lager
 @msg	the file's layers weren't read from its editing data ({_1}): they come from its PDF part	filens lager lästes inte från dess redigeringsdata ({_1}): de kommer från dess PDF-del

crates/ui-egui/src/i18n/tr.tsv

@@ -2891,6 +2891,7 @@ font-technology	Variable	Değişken
 	Simplify	Basitleştir
 	Simplify:	Basitleştirin:
 	Simplify…	Basitleştir…
+	Smooth…	Düzgünleştir…
 	Simulate Colored Paper	Renkli Kağıdı Simüle Et
 	Simulate Paper	Kağıdı Simüle Et
 	Double Column	Çift Sütun
@@ -5249,11 +5250,13 @@ theme	Appearance	Görünüm
 @msg	nothing in data set {name} was applied: no object is bound to a variable it has a value for	{name} veri kümesinden hiçbir şey uygulanmadı: değer içerdiği bir değişkene bağlı hiçbir nesne yok
 @msg	select an Objects on Path group	bir Yol Üzerindeki Nesneler grubu seçin
 @msg	the Simplify slider is not open	Basitleştirme kaydırıcısı açık değil
+@msg	the Smooth slider is not open	Düzgünleştirme kaydırıcısı açık değil
 @msg	{_1} is an exporter (File › Export › Export As…)	{_1} bir dışa aktarma eklentisidir (Dosya › Dışa Aktar › Farklı Dışa Aktar…)
 @msg	`documentData` is {size} bytes (limit {MAX_DOCUMENT_DATA})	`documentData` {size} bayt (sınır {MAX_DOCUMENT_DATA})
 	Alt key toggles to Smooth Tool	Alt tuşu Düzleştirme Aracına geçiş yapar
 	Live curve fitting	Çizerken eğri uydurma
 	Auto-Simplify	Otomatik Basitleştir
+	Auto-Smooth	Otomatik Düzgünleştir
 	Drag an item here, or right-click one, to put it in this group.	Bu gruba eklemek için bir öğeyi buraya sürükleyin veya sağ tıklayın.
 	Drop here to take it out of its group	Grup dışına çıkarmak için buraya bırakın
 	Locate Selected Objects	Seçili Nesneleri Bul

crates/ui-egui/src/i18n/uk.tsv

@@ -3042,6 +3042,7 @@ mark-style	Japanese	Японський
 	Show Original Path	Показати початковий контур
 	Open this dialog with these settings next time	Наступного разу відкривати це діалогове вікно з цими параметрами
 	Auto-Simplify	Автоматичне спрощення
+	Auto-Smooth	Автоматичне згладжування
 	Color Panel Options	Параметри панелі «Колір»
 	Show Package	Показати пакет
 	Show Panel	Показати панель
@@ -3078,6 +3079,7 @@ mark-style	Japanese	Японський
 	Simplify	Спростити
 	Simplify:	Спростити:
 	Simplify…	Спростити…
+	Smooth…	Згладити…
 	Simulate Colored Paper	Імітувати кольоровий папір
 	Simulate Paper	Імітувати папір
 	Double Column	Подвійний стовпець
@@ -4028,6 +4030,7 @@ axis	Both	Обидві
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio має бути числом від 0,1 до 10
 @msg	the Color Picker is not open	палітра кольорів не відкрита
 @msg	the Simplify slider is not open	повзунок «Спростити» не відкрито
+@msg	the Smooth slider is not open	повзунок «Згладити» не відкрито
 @msg	the screen color sampler is already open	засіб вибору кольору з екрана вже відкритий
 @msg	this system has no screen color sampler	у цій системі немає засобу вибору кольору з екрана
 @msg	bad colour `{hex}` (#rrggbb)	неприпустимий колір `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/vi.tsv

@@ -3380,6 +3380,7 @@ mark-style	Japanese	Kiểu Nhật
 	Show Original Path	Hiện đường dẫn gốc
 	Open this dialog with these settings next time	Lần sau mở hộp thoại này với các cài đặt này
 	Auto-Simplify	Tự động đơn giản hóa
+	Auto-Smooth	Tự động làm mượt
 	Color Panel Options	Tùy chọn bảng màu
 	Show Package	Hiện gói
 	Show Panel	Hiện bảng
@@ -3420,6 +3421,7 @@ mark-style	Japanese	Kiểu Nhật
 	Simplify	Đơn giản hóa
 	Simplify:	Đơn giản hóa:
 	Simplify…	Đơn giản hóa…
+	Smooth…	Làm mượt…
 	Simulate Colored Paper	Giả lập giấy có màu
 	Simulate Paper	Giả lập giấy
 	Single Left Quotation Mark	Dấu nháy đơn mở
@@ -4210,6 +4212,7 @@ theme	Appearance	Giao diện
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio phải là một số từ 0,1 đến 10
 @msg	the Color Picker is not open	Bộ chọn màu chưa được mở
 @msg	the Simplify slider is not open	Thanh trượt Đơn giản hóa chưa được mở
+@msg	the Smooth slider is not open	Thanh trượt Làm mượt chưa được mở
 @msg	the screen color sampler is already open	công cụ lấy mẫu màu trên màn hình đã được mở
 @msg	this system has no screen color sampler	hệ thống này không có công cụ lấy mẫu màu trên màn hình
 @msg	bad colour `{hex}` (#rrggbb)	màu không hợp lệ `{hex}` (#rrggbb)

crates/ui-egui/src/i18n/zh-hans.tsv

@@ -2882,6 +2882,7 @@ font-script	Japanese	汉字
 	Show Original Path	显示原始路径
 	Open this dialog with these settings next time	下次以这些设置打开此对话框
 	Auto-Simplify	自动简化
+	Auto-Smooth	自动平滑
 	Color Panel Options	颜色面板选项
 	Show Package	显示打包
 	Show Panel	显示面板
@@ -2918,6 +2919,7 @@ font-script	Japanese	汉字
 	Simplify	简化
 	Simplify:	简化：
 	Simplify…	简化…
+	Smooth…	平滑…
 	Simulate Colored Paper	模拟有色纸张
 	Simulate Paper	模拟纸张
 	Double Column	双列
@@ -4098,6 +4100,7 @@ imageTrace	Outline	轮廓
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio 必须是 0.1 到 10 之间的数字
 @msg	the Color Picker is not open	拾色器未打开
 @msg	the Simplify slider is not open	简化滑块未打开
+@msg	the Smooth slider is not open	平滑滑块未打开
 @msg	the screen color sampler is already open	屏幕取色器已打开
 @msg	this system has no screen color sampler	此系统没有屏幕取色器
 @msg	Corners edits the corners of a path	转角用于编辑路径的转角

crates/ui-egui/src/i18n/zh-hant.tsv

@@ -2055,6 +2055,7 @@ file-filter	Templates	範本
 @msg	videoRulerPixelAspectRatio must be a number from 0.1 to 10	videoRulerPixelAspectRatio 必須是 0.1 到 10 之間的數字
 @msg	the Color Picker is not open	「顏色選擇器」未開啟
 @msg	the Simplify slider is not open	「簡化」滑桿未開啟
+@msg	the Smooth slider is not open	「平滑」滑桿未開啟
 @msg	the screen color sampler is already open	螢幕取色器已開啟
 @msg	this system has no screen color sampler	此系統沒有螢幕取色器
 @msg	Corners edits the corners of a path	「轉角」用於編輯路徑的轉角
@@ -3831,6 +3832,7 @@ font-script	Japanese	漢字
 	Show Original Path	顯示原始路徑
 	Open this dialog with these settings next time	下次以這些設定開啟此對話方塊
 	Auto-Simplify	自動簡化
+	Auto-Smooth	自動平滑
 	Color Panel Options	顏色面板選項
 	Show Package	顯示封裝
 	Show Panel	顯示面板
@@ -3867,6 +3869,7 @@ font-script	Japanese	漢字
 	Simplify	簡化
 	Simplify:	簡化：
 	Simplify…	簡化…
+	Smooth…	平滑…
 	Simulate Colored Paper	模擬有色紙張
 	Simulate Paper	模擬紙張
 	Double Column	雙欄

crates/ui-egui/src/menus/invoke.rs

@@ -54,6 +54,7 @@ pub(super) fn menu_dialog(app: &VectorcraftApp, id: &str) -> Option<(&'static st
         // "Open this dialog with these settings next time" was ticked.
         "object.path.simplify" if app.ui.simplify.is_object() => ("simplify", app.ui.simplify.clone()),
         "object.path.simplify" => (crate::dialogs::simplify_slider::KIND, crate::dialogs::simplify_slider::fields(app)),
+        "object.path.smooth" => (crate::dialogs::smooth_slider::KIND, crate::dialogs::smooth_slider::fields()),
         "object.path.splitIntoGrid" => {
             // The grid starts at the size of the selection.
             let size =

crates/ui-egui/src/menus/run.rs

@@ -695,6 +695,7 @@ fn run_ui_part10(app: &mut VectorcraftApp, id: &str, p: &Value) -> Option<Result
         "ui.expandDialog" => crate::dialogs::expand::open(app),
         "ui.simplifyAuto" => crate::dialogs::simplify_slider::auto(app),
         "ui.simplifyMoreOptions" => crate::dialogs::simplify_slider::more_options(app),
+        "ui.smoothAuto" => crate::dialogs::smooth_slider::auto(app),
         "attributes.openUrl" => crate::panels::attributes::open_url(app, p),
         "ui.javascriptFilesDialog" => crate::panels::svg_interactivity::files_dialog(app, p),
         "ui.spotColors" => crate::dialogs::spot_colors::open(app),

crates/ui-egui/src/menus/state.rs

@@ -237,6 +237,7 @@ pub fn enabled(app: &VectorcraftApp, id: &str) -> bool {
         "ui.spotColors" => app.session.active().is_some(),
         "ui.menuDialog" => app.session.active().is_some_and(|d| !d.selection.is_empty()),
         "ui.simplifyAuto" | "ui.simplifyMoreOptions" => crate::dialogs::simplify_slider::showing(app),
+        "ui.smoothAuto" => crate::dialogs::smooth_slider::showing(app),
         "ui.dxfOptionsDialog" => app.session.active().is_some(),
         "links.editOriginal" | "links.reveal" => selected_image(app, |im| im.link.is_some()) || selected_placed(app),
         "ui.placementOptionsDialog" => selected_image(app, |_| true) || selected_placed(app),

crates/ui-egui/src/menus/tree.rs

@@ -219,6 +219,7 @@ pub fn menu_tree_named(english_names: bool) -> Vec<(&'static str, Vec<Item>)> {
                         c("Reverse Path Direction", "path.reverse"),
                         Sep,
                         c("Simplify…", "object.path.simplify"),
+                        c("Smooth…", "object.path.smooth"),
                         c("Add Anchor Points", "object.path.addAnchorPoints"),
                         c("Remove Anchor Points", "path.removeAnchors"),
                         c("Divide Objects Below", "object.path.divideObjectsBelow"),

crates/ui-egui/src/menus/ui_commands.rs

@@ -838,7 +838,7 @@ pub const UI_COMMANDS: &[(&str, &str, &str, &str)] = &[
         "ui.menuDialog",
         "Menu Dialog",
         "",
-        "{command: object.move|object.rotate|object.scale|object.reflect|object.shear|object.transformEach|path.average|object.path.offsetPath|object.path.simplify|object.path.splitIntoGrid|object.vectorHalftone|artboard.rearrange|object.envelope.makeWithWarp|object.envelope.resetWithWarp|object.envelope.makeWithMesh|object.envelope.resetWithMesh|object.envelope.options} open the dialog that command's menu item opens (dialog kind: move, rotate, scale, reflect, shear, transformEach, …, vectorHalftone, rearrangeArtboards, envelopeWarp, envelopeMesh, envelopeOptions; Scale and Transform Each have `corners` and `strokes`, from the preferences, which OK updates; Transform Each opens on the values it was last confirmed with (not `copy`), and its Copy button confirms with `copy: true`; the envelope dialogs start from the selected envelope, Make opens as Reset (`reset: true`) while one is selected)",
+        "{command: object.move|object.rotate|object.scale|object.reflect|object.shear|object.transformEach|path.average|object.path.offsetPath|object.path.simplify|object.path.smooth|object.path.splitIntoGrid|object.vectorHalftone|artboard.rearrange|object.envelope.makeWithWarp|object.envelope.resetWithWarp|object.envelope.makeWithMesh|object.envelope.resetWithMesh|object.envelope.options} open the dialog that command's menu item opens (dialog kind: move, rotate, scale, reflect, shear, transformEach, …, vectorHalftone, rearrangeArtboards, envelopeWarp, envelopeMesh, envelopeOptions; Scale and Transform Each have `corners` and `strokes`, from the preferences, which OK updates; Transform Each opens on the values it was last confirmed with (not `copy`), and its Copy button confirms with `copy: true`; the envelope dialogs start from the selected envelope, Make opens as Reset (`reset: true`) while one is selected)",
     ),
     (
         "ui.widthPointEdit",
@@ -858,6 +858,12 @@ pub const UI_COMMANDS: &[(&str, &str, &str, &str)] = &[
         "",
         "{} the open Simplify slider (Object › Path › Simplify opens it: dialog `simplifySlider` with field `level` 0..100, object.path.simplify's level, opening at the level object.path.simplify {auto: true} picks for the selection, previewed on the canvas until ui.dialog.confirm keeps it as one undo step; after OK in the Simplify dialog with `retain` ticked, the menu item opens the dialog `simplify` with the fields of that OK instead) moves to the level object.path.simplify {auto: true} picks for the selection and previews it → {level}; an error when the slider isn't open",
     ),
+    (
+        "ui.smoothAuto",
+        "Auto-Smooth",
+        "",
+        "{} the open Smooth slider (Object › Path › Smooth opens it: dialog `smoothSlider` with field `level` 0..100, object.path.smooth's level, opening at the level object.path.smooth {auto: true} picks, previewed on the canvas until ui.dialog.confirm keeps it as one undo step) moves to the level object.path.smooth {auto: true} picks and previews it → {level}; an error when the slider isn't open",
+    ),
     (
         "ui.simplifyMoreOptions",
         "More Options",

docs/mcp.md

@@ -2569,6 +2569,23 @@ dialog `simplifySlider` with field `level`) at the Auto-Simplify level for the s
 opens the Simplify dialog at the slider's tolerance. When OK confirms the dialog with `retain` ticked, the menu item opens
 the dialog on those settings next time.
 
+## Smooth
+
+`object.path.smooth` smooths the selected paths (or the objects in `ids`), compound path members included, as one undo
+step. `level` is the Smooth slider's, a whole number from 0 (minimum smoothing: the path stays within 0.1% of its longer
+side) to 100 (maximum smoothing); `auto: true` (Auto-Smooth) uses level 50, the default. Each path is refitted with
+curves within 0.1% to 2.5% of its longer side, keeping a corner only where it turns back on itself, so jags and kinks
+become curves; a refit never has more anchor points than the path had, so a shape whose corners the tolerance can't
+round, such as a rectangle, stays as it is. Closed paths stay closed and open paths keep their end points. The reply has the anchor counts `before` and `after` and the `level` used:
+
+```json
+{"name":"run_command","arguments":{"command":"object.path.smooth","params":{"level":80}}}
+```
+
+In the desktop app, Object › Path › Smooth opens the slider (`ui.menuDialog {command: "object.path.smooth"}`, dialog
+`smoothSlider` with field `level`) at the Auto-Smooth level and previews the result until `ui.dialog.confirm`;
+`ui.smoothAuto` moves the open slider back to the Auto-Smooth level.
+
 ## Editing a path with the Curvature tool
 
 The Curvature tool edits any selected path, whatever drew it, keeping its shape except where edited (#798). Each edit

docs/target-app-parity.md

@@ -786,6 +786,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
     The Simplify dialog also has Corner Point Angle Threshold, Convert to Straight Lines and Show Original Path. The threshold is a slider from 0° to 180° and opens at 150°: an anchor whose corner is sharper than the threshold stays a corner, so moving the slider right keeps more corners, and the dialog sends `cornerAngle` as 180° less the threshold. While Preview is on, Show Original Path draws the paths as they were before the preview in a wide, faint band of their layer's color under the selection's outlines.
     Object › Path › Simplify opens a slider under the selection ([Manually simplify paths](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/manually-simplify-paths.html), [Auto simplify paths](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/auto-simplify-paths.html)) with Auto-Simplify, a rail from the fewest anchor points to the closest fit, and More Options, which opens the dialog at the slider's tolerance. The rail's levels are VectorCraft's own scale (`object.path.simplify {level}`): level 50 is 1 pt, and every 10 levels halve or double the tolerance, from 32 pt at 0 to 1/32 pt at 100. Auto-Simplify picks the lowest level whose tolerance is at most 1/400 of the selection's longer side, or level 100 when that side is under 12.5 pt; the slider opens at that level, with its result previewed, as the manual-simplify page describes. The dialog's "Open this dialog with these settings next time" makes the menu item open the dialog on the settings of its last OK.
     With anchors or segments of a path selected with Direct Selection, Simplify acts on just that part of the path, as the [Manually simplify paths](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/manually-simplify-paths.html) page puts it: the slider, Auto-Simplify and the dialog refit only each run of selected segments, between its end anchors, which keep their place and their handles on the side away from the run. The anchors and segments outside the runs stay exactly as they were, a closed path's run may cross its start point, separate runs on one path are refitted independently in one undo step, and the runs stay selected. A path with only lone anchors selected is still simplified whole, and `object.path.simplify {wholePaths: true}` simplifies partly selected paths whole. Tests: `crates/engine/src/tests/simplify_part.rs` and `simplify_slider_and_dialog_simplify_only_the_direct_selected_part_of_a_path`.
+    Object › Path › Smooth… (#4115) opens a slider under the selection from Minimum to Maximum smoothing with an Auto-Smooth button, as the [Smooth slider](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/refine-path-segments-with-the-smooth-slider.html) page describes; the canvas previews it and Enter or a click outside keeps it as one undo step (`object.path.smooth {level, auto, ids}`). The page names only the ends, so the rest is VectorCraft's own rule: each selected path, compound path members included, is refitted with curves within 0.1% (level 0) to 2.5% (level 100) of its longer side, corners kept only where it turns back and never with more anchors (a rectangle stays as it is); Auto-Smooth is level 50. Closed paths stay closed and open ones keep their end points. Tests: `crates/engine/src/tests/smooth_path.rs` and `smooth_slider_previews_auto_smooth_and_keeps_the_result`.
 - **Devanagari shaping:** with an OpenType Devanagari font, Ka, virama and Ssa (क्ष) form one conjunct glyph, Ra and virama before a consonant (र्क) become a reph drawn after it, the i matra (कि) is drawn before its consonant, and Ka with a nukta is drawn like the precomposed क़ (U+0958), as [Microsoft's Devanagari shaping specification](https://learn.microsoft.com/en-us/typography/script-development/devanagari) describes. Each syllable is one cluster of its source bytes, and the arrow keys stop at its ends. A click inside a syllable drawn with several glyphs puts the caret at the syllable's nearer end, in point, area and path type. Tests: `crates/text/src/tests/devanagari.rs`; they print SKIPPED when no such font is installed.
 - **Vertical punctuation:** fullwidth `！` (U+FF01) and `？` (U+FF1F) use their nominal glyph upright when no vertical alternate is present, following the Tu fallback in [Unicode UAX #50 §3.1](https://www.unicode.org/reports/tr50/#vo). Code-built test fonts cover point and area type with and without `vert` alternates, retain the rotated fallback for a bracket and long vowel mark, and leave horizontal type unchanged. Tests: `crates/text/src/tests/vertical.rs`.
   - Free Distort's dialog (Effect › Distort & Transform › Free Distort…) shows a box in the proportions of the first selected object's bounds with a handle on each corner. Dragging a handle moves that corner. A handle focused by a click or Tab moves 1% of the box with each arrow key, and 10% with Shift. Reset puts the four corners back on the box. The preview and OK run `effect.apply`, or `effect.setParams` when the dialog edits an applied effect, and the Appearance panel's inline editor opens the dialog with Edit…. Behavior reference: Illustrator CC Help (2014, [PDF](https://help.adobe.com/archive/en/illustrator/cc/2014/illustrator_reference.pdf)), page 285 (PDF page 291).
@@ -1168,6 +1169,7 @@ applies to fills). Tests: `color::gradient::tests` (perceptual midpoint, expansi
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-29 | minor | Object › Path › Smooth… with its slider and Auto-Smooth (#4115) added to the evidence; score and hours unchanged. |
 | 2026-10-26 | minor | File formats: EPS Save and Save As: an opened EPS saves back to its own path as EPS, keeping the chosen artboard's page frame and transparent margins and the complete editable VectorCraft document; Save's TIFF preview is capped at 1024 px (Export keeps 2048); partly read, preview-only or damaged-editing-data sources still need confirmation before they are overwritten; evidence added ([file-format-parity.md](file-format-parity.md#eps-save-and-source-protection)); writing Illustrator's editing data (#868) and the `.ai` structure issues stay in the missing items; score and hours unchanged (estimated) |
 | 2026-10-26 | minor | View & navigation: New View… / Edit Views… taken off the missing items (all 25 saved views in the View menu, an Edit Views… list dialog, views checked on open); evidence added; score and hours unchanged. |
 | 2026-10-25 | minor | Type core: a double-click on a threaded port breaks the thread there (`text.thread.break`); evidence added; scores unchanged. |

docs/ui-parity.md

@@ -99,6 +99,7 @@ tools, never checked side by side) isn't captured row by row.
 | Smooth tool smooths only the stretch of path under the drag | done | #1512 |
 | Drawing modes apply to pastes: Draw Inside takes Paste, Paste in Place and Paste on All Artboards inside the object; Draw Behind puts Paste in Place and Paste on All Artboards behind the selection; Shift+D cycles past Draw Behind with any selection ([drawing modes](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/learn-drawing-basics/drawing-modes-overview.html)) | done | #3705; `pasting_in_draw_inside_puts_the_copies_inside_the_object`, `paste_in_place_in_draw_behind_goes_behind_the_selection`, `shift_d_goes_past_draw_behind_whatever_is_selected` |
 | Simplify (slider, auto, corner angle threshold), of a whole path or of the part of it selected with Direct Selection ([manually simplify paths](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/manually-simplify-paths.html)) | done | Tolerance, default-on Preview and original/new point counts (#1272); Corner Point Angle Threshold, Convert to Straight Lines and Show Original Path; the slider under the selection with Auto-Simplify and More Options, opening at the Auto-Simplify level for the selection with that result previewed, and the dialog's option to open it directly with its last settings. With anchors or segments direct-selected, the slider, Auto-Simplify and the dialog refit only each run of selected segments between its end anchors, a closed path's run across its start point included; the rest of the path stays exactly as it was (`tests/simplify_part.rs`, `simplify_slider_and_dialog_simplify_only_the_direct_selected_part_of_a_path`) |
+| Smooth (Object › Path › Smooth…: slider from minimum to maximum smoothing, Auto-Smooth) ([smooth slider](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/refine-path-segments-with-the-smooth-slider.html)) | done | #4115: the slider under the selection previews `object.path.smooth {level}`, Auto-Smooth picks level 50, Enter or a click outside keeps one undo step and Escape restores; the smoothing rule beyond the two ends is VectorCraft's own (`tests/smooth_path.rs`, `smooth_slider_previews_auto_smooth_and_keeps_the_result`) |
 | Draw Inside in isolation mode: art drawn or pasted inside the isolated object takes isolation mode into its clip group, clickable and undimmed ([isolation mode](https://helpx.adobe.com/illustrator/desktop/manage-objects/select-objects/isolate-objects.html), [drawing modes](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/learn-drawing-basics/drawing-modes-overview.html)) | done | #3705; `drawing_inside_an_isolated_object_keeps_the_new_art_in_isolation_mode` |
 | Simplify (slider, auto, corner angle threshold) | partial | Tolerance, default-on Preview and original/new point counts (#1272); Corner Point Angle Threshold, Convert to Straight Lines and Show Original Path; the slider under the selection with Auto-Simplify and More Options, and the dialog's option to open it directly with its last settings; the slider opens at 1 pt rather than at the Auto-Simplify level, and simplifying only a Direct Selection part of a path remains missing |
 | Simplify (slider, auto, corner angle threshold) | partial | Tolerance, default-on Preview and original/new point counts (#1272); Corner Point Angle Threshold, Convert to Straight Lines and Show Original Path; the slider under the selection with Auto-Simplify and More Options, opening at the Auto-Simplify level for the selection with that result previewed, and the dialog's option to open it directly with its last settings; simplifying only a Direct Selection part of a path remains missing |
@@ -357,6 +358,7 @@ separate. Scores and hours unchanged. [Behavior and command details](development
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-29 | minor | Object › Path › Smooth… with its slider and Auto-Smooth (#4115); scores and estimates unchanged |
 | 2026-10-25 | minor | Selection tool: a double-click on a threaded port breaks the thread there (`text.thread.break`); scores and estimates unchanged |
 | 2026-10-25 | minor | A selected Grid Repeat shows handles: the one below the grid adds or removes rows, the one right of it columns, the one past its bottom-right corner both, and the sliders between the first two columns and rows set the horizontal and vertical spacing; each drag is one undo step and Escape cancels it (#2691); headless canvas and tool regressions; scores and estimates unchanged. |
 | 2026-10-25 | minor | Floating panels open in OS windows of their own on the desktop (inside the window on the web and on Wayland); saved layouts from earlier versions convert to the shared docking layout (#4135); scores and estimates unchanged (estimated) |