Merge pull request #2537 from vangel76/feat/2530-tangent-perpendicular-snap

Snapping: tangent and perpendicular snapping, View > Snapping (#2530)

crates/engine/src/cmd/prefscmds.rs

@@ -235,6 +235,8 @@ pub const PREF_SPECS: &[PrefSpec] = &[
     p!("measurementLabels", "Smart Guides", "Display Options", "Measurement Labels", bool),
     p!("spacingGuides", "Smart Guides", "Display Options", "Spacing Guides", bool),
     p!("snappingTolerance", "Smart Guides", "", "Snapping Tolerance", num(0.0, 40.0, "pt")),
+    p!("snapTangent", "Smart Guides", "Geometric Guides", "Snap to Tangent", bool),
+    p!("snapPerpendicular", "Smart Guides", "Geometric Guides", "Snap to Perpendicular", bool),
     // Slices
     p!("showSliceNumbers", "Slices", "", "Show Slice Numbers", bool),
     p!("sliceLineColor", "Slices", "", "Line Color", color),

crates/engine/src/lib.rs

@@ -969,6 +969,8 @@ pub struct Prefs {
     pub measurement_labels: bool,
     pub spacing_guides: bool,
     pub snapping_tolerance: f64,
+    pub snap_tangent: bool,
+    pub snap_perpendicular: bool,
     // Slices
     pub show_slice_numbers: bool,
     pub slice_line_color: String,
@@ -1218,6 +1220,8 @@ impl Default for Prefs {
             measurement_labels: true,
             spacing_guides: true,
             snapping_tolerance: 4.0,
+            snap_tangent: true,
+            snap_perpendicular: true,
             show_slice_numbers: true,
             slice_line_color: s("#ff3f3f"),
             hyphenation_language: s("English: USA"),

crates/engine/src/tooling.rs

@@ -238,6 +238,8 @@ impl Session {
             // wins instead of pixels quietly rounding every drag to whole points (#1816).
             snap_to_pixel: view.snap_to_pixel && !view.snap_to_grid,
             snap_to_point: view.snap_to_point,
+            snap_tangent: self.prefs.snap_tangent,
+            snap_perpendicular: self.prefs.snap_perpendicular,
             snap_to_glyph: view.snap_to_glyph && view.smart_guides && !view.snap_to_grid,
             corner_widgets: view.corner_widgets,
             fill_active: self.fill_active,

crates/tools/src/draw2/curvature.rs

@@ -376,8 +376,8 @@ impl CurvatureTool {
     /// and the segment to it: the path being drawn, or the selected one whose end is current.
     fn leave(&self, cx: &ToolContext) -> Option<(NodeId, Leave)> {
         match self.active(cx) {
-            Some(id) => self.pts.last().map(|(p, _)| (id, Leave::segment(cx, *p, false))),
-            None => current_end(cx).map(|e| (e.id, Leave::segment(cx, e.p, false))),
+            Some(id) => self.pts.last().map(|(p, _)| (id, Leave::segment(cx, *p, false).without_contact())),
+            None => current_end(cx).map(|e| (e.id, Leave::segment(cx, e.p, false).without_contact())),
         }
     }
 
@@ -420,7 +420,7 @@ impl CurvatureTool {
             return Some(out);
         }
         if let Some(e) = end {
-            let q = self.snap.press(cx, p, &[e.id], Some(&Leave::segment(cx, e.p, false)));
+            let q = self.snap.press(cx, p, &[e.id], Some(&Leave::segment(cx, e.p, false).without_contact()));
             let how = self.how(&e);
             self.placed = Some(Placed { id: e.id, si: e.si, start: e.start, anchors: e.anchors + 1, corner: ev.mods.alt });
             let v = json!({"id": e.id.0, "subpath": e.si, "op": "extend", "end": e.name(), "x": q.x, "y": q.y, "from": how.name(), "corner": ev.mods.alt});

crates/tools/src/guides.rs

@@ -13,8 +13,8 @@ use std::sync::Arc;
 
 use vectorcraft_doc::hit::{HitOptions, hit_test};
 use vectorcraft_doc::{Document, Node, NodeId, NodeKind, OrientedBox, Selection};
-use vectorcraft_geom::kurbo::ParamCurveNearest;
-use vectorcraft_geom::{Affine, Line, ParamCurve, PathSeg, Point, Rect, Shape, SubPath, Vec2, constrain_angle_from};
+use vectorcraft_geom::kurbo::{ParamCurveDeriv, ParamCurveNearest};
+use vectorcraft_geom::{Affine, BezPath, Line, ParamCurve, PathSeg, Point, Rect, Shape, SubPath, Vec2, constrain_angle_from};
 use vectorcraft_text::{FontDb, layout as layout_text};
 
 use crate::bbox::Handle;
@@ -89,6 +89,10 @@ pub struct Targets {
     /// it ends, as the end that stays put and the unit direction towards the dragged one
     /// ([`Self::for_anchor_drag`]).
     extensions: Vec<(Point, Vec2)>,
+    /// Snap to Tangent and Snap to Perpendicular: a drawn line from an anchor lands where it
+    /// grazes a curve, or meets a segment square ([`Self::touching`]).
+    tangent: bool,
+    perpendicular: bool,
     /// How the guides these targets produce look.
     style: GuideStyle,
 }
@@ -560,6 +564,11 @@ impl Targets {
         if let Some(q) = self.crossing(p, tol) {
             return (q, self.label(q, "intersect").into_iter().collect());
         }
+        if let Some(f) = from.filter(|f| f.contact)
+            && let Some((q, perpendicular, dir)) = self.touching(f.at, p, tol)
+        {
+            return (q, self.touch_guides(f.at, q, perpendicular, dir, tol));
+        }
         if let Some(q) = self.on_segment(p, tol) {
             return (q, self.label(q, Kind::Edge.label()).into_iter().collect());
         }
@@ -602,6 +611,52 @@ impl Targets {
         (out, ov)
     }
 
+    /// Where a line from `at` through a point near `p` touches a target segment: square to it
+    /// (`perpendicular`, the foot of the perpendicular from `at`) or just grazing a curve
+    /// (`tangent`), within `tol` of `p`. The point, whether it is the perpendicular one, and the
+    /// segment's direction there. Targets gather segments for drawn points and dragged anchors only.
+    fn touching(&self, at: Point, p: Point, tol: f64) -> Option<(Point, bool, Vec2)> {
+        if !(self.tangent || self.perpendicular) || ![at.x, at.y, p.x, p.y, tol].iter().all(|v| v.is_finite()) {
+            return None;
+        }
+        let mut best: Option<(f64, Point, bool, Vec2)> = None;
+        // Every segment in reach is tried: their order is the document's, not the distance.
+        for (_, seg) in self.segments.iter().filter(|(b, _)| b.inflate(tol, tol).contains(p)) {
+            let curved = !matches!(seg, PathSeg::Line(_));
+            for (perpendicular, wanted) in [(true, self.perpendicular && !curved), (false, self.tangent && curved)] {
+                if !wanted {
+                    continue;
+                }
+                for t in touch_params(seg, at, perpendicular) {
+                    let (q, d) = (seg.eval(t), seg_direction(seg, t));
+                    let dist = q.distance(p);
+                    if dist <= tol && q.distance(at) > tol && best.is_none_or(|b| dist < b.0) {
+                        best = Some((dist, q, perpendicular, d));
+                    }
+                }
+            }
+        }
+        best.map(|(_, q, perpendicular, d)| (q, perpendicular, d))
+    }
+
+    /// The guides of a point landed where the line from `at` touches a segment at `q` running
+    /// along `dir`: the line itself, a square corner mark for the perpendicular, and the label.
+    fn touch_guides(&self, at: Point, q: Point, perpendicular: bool, dir: Vec2, tol: f64) -> Vec<Overlay> {
+        let mut out: Vec<Overlay> = self.line(at, q).into_iter().collect();
+        let (u, v) = (at - q, dir);
+        if perpendicular && self.style.lines && u.hypot2() > 1e-18 && v.hypot2() > 1e-18 {
+            let (u, v) = (u / u.hypot(), v / v.hypot());
+            let s = tol * 1.5;
+            let mut mark = BezPath::new();
+            mark.move_to(q + u * s);
+            mark.line_to(q + u * s + v * s);
+            mark.line_to(q + v * s);
+            out.push(Overlay::Path { path: mark, color: self.style.color, width: 1.0, dashed: false });
+        }
+        out.extend(self.label(q, if perpendicular { "perpendicular" } else { "tangent" }));
+        out
+    }
+
     /// The segment extension nearest `p`, within `tol` of it (and `p` farther than that from the
     /// end it starts at): that end, its direction and where `p` lands on it. Where `p` is nearer
     /// the horizontal or the vertical through that end there is none: lining up with it ("align")
@@ -1123,6 +1178,53 @@ fn meeting(a: &PathSeg, b: &PathSeg, p: Point) -> Option<Point> {
     None
 }
 
+/// The direction of `seg` at `t` (not normalised; zero in a cusp).
+fn seg_direction(seg: &PathSeg, t: f64) -> Vec2 {
+    match seg {
+        PathSeg::Line(l) => l.p1 - l.p0,
+        PathSeg::Quad(q) => q.deriv().eval(t).to_vec2(),
+        PathSeg::Cubic(c) => c.deriv().eval(t).to_vec2(),
+    }
+}
+
+/// The parameters in (0, 1) where the line from `at` to `seg` is square to it (`perpendicular`)
+/// or grazes it, found by sampling the curve for a change of sign and bisecting.
+fn touch_params(seg: &PathSeg, at: Point, perpendicular: bool) -> Vec<f64> {
+    const STEPS: usize = 24;
+    let f = |t: f64| {
+        let (v, d) = (seg.eval(t) - at, seg_direction(seg, t));
+        if perpendicular { v.dot(d) } else { v.cross(d) }
+    };
+    let mut out = vec![];
+    let mut prev = (0.0, f(0.0));
+    for i in 1..=STEPS {
+        let t = i as f64 / STEPS as f64;
+        let cur = (t, f(t));
+        if prev.1.is_finite() && cur.1.is_finite() && prev.1 * cur.1 < 0.0 {
+            let (mut lo, mut hi) = (prev, cur);
+            for _ in 0..40 {
+                let mid = 0.5 * (lo.0 + hi.0);
+                let m = (mid, f(mid));
+                if lo.1 * m.1 <= 0.0 {
+                    hi = m;
+                } else {
+                    lo = m;
+                }
+            }
+            let t = 0.5 * (lo.0 + hi.0);
+            // A jump through a cusp changes sign without crossing zero: the line must really
+            // run along (or square to) the curve there.
+            let (v, d) = (seg.eval(t) - at, seg_direction(seg, t));
+            let scale = v.hypot() * d.hypot();
+            if scale > 1e-12 && f(t).abs() <= 1e-3 * scale {
+                out.push(t);
+            }
+        }
+        prev = cur;
+    }
+    out
+}
+
 /// Snap `p` for a drawing tool when smart guides (or grid snapping) are on.
 pub fn snap_draw(cx: &ToolContext, p: Point, exclude: &[NodeId]) -> (Point, Vec<Overlay>) {
     snap_with(cx, p, || Targets::collect(cx.doc, exclude, None))
@@ -1148,7 +1250,8 @@ impl PointSnap {
             None
         } else if cx.smart_guides {
             // Snap to Point keeps pulling points onto the ruler guides with Smart Guides on (#812).
-            let t = targets().styled(cx);
+            let mut t = targets().styled(cx);
+            (t.tangent, t.perpendicular) = (cx.snap_tangent, cx.snap_perpendicular);
             Some((if cx.snap_to_point { t.with_rulers(cx) } else { t }, cx.snapping_tolerance))
         } else if cx.snap_to_point {
             Some((targets().for_snap_to_point(cx), cx.snap_tolerance))
@@ -1247,6 +1350,8 @@ pub struct Leave {
     shift: Option<Keep>,
     /// The angles of the construction guides through `at` (none with them off).
     angles: &'static [f64],
+    /// A drawn segment: it may land square to a segment or grazing a curve (a box does not).
+    contact: bool,
 }
 
 impl Leave {
@@ -1257,14 +1362,21 @@ impl Leave {
             at,
             shift: shift.then_some(Keep::Angle { step: 45.0, base: cx.constrain_angle }),
             angles: if cx.smart_guides { cx.construction_angles } else { &[] },
+            contact: true,
         }
     }
 
+    /// A curved source cannot make a line-to-line perpendicular or line-to-curve tangent contact.
+    pub fn without_contact(mut self) -> Self {
+        self.contact = false;
+        self
+    }
+
     /// A box dragged from its corner or centre `at` (Rectangle, Ellipse, Arc, the grids, and
     /// Artboard, which passes no Shift): Shift keeps the dragged corner on a diagonal, the box a
     /// square.
     pub fn diagonal(at: Point, shift: bool) -> Self {
-        Self { at, shift: shift.then_some(Keep::Square), angles: &[] }
+        Self { at, shift: shift.then_some(Keep::Square), angles: &[], contact: false }
     }
 
     /// Where Shift puts `p`: none without it.
@@ -1324,7 +1436,7 @@ struct SnapKey {
     revision: (u64, u64),
     exclude: Vec<NodeId>,
     screen: Option<ScreenFrame>,
-    view: [bool; 5],
+    view: [bool; 7],
     snap_to_glyph: bool,
     style: GuideStyle,
     tolerances: [f64; 2],
@@ -1336,7 +1448,7 @@ impl SnapKey {
             revision: cx.revision,
             exclude: exclude.to_vec(),
             screen: cx.screen,
-            view: [cx.smart_guides, cx.snap_to_point, cx.snap_to_pixel, cx.snap_to_grid, cx.guides],
+            view: [cx.smart_guides, cx.snap_to_point, cx.snap_to_pixel, cx.snap_to_grid, cx.guides, cx.snap_tangent, cx.snap_perpendicular],
             snap_to_glyph: cx.snap_to_glyph && cx.alignment_guides,
             style: GuideStyle::of(cx),
             tolerances: [cx.snapping_tolerance, cx.snap_tolerance],
@@ -1868,6 +1980,104 @@ mod tests {
         assert_eq!(labels(&t.snap_from(Point::new(170.0, 201.0), None, 4.0).1), ["path"]);
     }
 
+    #[test]
+    fn perpendicular_snapping_rejects_a_curved_target() {
+        let (mut d, _) = doc_with_rect();
+        let layer = d.layers[0].id;
+        let id = d.alloc_id();
+        d.insert(
+            Some(layer),
+            1,
+            vectorcraft_doc::Node::path(
+                id,
+                vectorcraft_geom::shapes::ellipse(Rect::new(450.0, 450.0, 550.0, 550.0)),
+                vectorcraft_doc::Appearance::default_art(),
+            ),
+        )
+        .unwrap();
+        let targets = Targets { tangent: false, perpendicular: true, ..Targets::for_drawing(&d, &[], None, false) };
+        assert!(targets.touching(Point::new(400.0, 500.0), Point::new(450.0, 500.0), 4.0).is_none());
+        assert!(targets.touching(Point::new(300.0, 160.0), Point::new(200.0, 160.0), 4.0).is_some());
+    }
+
+    /// A line drawn from an anchor lands square to a segment (the foot of its perpendicular) and
+    /// just grazing a curve, with a guide and a label; the options switch each off, and the
+    /// result is the same each time and survives non-finite input.
+    #[test]
+    fn drawn_lines_land_perpendicular_to_segments_and_tangent_to_curves() {
+        use vectorcraft_doc::{Appearance, Node};
+        use vectorcraft_geom::shapes;
+        let (mut d, _) = doc_with_rect();
+        let l = d.layers[0].id;
+        let id = d.alloc_id();
+        d.insert(Some(l), 1, Node::path(id, shapes::ellipse(Rect::new(450.0, 450.0, 550.0, 550.0)), Appearance::default_art())).unwrap();
+        let (s, p) = (Selection::default(), paint());
+        let c = cx(&d, &s, &p);
+        let snap = |c: &ToolContext, from: Point, to: Point| {
+            let leave = Leave::segment(c, from, false);
+            PointSnap::new(c, || Targets::for_drawing(&d, &[], None, false)).snap_from(c, to, Some(&leave))
+        };
+        // From (300, 160) the rect's right side (x = 200) is square at (200, 160).
+        let (q, ov) = snap(&c, Point::new(300.0, 160.0), Point::new(202.0, 163.0));
+        assert!((q - Point::new(200.0, 160.0)).hypot() < 1e-6, "{q:?}");
+        assert_eq!(labels(&ov), ["perpendicular"]);
+        assert_eq!(lines(&ov), vec![(Point::new(300.0, 160.0), q)]);
+        assert!(ov.iter().any(|o| matches!(o, Overlay::Path { .. })), "the square corner mark: {ov:?}");
+        assert_eq!(snap(&c, Point::new(300.0, 160.0), Point::new(202.0, 163.0)).0, q, "deterministic");
+        // Off, the point only lands on the path, where the pointer is.
+        let curved = Leave::segment(&c, Point::new(300.0, 160.0), false).without_contact();
+        let (_, ov) = PointSnap::new(&c, || Targets::for_drawing(&d, &[], None, false)).snap_from(&c, Point::new(202.0, 163.0), Some(&curved));
+        assert!(!labels(&ov).contains(&"perpendicular"));
+        let off = ToolContext { snap_perpendicular: false, ..cx(&d, &s, &p) };
+        let (q, ov) = snap(&off, Point::new(300.0, 160.0), Point::new(202.0, 163.0));
+        assert_eq!((q, labels(&ov)), (Point::new(200.0, 163.0), vec!["path"]));
+        // The circle (centre (500, 500), radius 50) seen from (400, 500): the tangent points are 60°
+        // round from the way back, at (475, 456.7) and (475, 543.3).
+        let (q, ov) = snap(&c, Point::new(400.0, 500.0), Point::new(477.0, 459.0));
+        assert_eq!(labels(&ov), ["tangent"]);
+        assert!((q - Point::new(475.0, 500.0 - 1875f64.sqrt())).hypot() < 0.1, "{q:?}");
+        assert!(((q - Point::new(400.0, 500.0)).dot(q - Point::new(500.0, 500.0))).abs() < 20.0, "{q:?}");
+        let none = ToolContext { snap_tangent: false, ..cx(&d, &s, &p) };
+        assert!(!labels(&snap(&none, Point::new(400.0, 500.0), Point::new(477.0, 459.0)).1).contains(&"tangent"));
+        // Out of reach, or with nothing finite to go on: left alone, no panic.
+        assert_eq!(snap(&c, Point::new(300.0, 160.0), Point::new(250.0, 175.0)).0, Point::new(250.0, 175.0));
+        let t = Targets::for_drawing(&d, &[], None, false);
+        let t = Targets { tangent: true, perpendicular: true, ..t };
+        for bad in [f64::NAN, f64::INFINITY] {
+            assert!(t.touching(Point::new(bad, 1.0), Point::new(200.0, 160.0), 4.0).is_none());
+            assert!(t.touching(Point::new(300.0, 160.0), Point::new(bad, 1.0), 4.0).is_none());
+            assert!(t.touching(Point::new(300.0, 160.0), Point::new(200.0, 160.0), bad).is_none());
+        }
+    }
+
+    /// A box dragged from a corner (Rectangle, Ellipse, ...) never snaps square to a segment, and
+    /// a busy spot does not hide the contact: every segment in reach is tried.
+    #[test]
+    fn contact_snaps_only_for_segments_and_in_busy_spots() {
+        use vectorcraft_geom::kurbo::Line;
+        let (d, _) = doc_with_rect();
+        let (s, p) = (Selection::default(), paint());
+        let c = cx(&d, &s, &p);
+        let snap = |t: &Targets, leave: &Leave| t.snap_from(Point::new(202.0, 163.0), Some(leave), 4.0);
+        let t = Targets { tangent: true, perpendicular: true, ..Targets::for_drawing(&d, &[], None, false) };
+        let (_, ov) = snap(&t, &Leave::segment(&c, Point::new(300.0, 160.0), false));
+        assert_eq!(labels(&ov), ["perpendicular"]);
+        let (_, ov) = snap(&t, &Leave::diagonal(Point::new(300.0, 160.0), false));
+        assert!(!labels(&ov).contains(&"perpendicular"), "{ov:?}");
+        // 70 short segments near the pointer, none square to the leave point, then the rect's side.
+        let mut busy = t;
+        let mut segments: Vec<(Rect, PathSeg)> = (0..70)
+            .map(|i| {
+                let y = 160.0 + f64::from(i) * 0.01;
+                (Rect::new(199.0, y, 205.0, y + 0.001), PathSeg::Line(Line::new((199.0, y), (205.0, y + 0.001))))
+            })
+            .collect();
+        segments.extend(busy.segments.iter().cloned());
+        busy.segments = segments;
+        let (_, ov) = snap(&busy, &Leave::segment(&c, Point::new(300.0, 160.0), false));
+        assert_eq!(labels(&ov), ["perpendicular"]);
+    }
+
     /// The angle sets of Preferences › Smart Guides › Construction Guides.
     #[test]
     fn construction_angle_sets() {

crates/tools/src/lib.rs

@@ -252,6 +252,11 @@ pub struct ToolContext<'a> {
     /// points (a transform's reference point) land on anchors and ruler guides within
     /// [`Self::snap_tolerance`].
     pub snap_to_point: bool,
+    /// View → Snapping → Snap to Tangent: with Smart Guides on, a line drawn
+    /// from an anchor lands where it touches a nearby curve.
+    pub snap_tangent: bool,
+    /// View → Snapping → Snap to Perpendicular: likewise where it meets a nearby segment square.
+    pub snap_perpendicular: bool,
     /// View → Snap to Glyph: drawn points snap to live-text baselines and glyph bounds (with Smart Guides).
     pub snap_to_glyph: bool,
     /// View → Show Corner Widget: paths show draggable Live Corners widgets in their corners.
@@ -1003,6 +1008,8 @@ pub(crate) mod testutil {
             show_bbox: true,
             snap_to_pixel: false,
             snap_to_point: true,
+            snap_tangent: true,
+            snap_perpendicular: true,
             snap_to_glyph: false,
             corner_widgets: true,
             fill_active: true,

crates/tools/src/pen.rs

@@ -190,7 +190,10 @@ impl Tool for PenTool {
         }
         // The path being drawn moves its bounds as it grows: only its anchors and segments pull.
         let drawn = active.map(|a| a.0);
-        let from = active.map(|(_, _, last, _)| Leave::segment(cx, last, ev.mods.shift));
+        let from = active.map(|(_, _, last, handle)| {
+            let leave = Leave::segment(cx, last, ev.mods.shift);
+            if handle == last { leave } else { leave.without_contact() }
+        });
         let p = match ev.kind {
             PointerKind::Move => self.snap.hover(cx, ev.pos, drawn.as_slice(), from.as_ref()),
             PointerKind::Down => self.snap.press(cx, ev.pos, drawn.as_slice(), from.as_ref()),

crates/ui-egui/src/chrome.rs

@@ -215,6 +215,35 @@ pub fn anchor_buttons(app: &mut VectorcraftApp, ui: &mut Ui, controls: AnchorCon
 /// The id of the Control bar's isolation button.
 const ISOLATION_BUTTON: &str = "cb-isolation";
 
+/// The room the Control bar needs for the Snapping menu next to the Artboard tool's controls; with
+/// less, the menu is left out so those controls still fit the narrowest window.
+const ARTBOARD_SNAPPING_WIDTH: f32 = 900.0;
+
+/// The Control bar's snapping quick access; every change uses its existing command.
+fn snapping_menu(app: &mut VectorcraftApp, ui: &mut Ui) {
+    ui.menu_button(tl!("Snapping"), |ui| {
+        for (label, cmd, on) in [
+            (tl!("Smart Guides"), "view.smartGuides", app.ui.view.smart_guides),
+            (tl!("Snap to Point"), "view.snapToPoint", app.ui.view.snap_to_point),
+            (tl!("Snap to Grid"), "view.snapToGrid", app.ui.view.snap_to_grid),
+            (tl!("Snap to Pixel"), "view.snapToPixel", app.ui.view.snap_to_pixel),
+        ] {
+            if widgets::check(ui, label, on, true) {
+                crate::menus::invoke(app, cmd, json!({}));
+            }
+        }
+        ui.separator();
+        for (key, label, on) in [
+            ("snapTangent", tl!("Snap to Tangent"), app.session.prefs.snap_tangent),
+            ("snapPerpendicular", tl!("Snap to Perpendicular"), app.session.prefs.snap_perpendicular),
+        ] {
+            if widgets::check(ui, label, on, true) {
+                crate::menus::invoke(app, "prefs.set", json!({"key": key, "value": !on}));
+            }
+        }
+    });
+}
+
 /// The Control bar's isolation button. In isolation mode it is Exit Isolation Mode, except while a
 /// pattern is edited (the isolation bar's Done and Cancel end that). Otherwise, with one object
 /// selected that [`vectorcraft_tools::select::isolates`], it is Isolate Selected Object, which
@@ -258,10 +287,15 @@ pub fn control_bar(app: &mut VectorcraftApp, ui: &mut Ui) {
                 for i in 0..5 {
                     ui.painter().circle_filled(g.center_top() + vec2(0.0, 2.0 + i as f32 * 4.0), 0.9, t.text_disabled);
                 }
-                let Some(st) = app.session.active() else {
+                if app.session.active().is_none() {
                     ui.label(egui::RichText::new(tl!("No Document")).color(t.text_dim));
                     return;
-                };
+                }
+                // The Artboard tool's controls fill the narrowest window, so they keep it to themselves there.
+                if app.session.tool_id() != "artboard" || ui.available_width() >= ARTBOARD_SNAPPING_WIDTH {
+                    snapping_menu(app, ui);
+                }
+                let Some(st) = app.session.active() else { return };
                 let sel = st.selection.objects.clone();
                 let units = app.session.general_unit();
                 let first = sel.first().and_then(|id| st.doc.node(*id)).cloned();

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

@@ -5307,6 +5307,10 @@ theme	Appearance	Външен вид
 	Persistent	Постоянна
 	Locate Library…	Намиране на библиотека…
 	Library Panel Options	Опции на панела с библиотека
+	Snapping	Прилепване
+	Snap to Tangent	Прилепване към допирателна
+	Snap to Perpendicular	Прилепване към перпендикуляр
+@msg	unknown snap option `{key}` (use {options})	неизвестна опция за прилепване `{key}` (използвайте {options})
 	Gap Length:	Дължина на пропуска:
 	Artboard {n} of {total}	Работна област {n} от {total}
 	Encoding and writing the file…	Кодиране и записване на файла…
@@ -5357,6 +5361,7 @@ theme	Appearance	Външен вид
 	Water Paper	Мокра хартия
 	Ruby…	Руби…
 	Ruby	Руби
+	Geometric Guides	Геометрични водачи
 	Ease In	Плавно начало
 	Ease Out	Плавен край
 	Ease In Out	Плавно начало и край

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

@@ -5352,6 +5352,10 @@ mark-style	Japanese	Japonské
 @msg	too many library panels were opened in this session	v této relaci bylo otevřeno příliš mnoho panelů knihoven
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Obraz má {_1} × {_2} pixelů, na jedné straně více než {LARGE_TRACE_SIDE}: vektorizuje se, ale pomaleji. Rychleji se vektorizuje s předvolbou nižší věrnosti nebo menší kopie obrazu.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Obraz byl vektorizován v rozlišení {_1} × {_2} pixelů, zmenšený z {_3} × {_4} (nejvýše {_5} megapixelů).
+	Snapping	Přichytávání
+	Snap to Tangent	Přichytávat k tečně
+	Snap to Perpendicular	Přichytávat ke kolmici
+@msg	unknown snap option `{key}` (use {options})	neznámá možnost přichytávání `{key}` (použijte {options})
 	Gap Length:	Délka mezery:
 	Artboard {n} of {total}	Pracovní plocha {n} z {total}
 	Encoding and writing the file…	Kódování a zápis souboru…
@@ -5402,6 +5406,7 @@ mark-style	Japanese	Japonské
 	Water Paper	Mokrý papír
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Geometrická vodítka
 	Ease In	Pozvolný začátek
 	Ease Out	Pozvolný konec
 	Ease In Out	Pozvolný začátek a konec

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

@@ -5303,6 +5303,10 @@ swatch	Bright Violet	Kraftig violet
 	Persistent	Vedvarende
 	Locate Library…	Lokalisér bibliotek…
 	Library Panel Options	Indstillinger for bibliotekspanel
+	Snapping	Fastgørelse
+	Snap to Tangent	Fastgør til tangent
+	Snap to Perpendicular	Fastgør vinkelret
+@msg	unknown snap option `{key}` (use {options})	ukendt fastgørelsesindstilling `{key}` (brug {options})
 	Gap Length:	Hullængde:
 	Artboard {n} of {total}	Tegneflade {n} af {total}
 	Encoding and writing the file…	Koder og skriver filen…
@@ -5373,6 +5377,7 @@ swatch	Bright Violet	Kraftig violet
 	Water Paper	Vådt papir
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Geometriske hjælpelinjer
 	Ease In	Langsom start
 	Ease Out	Langsom slutning
 	Ease In Out	Langsom start og slutning

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

@@ -4932,6 +4932,10 @@ effect	Soft	Weich
 @msg	too many library panels were opened in this session	in dieser Sitzung wurden zu viele Bibliotheksbedienfelder geöffnet
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Das Bild hat {_1} × {_2} Pixel, mehr als {LARGE_TRACE_SIDE} auf einer Seite: Es wird nachgezeichnet, aber langsamer. Eine Vorgabe mit geringerer Detailtreue oder eine kleinere Kopie des Bildes geht schneller.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Das Bild wurde mit {_1} × {_2} Pixeln nachgezeichnet, verkleinert von {_3} × {_4} (höchstens {_5} Megapixel).
+	Snapping	Einrasten
+	Snap to Tangent	An Tangente ausrichten
+	Snap to Perpendicular	An Senkrechter ausrichten
+@msg	unknown snap option `{key}` (use {options})	unbekannte Einrastoption `{key}` (möglich: {options})
 	Gap Length:	Lückenlänge:
 	Artboard {n} of {total}	Zeichenfläche {n} von {total}
 	Encoding and writing the file…	Datei wird codiert und geschrieben…
@@ -4983,6 +4987,7 @@ effect	Soft	Weich
 	Water Paper	Feuchtes Papier
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Geometrische Hilfslinien
 	Ease In	Langsam starten
 	Ease Out	Langsam enden
 	Ease In Out	Langsam starten und enden

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

@@ -5304,6 +5304,10 @@ effect	Points	Σημεία
 @msg	too many library panels were opened in this session	άνοιξαν πάρα πολλοί πίνακες βιβλιοθηκών σε αυτή τη συνεδρία
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Η εικόνα είναι {_1} × {_2} εικονοστοιχεία, πάνω από {LARGE_TRACE_SIDE} σε μία πλευρά: ανιχνεύεται, αλλά πιο αργά. Μια προρύθμιση χαμηλότερης πιστότητας ή ένα μικρότερο αντίγραφο της εικόνας ανιχνεύεται γρηγορότερα.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Η εικόνα ανιχνεύτηκε σε {_1} × {_2} εικονοστοιχεία, σμικρυμένη από {_3} × {_4} (το πολύ {_5} megapixel).
+	Snapping	Προσκόλληση
+	Snap to Tangent	Προσκόλληση σε εφαπτομένη
+	Snap to Perpendicular	Προσκόλληση σε κάθετο
+@msg	unknown snap option `{key}` (use {options})	άγνωστη επιλογή προσκόλλησης `{key}` (χρησιμοποιήστε {options})
 	Gap Length:	Μήκος κενού:
 	Artboard {n} of {total}	Πίνακας σχεδίασης {n} από {total}
 	Encoding and writing the file…	Κωδικοποίηση και εγγραφή του αρχείου…
@@ -5354,6 +5358,7 @@ effect	Points	Σημεία
 	Water Paper	Βρεγμένο χαρτί
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Γεωμετρικοί οδηγοί
 	Ease In	Ομαλή αρχή
 	Ease Out	Ομαλό τέλος
 	Ease In Out	Ομαλή αρχή και τέλος

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

@@ -5294,6 +5294,10 @@ mark-style	Japanese	Japonesas
 @msg	too many library panels were opened in this session	se abrieron demasiados paneles de biblioteca en esta sesión
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	La imagen tiene {_1} × {_2} píxeles, más de {LARGE_TRACE_SIDE} en un lado: se calcará, pero más despacio. Un ajuste preestablecido de menor fidelidad o una copia más pequeña de la imagen se calcan más rápido.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	La imagen se calcó a {_1} × {_2} píxeles, reducida desde {_3} × {_4} ({_5} megapíxeles como máximo).
+	Snapping	Ajuste
+	Snap to Tangent	Ajustar a tangente
+	Snap to Perpendicular	Ajustar a perpendicular
+@msg	unknown snap option `{key}` (use {options})	opción de ajuste desconocida `{key}` (use {options})
 	Gap Length:	Longitud del hueco:
 	Artboard {n} of {total}	Mesa de trabajo {n} de {total}
 	Encoding and writing the file…	Codificando y escribiendo el archivo…
@@ -5344,6 +5348,7 @@ mark-style	Japanese	Japonesas
 	Water Paper	Papel mojado
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Guías geométricas
 	Ease In	Entrada suave
 	Ease Out	Salida suave
 	Ease In Out	Entrada y salida suaves

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

@@ -5316,6 +5316,10 @@ mark-style	Japanese	Japanilainen
 @msg	too many library panels were opened in this session	tässä istunnossa on avattu liian monta kirjastopaneelia
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Kuva on {_1} × {_2} kuvapistettä, yhdeltä sivultaan yli {LARGE_TRACE_SIDE}: se jäljitetään, mutta hitaammin. Pienemmän tarkkuuden esiasetus tai kuvan pienempi kopio jäljittyy nopeammin.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Kuva jäljitettiin kokoon {_1} × {_2} kuvapistettä pienennettynä koosta {_3} × {_4} (enintään {_5} megapikseliä).
+	Snapping	Tartunta
+	Snap to Tangent	Kohdista tangenttiin
+	Snap to Perpendicular	Kohdista kohtisuoraan
+@msg	unknown snap option `{key}` (use {options})	tuntematon tartuntavalinta `{key}` (käytä: {options})
 	Gap Length:	Aukon pituus:
 	Artboard {n} of {total}	Piirtoalusta {n}/{total}
 	Encoding and writing the file…	Tiedostoa koodataan ja kirjoitetaan…
@@ -5433,6 +5437,7 @@ swatch	Bright Violet	Kirkas violetti
 	Water Paper	Märkä paperi
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Geometriset apuviivat
 	Ease In	Hidas alku
 	Ease Out	Hidas loppu
 	Ease In Out	Hidas alku ja loppu

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

@@ -5351,6 +5351,10 @@ theme	Appearance	Apparence
 @msg	too many library panels were opened in this session	trop de panneaux de bibliothèque ont été ouverts dans cette session
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	L’image fait {_1} × {_2} pixels, plus de {LARGE_TRACE_SIDE} sur un côté : elle est vectorisée, mais plus lentement. Un paramètre prédéfini moins fidèle ou une copie plus petite de l’image se vectorise plus vite.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	L’image a été vectorisée à {_1} × {_2} pixels, réduite de {_3} × {_4} ({_5} mégapixels au plus).
+	Snapping	Magnétisme
+	Snap to Tangent	Magnétisme de la tangente
+	Snap to Perpendicular	Magnétisme de la perpendiculaire
+@msg	unknown snap option `{key}` (use {options})	option de magnétisme inconnue `{key}` (utilisez {options})
 	Gap Length:	Longueur de lacune :
 	Artboard {n} of {total}	Plan de travail {n} sur {total}
 	Encoding and writing the file…	Encodage et écriture du fichier…
@@ -5401,6 +5405,7 @@ theme	Appearance	Apparence
 	Water Paper	Papier humide
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Repères géométriques
 	Ease In	Accélération progressive
 	Ease Out	Décélération progressive
 	Ease In Out	Accélération et décélération

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

@@ -5338,6 +5338,10 @@ imageTrace	Outline	Körvonal
 @msg	too many library panels were opened in this session	ebben a munkamenetben túl sok könyvtárpanel nyílt meg
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	A kép {_1} × {_2} képpont, egyik oldalán több mint {LARGE_TRACE_SIDE}: a vektorizálás megtörténik, de lassabban. Kisebb hűségű előbeállítással vagy a kép kisebb másolatával gyorsabb.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	A kép vektorizálása {_1} × {_2} képponton történt, {_3} × {_4} méretről kicsinyítve (legfeljebb {_5} megapixel).
+	Snapping	Illesztés
+	Snap to Tangent	Illesztés érintőre
+	Snap to Perpendicular	Illesztés merőlegesre
+@msg	unknown snap option `{key}` (use {options})	ismeretlen illesztési beállítás: `{key}` (használható: {options})
 	Gap Length:	Rés hossza:
 	Artboard {n} of {total}	Rajztábla: {n} / {total}
 	Encoding and writing the file…	A fájl kódolása és írása…
@@ -5388,6 +5392,7 @@ imageTrace	Outline	Körvonal
 	Water Paper	Nedves papír
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Geometriai segédvonalak
 	Ease In	Lassú kezdés
 	Ease Out	Lassú befejezés
 	Ease In Out	Lassú kezdés és befejezés

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

@@ -5303,6 +5303,10 @@ swatch	Bright Violet	Violet cerah
 	Persistent	Persisten
 	Locate Library…	Temukan pustaka…
 	Library Panel Options	Opsi panel pustaka
+	Snapping	Snap
+	Snap to Tangent	Snap ke garis singgung
+	Snap to Perpendicular	Snap tegak lurus
+@msg	unknown snap option `{key}` (use {options})	opsi snap `{key}` tidak dikenal (gunakan {options})
 	Gap Length:	Panjang celah:
 	Artboard {n} of {total}	Artboard {n} dari {total}
 	Encoding and writing the file…	Mengodekan dan menulis berkas…
@@ -5373,6 +5377,7 @@ swatch	Bright Violet	Violet cerah
 	Water Paper	Kertas Basah
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Panduan Geometris
 	Ease In	Awal Lambat
 	Ease Out	Akhir Lambat
 	Ease In Out	Awal dan Akhir Lambat

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

@@ -4966,6 +4966,10 @@ lighting	Light	Luce
 @msg	too many library panels were opened in this session	in questa sessione sono stati aperti troppi pannelli libreria
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	L’immagine è di {_1} × {_2} pixel, più di {LARGE_TRACE_SIDE} su un lato: viene vettorializzata, ma più lentamente. Un predefinito a fedeltà più bassa o una copia più piccola dell’immagine è più veloce.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	L’immagine è stata vettorializzata a {_1} × {_2} pixel, ridotta da {_3} × {_4} (al massimo {_5} megapixel).
+	Snapping	Aggancio
+	Snap to Tangent	Aggancia alla tangente
+	Snap to Perpendicular	Aggancia alla perpendicolare
+@msg	unknown snap option `{key}` (use {options})	opzione di aggancio sconosciuta `{key}` (usare {options})
 	Gap Length:	Lunghezza lacuna:
 	Artboard {n} of {total}	Tavola da disegno {n} di {total}
 	Encoding and writing the file…	Codifica e scrittura del file…
@@ -5017,6 +5021,7 @@ lighting	Light	Luce
 	Water Paper	Carta bagnata
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Guide geometriche
 	Ease In	Inizio graduale
 	Ease Out	Fine graduale
 	Ease In Out	Inizio e fine graduali

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

@@ -5006,6 +5006,10 @@ lighting	Light	ライト
 @msg	too many library panels were opened in this session	このセッションで開いたライブラリパネルが多すぎます
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	画像は {_1} × {_2} ピクセルで、一辺が {LARGE_TRACE_SIDE} を超えています。トレースはできますが、時間がかかります。忠実度の低いプリセットや画像の小さいコピーを使うと速くなります。
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	画像は {_3} × {_4} から縮小した {_1} × {_2} ピクセルでトレースされました (最大 {_5} メガピクセル)。
+	Snapping	スナップ
+	Snap to Tangent	接線にスナップ
+	Snap to Perpendicular	垂線にスナップ
+@msg	unknown snap option `{key}` (use {options})	不明なスナップオプション `{key}` ({options} を使用してください)
 	Gap Length:	ギャップの長さ:
 	Artboard {n} of {total}	アートボード {n} / {total}
 	Encoding and writing the file…	ファイルをエンコードして書き込み中…
@@ -5064,6 +5068,7 @@ lighting	Light	ライト
 	Yonroku-ban	四六判
 	Ruby…	ルビ…
 	Ruby	ルビ
+	Geometric Guides	幾何ガイド
 	Ease In	イーズイン
 	Ease Out	イーズアウト
 	Ease In Out	イーズインアウト

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

@@ -5257,6 +5257,10 @@ imageTrace	Outline	კონტური
 # Select by Color (select.color)
 	Select by Color	მონიშვნა ფერის მიხედვით
 @msg	thumbnail: no page {n} (the file has 1)	thumbnail: გვერდი {n} არ არსებობს (ფაილს 1 გვერდი აქვს)
+	Snapping	მიბმა
+	Snap to Tangent	მხებზე მიბმა
+	Snap to Perpendicular	პერპენდიკულარზე მიბმა
+@msg	unknown snap option `{key}` (use {options})	უცნობი მიბმის პარამეტრი `{key}` (გამოიყენეთ: {options})
 	Gap Length:	ღრეჩოს სიგრძე:
 	Smudge Stick…	დასაზელი ჯოხი…
 	Smudge Stick	დასაზელი ჯოხი
@@ -5307,6 +5311,7 @@ imageTrace	Outline	კონტური
 	 selects several, or draws one inside an artboard)	 რამდენიმეს მონიშნავს ან ახალს სამუშაო დაფის შიგნით ხატავს)
 	Ruby…	რუბი…
 	Ruby	რუბი
+	Geometric Guides	გეომეტრიული მიმმართველები
 	Ease In	ნელი დასაწყისი
 	Ease Out	ნელი დასასრული
 	Ease In Out	ნელი დასაწყისი და დასასრული

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

@@ -4929,6 +4929,10 @@ lighting	Light	광원
 @msg	too many library panels were opened in this session	이 세션에서 라이브러리 패널을 너무 많이 열었습니다
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	이미지가 {_1} × {_2}픽셀로 한 변이 {LARGE_TRACE_SIDE}을 넘습니다. 추적은 되지만 더 느립니다. 충실도가 낮은 사전 설정이나 이미지의 작은 사본을 사용하면 더 빠릅니다.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	이미지를 {_3} × {_4}에서 축소한 {_1} × {_2}픽셀로 추적했습니다(최대 {_5}메가픽셀).
+	Snapping	스냅
+	Snap to Tangent	접선에 스냅
+	Snap to Perpendicular	수직선에 스냅
+@msg	unknown snap option `{key}` (use {options})	알 수 없는 스냅 옵션 `{key}` ({options} 중에서 사용하세요)
 	Gap Length:	간격 길이:
 	Artboard {n} of {total}	아트보드 {n} / {total}
 	Encoding and writing the file…	파일을 인코딩하고 쓰는 중…
@@ -4980,6 +4984,7 @@ lighting	Light	광원
 	Water Paper	물 종이
 	Ruby…	루비…
 	Ruby	루비
+	Geometric Guides	기하학적 안내선
 	Ease In	서서히 시작
 	Ease Out	서서히 종료
 	Ease In Out	서서히 시작 및 종료

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

@@ -5313,6 +5313,10 @@ swatch	Bright Violet	Felviolet
 	Typing	Typen
 	Persistent	Permanent
 	Library Panel Options	Opties voor bibliotheekpaneel
+	Snapping	Uitlijnen
+	Snap to Tangent	Uitlijnen op raaklijn
+	Snap to Perpendicular	Uitlijnen op loodlijn
+@msg	unknown snap option `{key}` (use {options})	onbekende uitlijnoptie `{key}` (gebruik {options})
 	Gap Length:	Lengte van opening:
 	Locate Library…	Bibliotheek lokaliseren…
 
@@ -5416,6 +5420,7 @@ swatch	Bright Violet	Felviolet
 	Water Paper	Nat papier
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Geometrische hulplijnen
 	Ease In	Langzaam beginnen
 	Ease Out	Langzaam eindigen
 	Ease In Out	Langzaam beginnen en eindigen

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

@@ -5204,6 +5204,10 @@ mark-style	Japanese	Japońskie
 @msg	too many library panels were opened in this session	w tej sesji otwarto zbyt wiele paneli bibliotek
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Obraz ma {_1} × {_2} pikseli, ponad {LARGE_TRACE_SIDE} na jednym boku: zostanie obrysowany, ale wolniej. Ustawienie wstępne o niższej wierności lub mniejsza kopia obrazu obrysuje się szybciej.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Obraz obrysowano w rozdzielczości {_1} × {_2} pikseli, po zmniejszeniu z {_3} × {_4} (najwyżej {_5} megapikseli).
+	Snapping	Przyciąganie
+	Snap to Tangent	Przyciągaj do stycznych
+	Snap to Perpendicular	Przyciągaj do prostopadłych
+@msg	unknown snap option `{key}` (use {options})	nieznana opcja przyciągania `{key}` (użyj: {options})
 	Gap Length:	Długość przerwy:
 	Artboard {n} of {total}	Obszar kompozycji {n} z {total}
 	Encoding and writing the file…	Kodowanie i zapisywanie pliku…
@@ -5254,6 +5258,7 @@ mark-style	Japanese	Japońskie
 	Water Paper	Mokry papier
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Prowadnice geometryczne
 	Ease In	Łagodny początek
 	Ease Out	Łagodny koniec
 	Ease In Out	Łagodny początek i koniec

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

@@ -5269,6 +5269,10 @@ mark-style	Japanese	Japonesas
 @msg	too many library panels were opened in this session	foram abertos painéis de biblioteca demais nesta sessão
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	A imagem tem {_1} × {_2} pixels, mais de {LARGE_TRACE_SIDE} em um lado: ela é traçada, mas mais devagar. Uma predefinição de menor fidelidade ou uma cópia menor da imagem traça mais rápido.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	A imagem foi traçada em {_1} × {_2} pixels, reduzida de {_3} × {_4} (no máximo {_5} megapixels).
+	Snapping	Ajuste
+	Snap to Tangent	Ajustar à Tangente
+	Snap to Perpendicular	Ajustar à Perpendicular
+@msg	unknown snap option `{key}` (use {options})	opção de ajuste desconhecida `{key}` (use {options})
 	Gap Length:	Comprimento da Lacuna:
 	Artboard {n} of {total}	Mesa de Trabalho {n} de {total}
 	Encoding and writing the file…	Codificando e gravando o arquivo…
@@ -5319,6 +5323,7 @@ mark-style	Japanese	Japonesas
 	Water Paper	Papel molhado
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Guias geométricas
 	Ease In	Entrada suave
 	Ease Out	Saída suave
 	Ease In Out	Entrada e saída suaves

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

@@ -4962,6 +4962,10 @@ lighting	Light	Свет
 @msg	too many library panels were opened in this session	в этом сеансе открыто слишком много панелей библиотек
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Изображение {_1} × {_2} пикселей, больше {LARGE_TRACE_SIDE} по одной стороне: трассировка выполняется, но медленнее. Стиль с меньшей точностью или уменьшенная копия изображения трассируются быстрее.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Изображение трассировано в размере {_1} × {_2} пикселей, уменьшенное с {_3} × {_4} (не более {_5} мегапикселей).
+	Snapping	Привязка
+	Snap to Tangent	Привязать к касательной
+	Snap to Perpendicular	Привязать к перпендикуляру
+@msg	unknown snap option `{key}` (use {options})	неизвестный параметр привязки `{key}` (допустимо: {options})
 	Gap Length:	Длина зазора:
 	Artboard {n} of {total}	Монтажная область {n} из {total}
 	Encoding and writing the file…	Кодирование и запись файла…
@@ -5013,6 +5017,7 @@ lighting	Light	Свет
 	Water Paper	Мокрая бумага
 	Ruby…	Руби…
 	Ruby	Руби
+	Geometric Guides	Геометрические направляющие
 	Ease In	Плавное начало
 	Ease Out	Плавное окончание
 	Ease In Out	Плавное начало и окончание

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

@@ -5308,6 +5308,10 @@ theme	Appearance	Utseende
 @msg	too many library panels were opened in this session	för många bibliotekspaneler har öppnats i den här sessionen
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Bilden är {_1} × {_2} pixlar, mer än {LARGE_TRACE_SIDE} på en sida: den vektoriseras, men långsammare. En förinställning med lägre återgivning eller en mindre kopia av bilden går snabbare.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Bilden vektoriserades vid {_1} × {_2} pixlar, nedskalad från {_3} × {_4} (högst {_5} megapixlar).
+	Snapping	Fästning
+	Snap to Tangent	Fäst mot tangent
+	Snap to Perpendicular	Fäst mot vinkelrät
+@msg	unknown snap option `{key}` (use {options})	okänt fästalternativ `{key}` (använd {options})
 	Gap Length:	Lucklängd:
 	Artboard {n} of {total}	Rityta {n} av {total}
 	Encoding and writing the file…	Kodar och skriver filen…
@@ -5358,6 +5362,7 @@ theme	Appearance	Utseende
 	Water Paper	Vått papper
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Geometriska stödlinjer
 	Ease In	Långsam start
 	Ease Out	Långsamt slut
 	Ease In Out	Långsam start och slut

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

@@ -5399,4 +5399,8 @@ axis	Y Axis	Y ekseni
 @msg	`dither` applies to gradient fills (stroke: false)	`dither` degrade dolgulara uygulanır (stroke: false)
 @msg	`dither` applies to gradient fills (paint.setFill)	`dither` degrade dolgulara uygulanır (paint.setFill)
 @msg	`dither` must be true or false	"dither" doğru veya yanlış olmalıdır
+	Snapping	Yaslama
+	Snap to Tangent	Teğete Yasla
+	Snap to Perpendicular	Dikeye Yasla
+	Geometric Guides	Geometrik Kılavuzlar
 @msg	`method` must be classic or perceptual	`method` classic veya perceptual olmalıdır

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

@@ -4946,6 +4946,10 @@ lighting	Light	Світло
 @msg	too many library panels were opened in this session	у цьому сеансі відкрито забагато панелей бібліотек
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Зображення {_1} × {_2} пікселів, понад {LARGE_TRACE_SIDE} з одного боку: трасування виконується, але повільніше. Стиль із нижчою точністю або менша копія зображення трасуються швидше.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Зображення трасовано в розмірі {_1} × {_2} пікселів, зменшене з {_3} × {_4} (щонайбільше {_5} мегапікселів).
+	Snapping	Прив’язка
+	Snap to Tangent	Прив’язати до дотичної
+	Snap to Perpendicular	Прив’язати до перпендикуляра
+@msg	unknown snap option `{key}` (use {options})	невідомий параметр прив’язки `{key}` (використовуйте {options})
 	Gap Length:	Довжина проміжку:
 	Artboard {n} of {total}	Монтажна область {n} з {total}
 	Encoding and writing the file…	Кодування та запис файлу…
@@ -4997,6 +5001,7 @@ lighting	Light	Світло
 	Water Paper	Мокрий папір
 	Ruby…	Рубі…
 	Ruby	Рубі
+	Geometric Guides	Геометричні напрямні
 	Ease In	Плавний початок
 	Ease Out	Плавне завершення
 	Ease In Out	Плавний початок і завершення

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

@@ -4946,6 +4946,10 @@ theme	Appearance	Giao diện
 @msg	too many library panels were opened in this session	đã mở quá nhiều bảng thư viện trong phiên này
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Ảnh có kích thước {_1} × {_2} điểm ảnh, hơn {LARGE_TRACE_SIDE} ở một cạnh: ảnh vẫn được dò, nhưng chậm hơn. Một thiết lập sẵn có độ trung thực thấp hơn hoặc một bản sao nhỏ hơn của ảnh sẽ dò nhanh hơn.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Ảnh đã được dò ở {_1} × {_2} điểm ảnh, thu nhỏ từ {_3} × {_4} (tối đa {_5} megapixel).
+	Snapping	Hút
+	Snap to Tangent	Hút vào tiếp tuyến
+	Snap to Perpendicular	Hút vào đường vuông góc
+@msg	unknown snap option `{key}` (use {options})	tùy chọn hút không hợp lệ `{key}` (dùng {options})
 	Gap Length:	Độ dài khoảng hở:
 	Artboard {n} of {total}	Bảng vẽ {n} / {total}
 	Encoding and writing the file…	Đang mã hóa và ghi tệp…
@@ -4997,6 +5001,7 @@ theme	Appearance	Giao diện
 	Water Paper	Giấy ướt
 	Ruby…	Ruby…
 	Ruby	Ruby
+	Geometric Guides	Đường dẫn hình học
 	Ease In	Chậm lúc đầu
 	Ease Out	Chậm lúc cuối
 	Ease In Out	Chậm lúc đầu và cuối

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

@@ -5185,6 +5185,10 @@ lighting	Light	光源
 @msg	too many library panels were opened in this session	本次会话中打开的库面板过多
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	图像为 {_1} × {_2} 像素，某一边超过 {LARGE_TRACE_SIDE}：会进行描摹，但速度较慢。使用保真度较低的预设或图像的较小副本会更快。
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	图像已按 {_1} × {_2} 像素描摹，由 {_3} × {_4} 缩小而来（最多 {_5} 百万像素）。
+	Snapping	对齐
+	Snap to Tangent	对齐切线
+	Snap to Perpendicular	对齐垂线
+@msg	unknown snap option `{key}` (use {options})	未知的对齐选项 `{key}`（可用：{options}）
 	Gap Length:	间隙长度：
 # Links and Attributes: files and URLs handed to other apps.
 @msg	Edit Original opens image and document files only; “{name}” is not one	编辑原稿只能打开图像和文档文件；“{name}” 不是其中之一
@@ -5241,6 +5245,7 @@ lighting	Light	光源
 	Water Paper	水彩画纸
 	Ruby…	注音…
 	Ruby	注音
+	Geometric Guides	几何参考线
 	Ease In	缓入
 	Ease Out	缓出
 	Ease In Out	缓入缓出

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

@@ -4980,6 +4980,10 @@ lighting	Light	光源
 	Persistent	持久
 	Locate Library…	尋找資料庫…
 	Library Panel Options	資料庫面板選項
+	Snapping	靠齊
+	Snap to Tangent	靠齊切線
+	Snap to Perpendicular	靠齊垂線
+@msg	unknown snap option `{key}` (use {options})	未知的靠齊選項 `{key}`（可用：{options}）
 	Gap Length:	間隙長度：
 	Artboard {n} of {total}	工作區域 {n} / {total}
 	Encoding and writing the file…	正在編碼並寫入檔案…
@@ -5036,6 +5040,7 @@ lighting	Light	光源
 	Water Paper	水彩畫紙
 	Ruby…	注音…
 	Ruby	注音
+	Geometric Guides	幾何參考線
 	Ease In	緩入
 	Ease Out	緩出
 	Ease In Out	緩入緩出

crates/ui-egui/src/panels/artboards.rs

@@ -1372,11 +1372,14 @@ mod tests {
         bar_frame_in(&mut app, &ctx, vec![], width);
         let texts = bar_frame_in(&mut app, &ctx, vec![], width);
         assert!(has(&texts, "Scale Artwork with Artboard") && !has(&texts, "X:") && !has(&texts, "W:"), "{texts:?}");
+        // The Snapping menu sits first on a wide bar and leaves the narrow bar to the artboard controls.
+        assert!(has(&bar_texts(&mut app, &ctx), "Snapping"));
         // In the app's narrowest window, 800 points wide, the name and the Transform link still fit,
         // and a click on the link shows the artboard's X, Y, W and H in the Transform panel's popover.
         let narrow = |app: &mut VectorcraftApp, events| bar_frame_in(app, &ctx, events, 800.0);
         narrow(&mut app, vec![]);
         let texts = narrow(&mut app, vec![]);
+        assert!(!has(&texts, "Snapping"), "{texts:?}");
         let link = text_rect(&texts, "Transform");
         assert!(link.right() < 790.0 && text_rect(&texts, "Artboard 1").right() < link.left(), "{texts:?}");
         // Move and Scale Artwork with Artboard show as their boxes alone, inside the window, and the

crates/ui-egui/src/prefs_dialog.rs

@@ -423,6 +423,20 @@ mod tests {
     use crate::Services;
     use vectorcraft_engine::Session;
 
+    #[test]
+    fn geometric_snapping_is_a_saved_smart_guides_preference() {
+        let mut a = VectorcraftApp::new(vectorcraft_engine::Session::new(), Default::default());
+        open(&mut a, Some("Smart Guides"));
+        let text = crate::tests_labels::painted_text(&mut a, |a, ui| show(a, ui.ctx()));
+        assert!(text.contains("Geometric Guides") && text.contains("Snap to Perpendicular") && text.contains("Snap to Tangent"), "{text}");
+        a.ui.dialog.as_mut().unwrap().fields.insert("snapPerpendicular".into(), json!(false));
+        confirm(&mut a).unwrap();
+        assert!(!a.session.prefs.snap_perpendicular && a.session.prefs.snap_tangent);
+        let saved: Prefs = serde_json::from_value(a.ui.engine_prefs.clone()).unwrap();
+        assert!(!saved.snap_perpendicular && saved.snap_tangent);
+        assert!(a.run("view.snapping", json!({})).is_err());
+    }
+
     /// A resting checkbox must have a visible outline in both states and every brightness.
     #[test]
     fn preference_checkboxes_draw_outlines_without_hover() {