Merge #529: Fix #506: drawing tools snap to Smart Guides as the Selection tool does

# Conflicts: # ROADMAP.md
2026-10-24 09:46:59 -06:00 · 2026-10-09 00:44:46 +07:00
parent 01c9be7d35 4eac7b505f
commit 971b0bb95e
16 changed files with 1061 additions and 162 deletions
@@ -634,7 +634,7 @@ impl Default for Prefs {
            object_highlighting: true,
            transform_tools_guides: true,
            construction_guides: true,
-            construction_angles: s("90° & 45° Angles"),
+            construction_angles: s(vectorcraft_tools::guides::DEFAULT_CONSTRUCTION_ANGLES),
            anchor_path_labels: true,
            measurement_labels: true,
            spacing_guides: true,
@@ -1488,6 +1488,8 @@ mod tests_scalestrokes;
 #[cfg(test)]
 mod tests_slices;
 #[cfg(test)]
+mod tests_smartguides;
+#[cfg(test)]
 mod tests_strokegeom;
 #[cfg(test)]
 mod tests_strokegradient;
@@ -0,0 +1,109 @@
+//! Smart Guides for the drawing tools, driven through the session (#506): where the Rectangle
+//! tool's corners and the Pen's anchors land, and the guides they show.
+
+use serde_json::json;
+use vectorcraft_doc::NodeId;
+use vectorcraft_geom::{Point, Rect};
+use vectorcraft_tools::{Mods, Overlay, PointerEvent, PointerKind};
+
+use super::*;
+use crate::tooling::ViewInfo;
+
+/// An 800 × 600 document with a 100 × 100 square at (100, 100), nothing selected.
+fn session() -> Session {
+    let mut s = Session::new();
+    s.execute("file.new", &json!({"width": 800, "height": 600})).unwrap();
+    s.execute("shape.rectangle", &json!({"x": 100, "y": 100, "width": 100, "height": 100})).unwrap();
+    s.execute("select.none", &json!({})).unwrap();
+    s
+}
+
+fn pointer(s: &mut Session, kind: PointerKind, x: f64, y: f64) {
+    s.pointer(&PointerEvent::new(kind, x, y), ViewInfo::default()).unwrap();
+}
+
+fn labels(s: &mut Session) -> Vec<(String, Point)> {
+    s.overlays(ViewInfo::default()).into_iter().filter_map(|o| if let Overlay::Label { text, p, .. } = o { Some((text, p)) } else { None }).collect()
+}
+
+/// The bounds of the object the last gesture made (it is selected).
+fn made(s: &Session) -> Rect {
+    let d = s.doc().unwrap();
+    let id: NodeId = d.selection.objects[0];
+    d.doc.node(id).unwrap().geometric_bounds().unwrap()
+}
+
+#[test]
+fn a_rectangle_corner_lands_on_another_objects_anchor() {
+    let mut s = session();
+    s.select_tool("rectangle", ViewInfo::default()).unwrap();
+    // Hovering near the square's corner already says where the press goes.
+    pointer(&mut s, PointerKind::Move, 302.0, 297.0);
+    pointer(&mut s, PointerKind::Move, 202.0, 203.0);
+    assert_eq!(labels(&mut s), [("anchor".to_string(), Point::new(200.0, 200.0))]);
+    pointer(&mut s, PointerKind::Down, 302.0, 297.0);
+    pointer(&mut s, PointerKind::Drag, 250.0, 250.0);
+    pointer(&mut s, PointerKind::Drag, 202.0, 203.0);
+    assert_eq!(labels(&mut s), [("anchor".to_string(), Point::new(200.0, 200.0))]);
+    let measure = s.overlays(ViewInfo::default()).into_iter().find_map(|o| if let Overlay::Measure { text, .. } = o { Some(text) } else { None });
+    assert!(measure.as_deref().is_some_and(|t| t.starts_with("W: 102") && t.contains("H: 100")), "{measure:?}");
+    pointer(&mut s, PointerKind::Up, 202.0, 203.0);
+    // The start lined up with the artboard's centre (y = 300), the corner on the anchor.
+    assert_eq!(made(&s), Rect::new(200.0, 200.0, 302.0, 300.0));
+}
+
+/// The corner being dragged never snaps to the rectangle's own preview: dragged slowly, it follows
+/// the pointer instead of sticking where the last step left it.
+#[test]
+fn a_rectangle_does_not_snap_to_itself_while_drawn() {
+    let mut s = session();
+    s.select_tool("rectangle", ViewInfo::default()).unwrap();
+    pointer(&mut s, PointerKind::Down, 320.0, 420.0);
+    for x in 370..=380 {
+        pointer(&mut s, PointerKind::Drag, f64::from(x), 470.0 + f64::from(x - 370));
+    }
+    pointer(&mut s, PointerKind::Up, 380.0, 480.0);
+    assert_eq!(made(&s), Rect::new(320.0, 420.0, 380.0, 480.0));
+}
+
+#[test]
+fn a_pen_anchor_lines_up_with_another_objects_centre() {
+    let mut s = session();
+    s.select_tool("pen", ViewInfo::default()).unwrap();
+    pointer(&mut s, PointerKind::Down, 300.0, 420.0);
+    pointer(&mut s, PointerKind::Up, 300.0, 420.0);
+    // Hovering: in line with the square's centre (150, 150), the guide running from it.
+    pointer(&mut s, PointerKind::Move, 151.5, 431.0);
+    let ov = s.overlays(ViewInfo::default());
+    assert!(ov.iter().any(|o| matches!(o, Overlay::Line { a, b, .. } if *a == Point::new(150.0, 150.0) && *b == Point::new(150.0, 431.0))), "{ov:?}");
+    assert_eq!(labels(&mut s), [("align".to_string(), Point::new(150.0, 431.0))]);
+    pointer(&mut s, PointerKind::Down, 151.5, 431.0);
+    pointer(&mut s, PointerKind::Up, 151.5, 431.0);
+    // Shift: along the 45° step from it, slid into line with the square's left side (x = 100).
+    s.pointer(&PointerEvent::new(PointerKind::Down, 103.0, 386.0).with_mods(Mods { shift: true, ..Mods::default() }), ViewInfo::default()).unwrap();
+    pointer(&mut s, PointerKind::Up, 103.0, 386.0);
+    let d = s.doc().unwrap();
+    let path = d.doc.node(d.selection.objects[0]).unwrap().path_data().unwrap();
+    let pts: Vec<Point> = path.subpaths[0].anchors.iter().map(|a| a.p).collect();
+    assert_eq!(pts[..2], [Point::new(300.0, 420.0), Point::new(150.0, 431.0)]);
+    assert!((pts[2] - Point::new(100.0, 381.0)).hypot() < 1e-9, "{pts:?}");
+}
+
+/// Preferences › Smart Guides › Construction Guides: on (the default), a Pen anchor near the
+/// 45° guide through the last one lands on it; off, it stays where it was clicked.
+#[test]
+fn construction_guides_follow_the_preference() {
+    for on in [true, false] {
+        let mut s = session();
+        s.execute("prefs.set", &json!({"key": "constructionGuides", "value": on})).unwrap();
+        s.select_tool("pen", ViewInfo::default()).unwrap();
+        pointer(&mut s, PointerKind::Down, 500.0, 500.0);
+        pointer(&mut s, PointerKind::Up, 500.0, 500.0);
+        pointer(&mut s, PointerKind::Down, 561.0, 438.0);
+        pointer(&mut s, PointerKind::Up, 561.0, 438.0);
+        let d = s.doc().unwrap();
+        let last = d.doc.node(d.selection.objects[0]).unwrap().path_data().unwrap().subpaths[0].anchors[1].p;
+        let want = if on { Point::new(561.5, 438.5) } else { Point::new(561.0, 438.0) };
+        assert!((last - want).hypot() < 1e-9, "{on}: {last:?}");
+    }
+}
@@ -178,6 +178,7 @@ impl Session {
        let (unit, stroke_unit) = (self.general_unit(), self.stroke_unit());
        let cx = ToolContext {
            doc: &st.doc,
+            revision: (st.uid, st.revision),
            selection: &st.selection,
            zoom: view.zoom,
            isolation: st.isolation,
@@ -222,6 +223,11 @@ impl Session {
            measurement_labels: self.prefs.measurement_labels,
            transform_tools_guides: self.prefs.transform_tools_guides,
            snapping_tolerance: self.prefs.snapping_tolerance,
+            construction_angles: if self.prefs.construction_guides {
+                vectorcraft_tools::guides::construction_angles(&self.prefs.construction_angles)
+            } else {
+                &[]
+            },
            screen: view.screen,
            plane_widget: self.prefs.perspective_widget.show.then_some(self.prefs.perspective_widget.position),
        };
@@ -588,3 +588,30 @@ fn type_preferences_apply_to_agents() {
    assert_eq!(r["isError"], false, "{r}");
    assert_eq!(style(&mut s, 6), (size + 4.0, tracking + 50.0));
 }
+
+/// The drawing tools snap to Smart Guides over MCP as with the mouse (#506): a Rectangle drawn
+/// from near another object's corner starts on it, and a Pen anchor placed beside that object's
+/// centre lines up with it.
+#[test]
+fn drawing_gestures_snap_to_smart_guides() {
+    let mut s = server();
+    let r = call(&mut s, 1, "run_command", json!({"command": "file.new", "params": {"width": 800, "height": 600}}));
+    assert_eq!(r["isError"], false, "{r}");
+    let r = call(&mut s, 2, "draw_shape", json!({"shape": "rectangle", "x": 100, "y": 100, "width": 100, "height": 100}));
+    assert_eq!(r["isError"], false, "{r}");
+    let bounds = |s: &mut Server, n: u64, events: Value, tool: &str| {
+        let r = call(s, n, "pointer_gesture", json!({"tool": tool, "events": events}));
+        assert_eq!(r["isError"], false, "{r}");
+        let id = serde_json::from_str::<Value>(&text_of(&r)).unwrap()["selection"][0].clone();
+        let doc: Value = serde_json::from_str(&text_of(&call(s, n + 1, "inspect_document", json!({})))).unwrap();
+        let made = doc["layers"][0]["children"].as_array().unwrap().iter().find(|c| c["id"] == id).expect("drawn").clone();
+        let b = &made["bounds"];
+        [&b["x"], &b["y"], &b["width"], &b["height"]].map(|v| v.as_f64().unwrap())
+    };
+    let events = json!([{"kind": "move", "x": 202, "y": 203}, {"kind": "down", "x": 202, "y": 203}, {"kind": "drag", "x": 330, "y": 341}, {"kind": "up", "x": 330, "y": 341}]);
+    assert_eq!(bounds(&mut s, 3, events, "rectangle"), [200.0, 200.0, 130.0, 141.0]);
+    let r = call(&mut s, 5, "run_command", json!({"command": "select.none", "params": {}}));
+    assert_eq!(r["isError"], false, "{r}");
+    let events = json!([{"kind": "down", "x": 300, "y": 420}, {"kind": "up", "x": 300, "y": 420}, {"kind": "move", "x": 151.5, "y": 431}, {"kind": "down", "x": 151.5, "y": 431}, {"kind": "up", "x": 151.5, "y": 431}]);
+    assert_eq!(bounds(&mut s, 6, events, "pen"), [150.0, 420.0, 150.0, 11.0]);
+}
@@ -3,13 +3,15 @@
 //! Each click adds a point and the path curves smoothly through all points. Alt-click or
 //! double-click a point toggles it between smooth and corner; drag a point to move it; click the
 //! first point to close; Backspace/Delete removes the last touched point; Esc/Enter ends the path.
-//! A rubber band shows the curve to the cursor (Enable Rubber Band for Curvature Tool).
+//! A rubber band shows the curve to the cursor (Enable Rubber Band for Curvature Tool). Each point
+//! placed or dragged snaps to Smart Guides ([`DrawSnap`]), as the Pen's anchors do.

 use serde_json::{Value, json};
-use vectorcraft_doc::NodeId;
+use vectorcraft_doc::{NodeId, Selection};
 use vectorcraft_geom::Point;

 use super::{FEEDBACK, catmull_rom};
+use crate::guides::{DrawSnap, Leave, Targets};
 use crate::{Action, Cursor, Mods, Overlay, PointerEvent, PointerKind, Tool, ToolContext, ToolKey};

 #[derive(Default)]
@@ -22,6 +24,7 @@ pub struct CurvatureTool {
    /// Last touched point (Backspace removes it).
    current: Option<usize>,
    hover: Option<Point>,
+    snap: DrawSnap,
 }

 impl CurvatureTool {
@@ -55,6 +58,12 @@ impl CurvatureTool {
        self.id = None;
        self.drag = None;
        self.current = None;
+        self.snap.clear();
+    }
+
+    /// The segment to the next point leaves the last one.
+    fn leave(&self, cx: &ToolContext) -> Option<Leave> {
+        self.pts.last().map(|(p, _)| Leave::segment(cx, *p, false))
    }
 }

@@ -73,11 +82,12 @@ impl Tool for CurvatureTool {
        }
        match ev.kind {
            PointerKind::Move => {
-                self.hover = Some(p);
+                let from = active.and_then(|_| self.leave(cx));
+                self.hover = Some(self.snap.hover(cx, p, active.as_slice(), from.as_ref()));
                vec![]
            }
            PointerKind::Down => {
-                if active.is_some() {
+                if let Some(id) = active {
                    if let Some(i) = self.hit_point(cx, p) {
                        self.current = Some(i);
                        if ev.mods.alt {
@@ -88,10 +98,15 @@ impl Tool for CurvatureTool {
                            self.closed = true;
                            return vec![Action::Exec("path.curvature".into(), self.params())];
                        }
+                        // The point dragged and the curve through it move: the rest pull.
+                        let sel = Selection { objects: vec![id], anchors: [(id, [(0, i)].into())].into(), ..Selection::default() };
+                        self.snap.hold(cx, || Targets::for_anchor_drag(cx.doc, &sel));
                        self.drag = Some((i, p, false));
                        return vec![];
                    }
                    if !self.closed {
+                        let from = self.leave(cx);
+                        let p = self.snap.press(cx, p, &[id], from.as_ref());
                        self.pts.push((p, ev.mods.alt));
                        self.current = Some(self.pts.len() - 1);
                        return vec![Action::Exec("path.curvature".into(), self.params())];
@@ -99,6 +114,7 @@ impl Tool for CurvatureTool {
                }
                // Start a new path.
                self.reset();
+                let p = self.snap.press(cx, p, &[], None);
                self.pts.push((p, false));
                self.current = Some(0);
                vec![Action::Exec("path.curvature".into(), self.params()), Action::Notify("created".into())]
@@ -113,16 +129,20 @@ impl Tool for CurvatureTool {
                    out.push(Action::Begin("Curvature".into()));
                    self.drag = Some((i, start, true));
                }
+                let p = self.snap.drag(cx, p, None);
                if let Some(pt) = self.pts.get_mut(i) {
                    pt.0 = p;
                }
                out.push(Action::Preview("path.curvature".into(), self.params()));
                out
            }
-            PointerKind::Up => match self.drag.take() {
-                Some((_, _, true)) => vec![Action::Commit],
-                _ => vec![],
-            },
+            PointerKind::Up => {
+                self.snap.clear();
+                match self.drag.take() {
+                    Some((_, _, true)) => vec![Action::Commit],
+                    _ => vec![],
+                }
+            }
            PointerKind::DoubleClick => {
                if active.is_none() {
                    return vec![];
@@ -163,10 +183,10 @@ impl Tool for CurvatureTool {
        if dragging { vec![Action::Commit] } else { vec![] }
    }
    fn overlays(&self, cx: &ToolContext) -> Vec<Overlay> {
+        let mut o = self.snap.guides().to_vec();
        if self.active(cx).is_none() {
-            return vec![];
+            return o;
        }
-        let mut o = vec![];
        if cx.curvature_rubber_band
            && !self.closed
            && self.drag.is_none()
@@ -217,4 +237,19 @@ mod tests {
        let a = t.pointer(&cx2, &PointerEvent::new(PointerKind::Down, 400.0, 400.0));
        assert!(matches!(&a[0], Action::Exec(_, v) if v["id"] == id.0 && v["points"].as_array().unwrap().len() == 5));
    }
+
+    /// Points snap to Smart Guides (#506): the first lands on another object's anchor and says so.
+    #[test]
+    fn points_snap_to_smart_guides() {
+        let (d, _) = doc_with_rect();
+        let s = Selection::default();
+        let p = paint();
+        let cx = cx(&d, &s, &p);
+        let mut t = CurvatureTool::default();
+        let a = t.pointer(&cx, &PointerEvent::new(PointerKind::Down, 202.0, 99.0));
+        assert!(matches!(&a[0], Action::Exec(_, v) if v["points"][0]["x"] == 200.0 && v["points"][0]["y"] == 100.0), "{a:?}");
+        assert!(t.overlays(&cx).iter().any(|o| matches!(o, Overlay::Label { text, .. } if text == "anchor")));
+        t.pointer(&cx, &PointerEvent::new(PointerKind::Up, 202.0, 99.0));
+        assert!(t.overlays(&cx).is_empty());
+    }
 }
@@ -1,13 +1,16 @@
 //! Line Segment family drag tools: Arc, Spiral, Rectangular Grid and Polar Grid.
 //!
 //! Drag draws (Shift = equal axes / square, Alt = from the centre for arc and grids, Space held
-//! moves the shape being drawn); a click without dragging asks the UI for the options dialog.
+//! moves the shape being drawn); a click without dragging asks the UI for the options dialog. The
+//! start point and the dragged corner snap to Smart Guides ([`DrawSnap`]), hovering too.
 //! While dragging, ↑/↓ change the spiral's segments, the grid rows or the concentric dividers; ←/→
 //! change grid columns / radial dividers.

 use serde_json::{Value, json};
-use vectorcraft_geom::{Point, Rect, Vec2};
+use vectorcraft_geom::Point;

+use crate::guides::{DrawSnap, Leave, square};
+use crate::shape::drag_rect;
 use crate::{Action, Cursor, Mods, Overlay, PointerEvent, PointerKind, Tool, ToolContext, ToolKey};

 pub struct FamilyTool {
@@ -24,6 +27,7 @@ pub struct FamilyTool {
    pub rows: u32,
    /// Columns / radial dividers.
    pub columns: u32,
+    snap: DrawSnap,
 }

 impl FamilyTool {
@@ -46,6 +50,7 @@ impl FamilyTool {
            clockwise: true,
            rows: 5,
            columns: 5,
+            snap: DrawSnap::default(),
        }
    }

@@ -58,13 +63,10 @@ impl FamilyTool {
        }
    }

-    fn rect(start: Point, p: Point, m: Mods) -> Rect {
-        let mut d = p - start;
-        if m.shift {
-            let s = d.x.abs().max(d.y.abs());
-            d = Vec2::new(s * d.x.signum(), s * d.y.signum());
-        }
-        if m.alt { Rect::from_points(start - d, start + d) } else { Rect::from_points(start, start + d) }
+    /// How the dragged point keeps to the start: a spiral's radius goes anywhere, the arc's and
+    /// the grids' corner keeps to a diagonal with Shift.
+    fn leave(&self, start: Point, m: Mods) -> Option<Leave> {
+        (self.id != "spiral").then(|| Leave::diagonal(start, m.shift))
    }

    /// The command for a drag from `start` to `p`.
@@ -78,25 +80,21 @@ impl FamilyTool {
                )
            }
            "rectangularGrid" => {
-                let r = Self::rect(start, p, m);
+                let r = drag_rect(start, p, m);
                (
                    "shape.rectangularGrid".into(),
                    json!({"x": r.x0, "y": r.y0, "width": r.width(), "height": r.height(), "rows": self.rows, "columns": self.columns}),
                )
            }
            "polarGrid" => {
-                let r = Self::rect(start, p, m);
+                let r = drag_rect(start, p, m);
                (
                    "shape.polarGrid".into(),
                    json!({"x": r.x0, "y": r.y0, "width": r.width(), "height": r.height(), "concentric": self.rows, "radial": self.columns}),
                )
            }
            _ => {
-                let mut d = p - start;
-                if m.shift {
-                    let s = d.x.abs().max(d.y.abs());
-                    d = Vec2::new(s * d.x.signum(), s * d.y.signum());
-                }
+                let d = if m.shift { square(p - start) } else { p - start };
                let (a, b) = if m.alt { (start - d, start + d) } else { (start, start + d) };
                ("shape.arc".into(), json!({"x1": a.x, "y1": a.y, "x2": b.x, "y2": b.y, "closed": self.closed}))
            }
@@ -113,8 +111,12 @@ impl Tool for FamilyTool {
    }
    fn pointer(&mut self, cx: &ToolContext, ev: &PointerEvent) -> Vec<Action> {
        match ev.kind {
+            PointerKind::Move => {
+                self.snap.hover(cx, ev.pos, &[], None);
+                vec![]
+            }
            PointerKind::Down => {
-                let (p, _) = crate::guides::snap_draw(cx, ev.pos, &[]);
+                let p = self.snap.press(cx, ev.pos, &[], None);
                self.start = Some(p);
                self.last = p;
                self.began = false;
@@ -122,6 +124,8 @@ impl Tool for FamilyTool {
            }
            PointerKind::Drag => {
                let Some(mut s) = self.start else { return vec![] };
+                let pos = self.snap.drag(cx, ev.pos, self.leave(s, ev.mods).as_ref());
+                let ev = &PointerEvent { pos, ..*ev };
                crate::shape::space_moves(&mut s, &mut self.last, ev, self.began);
                self.start = Some(s);
                self.mods = ev.mods;
@@ -139,6 +143,7 @@ impl Tool for FamilyTool {
            }
            PointerKind::Up => {
                let Some(s) = self.start.take() else { return vec![] };
+                self.snap.clear();
                if std::mem::take(&mut self.began) { vec![Action::Commit] } else { vec![Action::Dialog(self.id.into(), json!({"x": s.x, "y": s.y}))] }
            }
            _ => vec![],
@@ -179,19 +184,21 @@ impl Tool for FamilyTool {
        } else if key == ToolKey::Escape {
            self.start = None;
            self.began = false;
+            self.snap.clear();
            vec![Action::Cancel]
        } else {
            vec![]
        }
    }
    fn overlays(&self, cx: &ToolContext) -> Vec<Overlay> {
-        match self.start {
-            Some(s) if self.began && cx.measurement_labels => {
-                let d = self.last - s;
-                vec![Overlay::Measure { p: self.last, text: cx.size_label(d.x.abs(), d.y.abs()) }]
-            }
-            _ => vec![],
+        let mut o = self.snap.guides().to_vec();
+        if let Some(s) = self.start.filter(|_| self.began && cx.measurement_labels) {
+            // The size as drawn (from the centre with Alt, square with Shift).
+            let r = drag_rect(s, self.last, self.mods);
+            let (w, h) = if self.id == "spiral" { ((self.last - s).x.abs(), (self.last - s).y.abs()) } else { (r.width(), r.height()) };
+            o.push(Overlay::Measure { p: self.last, text: cx.size_label(w, h) });
        }
+        o
    }
    fn cursor(&self, _cx: &ToolContext, _p: Point, _m: Mods) -> Cursor {
        Cursor::Crosshair
@@ -267,4 +274,23 @@ mod tests {
        assert_eq!(c, "shape.arc");
        assert_eq!(v, json!({"x1": 0.0, "y1": 0.0, "x2": 10.0, "y2": 10.0, "closed": false}));
    }
+
+    /// The start and the dragged corner snap to Smart Guides (#506), Shift sliding the corner of
+    /// a square grid along its diagonal into line.
+    #[test]
+    fn corners_snap_to_smart_guides() {
+        let (d, _) = doc_with_rect();
+        let s = Selection::default();
+        let p = paint();
+        let cx = cx(&d, &s, &p);
+        let mut t = FamilyTool::new("rectangularGrid");
+        t.pointer(&cx, &PointerEvent::new(PointerKind::Down, 202.0, 99.0));
+        let shift = Mods { shift: true, ..Mods::default() };
+        let a = t.pointer(&cx, &PointerEvent::new(PointerKind::Drag, 255.0, 147.0).with_mods(shift));
+        assert!(
+            matches!(&a[..], [Action::Begin(_), Action::Preview(_, v)] if v["x"] == 200.0 && v["y"] == 100.0 && v["width"] == 50.0 && v["height"] == 50.0),
+            "{a:?}"
+        );
+        assert!(t.overlays(&cx).iter().any(|o| matches!(o, Overlay::Label { text, .. } if text == "align")));
+    }
 }
@@ -3,14 +3,17 @@
 //!
 //! Pencil and Paintbrush preview the fitted path live (`path.freehand` re-applied on the snapshot)
 //! and commit on release; Alt on release (or ending near the start) closes the path, and starting
-//! near an end of a selected open path continues it. The other tools collect the drag polyline
-//! (shown as an overlay) and run one command on release.
+//! near an end of a selected open path continues it. The Pencil's new path starts and ends on
+//! Smart Guides ([`DrawSnap`]: an anchor, a path, in line with the art), hovering too; the points
+//! between follow the hand. The other tools collect the drag polyline (shown as an overlay) and run
+//! one command on release.

 use serde_json::{Value, json};
 use vectorcraft_doc::NodeId;
 use vectorcraft_geom::Point;

 use super::{FEEDBACK, points_json, polyline};
+use crate::guides::DrawSnap;
 use crate::{Action, Cursor, Mods, Overlay, PointerEvent, PointerKind, Tool, ToolContext, ToolKey};

 pub struct GestureTool {
@@ -30,6 +33,8 @@ pub struct GestureTool {
    pub edit_within: f64,
    /// "Close paths when ends are within N pixels".
    pub close_within: f64,
+    /// Smart Guides for the Pencil's ends.
+    snap: DrawSnap,
 }

 impl GestureTool {
@@ -56,9 +61,15 @@ impl GestureTool {
            fill: false,
            edit_within: 12.0,
            close_within: 15.0,
+            snap: DrawSnap::default(),
        }
    }

+    /// Do the ends of its strokes snap (the Pencil)?
+    fn snaps(&self) -> bool {
+        self.id == "pencil"
+    }
+
    fn draws_path(&self) -> bool {
        matches!(self.id, "pencil" | "paintbrush")
    }
@@ -147,17 +158,27 @@ impl Tool for GestureTool {
    fn pointer(&mut self, cx: &ToolContext, ev: &PointerEvent) -> Vec<Action> {
        let p = ev.pos;
        match ev.kind {
+            PointerKind::Move if self.snaps() => {
+                self.snap.hover(cx, p, &[], None);
+                vec![]
+            }
            PointerKind::Down => {
-                self.points = vec![p];
                self.active = true;
                self.began = false;
                self.extend = if self.draws_path() { self.find_extend(cx, p) } else { None };
+                // A path continued starts at its end; a new one where it snaps.
+                let start = if self.snaps() && self.extend.is_none() { self.snap.press(cx, p, &[], None) } else { p };
+                self.points = vec![start];
                vec![]
            }
            PointerKind::Drag => {
                if !self.active {
                    return vec![];
                }
+                if self.snaps() {
+                    // Where the stroke would end: shown, taken on release.
+                    self.snap.drag(cx, p, None);
+                }
                if self.points.last().is_some_and(|l| l.distance(p) < cx.tol(1.0)) {
                    return vec![];
                }
@@ -177,8 +198,16 @@ impl Tool for GestureTool {
                if !self.active {
                    return vec![];
                }
+                let end = if self.snaps() { self.snap.drag(cx, p, None) } else { p };
+                self.snap.clear();
                if self.points.last().is_some_and(|l| l.distance(p) >= cx.tol(1.0)) {
-                    self.points.push(p);
+                    self.points.push(end);
+                } else if self.snaps()
+                    && self.points.len() > 1
+                    && let Some(last) = self.points.last_mut()
+                {
+                    // The last step was where the button went up: it moves where that snaps.
+                    *last = end;
                }
                let out = self.finish(cx, ev.mods);
                self.active = false;
@@ -194,6 +223,7 @@ impl Tool for GestureTool {
        match key {
            ToolKey::Escape if self.active => {
                let began = self.began;
+                self.snap.clear();
                self.active = false;
                self.began = false;
                self.points.clear();
@@ -212,21 +242,24 @@ impl Tool for GestureTool {
    }
    fn deactivate(&mut self, _cx: &ToolContext) -> Vec<Action> {
        let began = self.began;
+        self.snap.clear();
        self.active = false;
        self.began = false;
        self.points.clear();
        if began { vec![Action::Commit] } else { vec![] }
    }
    fn overlays(&self, cx: &ToolContext) -> Vec<Overlay> {
+        let mut o = self.snap.guides().to_vec();
        if !self.active || self.points.len() < 2 || self.began {
-            return vec![];
+            return o;
        }
        let width = match self.id {
            "blobBrush" | "eraser" => (self.size * cx.zoom) as f32,
            _ => 1.0,
        };
        let color = if self.id == "eraser" { [0x80, 0x80, 0x80] } else { FEEDBACK };
-        vec![Overlay::Path { path: polyline(&self.points), color, width, dashed: self.id == "knife" }]
+        o.push(Overlay::Path { path: polyline(&self.points), color, width, dashed: self.id == "knife" });
+        o
    }
    fn cursor(&self, _cx: &ToolContext, _p: Point, _m: Mods) -> Cursor {
        Cursor::Crosshair
@@ -269,6 +302,25 @@ mod tests {
        v
    }

+    /// The Pencil's new path starts and ends on Smart Guides (#506), the points between where
+    /// the hand went.
+    #[test]
+    fn pencil_ends_snap_to_smart_guides() {
+        let (d, _) = doc_with_rect();
+        let s = Selection::default();
+        let p = paint();
+        let cx = cx(&d, &s, &p);
+        let mut t = GestureTool::new("pencil");
+        let acts = drag(&mut t, &cx, &[(102.0, 98.0), (151.0, 300.0), (250.0, 320.0), (198.0, 203.0)], Mods::default());
+        let Some(Action::Preview(_, v)) = acts.last().and_then(|a| a.first()) else { panic!("{acts:?}") };
+        assert_eq!(v["points"], json!([[100.0, 100.0], [151.0, 300.0], [250.0, 320.0], [200.0, 200.0]]));
+        // The Paintbrush follows the hand all the way.
+        let mut t = GestureTool::new("paintbrush");
+        let acts = drag(&mut t, &cx, &[(102.0, 98.0), (151.0, 300.0)], Mods::default());
+        let Some(Action::Preview(_, v)) = acts.last().and_then(|a| a.first()) else { panic!("{acts:?}") };
+        assert_eq!(v["points"][0], json!([102.0, 98.0]));
+    }
+
    #[test]
    fn pencil_previews_and_commits() {
        let (d, _) = doc_with_rect();
@@ -1,15 +1,23 @@
-//! Smart Guides: snapping to anchors, path segments (for dragged anchors), object bounds
-//! (edges/centres), artboards, with the magenta construction lines and labels Illustrator users
-//! expect. Preferences › Smart Guides sets their colour, which of them show ([`GuideStyle`]) and
-//! how near a target pulls (`ToolContext::snapping_tolerance`).
+//! Smart Guides: snapping to anchors, path segments (for dragged anchors and drawn points), object
+//! bounds (edges/centres), artboards, with the magenta construction lines and labels Illustrator
+//! users expect. Preferences › Smart Guides sets their colour, which of them show ([`GuideStyle`]),
+//! how near a target pulls (`ToolContext::snapping_tolerance`) and the angles of the construction
+//! guides drawn points land on (`ToolContext::construction_angles`).
+//!
+//! The drawing tools (Pen, Curvature, Pencil, the shape tools, Type, Artboard) all snap the points
+//! they place through one [`DrawSnap`]: their targets are gathered once per document state, sorted,
+//! and each pointer move looks up the few near the pointer by bisection.
+
+use std::collections::HashSet;
+use std::sync::Arc;

 use vectorcraft_doc::hit::{HitOptions, hit_test};
-use vectorcraft_doc::{Document, NodeId, NodeKind, OrientedBox, Selection};
+use vectorcraft_doc::{Document, Node, NodeId, NodeKind, OrientedBox, Selection};
 use vectorcraft_geom::kurbo::ParamCurveNearest;
-use vectorcraft_geom::{Affine, Line, ParamCurve, PathSeg, Point, Rect, SubPath, Vec2};
+use vectorcraft_geom::{Affine, Line, ParamCurve, PathSeg, Point, Rect, SubPath, Vec2, constrain_angle_from};

 use crate::bbox::Handle;
-use crate::{Overlay, ToolContext};
+use crate::{Overlay, ScreenFrame, ToolContext};

 pub const MAGENTA: [u8; 3] = [0xff, 0x3d, 0xfc];

@@ -102,9 +110,93 @@ impl Ruler {
 /// How many anchors, and how many segments, the targets gather at most.
 const BUDGET: usize = 20_000;

+/// What [`Targets::collect_inner`] gathers from each path besides its anchors and bounds.
+#[derive(Clone, Copy, PartialEq)]
+enum Gather {
+    /// Nothing more: a moved or resized selection lines up with bounds.
+    Bounds,
+    /// Its segments, which a dragged anchor lands on.
+    Segments,
+    /// Its segments, and its anchors as lines too: a drawn point lines up with them.
+    Drawing,
+}
+
+/// The entries of `sorted` (ascending by `key`) whose key is within `tol` of `v`, found by
+/// bisection.
+fn within<T>(sorted: &[T], key: impl Fn(&T) -> f64, v: f64, tol: f64) -> &[T] {
+    let lo = sorted.partition_point(|e| key(e) < v - tol);
+    let hi = sorted.partition_point(|e| key(e) <= v + tol);
+    sorted.get(lo..hi).unwrap_or_default()
+}
+
+/// Visit `nodes` and everything inside them, but the nodes in `skip` and everything inside those:
+/// one pass, however many are skipped.
+fn walk_but<'a>(nodes: &'a [Arc<Node>], skip: &HashSet<NodeId>, f: &mut impl FnMut(&'a Node)) {
+    for n in nodes.iter().filter(|n| !skip.contains(&n.id)) {
+        f(n);
+        if let Some(ch) = n.children() {
+            walk_but(ch, skip, f);
+        }
+    }
+}
+
+/// The lines of `lines` (sorted by where they run) within `tol` of `v`.
+fn lines_near(lines: &[(f64, Point, Kind)], v: f64, tol: f64) -> &[(f64, Point, Kind)] {
+    within(lines, |l| l.0, v, tol)
+}
+
 impl Targets {
    pub fn collect(doc: &Document, exclude: &[NodeId], visible: Option<Rect>) -> Self {
-        Self::collect_inner(doc, exclude, None, visible, false)
+        Self::collect_inner(doc, exclude, None, visible, Gather::Bounds)
+    }
+
+    /// Targets for a drawn point: the art in `visible` (all of it for None) but `exclude`, its
+    /// anchors, centres, edges and path segments, its anchors in line too. The anchors and
+    /// segments of `exclude` (the path being drawn, whose bounds grow with it) stay targets.
+    pub fn for_drawing(doc: &Document, exclude: &[NodeId], visible: Option<Rect>) -> Self {
+        let mut t = Self::collect_inner(doc, exclude, None, visible, Gather::Drawing);
+        t.push_paths(doc, exclude, true);
+        t.index()
+    }
+
+    /// Targets for a dragged direction handle of path `id`: the other art, and the anchors of `id`
+    /// (its bounds and the segments through the handle move with it, so they would chase it).
+    pub fn for_handle(doc: &Document, id: NodeId) -> Self {
+        let mut t = Self::collect_inner(doc, &[id], None, None, Gather::Bounds);
+        t.push_paths(doc, &[id], false);
+        t.index()
+    }
+
+    /// The anchors of the paths `ids` as targets, on them and in line, and their segments too
+    /// when `segments`: at most [`BUDGET`] of each.
+    fn push_paths(&mut self, doc: &Document, ids: &[NodeId], segments: bool) {
+        let (mut anchors, mut segment_budget) = (BUDGET, if segments { BUDGET } else { 0 });
+        for path in ids.iter().filter_map(|id| doc.node(*id)?.path_data()) {
+            for sp in &path.subpaths {
+                for a in sp.anchors.iter().take(anchors) {
+                    self.push_anchor(a.p);
+                    anchors -= 1;
+                }
+                self.push_segments(sp, |_| false, &mut segment_budget);
+            }
+        }
+    }
+
+    /// Sort the targets so that [`within`] finds those near a point by bisection: the anchors
+    /// and centres by x, the lines by where they run. Every constructor ends with it (the sort
+    /// is stable: of targets alike, the first gathered still wins).
+    fn index(mut self) -> Self {
+        self.points.sort_by(|a, b| a.0.x.total_cmp(&b.0.x));
+        self.xs.sort_by(|a, b| a.0.total_cmp(&b.0));
+        self.ys.sort_by(|a, b| a.0.total_cmp(&b.0));
+        self
+    }
+
+    /// Anchor `a` as a target: a point lands on it and lines up with it.
+    fn push_anchor(&mut self, a: Point) {
+        self.points.push((a, Kind::Anchor));
+        self.xs.push((a.x, a, Kind::Anchor));
+        self.ys.push((a.y, a, Kind::Anchor));
    }

    /// The same targets drawing their guides as the Smart Guides preferences in `cx` ask
@@ -127,29 +219,27 @@ impl Targets {
    /// Targets for dragging artboard `index`: everything except that artboard and `exclude` (the
    /// art that moves along with it).
    pub fn for_artboard(doc: &Document, index: usize, exclude: &[NodeId]) -> Self {
-        Self::collect_inner(doc, exclude, Some(index), None, false)
+        Self::collect_inner(doc, exclude, Some(index), None, Gather::Bounds)
    }

    /// Targets for dragging the direct-selected anchors of `sel` (and its objects selected as a
    /// whole): the other art, its path segments too, and the anchors and segments that stay put on
    /// the paths being reshaped (their bounds move along, so they are no targets).
    pub fn for_anchor_drag(doc: &Document, sel: &Selection) -> Self {
-        let mut t = Self::collect_inner(doc, &sel.objects, None, None, true);
+        let mut t = Self::collect_inner(doc, &sel.objects, None, None, Gather::Segments);
        let (mut anchors, mut segments) = (BUDGET, BUDGET);
        for (id, set) in &sel.anchors {
            let Some(path) = doc.node(*id).and_then(|n| n.path_data()) else { continue };
            for (si, sp) in path.subpaths.iter().enumerate() {
                let moving = |ai: usize| set.contains(&(si, ai));
                for a in sp.anchors.iter().enumerate().filter(|(ai, _)| !moving(*ai)).map(|(_, a)| a.p).take(anchors) {
-                    t.points.push((a, Kind::Anchor));
-                    t.xs.push((a.x, a, Kind::Anchor));
-                    t.ys.push((a.y, a, Kind::Anchor));
+                    t.push_anchor(a);
                    anchors -= 1;
                }
                t.push_segments(sp, moving, &mut segments);
            }
        }
-        t
+        t.index()
    }

    /// The segments of `sp` that stay put while the anchors `moving` accepts move, as targets, at
@@ -171,9 +261,8 @@ impl Targets {
        }
    }

-    fn collect_inner(doc: &Document, exclude: &[NodeId], skip_artboard: Option<usize>, visible: Option<Rect>, segments: bool) -> Self {
+    fn collect_inner(doc: &Document, exclude: &[NodeId], skip_artboard: Option<usize>, visible: Option<Rect>, gather: Gather) -> Self {
        let mut t = Targets::default();
-        let excluded = |id: NodeId| exclude.iter().any(|e| doc.ancestry(id).is_some_and(|a| a.contains(e)));
        let add_rect = |t: &mut Targets, r: Rect, kind: Kind| {
            let c = r.center();
            for p in [Point::new(r.x0, r.y0), Point::new(r.x1, r.y0), Point::new(r.x1, r.y1), Point::new(r.x0, r.y1)] {
@@ -194,8 +283,8 @@ impl Targets {
            }
        }
        let (mut budget, mut segment_budget) = (BUDGET, BUDGET);
-        doc.walk(|n| {
-            if budget == 0 || n.is_container() || !n.visible || excluded(n.id) {
+        walk_but(&doc.layers, &exclude.iter().copied().collect(), &mut |n| {
+            if budget == 0 || n.is_container() || !n.visible {
                return;
            }
            let Some(b) = n.geometric_bounds() else { return };
@@ -207,10 +296,14 @@ impl Targets {
            }
            if let NodeKind::Path { path, .. } = &n.kind {
                for (_, _, a) in path.anchors() {
-                    t.points.push((a.p, Kind::Anchor));
+                    if gather == Gather::Drawing {
+                        t.push_anchor(a.p);
+                    } else {
+                        t.points.push((a.p, Kind::Anchor));
+                    }
                    budget = budget.saturating_sub(1);
                }
-                if segments {
+                if gather != Gather::Bounds {
                    for sp in &path.subpaths {
                        t.push_segments(sp, |_| false, &mut segment_budget);
                    }
@@ -218,7 +311,7 @@ impl Targets {
            }
            add_rect(&mut t, b, Kind::Edge);
        });
-        t
+        t.index()
    }

    /// Only these targets' anchors pull (View → Snap to Point).
@@ -265,25 +358,55 @@ impl Targets {
                t.points.push((b.center(), Kind::Center));
            });
        }
-        t
+        t.index()
    }

    /// Snap a single point: onto the nearest anchor or centre, else onto the nearest segment, else
    /// into line with targets. Returns the snapped point and guide overlays.
    pub fn snap_point(&self, p: Point, tol: f64) -> (Point, Vec<Overlay>) {
+        self.snap_from(p, None, tol)
+    }
+
+    /// Snap a drawn point `p` as [`Self::snap_point`] does, and when it leaves `from` (the anchor
+    /// before it, a shape's start): with Shift held it keeps to its angles round it, sliding along
+    /// that way into line with the nearest target; else, before lining up, it lands on a
+    /// construction guide through it, where a target's line crosses the guide if one does nearby.
+    pub fn snap_from(&self, p: Point, from: Option<&Leave>, tol: f64) -> (Point, Vec<Overlay>) {
+        if let Some(f) = from
+            && let Some(q) = f.constrained(p)
+        {
+            return match self.slide(f.at, q - f.at, q, tol, true) {
+                Some((q, target)) => (q, self.lined_up(q, target)),
+                None => (q, vec![]),
+            };
+        }
        if let Some((q, k)) = self.nearest_point(p, tol) {
            return (q, self.label(q, k.label()).into_iter().collect());
        }
        if let Some(q) = self.on_segment(p, tol) {
            return (q, self.label(q, Kind::Edge.label()).into_iter().collect());
        }
+        if let Some(f) = from
+            && let Some((dir, q)) = f.construction(p, tol)
+        {
+            let construction = |q: Point| Overlay::Line { a: f.at, b: q, color: self.style.color, dashed: false };
+            return match self.slide(f.at, dir, q, tol, false) {
+                Some((q, target)) => (q, std::iter::once(construction(q)).chain(self.lined_up(q, target)).collect()),
+                None => (q, vec![construction(q)]),
+            };
+        }
        let mut out = p;
        let mut ov = vec![];
        // The targets' lines along one axis and the ruler guides running past `p`, the nearest
        // within reach of `v`.
        let nearest = |lines: &[(f64, Point, Kind)], vertical: bool, v: f64| {
            let rulers = self.rulers.iter().filter(|r| r.vertical == vertical).filter_map(|r| r.line_at(p, tol));
-            lines.iter().copied().chain(rulers).filter(|(t, ..)| (t - v).abs() <= tol).min_by(|a, b| (a.0 - v).abs().total_cmp(&(b.0 - v).abs()))
+            lines_near(lines, v, tol)
+                .iter()
+                .copied()
+                .chain(rulers)
+                .filter(|(t, ..)| (t - v).abs() <= tol)
+                .min_by(|a, b| (a.0 - v).abs().total_cmp(&(b.0 - v).abs()))
        };
        let mut aligned = false;
        if let Some((x, from, _)) = nearest(&self.xs, true, p.x) {
@@ -304,7 +427,47 @@ impl Targets {

    /// The anchor or centre nearest `p`, within `tol`.
    fn nearest_point(&self, p: Point, tol: f64) -> Option<(Point, Kind)> {
-        self.points.iter().copied().filter(|(q, _)| q.distance(p) <= tol).min_by(|a, b| a.0.distance(p).total_cmp(&b.0.distance(p)))
+        within(&self.points, |q| q.0.x, p.x, tol)
+            .iter()
+            .copied()
+            .filter(|(q, _)| q.distance(p) <= tol)
+            .min_by(|a, b| a.0.distance(p).total_cmp(&b.0.distance(p)))
+    }
+
+    /// Slide `q`, on the line through `at` along `dir` (beyond `at` only, for a `ray`), to where
+    /// the nearest target line crosses it, at most twice `tol` away: where it lands and the
+    /// target's own point (where its line starts).
+    fn slide(&self, at: Point, dir: Vec2, q: Point, tol: f64, ray: bool) -> Option<(Point, Point)> {
+        if !dir.hypot2().is_finite() || dir.hypot2() <= 1e-18 {
+            return None;
+        }
+        let reach = 2.0 * tol;
+        let mut best: Option<(f64, Point, Point)> = None;
+        for (vertical, lines, d, a, v) in [(true, &self.xs, dir.x, at.x, q.x), (false, &self.ys, dir.y, at.y, q.y)] {
+            if d.abs() <= 1e-9 {
+                continue;
+            }
+            // A line that far across the way crosses it at least that far along.
+            for (t, from, _) in lines_near(lines, v, reach) {
+                let s = (t - a) / d;
+                // Exactly on the line, whatever the rounding along the way.
+                let hit = if vertical { Point::new(*t, at.y + dir.y * s) } else { Point::new(at.x + dir.x * s, *t) };
+                let moved = hit.distance(q);
+                if moved <= reach && (!ray || s > 0.0) && best.is_none_or(|b| moved < b.0) {
+                    best = Some((moved, hit, *from));
+                }
+            }
+        }
+        best.map(|(_, hit, from)| (hit, from))
+    }
+
+    /// The guides of a point `q` slid into line with the target at `from`: the line from it and
+    /// "align", or the target's own label when `q` sits right on it.
+    fn lined_up(&self, q: Point, from: Point) -> Vec<Overlay> {
+        if let Some((on, k)) = self.nearest_point(q, 1e-9) {
+            return self.label(on, k.label()).into_iter().collect();
+        }
+        self.line(from, q).into_iter().chain(self.label(q, "align")).collect()
    }

    /// The nearest point within `tol` of `p` on a target segment.
@@ -323,7 +486,7 @@ impl Targets {
    pub fn snap_guide(&self, vertical: bool, v: f64, tol: f64) -> (f64, Vec<Overlay>) {
        let along = |q: &Point| if vertical { q.x } else { q.y };
        let lines = if vertical { &self.xs } else { &self.ys };
-        let best = lines
+        let best = lines_near(lines, v, tol)
            .iter()
            .map(|(t, from, k)| (*t, *from, *k))
            .chain(self.points.iter().map(|(q, k)| (along(q), *q, *k)))
@@ -370,7 +533,7 @@ impl Targets {
            rects
                .iter()
                .flat_map(|r| along(r).into_iter().map(move |v| (v, *r)))
-                .flat_map(|(v, r)| targets.iter().map(move |(t, from, _)| (t - v, *from, v, r)))
+                .flat_map(|(v, r)| lines_near(targets, v, tol).iter().map(move |(t, from, _)| (t - v, *from, v, r)))
                .filter(|(d, ..)| d.abs() <= tol)
                .min_by(|a, b| a.0.abs().total_cmp(&b.0.abs()))
        };
@@ -410,7 +573,11 @@ impl Targets {
        // A scale that collapses or flips the box is no snap.
        let valid = |n: f64, s: f64| n.is_finite() && n * s > 0.0;
        let nearest = |v: f64, ts: &[(f64, Point, Kind)]| -> Hit {
-            ts.iter().map(|(t, from, _)| (*t, *from)).filter(|(t, _)| (t - v).abs() <= tol).min_by(|p, q| (p.0 - v).abs().total_cmp(&(q.0 - v).abs()))
+            lines_near(ts, v, tol)
+                .iter()
+                .map(|(t, from, _)| (*t, *from))
+                .filter(|(t, _)| (t - v).abs() <= tol)
+                .min_by(|p, q| (p.0 - v).abs().total_cmp(&(q.0 - v).abs()))
        };
        let (mut nx, mut ny) = (sx, sy);
        let mut snap: Snap = (None, None, None);
@@ -540,24 +707,225 @@ impl PointSnap {

    /// Where `p` goes, and the guides showing why.
    pub fn snap(&self, cx: &ToolContext, p: Point) -> (Point, Vec<Overlay>) {
+        self.snap_from(cx, p, None)
+    }
+
+    /// Where a drawn point `p` leaving `from` goes ([`Targets::snap_from`]), and the guides
+    /// showing why. Pixels and the grid round it before Shift turns it onto its angle.
+    pub fn snap_from(&self, cx: &ToolContext, p: Point, from: Option<&Leave>) -> (Point, Vec<Overlay>) {
+        let keep = |q: Point| from.and_then(|f| f.constrained(q)).unwrap_or(q);
        if cx.snap_to_pixel {
-            return (Point::new(p.x.round(), p.y.round()), vec![]);
+            return (keep(Point::new(p.x.round(), p.y.round())), vec![]);
        }
        if cx.snap_to_grid {
-            return (vectorcraft_geom::snap::snap_point_to_grid(p, cx.grid_step()), vec![]);
+            return (keep(vectorcraft_geom::snap::snap_point_to_grid(p, cx.grid_step())), vec![]);
        }
        match &self.targets {
-            Some((t, tol)) => t.snap_point(p, cx.tol(*tol)),
-            None => (p, vec![]),
+            Some((t, tol)) => t.snap_from(p, from, cx.tol(*tol)),
+            None => (keep(p), vec![]),
        }
    }
 }

-/// Snapping for a dragged direction handle: Shift keeps it at 45° steps round its anchor, else it
-/// snaps as a drawn point does. The targets are gathered on the first move that needs them and
-/// kept for the rest of the drag (gathering them takes as long as the document is big).
+/// The Construction Guides angle set new preferences start with.
+pub const DEFAULT_CONSTRUCTION_ANGLES: &str = "90° & 45° Angles";
+
+/// The angles (degrees) of the construction guides of a Smart Guides › Angles set: "90°" gives the
+/// horizontal and the vertical, "45°" the diagonals, "60°" and "30°" their multiples between those.
+pub fn construction_angles(set: &str) -> &'static [f64] {
+    match set {
+        "30° Angles" => &[30.0, 60.0, 120.0, 150.0],
+        "45° Angles" => &[45.0, 135.0],
+        "60° Angles" => &[60.0, 120.0],
+        "90° Angles" => &[0.0, 90.0],
+        "90° & 45° & 30° Angles" => &[0.0, 30.0, 45.0, 60.0, 90.0, 120.0, 135.0, 150.0],
+        _ => &[0.0, 45.0, 90.0, 135.0],
+    }
+}
+
+/// How Shift keeps a drawn point to the point it leaves from.
+#[derive(Clone, Copy, Debug, PartialEq)]
+enum Keep {
+    /// At steps of `step` degrees counted from `base` (a segment).
+    Angle { step: f64, base: f64 },
+    /// On a diagonal, as far along as the pointer's farther axis (a square's corner).
+    Square,
+}
+
+/// The point a drawn point leaves from (the anchor before it, a shape's start) and how it keeps
+/// to it: with Shift held at fixed angles round it, and onto the construction guides through it
+/// (Smart Guides › Construction Guides).
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Leave {
+    pub at: Point,
+    /// Shift held: how the point keeps to `at`.
+    shift: Option<Keep>,
+    /// The angles of the construction guides through `at` (none with them off).
+    angles: &'static [f64],
+}
+
+impl Leave {
+    /// A segment from `at` (Pen, Curvature, Line Segment): Shift keeps it at 45° steps from
+    /// General › Constrain Angle; with Smart Guides on it lands on the construction guides.
+    pub fn segment(cx: &ToolContext, at: Point, shift: bool) -> Self {
+        Self {
+            at,
+            shift: shift.then_some(Keep::Angle { step: 45.0, base: cx.constrain_angle }),
+            angles: if cx.smart_guides { cx.construction_angles } else { &[] },
+        }
+    }
+
+    /// A box dragged from its corner or centre `at` (Rectangle, Ellipse, Arc, the grids,
+    /// Artboard): 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: &[] }
+    }
+
+    /// Where Shift puts `p`: none without it.
+    fn constrained(&self, p: Point) -> Option<Point> {
+        let v = p - self.at;
+        Some(match self.shift? {
+            Keep::Angle { step, base } => self.at + constrain_angle_from(v, step, base),
+            Keep::Square => self.at + square(v),
+        })
+    }
+
+    /// The construction guide through `at` nearest `p`, within `tol` of it (and `p` farther than
+    /// that from `at`, where every guide meets): its direction and where `p` lands on it.
+    fn construction(&self, p: Point, tol: f64) -> Option<(Vec2, Point)> {
+        let v = p - self.at;
+        if v.hypot() <= tol {
+            return None;
+        }
+        self.angles
+            .iter()
+            // Counter-clockwise as seen on the y-down page.
+            .map(|a| Vec2::new(a.to_radians().cos(), -a.to_radians().sin()))
+            .map(|d| (d, self.at + d * v.dot(d)))
+            .map(|(d, q)| (d, q, q.distance(p)))
+            .filter(|(.., dist)| *dist <= tol)
+            .min_by(|a, b| a.2.total_cmp(&b.2))
+            .map(|(d, q, _)| (d, q))
+    }
+}
+
+/// `d` made square: as long on both axes as on its longer one, each keeping its sign.
+pub fn square(d: Vec2) -> Vec2 {
+    let s = d.x.abs().max(d.y.abs());
+    Vec2::new(s * d.x.signum(), s * d.y.signum())
+}
+
+/// Smart Guides for the points a drawing tool places: the Pen's and Curvature tool's anchors,
+/// the Pencil's ends, the shape tools' start and dragged corner, the Type tool's click and the
+/// Artboard tool's new artboard. Each such tool keeps one and asks it for every point, hovering
+/// too, so they all snap alike, and shows its [`Self::guides`].
+///
+/// The targets ([`Targets::for_drawing`], the art in the window) are gathered once per document
+/// state: hovering gathers them again only after the document, the selection, what is left out,
+/// the window or the snapping options changed; a press always gathers them afresh, and the drag
+/// it starts keeps them, the document then showing the drag's own previews.
 #[derive(Default)]
-pub struct HandleSnap(Option<PointSnap>);
+pub struct DrawSnap {
+    /// The targets, and what they were gathered for (none: for one drag only).
+    targets: Option<(Option<SnapKey>, PointSnap)>,
+    guides: Vec<Overlay>,
+}
+
+/// What a [`DrawSnap`]'s targets were gathered for: the document state, the art left out, the
+/// window and every option [`PointSnap::new`] reads.
+#[derive(PartialEq)]
+struct SnapKey {
+    revision: (u64, u64),
+    exclude: Vec<NodeId>,
+    screen: Option<ScreenFrame>,
+    view: [bool; 5],
+    style: GuideStyle,
+    tolerances: [f64; 2],
+}
+
+impl SnapKey {
+    fn of(cx: &ToolContext, exclude: &[NodeId]) -> Self {
+        Self {
+            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],
+            style: GuideStyle::of(cx),
+            tolerances: [cx.snapping_tolerance, cx.snap_tolerance],
+        }
+    }
+}
+
+/// The part of the document the window shows (none headless: all of it).
+fn visible(cx: &ToolContext) -> Option<Rect> {
+    let s = cx.screen?;
+    let (w, h) = s.size;
+    Some(Rect::from_points(s.at(0.0, 0.0), s.at(w, h)).union_pt(s.at(w, 0.0)).union_pt(s.at(0.0, h)))
+}
+
+impl DrawSnap {
+    /// Snap the pointer hovering at `p` (the art but `exclude` as targets, the anchors of
+    /// `exclude` still pulling), reusing the targets while nothing they depend on changed.
+    pub fn hover(&mut self, cx: &ToolContext, p: Point, exclude: &[NodeId], from: Option<&Leave>) -> Point {
+        let key = SnapKey::of(cx, exclude);
+        if self.targets.as_ref().is_none_or(|(k, _)| k.as_ref() != Some(&key)) {
+            self.gather(cx, key);
+        }
+        self.snap(cx, p, from)
+    }
+
+    /// Snap the point pressed at `p`, the targets gathered afresh: the drag that follows keeps
+    /// them ([`Self::drag`]).
+    pub fn press(&mut self, cx: &ToolContext, p: Point, exclude: &[NodeId], from: Option<&Leave>) -> Point {
+        self.gather(cx, SnapKey::of(cx, exclude));
+        self.snap(cx, p, from)
+    }
+
+    /// Gather `targets` other than the art for the drag a press starts (a point being dragged
+    /// leaves itself out); the next hover gathers its own again.
+    pub fn hold(&mut self, cx: &ToolContext, targets: impl FnOnce() -> Targets) {
+        self.targets = Some((None, PointSnap::new(cx, targets)));
+        self.guides.clear();
+    }
+
+    /// Snap `p`, dragged since the press, with the targets the press gathered.
+    pub fn drag(&mut self, cx: &ToolContext, p: Point, from: Option<&Leave>) -> Point {
+        if self.targets.is_none() {
+            self.gather(cx, SnapKey::of(cx, &[]));
+        }
+        self.snap(cx, p, from)
+    }
+
+    /// The guides of the last snap.
+    pub fn guides(&self) -> &[Overlay] {
+        &self.guides
+    }
+
+    /// Hide the guides (the gesture ended).
+    pub fn clear(&mut self) {
+        self.guides.clear();
+    }
+
+    fn gather(&mut self, cx: &ToolContext, key: SnapKey) {
+        let snap = PointSnap::new(cx, || Targets::for_drawing(cx.doc, &key.exclude, visible(cx)));
+        self.targets = Some((Some(key), snap));
+    }
+
+    fn snap(&mut self, cx: &ToolContext, p: Point, from: Option<&Leave>) -> Point {
+        let (q, guides) = match &self.targets {
+            Some((_, t)) => t.snap_from(cx, p, from),
+            None => (p, vec![]),
+        };
+        self.guides = guides;
+        q
+    }
+}
+
+/// Snapping for a dragged direction handle: Shift keeps it at 45° steps round its anchor, else it
+/// snaps as a drawn point does ([`DrawSnap`]). The targets ([`Targets::for_handle`]) are gathered
+/// on the first move that needs them and kept for the rest of the drag.
+#[derive(Default)]
+pub struct HandleSnap(DrawSnap);

 impl HandleSnap {
    /// Where the handle of anchor `ai` of subpath `si` of path `id` goes with the pointer at `p`,
@@ -565,22 +933,13 @@ impl HandleSnap {
    pub fn snap(&mut self, cx: &ToolContext, (id, si, ai): (NodeId, usize, usize), p: Point, shift: bool) -> (Point, Vec<Overlay>) {
        let path = cx.doc.node(id).and_then(|n| n.path_data());
        if shift && let Some(a) = path.and_then(|pd| pd.subpaths.get(si)?.anchors.get(ai)) {
-            return (a.p + vectorcraft_geom::constrain_angle_from(p - a.p, 45.0, cx.constrain_angle), vec![]);
+            return (a.p + constrain_angle_from(p - a.p, 45.0, cx.constrain_angle), vec![]);
        }
-        let snap = self.0.get_or_insert_with(|| {
-            PointSnap::new(cx, || {
-                // The path's bounds move with the handle, so they would chase it: its anchors
-                // (which stay put) are the targets instead, the handle lining up with them too.
-                let mut t = Targets::collect(cx.doc, &[id], None);
-                for (_, _, a) in path.into_iter().flat_map(|pd| pd.anchors()).take(20_000) {
-                    t.points.push((a.p, Kind::Anchor));
-                    t.xs.push((a.p.x, a.p, Kind::Anchor));
-                    t.ys.push((a.p.y, a.p, Kind::Anchor));
-                }
-                t
-            })
-        });
-        snap.snap(cx, p)
+        if self.0.targets.is_none() {
+            self.0.hold(cx, || Targets::for_handle(cx.doc, id));
+        }
+        let q = self.0.drag(cx, p, None);
+        (q, self.0.guides().to_vec())
    }
 }

@@ -758,9 +1117,138 @@ mod tests {
        s.anchors.insert(id, [(0, 0)].into_iter().collect());
        let t = Targets::for_anchor_drag(&d, &s);
        let anchors: Vec<Point> = t.points.iter().filter(|(_, k)| *k == Kind::Anchor).map(|(p, _)| *p).collect();
-        assert_eq!(anchors, [Point::new(200.0, 100.0), Point::new(200.0, 200.0), Point::new(100.0, 200.0)]);
+        assert_eq!(anchors, [Point::new(100.0, 200.0), Point::new(200.0, 100.0), Point::new(200.0, 200.0)], "by x");
        assert_eq!(t.segments.len(), 2);
        assert!(!t.points.iter().any(|(p, k)| *k == Kind::Center && *p == Point::new(150.0, 150.0)), "the rect's centre moves");
        assert_eq!(t.snap_point(Point::new(101.0, 99.0), 4.0).0, Point::new(100.0, 100.0), "in line with its neighbours, not on itself");
    }
+
+    fn labels(ov: &[Overlay]) -> Vec<&str> {
+        ov.iter().filter_map(|o| if let Overlay::Label { text, .. } = o { Some(text.as_str()) } else { None }).collect()
+    }
+
+    fn lines(ov: &[Overlay]) -> Vec<(Point, Point)> {
+        ov.iter().filter_map(|o| if let Overlay::Line { a, b, .. } = o { Some((*a, *b)) } else { None }).collect()
+    }
+
+    /// A drawn point (#506): on another object's anchors, in line with them too (not only with its
+    /// bounds), onto its paths; Shift slides it along its 45° step into line; near a construction
+    /// guide through the point it leaves from it lands on the guide, where a target's line crosses
+    /// it if one does nearby.
+    #[test]
+    fn drawn_points_land_on_anchors_paths_alignments_and_construction_guides() {
+        let (d, _) = doc_with_rect();
+        let (s, p) = (Selection::default(), paint());
+        let c = cx(&d, &s, &p);
+        let t = Targets::for_drawing(&d, &[], None).styled(&c);
+        // The rect is 100..200: its corner, a point on its side, and in line with an anchor.
+        let (q, ov) = t.snap_from(Point::new(202.0, 198.0), None, 4.0);
+        assert_eq!((q, labels(&ov)), (Point::new(200.0, 200.0), vec!["anchor"]));
+        let (q, ov) = t.snap_from(Point::new(202.0, 160.0), None, 4.0);
+        assert_eq!((q, labels(&ov)), (Point::new(200.0, 160.0), vec!["path"]));
+        let (q, ov) = t.snap_from(Point::new(330.0, 102.0), None, 4.0);
+        assert_eq!((q, labels(&ov)), (Point::new(330.0, 100.0), vec!["align"]));
+        // Shift from (300, 300): the pointer at 2° keeps to 0°, then slides onto x = 200.
+        let shift = Leave::segment(&c, Point::new(300.0, 300.0), true);
+        let (q, ov) = t.snap_from(Point::new(203.0, 303.0), Some(&shift), 4.0);
+        assert!((q - Point::new(200.0, 300.0)).hypot() < 1e-9, "{q:?}");
+        assert_eq!(labels(&ov), ["align"]);
+        assert_eq!(lines(&ov).len(), 1, "{ov:?}");
+        // Nothing in reach: on its angle, as far as the pointer.
+        let (q, ov) = t.snap_from(Point::new(300.0, 380.0), Some(&shift), 4.0);
+        assert_eq!((q, ov.len()), (Point::new(300.0, 380.0), 0));
+        // Construction guides through (300, 320): onto the 135° one…
+        let from = Leave::segment(&c, Point::new(300.0, 320.0), false);
+        let (q, ov) = t.snap_from(Point::new(352.0, 373.0), Some(&from), 4.0);
+        assert!((q - Point::new(352.5, 372.5)).hypot() < 1e-9, "{q:?}");
+        assert_eq!(lines(&ov), vec![(Point::new(300.0, 320.0), q)]);
+        // …where x = 200 crosses it.
+        let (q, ov) = t.snap_from(Point::new(203.0, 222.5), Some(&from), 4.0);
+        assert!((q - Point::new(200.0, 220.0)).hypot() < 1e-9, "{q:?}");
+        assert_eq!((lines(&ov).len(), labels(&ov)), (2, vec!["align"]));
+        // Construction Guides off (or Smart Guides off): in line, not on a guide.
+        let off = ToolContext { construction_angles: &[], ..cx(&d, &s, &p) };
+        let (q, _) = t.snap_from(Point::new(352.0, 373.0), Some(&Leave::segment(&off, Point::new(300.0, 320.0), false)), 4.0);
+        assert_eq!(q, Point::new(352.0, 373.0));
+        // A box's corner keeps to a diagonal with Shift, the farther axis giving its size.
+        let (q, _) = t.snap_from(Point::new(340.0, 310.0), Some(&Leave::diagonal(Point::new(300.0, 300.0), true)), 4.0);
+        assert_eq!(q, Point::new(340.0, 340.0));
+    }
+
+    /// The angle sets of Preferences › Smart Guides › Construction Guides.
+    #[test]
+    fn construction_angle_sets() {
+        assert_eq!(construction_angles(DEFAULT_CONSTRUCTION_ANGLES), [0.0, 45.0, 90.0, 135.0]);
+        assert_eq!(construction_angles("90° Angles"), [0.0, 90.0]);
+        assert_eq!(construction_angles("30° Angles"), [30.0, 60.0, 120.0, 150.0]);
+        assert_eq!(construction_angles("90° & 45° & 30° Angles").len(), 8);
+        assert_eq!(construction_angles("nonsense"), construction_angles(DEFAULT_CONSTRUCTION_ANGLES));
+    }
+
+    /// The sorted targets find by bisection just what a scan of all of them finds, whatever
+    /// gathered them.
+    #[test]
+    fn bisection_finds_what_a_scan_finds() {
+        use vectorcraft_doc::{Appearance, Node};
+        let (mut d, id) = doc_with_rect();
+        let l = d.layers[0].id;
+        for i in 0..60 {
+            let (x, y) = ((i * 37 % 450) as f64, (i * 53 % 430) as f64);
+            let tri = vectorcraft_geom::PathData::single(SubPath::polyline(
+                &[Point::new(x, y), Point::new(x + 13.0, y + 3.0), Point::new(x + 5.0, y + 17.0)],
+                true,
+            ));
+            let n = d.alloc_id();
+            d.insert(Some(l), 1, Node::path(n, tri, Appearance::default_art())).unwrap();
+        }
+        let mut s = Selection::default();
+        s.set([id]);
+        s.anchors.insert(id, [(0, 1)].into_iter().collect());
+        for t in [Targets::collect(&d, &[], None), Targets::for_drawing(&d, &[id], None), Targets::for_anchor_drag(&d, &s)] {
+            for q in (0..40).flat_map(|i| (0..40).map(move |j| Point::new(i as f64 * 12.7, j as f64 * 11.3))) {
+                let scan = t.points.iter().copied().filter(|(a, _)| a.distance(q) <= 6.0).min_by(|a, b| a.0.distance(q).total_cmp(&b.0.distance(q)));
+                assert_eq!(t.nearest_point(q, 6.0).map(|h| h.0.distance(q)), scan.map(|h| h.0.distance(q)), "{q:?}");
+                for (lines, v) in [(&t.xs, q.x), (&t.ys, q.y)] {
+                    let mut near: Vec<f64> = lines_near(lines, v, 6.0).iter().map(|l| l.0).collect();
+                    let mut all: Vec<f64> = lines.iter().map(|l| l.0).filter(|w| (w - v).abs() <= 6.0).collect();
+                    near.sort_by(f64::total_cmp);
+                    all.sort_by(f64::total_cmp);
+                    assert_eq!(near, all);
+                }
+            }
+        }
+    }
+
+    /// A drawing tool's snapper reuses its targets while hovering over the same document state, and
+    /// gathers them again when it changes, and on every press.
+    #[test]
+    fn draw_snap_gathers_once_per_document_state() {
+        let (d, _) = doc_with_rect();
+        let empty = vectorcraft_doc::Document::new(500.0, 500.0);
+        let (s, p) = (Selection::default(), paint());
+        let at = Point::new(202.0, 198.0);
+        let mut snap = DrawSnap::default();
+        let c = ToolContext { revision: (1, 1), ..cx(&d, &s, &p) };
+        assert_eq!(snap.hover(&c, at, &[], None), Point::new(200.0, 200.0));
+        assert_eq!(labels(snap.guides()), ["anchor"]);
+        // The same revision: the targets are the ones gathered (the document isn't read again).
+        let c = ToolContext { revision: (1, 1), ..cx(&empty, &s, &p) };
+        assert_eq!(snap.hover(&c, at, &[], None), Point::new(200.0, 200.0));
+        // A new revision, or a press, reads it.
+        let c = ToolContext { revision: (1, 2), ..cx(&empty, &s, &p) };
+        assert_eq!(snap.hover(&c, at, &[], None), at);
+        assert!(snap.guides().is_empty());
+        let c = ToolContext { revision: (1, 2), ..cx(&d, &s, &p) };
+        assert_eq!(snap.press(&c, at, &[], None), Point::new(200.0, 200.0));
+        // The drag keeps what the press gathered, though the document now shows its preview.
+        let c = ToolContext { revision: (1, 3), ..cx(&empty, &s, &p) };
+        assert_eq!(snap.drag(&c, at, None), Point::new(200.0, 200.0));
+        snap.clear();
+        assert!(snap.guides().is_empty());
+        // Snap to Grid wins over Smart Guides, Shift still keeping the angle.
+        let c = ToolContext { snap_to_grid: true, ..cx(&d, &s, &p) };
+        let from = Leave::segment(&c, Point::ZERO, true);
+        let q = snap.press(&c, Point::new(31.0, 2.0), &[], Some(&from));
+        assert!((q.y - 0.0).abs() < 1e-9, "{q:?}");
+    }
 }
@@ -216,6 +216,10 @@ impl ScreenFrame {
 /// Read-only context a tool sees.
 pub struct ToolContext<'a> {
    pub doc: &'a Document,
+    /// Which open document `doc` is (its process-unique id) and its revision, which moves with
+    /// every change of the document or the selection: what a tool keeps between pointer events
+    /// for the document as it is (the snap targets of hovering) is keyed on it.
+    pub revision: (u64, u64),
    pub selection: &'a Selection,
    /// Screen pixels per document point.
    pub zoom: f64,
@@ -319,6 +323,10 @@ pub struct ToolContext<'a> {
    /// Smart Guides → Snapping Tolerance (screen pixels): how near a smart guide target pulls the
    /// pointer, a dragged edge or a drawn point.
    pub snapping_tolerance: f64,
+    /// Smart Guides → Construction Guides: the angles (degrees, counter-clockwise from the x axis
+    /// as seen on the page) of the lines through the point a drawn point leaves from, onto which a
+    /// point near one lands ([`guides::construction_angles`]); none with the option off.
+    pub construction_angles: &'static [f64],
    /// The document window (none headless): screen-fixed widgets sit in it.
    pub screen: Option<ScreenFrame>,
    /// Where the Plane Switching Widget sits (Perspective Grid Options); None while it's hidden.
@@ -631,6 +639,7 @@ pub(crate) mod testutil {
    pub fn cx<'a>(d: &'a Document, s: &'a Selection, p: &'a PaintDefaults) -> ToolContext<'a> {
        ToolContext {
            doc: d,
+            revision: (0, 0),
            selection: s,
            zoom: 1.0,
            isolation: None,
@@ -675,6 +684,7 @@ pub(crate) mod testutil {
            measurement_labels: true,
            transform_tools_guides: true,
            snapping_tolerance: 4.0,
+            construction_angles: guides::construction_angles(guides::DEFAULT_CONSTRUCTION_ANGLES),
            screen: None,
            plane_widget: Some(Default::default()),
        }
@@ -16,6 +16,10 @@
 //! segment of a selected path adds an anchor there and a click on one of its anchors deletes it
 //! (Shift held or General → Disable Auto Add/Delete starts a new path instead). On a selected
 //! blend's spine a click adds a point (on a point no key object sits on: deletes it).
+//! Each anchor placed snaps to Smart Guides ([`DrawSnap`]): onto the anchors, centres and paths of
+//! the other art and of the path being drawn, into line with them, onto the construction guides
+//! through the last anchor; with Shift held it slides along its 45° step into line. Hovering shows
+//! where the next one would go.

 use serde_json::json;
 use vectorcraft_doc::{NodeId, NodeKind};
@@ -23,6 +27,7 @@ use vectorcraft_geom::{BezPath, Point};

 use crate::direct::hit_handle;
 use crate::draw2::AnchorTool;
+use crate::guides::{DrawSnap, Leave};
 use crate::{Action, Cursor, Mods, Overlay, PointerEvent, PointerKind, Tool, ToolContext, ToolKey};

 #[derive(Default)]
@@ -43,6 +48,8 @@ pub struct PenTool {
    handle: Option<(NodeId, usize, usize, Point)>,
    /// The Anchor Point tool, while an Alt gesture on a selected path's handle or anchor lasts.
    convert: Option<AnchorTool>,
+    /// Smart Guides for the anchors placed (and the pointer hovering).
+    snap: DrawSnap,
 }

 /// An anchor being placed, as the press decided: where it is, the path it goes on (none: the
@@ -116,8 +123,6 @@ impl Tool for PenTool {
        self.drag.is_some() || self.handle.is_some() || self.convert.is_some()
    }
    fn pointer(&mut self, cx: &ToolContext, ev: &PointerEvent) -> Vec<Action> {
-        let exclude: Vec<vectorcraft_doc::NodeId> = if self.drawing { cx.selection.objects.clone() } else { vec![] };
-        let (mut p, _) = if matches!(ev.kind, PointerKind::Down) { crate::guides::snap_draw(cx, ev.pos, &exclude) } else { (ev.pos, vec![]) };
        let tol = cx.tol(5.0);
        // The path a press began is the selected one by the next event.
        if self.drawing && self.path.is_none() {
@@ -127,6 +132,14 @@ impl Tool for PenTool {
        if self.drawing && active.is_none() && ev.kind == PointerKind::Down {
            self.stop();
        }
+        // 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 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()),
+            _ => ev.pos,
+        };
        match ev.kind {
            PointerKind::Move => {
                self.hover = Some(p);
@@ -135,9 +148,6 @@ impl Tool for PenTool {
            PointerKind::Down => {
                self.last = ev.pos;
                if let Some((id, first, last, _)) = active {
-                    if ev.mods.shift {
-                        p = last + vectorcraft_geom::constrain_angle(p - last, 45.0);
-                    }
                    let end = last_anchor(cx, id);
                    // A one-anchor path doesn't close on itself: its anchor is the last one too.
                    if p.distance(first) <= tol && end.is_some_and(|(_, ai)| ai > 0) {
@@ -230,6 +240,7 @@ impl Tool for PenTool {
                )]
            }
            PointerKind::Up => {
+                self.snap.clear();
                if let Some(mut t) = self.convert.take() {
                    return t.pointer(cx, ev);
                }
@@ -251,6 +262,7 @@ impl Tool for PenTool {
                self.stop();
                self.drag = None;
                self.handle = None;
+                self.snap.clear();
                // An Alt gesture under way ends as it stands.
                self.convert.take().map(|mut t| t.deactivate(cx)).unwrap_or_default()
            }
@@ -259,25 +271,30 @@ impl Tool for PenTool {
    }
    fn deactivate(&mut self, cx: &ToolContext) -> Vec<Action> {
        self.stop();
+        self.snap.clear();
        self.convert.take().map(|mut t| t.deactivate(cx)).unwrap_or_default()
    }
    fn overlays(&self, cx: &ToolContext) -> Vec<Overlay> {
        if let Some(t) = &self.convert {
            return t.overlays(cx);
        }
-        if !cx.pen_rubber_band || self.drag.is_some() || self.handle.is_some() {
-            return vec![];
+        let mut o = vec![];
+        if cx.pen_rubber_band
+            && self.drag.is_none()
+            && self.handle.is_none()
+            && let (Some((id, _, last, out)), Some(h)) = (self.active(cx), self.hover)
+        {
+            let mut bp = BezPath::new();
+            bp.move_to(last);
+            if out.distance(last) > 1e-9 {
+                bp.quad_to(out, h);
+            } else {
+                bp.line_to(h);
+            }
+            o.push(Overlay::Path { path: bp, color: cx.doc.layer_color(id), width: 1.0, dashed: false });
        }
-        let (Some((id, _, last, out)), Some(h)) = (self.active(cx), self.hover) else { return vec![] };
-        let mut bp = BezPath::new();
-        bp.move_to(last);
-        if out.distance(last) > 1e-9 {
-            bp.quad_to(out, h);
-        } else {
-            bp.line_to(h);
-        }
-        let c = cx.doc.layer_color(id);
-        vec![Overlay::Path { path: bp, color: c, width: 1.0, dashed: false }]
+        o.extend_from_slice(self.snap.guides());
+        o
    }
    fn cursor(&self, cx: &ToolContext, p: Point, m: Mods) -> Cursor {
        let tol = cx.tol(5.0);
@@ -614,6 +631,31 @@ mod tests {
        assert!(matches!(&a[..], [Action::Begin(_), Action::Preview(c, _)] if c == "path.create"), "{a:?}");
    }

+    /// Each anchor snaps to Smart Guides (#506): hovering shows where it goes (the rubber band ends
+    /// there), in line with another object's centre; Shift slides it along its 45° step into line.
+    #[test]
+    fn anchors_snap_to_smart_guides() {
+        let (d, id, s) = drawing(vectorcraft_geom::SubPath::polyline(&[Point::new(10.0, 300.0), Point::new(60.0, 300.0)], false));
+        let p = paint();
+        let cx = cx(&d, &s, &p);
+        let mut t = PenTool { drawing: true, ..PenTool::default() };
+        t.pointer(&cx, &PointerEvent::new(PointerKind::Move, 152.0, 318.0));
+        let o = t.overlays(&cx);
+        assert!(o.iter().any(|o| matches!(o, Overlay::Label { text, p, .. } if text == "align" && *p == Point::new(150.0, 318.0))), "{o:?}");
+        assert!(o.iter().any(
+            |o| matches!(o, Overlay::Path { path, .. } if path.elements().last().and_then(|e| e.end_point()) == Some(Point::new(150.0, 318.0)))
+        ));
+        let a = click(&mut t, &cx, 152.0, 318.0, Mods::default());
+        assert_eq!(a[1], Action::Preview("path.appendAnchor".into(), json!({"id": id.0, "x": 150.0, "y": 318.0})));
+        let shift = Mods { shift: true, ..Mods::default() };
+        let a = click(&mut t, &cx, 152.0, 310.0, shift);
+        assert_eq!(a[1], Action::Preview("path.appendAnchor".into(), json!({"id": id.0, "x": 150.0, "y": 300.0})));
+        // The first anchor of a new path lands on the rect's corner.
+        let mut t = PenTool::default();
+        let a = click(&mut t, &cx, 102.0, 99.0, Mods::default());
+        assert_eq!(a[1], Action::Preview("path.create".into(), json!({"anchors": [{"x": 100.0, "y": 100.0}]})));
+    }
+
    #[test]
    fn alt_over_a_shown_handle_or_an_anchor_converts() {
        // The middle anchor is smooth: handles at (150, 100) and (250, 100) round (200, 100).
@@ -2,11 +2,13 @@
 //!
 //! Drag draws (Shift constrains to square/circle/45°, Alt draws from the centre, Space held moves
 //! the shape being drawn); a click without a drag asks the UI for the size dialog (like
-//! Illustrator). ↑/↓ during a polygon/star drag change the side/point count.
+//! Illustrator). ↑/↓ during a polygon/star drag change the side/point count. The start point and
+//! the dragged corner snap to Smart Guides ([`DrawSnap`]), hovering before the press too.

 use serde_json::{Value, json};
 use vectorcraft_geom::{Point, Rect};

+use crate::guides::{DrawSnap, Leave, square};
 use crate::{Action, Cursor, Mods, Overlay, PointerEvent, PointerKind, Tool, ToolContext, ToolKey};

 pub struct ShapeTool {
@@ -20,7 +22,7 @@ pub struct ShapeTool {
    pub corner_radius: f64,
    /// Star inner radius as a fraction of the outer radius.
    pub star_ratio: f64,
-    guides: Vec<Overlay>,
+    snap: DrawSnap,
 }

 impl ShapeTool {
@@ -43,7 +45,7 @@ impl ShapeTool {
            points: 5,
            corner_radius: 12.0,
            star_ratio: 0.5,
-            guides: vec![],
+            snap: DrawSnap::default(),
        }
    }

@@ -58,7 +60,18 @@ impl ShapeTool {
        }
    }

-    /// The command for the current drag.
+    /// How the dragged point keeps to the start: a polygon's or star's radius goes anywhere, a
+    /// line is a segment (Shift: 45° steps), the rest are boxes (Shift: a square).
+    fn leave(&self, cx: &ToolContext, start: Point, m: Mods) -> Option<Leave> {
+        match self.id {
+            "polygon" | "star" => None,
+            "lineSegment" => Some(Leave::segment(cx, start, m.shift)),
+            _ => Some(Leave::diagonal(start, m.shift)),
+        }
+    }
+
+    /// The command for a drag from `start` to `p` (snapped: a line's end already keeps Shift's
+    /// angle).
    pub fn command(&self, start: Point, p: Point, m: Mods) -> (String, Value) {
        match self.id {
            "polygon" | "star" => {
@@ -76,7 +89,6 @@ impl ShapeTool {
            }
            "lineSegment" => {
                let (a, b) = if m.alt { (start - (p - start), p) } else { (start, p) };
-                let b = if m.shift { a + vectorcraft_geom::constrain_angle(b - a, 45.0) } else { b };
                ("shape.line".into(), json!({ "x1": a.x, "y1": a.y, "x2": b.x, "y2": b.y }))
            }
            _ => {
@@ -104,11 +116,7 @@ pub(crate) fn space_moves(start: &mut Point, last: &mut Point, ev: &PointerEvent
 /// The rectangle a drag from `start` to `p` draws: Shift makes it a square, Alt draws it from its
 /// centre.
 pub(crate) fn drag_rect(start: Point, p: Point, m: Mods) -> Rect {
-    let mut d = p - start;
-    if m.shift {
-        let s = d.x.abs().max(d.y.abs());
-        d = vectorcraft_geom::Vec2::new(s * d.x.signum(), s * d.y.signum());
-    }
+    let d = if m.shift { square(p - start) } else { p - start };
    if m.alt { Rect::from_points(start - d, start + d) } else { Rect::from_points(start, start + d) }
 }

@@ -121,8 +129,12 @@ impl Tool for ShapeTool {
    }
    fn pointer(&mut self, cx: &ToolContext, ev: &PointerEvent) -> Vec<Action> {
        match ev.kind {
+            PointerKind::Move => {
+                self.snap.hover(cx, ev.pos, &[], None);
+                vec![]
+            }
            PointerKind::Down => {
-                let (p, _) = crate::guides::snap_draw(cx, ev.pos, &[]);
+                let p = self.snap.press(cx, ev.pos, &[], None);
                self.start = Some(p);
                self.last = ev.pos;
                self.began = false;
@@ -130,8 +142,7 @@ impl Tool for ShapeTool {
            }
            PointerKind::Drag => {
                let Some(mut s) = self.start else { return vec![] };
-                let (pos, g) = crate::guides::snap_draw(cx, ev.pos, &[]);
-                self.guides = g;
+                let pos = self.snap.drag(cx, ev.pos, self.leave(cx, s, ev.mods).as_ref());
                let ev = &PointerEvent { pos, ..*ev };
                space_moves(&mut s, &mut self.last, ev, self.began);
                self.start = Some(s);
@@ -150,7 +161,7 @@ impl Tool for ShapeTool {
            }
            PointerKind::Up => {
                let Some(s) = self.start.take() else { return vec![] };
-                self.guides.clear();
+                self.snap.clear();
                if self.began {
                    self.began = false;
                    vec![Action::Commit]
@@ -196,23 +207,26 @@ impl Tool for ShapeTool {
        } else if key == ToolKey::Escape {
            self.start = None;
            self.began = false;
+            self.snap.clear();
            vec![Action::Cancel]
        } else {
            vec![]
        }
    }
    fn overlays(&self, cx: &ToolContext) -> Vec<Overlay> {
-        match self.start {
-            Some(s) if self.began => {
-                let d = self.last - s;
-                let mut o = self.guides.clone();
-                if cx.measurement_labels {
-                    o.push(Overlay::Measure { p: self.last, text: cx.size_label(d.x.abs(), d.y.abs()) });
+        let mut o = self.snap.guides().to_vec();
+        if let Some(s) = self.start.filter(|_| self.began && cx.measurement_labels) {
+            // A box's size as drawn (from its centre with Alt, square with Shift).
+            let (w, h) = match self.id {
+                "polygon" | "star" | "lineSegment" => ((self.last - s).x.abs(), (self.last - s).y.abs()),
+                _ => {
+                    let r = drag_rect(s, self.last, self.mods);
+                    (r.width(), r.height())
                }
-                o
-            }
-            _ => vec![],
+            };
+            o.push(Overlay::Measure { p: self.last, text: cx.size_label(w, h) });
        }
+        o
    }
    fn cursor(&self, _cx: &ToolContext, _p: Point, _m: Mods) -> Cursor {
        Cursor::Crosshair
@@ -310,4 +324,36 @@ mod tests {
        let a = t.key(&cx, ToolKey::Up, Mods::default());
        assert!(matches!(&a[0], Action::Preview(_, v) if v["sides"] == 7));
    }
+
+    /// The start and the dragged corner land on another object's anchors (#506), hovering shows
+    /// it before the press, and the measurement label gives the size drawn.
+    #[test]
+    fn corners_snap_to_smart_guides() {
+        let (d, _) = doc_with_rect();
+        let s = Selection::default();
+        let p = paint();
+        let cx = cx(&d, &s, &p);
+        let mut t = ShapeTool::new("rectangle");
+        let anchor = |o: &[Overlay], at: Point| o.iter().any(|o| matches!(o, Overlay::Label { text, p, .. } if text == "anchor" && *p == at));
+        t.pointer(&cx, &PointerEvent::new(PointerKind::Move, 98.0, 102.0));
+        assert!(anchor(&t.overlays(&cx), Point::new(100.0, 100.0)));
+        t.pointer(&cx, &PointerEvent::new(PointerKind::Down, 98.0, 102.0));
+        let a = t.pointer(&cx, &PointerEvent::new(PointerKind::Drag, 198.0, 202.0));
+        assert_eq!(a[1], Action::Preview("shape.rectangle".into(), json!({"x": 100.0, "y": 100.0, "width": 100.0, "height": 100.0})));
+        let o = t.overlays(&cx);
+        assert!(anchor(&o, Point::new(200.0, 200.0)), "{o:?}");
+        assert!(o.iter().any(|o| matches!(o, Overlay::Measure { text, .. } if text == &cx.size_label(100.0, 100.0))));
+        // Alt draws from the centre: the label gives the whole size.
+        let alt = Mods { alt: true, ..Mods::default() };
+        t.pointer(&cx, &PointerEvent::new(PointerKind::Drag, 198.0, 202.0).with_mods(alt));
+        assert!(t.overlays(&cx).iter().any(|o| matches!(o, Overlay::Measure { text, .. } if text == &cx.size_label(200.0, 200.0))));
+        t.pointer(&cx, &PointerEvent::new(PointerKind::Up, 198.0, 202.0));
+        assert!(t.overlays(&cx).is_empty());
+        // A line with Shift keeps to 45° steps, sliding into line with the rect's right side.
+        let mut t = ShapeTool::new("lineSegment");
+        t.pointer(&cx, &PointerEvent::new(PointerKind::Down, 300.0, 300.0));
+        let shift = Mods { shift: true, ..Mods::default() };
+        let a = t.pointer(&cx, &PointerEvent::new(PointerKind::Drag, 203.0, 302.0).with_mods(shift));
+        assert!(matches!(&a[..], [_, Action::Preview(_, v)] if v["x2"] == 200.0 && (v["y2"].as_f64().unwrap() - 300.0).abs() < 1e-9), "{a:?}");
+    }
 }
@@ -3,7 +3,8 @@
 //! Type: click places point type, drag draws an area-type frame, clicking into existing text
 //! places the caret. Area Type / Type on a Path: click a path to turn it into a text frame or a
 //! baseline (`text.createInPath`). Point type placed by a click and left empty is discarded when
-//! editing ends (`text.discardEmpty`); frames keep their shape.
+//! editing ends (`text.discardEmpty`); frames keep their shape. Where new type goes (the click, the
+//! frame's corners) snaps to Smart Guides ([`DrawSnap`]), hovering too.
 //!
 //! While editing: caret movement by character / word (Cmd or Alt) / line (Up/Down) / line ends
 //! (Home/End; Cmd = whole text), Shift extends the selection, drag selects, double-click selects a
@@ -27,6 +28,7 @@ use vectorcraft_doc::{NodeId, NodeKind, TextKind, TextObject, TextRun};
 use vectorcraft_geom::{BezPath, Point, Rect, Shape};
 use vectorcraft_text::{FontDb, TextLayout, edit};

+use crate::guides::DrawSnap;
 use crate::{Action, Cursor, Mods, Overlay, PointerEvent, PointerKind, Tool, ToolContext, ToolKey};

 /// Which of the Type tools this is.
@@ -68,8 +70,12 @@ pub struct TypeTool {
    goal_x: Option<f64>,
    typing: Option<Typing>,
    preedit: Option<Preedit>,
-    press: Option<Point>,
+    /// Where the button went down, and where new type goes from there (snapped to Smart Guides).
+    press: Option<(Point, Point)>,
+    /// The other corner of an area dragged out (snapped).
    drag: Option<Point>,
+    /// Smart Guides for where new type goes.
+    snap: DrawSnap,
    /// The press landed in the edited text: dragging selects.
    selecting: bool,
    /// Click counting for double/triple click (position of the last click, count).
@@ -252,7 +258,8 @@ impl TypeTool {
        Some(out)
    }

-    fn on_up(&mut self, cx: &ToolContext, start: Point) -> Vec<Action> {
+    /// The button released after a press at `start` (new type goes at `at`).
+    fn on_up(&mut self, cx: &ToolContext, start: Point, at: Point) -> Vec<Action> {
        // Click into existing text: place the caret.
        if let Some(out) = self.edit_at(cx, start) {
            return out;
@@ -272,10 +279,10 @@ impl TypeTool {
                return out;
            }
        }
-        let area = drag.map(|d| Rect::from_points(start, d)).filter(|r| r.width() > cx.tol(6.0) && r.height() > cx.tol(6.0));
+        let area = drag.map(|d| Rect::from_points(at, d)).filter(|r| r.width() > cx.tol(6.0) && r.height() > cx.tol(6.0));
        let mut params = match area {
            Some(r) => json!({"x": r.x0, "y": r.y0, "text": "", "area": {"width": r.width(), "height": r.height()}}),
-            None => json!({"x": start.x, "y": start.y, "text": ""}),
+            None => json!({"x": at.x, "y": at.y, "text": ""}),
        };
        params["vertical"] = json!(self.vertical);
        params["placeholder"] = json!(cx.placeholder_text);
@@ -386,7 +393,7 @@ impl Tool for TypeTool {
                    self.selecting = true;
                    return out;
                }
-                self.press = Some(ev.pos);
+                self.press = Some((ev.pos, self.snap.press(cx, ev.pos, self.editing.as_slice(), None)));
                self.drag = None;
                vec![]
            }
@@ -398,7 +405,7 @@ impl Tool for TypeTool {
                        self.clicks = (None, 0);
                    }
                } else if self.press.is_some() {
-                    self.drag = Some(ev.pos);
+                    self.drag = Some(self.snap.drag(cx, ev.pos, None));
                }
                vec![]
            }
@@ -407,8 +414,9 @@ impl Tool for TypeTool {
                    self.selecting = false;
                    return vec![];
                }
-                let Some(start) = self.press.take() else { return vec![] };
-                self.on_up(cx, start)
+                self.snap.clear();
+                let Some((start, at)) = self.press.take() else { return vec![] };
+                self.on_up(cx, start, at)
            }
            PointerKind::DoubleClick => {
                if self.editing.is_some() && self.hit_edited(cx, ev.pos).is_some() {
@@ -417,7 +425,11 @@ impl Tool for TypeTool {
                }
                vec![]
            }
-            PointerKind::Move => vec![],
+            PointerKind::Move => {
+                // The type being edited is no target: its guides would only point at itself.
+                self.snap.hover(cx, ev.pos, self.editing.as_slice(), None);
+                vec![]
+            }
        }
    }
    fn text_input(&mut self, cx: &ToolContext, s: &str) -> Vec<Action> {
@@ -700,8 +712,8 @@ impl Tool for TypeTool {
        }
    }
    fn overlays(&self, cx: &ToolContext) -> Vec<Overlay> {
-        let mut o = vec![];
-        if let (Some(s), Some(d)) = (self.press, self.drag) {
+        let mut o = self.snap.guides().to_vec();
+        if let (Some((_, s)), Some(d)) = (self.press, self.drag) {
            o.push(Overlay::Marquee(Rect::from_points(s, d)));
        }
        // Overflow markers on selected text.
@@ -335,3 +335,24 @@ fn hebrew_typing_and_visual_arrows_keep_logical_text() {
    let NodeKind::Text(t) = &d.node(id).unwrap().kind else { panic!() };
    assert_eq!(t.plain_text(), "שלום");
 }
+
+/// Where new type goes snaps to Smart Guides (#506): a click beside a rect lines up with its
+/// centre, and hovering shows it first; an area's corners land on its anchors.
+#[test]
+fn new_type_snaps_to_smart_guides() {
+    let (d, _) = crate::testutil::doc_with_rect();
+    let (sel, p) = (Selection::default(), paint());
+    let c = cx(&d, &sel, &p);
+    let mut tool = TypeTool::new("type");
+    tool.pointer(&c, &PointerEvent::new(PointerKind::Move, 151.0, 330.0));
+    assert!(tool.overlays(&c).iter().any(|o| matches!(o, Overlay::Label { text, p, .. } if text == "align" && *p == Point::new(150.0, 330.0))));
+    tool.pointer(&c, &PointerEvent::new(PointerKind::Down, 151.0, 330.0));
+    let acts = tool.pointer(&c, &PointerEvent::new(PointerKind::Up, 151.0, 330.0));
+    assert!(acts.iter().any(|a| matches!(a, Action::Exec(cmd, v) if cmd == "text.create" && v["x"] == 150.0 && v["y"] == 330.0)), "{acts:?}");
+    let mut tool = TypeTool::new("type");
+    tool.pointer(&c, &PointerEvent::new(PointerKind::Down, 102.0, 98.0));
+    tool.pointer(&c, &PointerEvent::new(PointerKind::Drag, 199.0, 202.0));
+    let acts = tool.pointer(&c, &PointerEvent::new(PointerKind::Up, 199.0, 202.0));
+    let area = json!({"width": 100.0, "height": 100.0});
+    assert!(acts.iter().any(|a| matches!(a, Action::Exec(cmd, v) if cmd == "text.create" && v["x"] == 100.0 && v["area"] == area)), "{acts:?}");
+}
@@ -8,14 +8,14 @@
 //! the Selection tool. Moving and resizing snap like drawing
 //! does: to whole pixels, to the grid, or with Smart Guides to other artboards, their bleed and
 //! objects (never to the dragged artboard or the art moving with it); the artboard's own bleed edges
-//! snap too.
+//! snap too. A new artboard's corners snap as drawn points do ([`DrawSnap`]).

 use serde_json::{Value, json};
 use vectorcraft_geom::{Point, Rect, Vec2};

 use super::{BLUE, polygon, rect_corners};
 use crate::bbox::{Handle, hit_handle, move_delta, scale_for_drag};
-use crate::guides::Targets;
+use crate::guides::{DrawSnap, Leave, Targets};
 use crate::{Action, Cursor, Mods, Overlay, PointerEvent, PointerKind, Tool, ToolContext, ToolKey};

 #[derive(Clone, Copy, Debug)]
@@ -57,11 +57,13 @@ pub struct ArtboardTool {
    copy_targets: Option<Targets>,
    /// Smart Guides shown while dragging.
    guides: Vec<Overlay>,
+    /// Smart Guides for the corners of a new artboard.
+    draw: DrawSnap,
 }

 impl Default for ArtboardTool {
    fn default() -> Self {
-        Self { active: 0, move_art: true, drag: None, preview: None, targets: None, copy_targets: None, guides: vec![] }
+        Self { active: 0, move_art: true, drag: None, preview: None, targets: None, copy_targets: None, guides: vec![], draw: DrawSnap::default() }
    }
 }

@@ -134,6 +136,7 @@ impl ArtboardTool {
        self.targets = None;
        self.copy_targets = None;
        self.guides.clear();
+        self.draw.clear();
    }
 }

@@ -171,7 +174,7 @@ impl Tool for ArtboardTool {
                    self.active = i;
                    self.drag = Some(Drag::Move { index: i, start: p, rect: a.rect, began: false, copy: false });
                } else {
-                    let (p, _) = crate::guides::snap_draw(cx, p, &[]);
+                    let p = self.draw.press(cx, p, &[], None);
                    self.drag = Some(Drag::Create { start: p, cur: p });
                }
                vec![]
@@ -213,12 +216,7 @@ impl Tool for ArtboardTool {
                out
            }
            (PointerKind::Drag, Some(Drag::Create { start, .. })) => {
-                let (mut cur, _) = crate::guides::snap_draw(cx, p, &[]);
-                if m.shift {
-                    let d = cur - start;
-                    let s = d.x.abs().max(d.y.abs());
-                    cur = start + Vec2::new(s.copysign(d.x), s.copysign(d.y));
-                }
+                let cur = self.draw.drag(cx, p, Some(&Leave::diagonal(start, m.shift)));
                self.drag = Some(Drag::Create { start, cur });
                vec![]
            }
@@ -289,6 +287,7 @@ impl Tool for ArtboardTool {
    fn overlays(&self, cx: &ToolContext) -> Vec<Overlay> {
        let mut o = vec![];
        if let Some(Drag::Create { start, cur }) = self.drag {
+            o.extend_from_slice(self.draw.guides());
            let r = Rect::from_points(start, cur);
            o.push(Overlay::Marquee(r));
            if cx.measurement_labels {
@@ -1226,8 +1226,8 @@ off, an empty window, and the Home button or `app.home` still shows the screen)
 default: on, a click away from a panel popped out of the icon column puts it away).

 The Smart Guides preferences (Preferences › Smart Guides) apply to `pointer_gesture` with Smart Guides on (the
-default view) and to the mouse; they change what the tools show and how far a target pulls, never where a snapped
-point lands:
+default view) and to the mouse; they change what the tools show and how far a target pulls, and only Construction
+Guides change where a snapped point lands:

 - `smartGuideColor` (`#ff3dfc` by default): the colour of the smart guides' lines and labels.
 - `alignmentGuides` (on by default): off, no line is drawn along the edge or centre the art lines up with; the art
@@ -1242,6 +1242,11 @@ point lands:
 - `snappingTolerance` (0–40 px, 4 by default): how near an anchor, edge, centre or artboard edge pulls a drawn point,
  a dragged selection, a bounding-box handle, a ruler guide or an artboard. With Smart Guides off, Snap to Point uses
  `snapToPointTolerance` instead.
+- `constructionGuides` (on by default) and `constructionAngles` (`90° & 45° Angles` by default; also `90° Angles`,
+  `45° Angles`, `60° Angles`, `30° Angles`, `90° & 45° & 30° Angles`): a point drawn near a line at one of those
+  angles through the point it leaves from (the Pen's or Curvature tool's last anchor, a line's start) lands on that
+  line, where a target's alignment line crosses it if one does nearby. "90°" gives the horizontal and the vertical,
+  "45°" the diagonals, "60°" and "30°" the multiples of those angles in between. Off, the point only lines up.

 With Smart Guides on, a bounding-box handle dragged with the Selection or Free Transform tool (`mods.shift`
 proportional, `mods.alt` from the centre) lands on another object's anchor or centre (labelled "anchor" or
@@ -1253,7 +1258,26 @@ snap the pointer as drawing tools do, so dragging a corner onto another object's
 {"name":"pointer_gesture","arguments":{"tool":"scale","events":[{"kind":"down","x":100,"y":100},{"kind":"up","x":100,"y":100},{"kind":"down","x":199,"y":198},{"kind":"drag","x":302,"y":262},{"kind":"up","x":302,"y":262}]}}
 ```

-Not read yet: Construction Guides and their Angles, and Spacing Guides (the tools draw neither).
+Every point a drawing tool places snaps the same way, through one snapper (#506): the Pen's and Curvature tool's
+anchors, the Pencil's first and last point, the shape tools' start and dragged corner or radius (`rectangle`,
+`roundedRectangle`, `ellipse`, `polygon`, `star`, `lineSegment`, `arc`, `spiral`, `rectangularGrid`, `polarGrid`), the
+Type tool's click and frame, and a new artboard's corners. The point lands on another object's anchor, centre or
+path ("anchor", "center", "path"), else lines up with the anchors, edges and centres of the art and the artboards (a
+line from the target and "align"); the Pen's lands on the path being drawn too, so a click on its first anchor closes
+it exactly. With `mods.shift` the point keeps to its 45° step from the anchor before it (from `constrainAngle`; a box
+dragged keeps its corner on a diagonal) and slides along that way into line with the nearest target. A `move` event
+before the press shows where it would go, as hovering does with the mouse. The targets are the art in the window (all
+of it headless), gathered once per document state; the shape being drawn is never one of them:
+
+```json
+{"name":"pointer_gesture","arguments":{"tool":"rectangle","events":[{"kind":"down","x":202,"y":203},{"kind":"drag","x":330,"y":341},{"kind":"up","x":330,"y":341}]}}
+{"name":"pointer_gesture","arguments":{"tool":"pen","events":[{"kind":"down","x":300,"y":420},{"kind":"up","x":300,"y":420},{"kind":"down","x":151.5,"y":431},{"kind":"up","x":151.5,"y":431}]}}
+```
+
+With a 100 × 100 square at (100, 100), the first starts the rectangle on its corner (200, 200); the second puts the
+Pen's second anchor at (150, 431), in line with the square's centre.
+
+Not read yet: Spacing Guides (the tools draw none).

 ## Type preferences