Type Object Selection by Path Only: every baseline, Type tool and Eyedropper (review of #475)

- Type is picked on the baseline of any of its lines (point type and area type, besides area type's frame), as in Illustrator, not only the first one: the layout's baselines are cached with its bounds (`TextObject::cached_baselines`, from `TextLayout::baselines`), with the first one across the bounds as the fallback. Vertical type's runs down each column's centre line. - Type in perspective is picked where it is drawn (through its projection). - The bounds rule type out before its path is built, so hovering stays free of allocations away from type. - The Type tools still edit type clicked among its characters (they made new type there with the preference on), and the Eyedropper still samples it there, as it does inside fills with Object Selection by Path Only. - Tests for all of it; docs/mcp.md and ROADMAP say so. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-29 12:17:14 -06:00 · 2026-10-08 18:59:47 +07:00
parent beea693ee1
commit afb438367d
15 changed files with 208 additions and 32 deletions
@@ -687,6 +687,7 @@ fn lerp_text(o: &mut TextObject, x: &TextObject, y: &TextObject, t: f64) {
    }
    if resized {
        o.cached_bounds = None;
+        o.cached_baselines.clear();
    }
 }

@@ -194,7 +194,11 @@ fn hit_leaf(n: &Node, p: Point, opt: HitOptions) -> Option<HitKind> {
            }
            (!opt.outline && !opt.path_only && fill_contains(&bp, *rule, p)).then_some(HitKind::Fill)
        }
-        NodeKind::Text(t) if opt.type_path_only => stroke_contains(&type_path(t), 0.0, opt.tol, p).then_some(HitKind::Outline),
+        // The type path lies within the bounds: they rule out the rest before it is measured.
+        NodeKind::Text(t) if opt.type_path_only => {
+            n.geometric_bounds().filter(|b| b.inflate(opt.tol, opt.tol).contains(p))?;
+            on_type_path(n, t, p, opt.tol).then_some(HitKind::Outline)
+        }
        NodeKind::Text(_) | NodeKind::Image(_) | NodeKind::SymbolInstance { .. } | NodeKind::Blend { .. } | NodeKind::Envelope { .. } => {
            n.geometric_bounds().filter(|b| b.inflate(opt.tol, opt.tol).contains(p)).map(|_| HitKind::Bounds)
        }
@@ -210,22 +214,26 @@ fn hit_leaf(n: &Node, p: Point, opt: HitOptions) -> Option<HitKind> {
    }
 }

-/// The type path of `t` in document space, what "Type Object Selection by Path Only" picks type
-/// by: area type's frame, type on a path's path, and for point type its first baseline (the line
-/// the selection marks under it), across the width of its layout.
-fn type_path(t: &crate::TextObject) -> vectorcraft_geom::BezPath {
+/// Is `p` within `tol` of the type path of `t` (in `n`), what "Type Object Selection by Path
+/// Only" picks type by: its baselines ([`crate::TextObject::baselines`]), area type's frame and
+/// type on a path's path, drawn through `n`'s perspective projection if it has one.
+fn on_type_path(n: &Node, t: &crate::TextObject, p: Point, tol: f64) -> bool {
    use crate::TextKind;
-    match &t.kind {
-        TextKind::Area { frame } => frame.transformed(t.xf).to_bezpath(),
-        TextKind::OnPath { path, .. } => path.transformed(t.xf).to_bezpath(),
-        TextKind::Point => {
-            let b = t.cached_bounds.unwrap_or_else(|| t.estimate_bounds());
-            let mut bp = vectorcraft_geom::BezPath::new();
-            bp.move_to(t.xf * Point::new(b.x0, 0.0));
-            bp.line_to(t.xf * Point::new(b.x1, 0.0));
-            bp
-        }
+    use vectorcraft_geom::kurbo::ParamCurveNearest;
+    let h = n.projection();
+    let project = |q: Point| h.as_ref().and_then(|h| h.apply(q)).unwrap_or(q);
+    // A homography keeps straight lines straight: a baseline's ends are enough.
+    let near = |(a, b): (Point, Point)| vectorcraft_geom::Line::new(project(t.xf * a), project(t.xf * b)).nearest(p, 1e-9).distance_sq <= tol * tol;
+    if t.baselines().any(near) {
+        return true;
    }
+    let (TextKind::Area { frame: path } | TextKind::OnPath { path, .. }) = &t.kind else { return false };
+    let mut path = path.transformed(t.xf);
+    if h.is_some() {
+        let piece = path.bounds().map_or(1.0, |b| (b.width().max(b.height()) / 64.0).max(0.25));
+        path = crate::live::map_nonlinear(&path, piece, project);
+    }
+    stroke_contains(&path.to_bezpath(), 0.0, tol, p)
 }

 /// Hit anywhere in an evaluated subtree (groups recurse; leaves use [`hit_leaf`]).
@@ -466,6 +474,63 @@ mod tests {
        assert_eq!(hit(Point::new(60.0, 339.5), path_only), Some((on_path, HitKind::Outline)), "type on a path: its path");
    }

+    /// Type Object Selection by Path Only with the layout's baselines: every line's for point type,
+    /// area type's besides its frame, a vertical column's centre line, and type in perspective
+    /// where it is drawn.
+    #[test]
+    fn type_path_only_picks_every_baseline() {
+        use crate::{CharStyle, PerspectiveAttachment, TextKind, TextObject};
+        use vectorcraft_geom::{Affine, Homography};
+        let mut d = Document::new(400.0, 400.0);
+        let l = d.layers[0].id;
+        let mut add = |t: TextObject, perspective: Option<Affine>| {
+            let mut n = Node::new(d.alloc_id(), NodeKind::Text(Box::new(t)));
+            n.perspective = perspective.map(|a| {
+                Box::new(PerspectiveAttachment { projection: Some(Homography::from_affine(a).to_array()), ..PerspectiveAttachment::new("left", 0.0) })
+            });
+            let id = n.id;
+            d.insert(Some(l), 9, n).unwrap();
+            id
+        };
+        let style = CharStyle { size: 20.0, ..CharStyle::default() };
+        // Two lines of point type at (10, 100), 24 pt apart.
+        let mut point = TextObject::point(
+            Point::new(10.0, 100.0),
+            "Hello
+world",
+            style.clone(),
+        );
+        point.cached_bounds = Some(Rect::new(0.0, -16.0, 60.0, 28.0));
+        point.cached_baselines = vec![(Point::ZERO, Point::new(60.0, 0.0)), (Point::new(0.0, 24.0), Point::new(50.0, 24.0))];
+        let point = add(point, None);
+        // Area type: a line inside its frame.
+        let mut area = TextObject::point(Point::new(200.0, 50.0), "Area", style.clone());
+        area.kind = TextKind::Area { frame: shapes::rectangle(Rect::new(0.0, 0.0, 100.0, 50.0)) };
+        area.cached_baselines = vec![(Point::new(0.0, 16.0), Point::new(40.0, 16.0))];
+        let area = add(area, None);
+        // Vertical point type at (300, 200) with no baselines cached: down its first column.
+        let mut vertical = TextObject::point(Point::new(300.0, 200.0), "Tate", style.clone());
+        vertical.vertical = true;
+        vertical.cached_bounds = Some(Rect::new(-10.0, 0.0, 10.0, 80.0));
+        let vertical = add(vertical, None);
+        // Point type drawn 100 to the right of where it is laid out.
+        let mut moved = TextObject::point(Point::new(10.0, 350.0), "Moved", style);
+        moved.cached_bounds = Some(Rect::new(0.0, -16.0, 60.0, 4.0));
+        let moved = add(moved, Some(Affine::translate((100.0, 0.0))));
+        let path_only = HitOptions { type_path_only: true, ..Default::default() };
+        let hit = |p: Point| hit_test(&d, p, path_only).map(|h| h.leaf);
+        assert_eq!(hit(Point::new(40.0, 100.0)), Some(point), "the first line's baseline");
+        assert_eq!(hit(Point::new(40.0, 125.0)), Some(point), "the second line's");
+        assert_eq!(hit(Point::new(40.0, 112.0)), None, "between the lines");
+        assert_eq!(hit(Point::new(65.0, 124.0)), None, "past the end of the shorter second line");
+        assert_eq!(hit(Point::new(220.0, 66.0)), Some(area), "area type: a line's baseline");
+        assert_eq!(hit(Point::new(220.0, 80.0)), None, "area type: inside the frame, off the baselines");
+        assert_eq!(hit(Point::new(299.0, 260.0)), Some(vertical), "vertical type: down the column");
+        assert_eq!(hit(Point::new(306.0, 260.0)), None, "vertical type: beside it");
+        assert_eq!(hit(Point::new(140.0, 351.0)), Some(moved), "in perspective: where it is drawn");
+        assert_eq!(hit(Point::new(40.0, 351.0)), None, "in perspective: not where it is laid out");
+    }
+
    /// `objects_at`: every object under the point, topmost first; a group counts once.
    #[test]
    fn objects_at_lists_the_stack() {
@@ -715,6 +715,10 @@ pub struct TextObject {
    /// Cached layout bounds in text space, filled in by the layout engine (not serialized).
    #[serde(skip)]
    pub cached_bounds: Option<Rect>,
+    /// Cached baselines in text space, start to end, one per line that holds characters (a
+    /// vertical column's centre line), filled in with `cached_bounds` (not serialized).
+    #[serde(skip)]
+    pub cached_baselines: Vec<(Point, Point)>,
 }

 impl TextObject {
@@ -731,6 +735,7 @@ impl TextObject {
            path_spacing: 0.0,
            wrap: Vec::new(),
            cached_bounds: None,
+            cached_baselines: Vec::new(),
        }
    }
    pub fn plain_text(&self) -> String {
@@ -839,6 +844,15 @@ impl TextObject {
    pub fn local_bounds(&self) -> Rect {
        self.cached_bounds.unwrap_or_else(|| self.estimate_bounds())
    }
+    /// The baselines in text space (the layout cache): for point type with none cached, the first
+    /// one across [`Self::local_bounds`] (down the first column's centre line for vertical type).
+    pub fn baselines(&self) -> impl Iterator<Item = (Point, Point)> + '_ {
+        let first = (self.cached_baselines.is_empty() && matches!(self.kind, TextKind::Point)).then(|| {
+            let b = self.local_bounds();
+            if self.vertical { (Point::new(0.0, b.y0), Point::new(0.0, b.y1)) } else { (Point::new(b.x0, 0.0), Point::new(b.x1, 0.0)) }
+        });
+        self.cached_baselines.iter().copied().chain(first)
+    }
 }

 #[cfg(test)]