fix: text extrudes as letters with their counters, alone or beside drawn curves (#502)

Text outlines count as drawn geometry when picking profiles, and "all profiles" leaves out the counters of letters (the holes of A, B, 8), so text extrudes as letters with their holes whether or not other curves are drawn next to it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

crates/engine/src/cmd/sketch_modify_tests.rs

@@ -429,6 +429,72 @@ fn text_makes_profiles_that_extrude_and_edit() {
     assert!(s.execute("sketch.text", &json!({"text": "", "at": [0, 0]})).is_err());
 }
 
+/// Volumes (mm³) of the bodies in the design, smallest first.
+fn body_volumes(s: &mut Session) -> Vec<f64> {
+    let m = run(s, "inspect.measure", json!({}));
+    let mut v: Vec<f64> = m["bodies"].as_array().unwrap().iter().map(|b| b["volume_mm3"].as_f64().unwrap()).collect();
+    v.sort_by(f64::total_cmp);
+    v
+}
+
+#[test]
+fn text_extrudes_with_its_counters_and_beside_other_curves() {
+    // Letter areas in mm² at a capital height of 10 mm, summed from the Liberation Sans contours (shoelace
+    // formula, quadratic pieces flattened finely), each outer contour minus its counters:
+    //   A 39.2159 - 9.0647   B 68.9283 - 12.9336 - 16.6277   8 56.8394 - 10.6451 - 13.7347   I 13.5557
+    // Extruded 2 mm, so the volumes are twice that. Faceted walls: within 0.02 mm³.
+    let near = |got: &[f64], want: &[f64]| {
+        assert_eq!(got.len(), want.len(), "{got:?} against {want:?}");
+        assert!(got.iter().zip(want).all(|(g, w)| (g - w).abs() < 0.02), "{got:?} against {want:?}");
+    };
+    // Letters with counters, alone: a letter is one body with its counters as holes. (A counter used to be
+    // extruded as a body of its own, or the extrude failed with "profile has no area".)
+    for (text, want) in
+        [("AB", vec![2.0 * (39.2159 - 9.0647), 2.0 * (68.9283 - 12.9336 - 16.6277)]), ("8", vec![2.0 * (56.8394 - 10.6451 - 13.7347)])]
+    {
+        let mut s = new_sketch();
+        run(&mut s, "sketch.text", json!({"text": text, "at": [0, 0], "height": 10}));
+        run(&mut s, "sketch.finish", json!({}));
+        run(&mut s, "solid.extrude", json!({"distance": 2}));
+        near(&body_volumes(&mut s), &want);
+    }
+    // Text beside a drawn rectangle is extruded with it (it used to be left out): the 30 x 20 x 2 plate and an "I".
+    let mut s = new_sketch();
+    run(&mut s, "sketch.rectangle.two_point", json!({"p0": [0, 0], "p1": [30, 20]}));
+    run(&mut s, "sketch.text", json!({"text": "I", "at": [40, 0], "height": 10}));
+    run(&mut s, "sketch.finish", json!({}));
+    run(&mut s, "solid.extrude", json!({"distance": 2}));
+    near(&body_volumes(&mut s), &[2.0 * 13.5557, 1200.0]);
+    // A counter can still be picked on its own, by a point inside it: the inner contour of an O, 47.4584 mm².
+    let mut s = new_sketch();
+    run(&mut s, "sketch.text", json!({"text": "O", "at": [0, 0], "height": 10}));
+    run(&mut s, "sketch.finish", json!({}));
+    run(&mut s, "solid.extrude", json!({"distance": 2, "profiles": [{"point": [5.65, 5.0]}]}));
+    near(&body_volumes(&mut s), &[2.0 * 47.4584]);
+}
+
+#[test]
+fn text_embossed_or_debossed_leaves_its_counters_alone() {
+    // A 40 x 30 x 5 plate (6000 mm³) with 10 mm tall text raised from, or cut 1 mm into, its top. Only the letters
+    // change the volume, by their area in mm² (see above) x 1 mm; the counters of the O and of A and B stay as
+    // they are. (Emboss and deboss used to fail with "boolean Cut: no result" or "boolean Union: no result",
+    // because each counter was a tool body of its own, filling the hole of its letter.)
+    let (o, ab) = (83.3133 - 47.4584, (39.2159 - 9.0647) + (68.9283 - 12.9336 - 16.6277));
+    for (text, mode, change) in [("O", "deboss", -o), ("O", "emboss", o), ("AB", "deboss", -ab)] {
+        let mut s = new_sketch();
+        run(&mut s, "sketch.rectangle.two_point", json!({"p0": [0, 0], "p1": [40, 30]}));
+        run(&mut s, "sketch.finish", json!({}));
+        run(&mut s, "solid.extrude", json!({"distance": 5, "body_name": "Plate"}));
+        run(&mut s, "construct.plane.offset", json!({"base": "XY", "offset": 5, "name": "Lid"}));
+        run(&mut s, "sketch.create", json!({"plane": "Lid", "name": "Text"}));
+        run(&mut s, "sketch.text", json!({"text": text, "at": [10, 10], "height": 10}));
+        run(&mut s, "sketch.finish", json!({}));
+        run(&mut s, "solid.emboss", json!({"sketch": "Text", "depth": 1, "mode": mode}));
+        let v = body_volumes(&mut s);
+        assert!(v.len() == 1 && (v[0] - (6000.0 + change)).abs() < 0.02, "{text} {mode}: {v:?} against {}", 6000.0 + change);
+    }
+}
+
 #[test]
 fn blend_curve_joins_tangentially() {
     let mut s = new_sketch();