Live Paint: Make keeps the direction of gradient strokes along or across the path

A stroke whose only setting that depends on direction is a gradient along or
across the stroke now goes through the same edge fitting as dashed strokes, so
each cut edge runs the way its source path does and the gradient keeps its
direction.

crates/engine/src/cmd/buildcmds.rs

@@ -471,10 +471,11 @@ impl SourceStyle {
 /// How far, in points, a place on an edge may be from its source path and still be on it.
 const ON_SOURCE: f64 = 0.05;
 
-/// Does stroke row `i` have settings that depend on where along its path a piece of it lies:
-/// dashes, arrowheads, a width profile or a brush?
+/// Does stroke row `i` have settings that depend on where along its path a piece of it lies or
+/// which way it runs: dashes, arrowheads, a width profile, a brush, or a gradient along or across
+/// the stroke?
 fn depends_on_place(i: &AppearanceItem) -> bool {
-    matches!(i, AppearanceItem::Stroke(s) if s.dash.is_some() || s.start_arrow.is_some() || s.end_arrow.is_some() || s.profile.is_some() || s.brush.is_some())
+    matches!(i, AppearanceItem::Stroke(s) if s.dash.is_some() || s.start_arrow.is_some() || s.end_arrow.is_some() || s.profile.is_some() || s.brush.is_some() || s.gradient_mode != vectorcraft_doc::StrokeGradientMode::Within)
 }
 
 /// One subpath's segments with the length along it where each starts, then its whole length, and

crates/engine/src/tests/build.rs

@@ -2753,6 +2753,37 @@ fn live_paint_make_fits_dashes_and_arrowheads_to_each_edge() {
     assert_eq!(edges, vec![rows]);
 }
 
+/// When Make cuts a stroke whose only setting that depends on direction is a gradient along or
+/// across it, each edge runs the way its source path does, so the gradient keeps its direction.
+#[test]
+fn live_paint_make_keeps_the_direction_of_gradient_strokes() {
+    use vectorcraft_doc::StrokeGradientMode;
+    for mode in [StrokeGradientMode::Along, StrokeGradientMode::Across] {
+        for (x0, x1) in [(-20.0, 120.0), (120.0, -20.0)] {
+            let mut s = session();
+            let a = rect(&mut s, 0.0, 0.0, 100.0, 100.0);
+            let l = line(&mut s, (x0, 50.0), (x1, 50.0));
+            let gradient = Paint::Gradient(Box::new(vectorcraft_color::GradientPaint::new(vectorcraft_color::Gradient::default())));
+            set_rows(&mut s, l, vec![stroke_row(gradient, 2.0, |st| st.gradient_mode = mode)]);
+            s.execute("select.set", &json!({"ids": [a.0, l.0]})).unwrap();
+            let g = NodeId(s.execute("livePaint.make", &json!({})).unwrap()["id"].as_u64().unwrap());
+            let pieces: Vec<(f64, f64)> = vectorcraft_tools::builder::edges(&node(&s, g))
+                .iter()
+                .filter_map(|e| {
+                    e.appearance.stroke().filter(|st| st.gradient_mode == mode)?;
+                    let sp = e.path_data()?.subpaths.first()?;
+                    Some((sp.anchors.first()?.p.x, sp.anchors.last()?.p.x))
+                })
+                .collect();
+            assert_eq!(pieces.len(), 3, "{mode:?}, from {x0}");
+            assert!(
+                pieces.iter().all(|&(p, q)| (q - p).signum() == (x1 - x0).signum()),
+                "{mode:?}, from {x0}: each piece runs the way the line does: {pieces:?}"
+            );
+        }
+    }
+}
+
 /// Make gives each face every fill row of its source that draws, in order and with their
 /// opacity, blending mode, overprint and effects, and the source's gradients keep their fit on
 /// the source; Expand keeps the rows, and Undo and Redo bring the group back with them.