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fix: Dynamically calculated control point offsets per segment

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Signed-off-by: Mark Tolmacs <mark@lazycat.hu>
This commit is contained in:
Mark Tolmacs
2026-03-21 17:13:44 +00:00
parent 53a49e71a8
commit 62aa998f9a
1 changed files with 13 additions and 6 deletions
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packages/element/src/shape.ts
+13 -6
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@@ -1035,10 +1035,10 @@ const generateSimpleArrowShape = (
// Catmull-Rom spline converted to cubic Bézier segments.
// Tangents are computed from neighboring points (one-sided at endpoints),
// guaranteeing C1 continuity — smooth tangent direction at every data point
// guaranteeing C1 continuity, smooth tangent direction at every data point
// with no pinching at segment joints.
//
// tension=0 → straight lines; tension=0.5 → standard Catmull-Rom.
// tension=0; straight lines; tension=0.5, standard Catmull-Rom.
const n = points.length;
// Compute tangent vectors at each point.
@@ -1070,10 +1070,17 @@ const generateSimpleArrowShape = (
const path: string[] = [`M ${points[0][0]} ${points[0][1]}`];
for (let i = 0; i < n - 1; i++) {
const cp1x = points[i][0] + tx[i] / 3;
const cp1y = points[i][1] + ty[i] / 3;
const cp2x = points[i + 1][0] - tx[i + 1] / 3;
const cp2y = points[i + 1][1] - ty[i + 1] / 3;
const segLen = pointDistance(points[i], points[i + 1]);
// Clamp each control point offset to at most half the segment length so
// that curvature decreases linearly to 0 as the two endpoints converge.
const tanMag1 = Math.sqrt(tx[i] * tx[i] + ty[i] * ty[i]);
const tanMag2 = Math.sqrt(tx[i + 1] * tx[i + 1] + ty[i + 1] * ty[i + 1]);
const s1 = tanMag1 > 0 ? Math.min(1, (segLen * 1.5) / tanMag1) : 1;
const s2 = tanMag2 > 0 ? Math.min(1, (segLen * 1.5) / tanMag2) : 1;
const cp1x = points[i][0] + (tx[i] / 3) * s1;
const cp1y = points[i][1] + (ty[i] / 3) * s1;
const cp2x = points[i + 1][0] - (tx[i + 1] / 3) * s2;
const cp2y = points[i + 1][1] - (ty[i + 1] / 3) * s2;
path.push(
`C ${cp1x} ${cp1y} ${cp2x} ${cp2y} ${points[i + 1][0]} ${
points[i + 1][1]