handle special solution in cubic_bezier_bbox()
@@ -214,7 +214,8 @@ def cubic_bezier_bbox(curve: Bezier4P, *, abs_tol=1e-12) -> BoundingBox:
c = 3.0 * (p2 - p1)
if abs(a) < abs_tol:
if abs(b) < abs_tol:
- continue
+ t = -c # or skip this case?
+ else:
t = -c / b
if 0.0 < t < 1.0:
points.append((curve.point(t)))
