将 Xynova 笔画延长至 50% 黑色覆盖率

沿现有笔画向空白处增长，保留最小线宽和笔画间隙。41 项测试通过，双 UV 矢量图无重叠。

tests/test_stroke_geometry.py

@@ -24,3 +24,12 @@ def test_near_parallel_capsules_need_edge_spacing() -> None:
 def test_disjoint_collinear_capsules_can_clear() -> None:
     existing = [((0, 0), (0.2, 0), 0.1)]
     assert has_clearance(((0.45, 0), (0.65, 0), 0.1), existing, 0.03)
+
+
+def test_extension_ignores_only_its_original_capsule() -> None:
+    original = ((0, 0), (0.2, 0), 0.1)
+    neighbour = ((0.6, 0), (0.8, 0), 0.1)
+    assert has_clearance(((-0.1, 0), (0.3, 0), 0.1), [original, neighbour], 0.03,
+                         skip_index=0)
+    assert not has_clearance(((-0.1, 0), (0.4, 0), 0.1), [original, neighbour], 0.03,
+                             skip_index=0)

tests/test_stroke_pattern.py

@@ -116,6 +116,8 @@ def test_boolean_is_not_a_number() -> None:
         ("neighbourhood_mm", 0.0, "must be > 0"),
         ("clearance_mm", -0.01, "must be >= 0"),
         ("candidate_count", 0, "must be >= 1"),
+        ("target_coverage", -0.01, "within [0, 1)"),
+        ("target_coverage", 1.0, "within [0, 1)"),
     ],
 )
 def test_range_rules(key: str, value, expected: str) -> None:
@@ -184,5 +186,6 @@ def test_shipped_revisions_declare_the_expected_block(sensor: str) -> None:
     resolved = stroke_pattern.resolve_stroke_settings(block)
     expected = dict(stroke_pattern.STROKE_DEFAULTS)
     if sensor == "finger-xynova":
-        expected.update(width_min_mm=0.20, clearance_mm=0.03, candidate_count=12)
+        expected.update(width_min_mm=0.20, clearance_mm=0.03, candidate_count=12,
+                        target_coverage=0.50)
     assert resolved == expected