生成无重叠的 0.2 mm Xynova 笔画图案

在打印页毫米坐标中筛选候选笔画，更新双 UV 产物。38 项测试通过；SVG 检查无交叠。

blender/scripts/stroke_geometry.py

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+"""Physical-space clearance checks for capsule-shaped laser marks."""
+
+from __future__ import annotations
+
+import math
+
+
+def point_segment_distance_sq(point, start, end):
+    dx, dy = end[0] - start[0], end[1] - start[1]
+    length_sq = dx * dx + dy * dy
+    if length_sq == 0:
+        return (point[0] - start[0]) ** 2 + (point[1] - start[1]) ** 2
+    t = max(0.0, min(1.0, ((point[0] - start[0]) * dx + (point[1] - start[1]) * dy) / length_sq))
+    return (point[0] - start[0] - t * dx) ** 2 + (point[1] - start[1] - t * dy) ** 2
+
+
+def segments_distance_sq(a0, a1, b0, b1):
+    """Minimum squared distance, including a proper crossing at zero."""
+    def cross(p, q, r):
+        return (q[0] - p[0]) * (r[1] - p[1]) - (q[1] - p[1]) * (r[0] - p[0])
+
+    ab0, ab1 = cross(a0, a1, b0), cross(a0, a1, b1)
+    ba0, ba1 = cross(b0, b1, a0), cross(b0, b1, a1)
+    if ab0 * ab1 < 0 and ba0 * ba1 < 0:
+        return 0.0
+    return min(
+        point_segment_distance_sq(a0, b0, b1),
+        point_segment_distance_sq(a1, b0, b1),
+        point_segment_distance_sq(b0, a0, a1),
+        point_segment_distance_sq(b1, a0, a1),
+    )
+
+
+def capsule_segment(cx, cy, half_length, angle):
+    dx, dy = half_length * math.cos(angle), half_length * math.sin(angle)
+    return (cx - dx, cy - dy), (cx + dx, cy + dy)
+
+
+def has_clearance(candidate, accepted, clearance):
+    """Capsules are (start, end, radius), all in the same physical units."""
+    start, end, radius = candidate
+    for other_start, other_end, other_radius in accepted:
+        limit = radius + other_radius + clearance
+        if (max(start[0], end[0]) + limit < min(other_start[0], other_end[0])
+                or max(other_start[0], other_end[0]) + limit < min(start[0], end[0])
+                or max(start[1], end[1]) + limit < min(other_start[1], other_end[1])
+                or max(other_start[1], other_end[1]) + limit < min(start[1], end[1])):
+            continue
+        if segments_distance_sq(start, end, other_start, other_end) < limit * limit:
+            return False
+    return True