""" SVG 路径平滑脚本 - 读取复合 path，拆分成子路径 - 对每个子路径应用 RDP (Ramer-Douglas-Peucker) 简化，去掉锯齿 - 用 Catmull-Rom 样条转三次贝塞尔曲线，使边缘平滑 - 输出新的 SVG 文件 """ import re import math import xml.etree.ElementTree as ET import numpy as np INPUT_PATH = r"C:\Users\jwj_5\Downloads\cat_mandala_safe_v2.svg\cat_mandala_safe_v2.svg" OUTPUT_PATH = r"C:\Users\jwj_5\Downloads\cat_mandala_safe_v2.svg\cat_mandala_smoothed.svg" NS = {'svg': 'http://www.w3.org/2000/svg'} # ===================== 参数 ===================== RDP_EPSILON = 1.5 # RDP 简化容差（SVG 单位），越大越简化 SMOOTH_TENSION = 0.5 # Catmull-Rom 张力 0~1，越小越平滑 MIN_POINTS = 3 # 子路径最少保留点数 # ================================================ def split_subpaths(d): """按 M/m 拆分子路径""" parts = re.split(r'(?=[Mm])', d) return [p.strip() for p in parts if p.strip()] def parse_subpath(sub): """解析子路径为点列表""" pts = [] cx, cy = 0.0, 0.0 cmd = None for tok in re.split(r'([MmLlHhVvCcSsQqTtAaZz])', sub): tok = tok.strip() if not tok: continue if tok in 'MmLlHhVvCcSsQqTtAaZz': cmd = tok continue vals = [float(v) for v in re.findall(r'[-+]?\d*\.?\d+', tok)] if not vals: continue if cmd in 'Mm': for k in range(0, len(vals) - 1, 2): if cmd == 'm' and pts: cx += vals[k]; cy += vals[k + 1] else: cx, cy = vals[k], vals[k + 1] pts.append((cx, cy)) elif cmd in 'Ll': for k in range(0, len(vals) - 1, 2): if cmd == 'l': cx += vals[k]; cy += vals[k + 1] else: cx, cy = vals[k], vals[k + 1] pts.append((cx, cy)) elif cmd in 'Hh': for v in vals: cx = cx + v if cmd == 'h' else v pts.append((cx, cy)) elif cmd in 'Vv': for v in vals: cy = cy + v if cmd == 'v' else v pts.append((cx, cy)) elif cmd in 'Cc': for k in range(0, len(vals) - 5, 6): if cmd == 'c': cx += vals[k + 4]; cy += vals[k + 5] else: cx, cy = vals[k + 4], vals[k + 5] pts.append((cx, cy)) elif cmd in 'Ss': for k in range(0, len(vals) - 3, 4): if cmd == 's': cx += vals[k + 2]; cy += vals[k + 3] else: cx, cy = vals[k + 2], vals[k + 3] pts.append((cx, cy)) elif cmd in 'Qq': for k in range(0, len(vals) - 3, 4): if cmd == 'q': cx += vals[k + 2]; cy += vals[k + 3] else: cx, cy = vals[k + 2], vals[k + 3] pts.append((cx, cy)) elif cmd in 'Tt': for k in range(0, len(vals) - 1, 2): if cmd == 't': cx += vals[k]; cy += vals[k + 1] else: cx, cy = vals[k], vals[k + 1] pts.append((cx, cy)) elif cmd in 'Aa': for k in range(0, len(vals) - 6, 7): if cmd == 'a': cx += vals[k + 5]; cy += vals[k + 6] else: cx, cy = vals[k + 5], vals[k + 6] pts.append((cx, cy)) return pts def is_closed(sub): s = sub.rstrip() return s.endswith('Z') or s.endswith('z') # ---------- RDP 简化 ---------- def rdp(points, epsilon): """Ramer-Douglas-Peucker 简化（numpy 版）""" if len(points) < 3: return points pts = np.array(points, dtype=np.float64) def _rdp_recursive(pts, epsilon): if len(pts) < 3: return pts start = pts[0] end = pts[-1] # 点到线段距离 if np.allclose(start, end): dists = np.linalg.norm(pts - start, axis=1) else: line = end - start line_len = np.linalg.norm(line) line_unit = line / line_len vecs = pts - start proj = np.dot(vecs, line_unit) proj = np.clip(proj, 0, line_len) proj_pts = start + np.outer(proj, line_unit) dists = np.linalg.norm(pts - proj_pts, axis=1) max_idx = np.argmax(dists) max_dist = dists[max_idx] if max_dist < epsilon: return np.array([start, end]) left = _rdp_recursive(pts[:max_idx + 1], epsilon) right = _rdp_recursive(pts[max_idx:], epsilon) return np.vstack([left[:-1], right]) result = _rdp_recursive(pts, epsilon) return [tuple(p) for p in result] # ---------- Catmull-Rom 转贝塞尔 ---------- def catmull_rom_to_bezier(points, closed, tension=0.5): """ 将点序列转换为平滑的三次贝塞尔曲线段 返回 [(p0, c1, c2, p1), ...] 的列表 """ n = len(points) if n < 2: return [] if n == 2: return [(points[0], points[0], points[1], points[1])] # 为闭合/开放路径准备扩展点 if closed: ext = [points[-1]] + list(points) + [points[0], points[1]] seg_count = n else: ext = [points[0]] + list(points) + [points[-1]] seg_count = n - 1 segments = [] for i in range(seg_count): p0 = ext[i] p1 = ext[i + 1] p2 = ext[i + 2] p3 = ext[i + 3] # Catmull-Rom 控制点 c1 = (p1[0] + (p2[0] - p0[0]) * tension / 6, p1[1] + (p2[1] - p0[1]) * tension / 6) c2 = (p2[0] - (p3[0] - p1[0]) * tension / 6, p2[1] - (p3[1] - p1[1]) * tension / 6) segments.append((p1, c1, c2, p2)) return segments def segments_to_d(segments, closed): """将贝塞尔段转为 SVG path d 字符串""" if not segments: return "" parts = [] first_p = segments[0][0] parts.append(f"M{first_p[0]:.2f},{first_p[1]:.2f}") for p0, c1, c2, p1 in segments: parts.append(f"C{c1[0]:.2f},{c1[1]:.2f} {c2[0]:.2f},{c2[1]:.2f} {p1[0]:.2f},{p1[1]:.2f}") if closed: parts.append("Z") return "".join(parts) def main(): print(f"读取: {INPUT_PATH}") tree = ET.parse(INPUT_PATH) root = tree.getroot() paths = root.findall('.//svg:path', NS) if not paths: print("未找到 path 元素") return total_in = 0 total_out = 0 sub_count = 0 # 处理每条 path for path_el in paths: d = path_el.get('d', '') subs = split_subpaths(d) new_d_parts = [] for sub in subs: pts = parse_subpath(sub) if len(pts) < 2: continue closed = is_closed(sub) total_in += len(pts) sub_count += 1 # RDP 简化 simplified = rdp(pts, RDP_EPSILON) if len(simplified) < MIN_POINTS: # 太小的子路径保留原样（避免碎点丢失后出错） simplified = pts # 转为平滑贝塞尔 segments = catmull_rom_to_bezier(simplified, closed, SMOOTH_TENSION) sub_d = segments_to_d(segments, closed) total_out += len(simplified) new_d_parts.append(sub_d) path_el.set('d', "".join(new_d_parts)) # 写出 ET.register_namespace('', 'http://www.w3.org/2000/svg') tree.write(OUTPUT_PATH, encoding='utf-8', xml_declaration=True) print(f"处理完成") print(f" 子路径数: {sub_count}") print(f" 原始总节点: {total_in}") print(f" 简化后节点: {total_out}") print(f" 节点减少: {total_in - total_out} ({(1-total_out/total_in)*100:.1f}%)") print(f" RDP epsilon: {RDP_EPSILON}") print(f" 平滑张力: {SMOOTH_TENSION}") print(f"输出: {OUTPUT_PATH}") if __name__ == '__main__': main()