feat: path closure

src/plotcutter/plotter.ts

@@ -22,15 +22,8 @@ export function pts2plotter(
 
   let str = init(width * px2mm, height * px2mm);
 
-  // 按 X 轴然后 Y 轴排序路径
-  const sorted = pts.slice();
-  sorted.sort(function (a, b) {
-    const [ax, ay] = topleft(a);
-    const [bx, by] = topleft(b);
-
-    if (ax !== bx) return ax - bx;
-    return ay - by;
-  });
+  // 使用最近邻算法排序路径
+  const sorted = sortPathsByNearestNeighbor(pts, start);
 
   // 从起点到第一个路径
   if (sorted.length > 0) {
@@ -44,6 +37,11 @@ export function pts2plotter(
       str += ` D${plu(pt[0] * px2mm)},${plu((height - pt[1]) * px2mm)}`;
     }
 
+    // 如果第一个路径未闭合，添加闭合命令
+    if (!isPathClosed(firstPath)) {
+      str += ` D${plu(firstPath[0][0] * px2mm)},${plu((height - firstPath[0][1]) * px2mm)}`;
+    }
+
     // 路径之间移动
     for (let i = 1; i < sorted.length; i++) {
       const prevPath = sorted[i - 1];
@@ -58,6 +56,11 @@ export function pts2plotter(
         const pt = currPath[j];
         str += ` D${plu(pt[0] * px2mm)},${plu((height - pt[1]) * px2mm)}`;
       }
+
+      // 如果当前路径未闭合，添加闭合命令
+      if (!isPathClosed(currPath)) {
+        str += ` D${plu(currPath[0][0] * px2mm)},${plu((height - currPath[0][1]) * px2mm)}`;
+      }
     }
   }
 
@@ -88,6 +91,72 @@ function topleft(pts: [number, number][]) {
   return [minx, miny] as [number, number];
 }
 
+/**
+ * 检测路径是否已闭合（起点和终点距离小于阈值）
+ * @param path 路径点数组
+ * @param threshold 距离阈值（像素），默认 0.01
+ */
+function isPathClosed(path: [number, number][], threshold = 0.01): boolean {
+  if (path.length < 2) return true;
+  const [sx, sy] = path[0];
+  const [ex, ey] = path[path.length - 1];
+  const dist = Math.sqrt((sx - ex) ** 2 + (sy - ey) ** 2);
+  return dist < threshold;
+}
+
+/**
+ * 计算点到路径的最近距离
+ * @param pt 点坐标
+ * @param path 路径点数组
+ */
+function distanceToPath(pt: [number, number], path: [number, number][]): number {
+  let minDist = Infinity;
+  for (const p of path) {
+    const dist = Math.sqrt((pt[0] - p[0]) ** 2 + (pt[1] - p[1]) ** 2);
+    if (dist < minDist) minDist = dist;
+  }
+  return minDist;
+}
+
+/**
+ * 使用最近邻算法排序路径
+ * @param paths 路径数组
+ * @param startPos 起始位置
+ */
+function sortPathsByNearestNeighbor(
+  paths: [number, number][][],
+  startPos: [number, number]
+): [number, number][][] {
+  if (paths.length === 0) return [];
+
+  const result: [number, number][][] = [];
+  const remaining = paths.slice();
+  let currentPos = startPos;
+
+  while (remaining.length > 0) {
+    // 找到距离当前位置最近的路径
+    let nearestIndex = 0;
+    let nearestDist = Infinity;
+
+    for (let i = 0; i < remaining.length; i++) {
+      const dist = distanceToPath(currentPos, remaining[i]);
+      if (dist < nearestDist) {
+        nearestDist = dist;
+        nearestIndex = i;
+      }
+    }
+
+    // 将最近的路径添加到结果中
+    const nearestPath = remaining.splice(nearestIndex, 1)[0];
+    result.push(nearestPath);
+
+    // 更新当前位置为该路径的终点
+    currentPos = nearestPath[nearestPath.length - 1];
+  }
+
+  return result;
+}
+
 function init(w: number, h: number) {
   return ` IN TB26,${plu(w)},${plu(h)} CT1`;
 }