update single width extrusion claim system. does not require splitting medial axis segments

src/geo/point.js

@@ -114,11 +114,16 @@ class Point {
         return this.key;
     }
 
-    clone() {
+    clone(keys) {
         let p = newPoint(this.x, this.y, this.z, this._key);
         if (this.a !== undefined) {
             p.a = this.a;
         }
+        if (keys) {
+            for (let key of keys) {
+                p[key] = this[key];
+            }
+        }
         return p;
     }
 

src/geo/polygon.js

@@ -2322,7 +2322,7 @@ export class Polygon {
 
     // split long straight lines into segments no longer than max
     // and return a new polygon
-    segment(max = 1) {
+    segment(max = 1, mark) {
         const newp = [];
         const points = this.points;
         const length = points.length;
@@ -2334,6 +2334,7 @@ export class Polygon {
             const dy = p2.y - p1.y;
             const dl = Math.sqrt(dx * dx + dy * dy);
             newp.push(p1);
+            if (mark) p1.segment = p1;
             if (dl < max) {
                 continue;
             }
@@ -2348,10 +2349,12 @@ export class Polygon {
                 newp.push(newPoint(ox, oy, (p1.z + p2.z) / 2));
                 ox += ix;
                 oy += iy;
+                // mark new point with first point of originating segment
+                if (mark) newp.peek().segment = p1;
             }
         }
         if (newp.length > length) {
-            return newPolygon().addPoints(newp.map(p => p.clone())).setOpenValue(this.open);
+            return newPolygon().addPoints(newp.map(p => p.clone(['segment']))).setOpenValue(this.open);
         }
         return this;
     }