add codec optional extended point data encoding

src/kiri/core/codec.js

@@ -312,7 +312,7 @@ Polygon.prototype.encode = function(state) {
 
     state.poly[this.id] = this;
 
-    return {
+    let enc = {
         type: TYPE.POLY,
         id: this.id,
         array: encodePointArray(this.points, state, this.z),
@@ -322,6 +322,20 @@ Polygon.prototype.encode = function(state) {
         color: this.color,
         open: this.open
     };
+
+    // encode extended point info for tagged polys
+    if (this._epk) {
+        let epk = enc.epk = {};
+        for (let key of this._epk) {
+            let arr = epk[key] = [];
+            let pts = this.points;
+            for (let i=0, l=pts.length; i<l; i++) {
+                if (pts[i][key]) arr.push(i, pts[i][key]);
+            }
+        }
+    }
+
+    return enc;
 };
 
 registerDecoder(TYPE.POLY, function(v, state) {
@@ -340,6 +354,18 @@ registerDecoder(TYPE.POLY, function(v, state) {
         poly.push(newPoint(array[vid++], array[vid++], array[vid++]));
     }
 
+    // decode extended point when present
+    if (v.epk) {
+        let pts = poly.points;
+        for (let [key, arr] of Object.entries(v.epk)) {
+            for (let i=0; i<arr.length; ) {
+                let pos = arr[i++];
+                let val = arr[i++];
+                pts[pos][key] = val;
+            }
+        }
+    }
+
     state.poly[v.id] = poly;
 
     poly.id = v.id;

src/kiri/mode/fdm/post.js

@@ -152,8 +152,8 @@ function offset_default(params) {
                         // merge points marking point offset and skip
                         let mid = p0.midPointTo(p1);
                         let inc = p0.distTo2D(mid) / offset1;
-                        moved = p0.moved = p1.moved = inc;
-                        p1.skip = true;
+                        moved = p0.moved = p1.moved = inc.round(4);
+                        p1.skip = 1;
                         p0.x = p1.x = mid.x;
                         p0.y = p1.y = mid.y;
                     }
@@ -168,6 +168,8 @@ function offset_default(params) {
     for (let rec of thin_test) {
         if (rec.moved) {
             let last_seg;
+            // tag for codec extended point encoding
+            rec.poly._epk = ["moved", "skip"];
             rec.poly.points = rec.points.filter((p,i) => {
                 let keep = (last_seg !== p.segment || p.moved || p.skip);
                 last_seg = p.segment;