more mem optimizations: poly length/area. worker now cleans up widget groups

src/geo/polygon.js

@@ -31,14 +31,16 @@
         constructor(points) {
             this.id = seqid++; // polygon unique id
             this.open = false;
-            this.length = 0; // number of points
             this.points = []; // ordered array of points
-            this.area2 = 0.0; // computed as 2x area (sign = direction)
             this.parent = null; // enclosing parent polygon
             this.depth = 0; // depth nested from top parent (density for support fill)
             if (points) this.addPoints(points);
         }
 
+        get length() {
+            return this.points.length;
+        }
+
         get bounds() {
             if (this._bounds) {
                 return this._bounds;
@@ -891,7 +893,6 @@
         // clone any point belonging to another polygon
         if (p.poly) p = p.clone();
         p.poly = this;
-        this.length++;
         this.points.push(p);
         return p;
     };
@@ -991,7 +992,9 @@
      * @returns {Polygon} self
      */
     PRO.reverse = function() {
+        if (this.area2) {
             this.area2 = -this.area2;
+        }
         this.points = this.points.reverse();
         return this;
     };
@@ -1351,8 +1354,11 @@
      * @returns {number} area
      */
     PRO.area = function(raw) {
-        if (this.length < 3) return 0;
+        if (this.length < 3) {
-        if (this.area2 === 0.0) {
+            return 0;
+        }
+        if (this.area2 === undefined) {
+            this.area2 = 0.0;
             for (let p=this.points,pl=p.length,pi=0,p1,p2; pi<pl; pi++) {
                 p1 = p[pi];
                 p2 = p[(pi+1)%pl];
@@ -1369,7 +1375,9 @@
      * @returns {number} area
      */
     PRO.areaDeep = function() {
-        if (!this.inner) return this.area();
+        if (!this.inner) {
+            return this.area();
+        }
         let i, c = this.inner, a = this.area();
         for (i=0; i<c.length; i++) {
             a -= c[i].area();

src/kiri/main.js

@@ -2872,7 +2872,7 @@
                 complete = {};
                 UI.back.style.display = '';
                 UI.render.style.display = '';
-                // KIRI.work.clear();
+                KIRI.client.clear();
                 STACKS.clear();
                 hideSlider();
                 updateSpeeds();

src/kiri/widget.js

@@ -123,6 +123,10 @@
                 }
             });
             return bounds;
+        },
+
+        clear: function() {
+            groups.length = 0;
         }
     };
 

src/kiri/worker.js

@@ -47,6 +47,7 @@ KIRI.worker = {
         current.print = null;
         dispatch.group = wgroup = {};
         dispatch.cache = wcache = {};
+        KIRI.Widget.Groups.clear();
         send.done({ clear: true });
     },
 
@@ -162,6 +163,8 @@ KIRI.worker = {
     slice: function(data, send) {
         send.data({update:0.001, updateStatus:"slicing"});
 
+        current.print = null;
+
         let settings = data.settings,
             widget = wcache[data.id],
             last = time(),