change fingerprinting algorithm

src/geo/bounds.js

@@ -58,6 +58,17 @@
             UTIL.isCloseTo(this.maxy, bounds.maxy, margin);
     };
 
+    /**
+     * @returns {Number} absolute delta in x,y coordinate space
+     */
+    PRO.delta = function(bounds) {
+        return
+            Math.abs(this.minx - bounds.minx) +
+            Math.abs(this.miny - bounds.miny) +
+            Math.abs(this.maxx - bounds.maxx) +
+            Math.abs(this.maxy - bounds.maxy);
+    };
+
     /**
      * @param {Bounds} b
      */

src/geo/polygon.js

@@ -476,7 +476,7 @@
         const pa = this.points,
             pln = pa.length,
             open = this.open,
-            newp = newPolygon(),
+            newp = newPolygon().copyZ(this.z),
             min = dist || BASE.config.precision_merge;
         let lo;
         newp.push(lo = pa[0]);
@@ -519,7 +519,7 @@
             redo |= ang[0] > 90;
         }
         if (redo) {
-            const newp = newPolygon();
+            const newp = newPolygon().copyZ(this.z);
             // newp.debug = this.debug = true;
             newp.open = open;
             for (let i=0; i<pln; i++) {
@@ -803,7 +803,7 @@
      * @returns {Polygon}
      */
     PRO.clone = function(deep) {
-        let np = newPolygon(),
+        let np = newPolygon().copyZ(this.z),
             ln = this.length,
             i = 0;
 
@@ -820,6 +820,25 @@
         return np;
     };
 
+    // special shallow for-render-or-read-only cloning
+    PRO.cloneZ = function(z, stop) {
+        let p = newPolygon();
+        p.z = z;
+        p.open = this.open;
+        p.points = this.points;
+        if (this.inner) {
+            p.inner = this.inner.map(p => p.cloneZ(z, true));
+        }
+        return p;
+    };
+
+    PRO.copyZ = function(z) {
+        if (z !== undefined) {
+            this.z = z;
+        }
+        return this;
+    };
+
     /**
      * set all points' z value
      *
@@ -839,7 +858,7 @@
      * @returns {number} z value of first point
      */
     PRO.getZ = function(i) {
-        return this.points[i || 0].z;
+        return this.z !== undefined ? this.z : this.points[i || 0].z;
     };
 
     /**

src/geo/polygons.js

@@ -871,37 +871,62 @@
         flatten(polys).sort((a,b) => {
             return a.area() > b.area();
         }).forEach(p => {
-            finger.push(p.area());
-            finger.push(p.perimeter());
-            finger.push(p.bounds);
+            // finger.push(p.area());
+            // finger.push(p.perimeter());
+            // finger.push(p.bounds);
+            finger.push({
+                c: p.circularityDeep(),
+                p: p.perimeterDeep(),
+                b: p.bounds
+            });
         });
         return finger;
     }
 
+    // compare fingerprint arrays
     function fingerprintCompare(a, b) {
+        // true if array is the same object
         if (a === b) {
             return true;
         }
+        // fail on missing array
         if (!a || !b) {
             return false;
         }
+        // require identical length arrays
         if (a.length !== b.length) {
             return false;
         }
-        for (let i=0; i<a.length; i += 3) {
-            if (Math.abs(a[i] - b[i]) > 0.001) {
+        for (let i=0; i<a.length; i++) {
+            let ra = a[i];
+            let rb = b[i];
+            // test circularity
+            if (Math.abs(ra.c - rb.c) > 0.001) {
                 return false;
             }
-            if (Math.abs(a[i+1] - b[i+1]) > 0.0001) {
+            // test perimeter
+            if (Math.abs(ra.p - rb.p) > 0.001) {
                 return false;
             }
-            if (Math.abs(a[i+2].centerx() - b[i+2].centerx()) > 0.0001) {
-                return false;
-            }
-            if (Math.abs(a[i+2].centery() - b[i+2].centery()) > 0.0001) {
+            // test bounds
+            if (ra.b.delta(rb.b) > 0.001) {
                 return false;
             }
         }
+        // for (let i=0; i<a.length; i += 3) {
+        //     if (Math.abs(a[i] - b[i]) > 0.001) {
+        //         return false;
+        //     }
+        //     if (Math.abs(a[i+1] - b[i+1]) > 0.0001) {
+        //         return false;
+        //     }
+        //     if (Math.abs(a[i+2].centerx() - b[i+2].centerx()) > 0.0001) {
+        //         return false;
+        //     }
+        //     if (Math.abs(a[i+2].centery() - b[i+2].centery()) > 0.0001) {
+        //         return false;
+        //     }
+        // }
         return true;
     }