Implement unique ids, and fix issue with Base.deserialize()

Gradient and Symbol were overriding each other in the dictionary, and dictionary entries could not contain references to other dictionary entries.

Closes #690

examples/JSON/Gradients.html

@@ -6,15 +6,20 @@
     <link rel="stylesheet" href="../css/style.css">
     <script type="text/javascript" src="../../dist/paper-full.js"></script>
     <script type="text/paperscript" canvas="canvas1">
-        var path = new Path.Circle(view.center, view.bounds.height * 0.4);
+        var path = new Path.Circle({
+            center: view.center,
+            radius: view.bounds.height * 0.4
+        });
         path.fillColor = {
-            // gradient: [['yellow', 'red', 'black'], true],
             stops: ['yellow', 'red', 'black'],
             radial: true,
             origin: path.position,
             destination: path.bounds.rightCenter
         }
-        path.strokeColor = 'black';
+
+        var symbol = new Symbol(path);
+        symbol.place(view.center);
+
         window._json = project.exportJSON();
         console.log(window._json);
     </script>

src/core/Base.js

@@ -392,7 +392,7 @@ Base.inject(/** @lends Base# */{
          * The passed json data is recoursively traversed and converted, leaves
          * first
          */
-        deserialize: function(json, create, _data) {
+        deserialize: function(json, create, _data, _isDictionary) {
             var res = json,
                 isRoot = !_data;
             // A _data side-car to deserialize that can hold any kind of
@@ -405,22 +405,24 @@ Base.inject(/** @lends Base# */{
                 // deserialize all elements of the array.
                 var type = json[0],
                     // Handle stored dictionary specially, since we need to
-                    // keep is a lookup table to retrieve referenced items from.
+                    // keep a lookup table to retrieve referenced items from.
                     isDictionary = type === 'dictionary';
-                if (!isDictionary) {
-                    // First see if this is perhaps a dictionary reference, and
-                    // if so return its definition instead.
-                    if (_data.dictionary && json.length == 1 && /^#/.test(type))
-                        return _data.dictionary[type];
-                    type = Base.exports[type];
-                }
+                // First see if this is perhaps a dictionary reference, and
+                // if so return its definition instead.
+                if (json.length == 1 && /^#/.test(type))
+                    return _data.dictionary[type];
+                type = Base.exports[type];
                 res = [];
+                // We need to set the dictionary object before further
+                // deserialization, because serialized symbols may contain
+                // references to serialized gradients
+                if (_isDictionary)
+                    _data.dictionary = res;
                 // Skip first type entry for arguments
                 for (var i = type ? 1 : 0, l = json.length; i < l; i++)
-                    res.push(Base.deserialize(json[i], create, _data));
-                if (isDictionary) {
-                    _data.dictionary = res[0];
-                } else if (type) {
+                    res.push(Base.deserialize(json[i], create, _data,
+                            isDictionary));
+                if (type) {
                     // Create serialized type and pass collected arguments to
                     // constructor().
                     var args = res;
@@ -436,6 +438,9 @@ Base.inject(/** @lends Base# */{
                 }
             } else if (Base.isPlainObject(json)) {
                 res = {};
+                // See above why we have to set this before Base.deserialize()
+                if (_isDictionary)
+                    _data.dictionary = res;
                 for (var key in json)
                     res[key] = Base.deserialize(json[key], create, _data);
             }

src/item/Item.js

@@ -91,7 +91,7 @@ var Item = Base.extend(Emitter, /** @lends Item# */{
             // Allow setting another project than the currently active one.
             project = hasProps && props.project || paper.project;
         if (!internal)
-            this._id = Item._id = (Item._id || 0) + 1;
+            this._id = UID.get();
         // Inherit the applyMatrix setting from paper.settings.applyMatrix
         this._applyMatrix = this._canApplyMatrix && paper.settings.applyMatrix;
         // Handle matrix before everything else, to avoid issues with

src/paper.js

@@ -51,6 +51,7 @@ var paper = new function(undefined) {
 
 /*#*/ include('util/Formatter.js');
 /*#*/ include('util/Numerical.js');
+/*#*/ include('util/UID.js');
 
 // Include Paper classes, which are later injected into PaperScope by setting
 // them on the 'this' object, e.g.:

src/path/CurveLocation.js

@@ -44,6 +44,9 @@ var CurveLocation = Base.extend(/** @lends CurveLocation# */{
     initialize: function CurveLocation(curve, parameter, point, _curve2,
             _parameter2, _point2, _distance) {
         // Define this CurveLocation's unique id.
+        // NOTE: We do not use the same pool as the rest of the library here,
+        // since this is only required to be unique at runtime among other
+        // CurveLocation objects.
         this._id = CurveLocation._id = (CurveLocation._id || 0) + 1;
         this._curve = curve;
         // Also store references to segment1 and segment2, in case path

src/project/Symbol.js

@@ -61,7 +61,7 @@ var Symbol = Base.extend(/** @lends Symbol# */{
      */
     initialize: function Symbol(item, dontCenter) {
         // Define this Symbols's unique id.
-        this._id = Symbol._id = (Symbol._id || 0) + 1;
+        this._id = UID.get();
         this.project = paper.project;
         this.project.symbols.push(this);
         if (item)

src/style/Color.js

@@ -608,9 +608,6 @@ var Color = Base.extend(new function() {
             }
             // Default fallbacks: rgb, black
             this._type = type || 'rgb';
-            // Define this gradient Color's unique id.
-            if (type === 'gradient')
-                this._id = Color._id = (Color._id || 0) + 1;
             if (!components) {
                 // Produce a components array now, and parse values. Even if no
                 // values are defined, parsers are still called to produce

src/style/Gradient.js

@@ -66,8 +66,8 @@ var Gradient = Base.extend(/** @lends Gradient# */{
 
     // DOCS: Document #initialize()
     initialize: function Gradient(stops, radial) {
-        // Define this Gradient's unique id.
-        this._id = Gradient._id = (Gradient._id || 0) + 1;
+        // Use UID here since Gradients are exported through dictionary.add().
+        this._id = UID.get();
         if (stops && this._set(stops))
             stops = radial = null;
         if (!this._stops)

src/util/UID.js

@@ -0,0 +1,30 @@
+/*
+ * Paper.js - The Swiss Army Knife of Vector Graphics Scripting.
+ * http://paperjs.org/
+ *
+ * Copyright (c) 2011 - 2014, Juerg Lehni & Jonathan Puckey
+ * http://scratchdisk.com/ & http://jonathanpuckey.com/
+ *
+ * Distributed under the MIT license. See LICENSE file for details.
+ *
+ * All rights reserved.
+ */
+
+/**
+ * @name UID
+ * @namespace
+ * @private
+ */
+var UID = {
+    _id: 1,
+
+    /**
+     * Returns the next unique id.
+     * @method get
+     * @return {Number} The next unique id
+     * @static
+     **/
+    get: function() {
+        return this._id++;
+    }
+};