History for undo redo added

javascript/src/History.js

+/**
+ * @author Benjamin Baer <benjamin.baer@math.uzh.ch>
+ */
+
+/* global $ */
+
+/**
+ * Qfq Namespace
+ *
+ * @namespace QfqNS
+ */
+var QfqNS = QfqNS || {};
+
+(function (n) {
+    'use strict';
+
+/**
+ * A custom history to use for undo and redo functionality.
+ **/
+
+    n.History = function() {
+        this.history = [];
+        this.pointer = 0;
+    };
+
+    n.History.prototype.put = function(object) {
+        if (this.pointerAtCurrent()) {
+            this._removeForwardHistory();
+        }
+        this.history.push(object);
+        this.pointer = this.history.length - 1;
+    };
+
+    n.History.prototype.back = function() {
+        if (this.canGoBack()) {
+            this.pointer--;
+            return this.history[this.pointer];
+        } else {
+            console.log("At the beginning of history");
+            return false;
+        }
+    };
+
+    n.History.prototype.forward = function() {
+        if (this.canGoForward()) {
+            this.pointer++;
+            return this.history[this.pointer];
+        } else {
+            console.log("At the end of history");
+            return false;
+        }
+    };
+
+    n.History.prototype.canGoBack = function() {
+        return this.pointer > 0;
+    };
+
+    n.History.prototype.canGoForward = function() {
+        return this.pointer < this.history.length - 1;
+    };
+
+    n.History.prototype.pointerAtCurrent = function() {
+        return this.pointer === this.history.length - 1;
+    };
+
+    n.History.prototype._removeForwardHistory = function() {
+        var tempPointer = this.history.length - 1;
+        while (tempPointer > this.pointer && this.history.length > 0) {
+            this.history.pop();
+            tempPointer--;
+        }
+    };
+
+
+
+})(QfqNS);
\ No newline at end of file

javascript/src/Plugins/qfq.fabric.js

@@ -63,6 +63,7 @@ $(function (n) {
         this.mouseInsideCanvas = false;
         this.imageOutput = '';
         this.localStore = new n.LocalStorage("fabric");
+        this.history = new n.History();
 
         // Handles button states and generation of said buttons. Should be renamed.
         function ModeSettings() {