Grid sorter first approach

mindplot/src/main/javascript/nlayout/GridSorter.js

@@ -1,12 +1,48 @@
 mindplot.nlayout.GridSorter = new Class({
     Extends: mindplot.nlayout.SymetricSorder,
 
+    computeOffsets: function(treeSet, node) {
+        $assert(treeSet, "treeSet can no be null.");
+        $assert(node, "node can no be null.");
+        $assert("order can no be null.");
+
+        var children = this._getSortedChildren(treeSet, node);
+
+        // Compute heights ...
+        var heights = children.map(function(child) {
+            return {id:child.getId(),height:this._computeChildrenHeight(treeSet, child)};
+        }.bind(this));
+
+        // Calculate the offsets ...
+        var result = {};
+        for (var i = 0; i < heights.length; i++) {
+            var even = i%2 == 0 ? 1 : -1;
+
+            var zeroHeight = i == 0 ? 0 : heights[0].height/2 * even;
+            var middleHeight = 0;
+            for (var j=i-2; j>0; j=j-2) {
+                middleHeight += heights[j].height * even;
+            }
+            var finalHeight = i == 0 ? 0 : heights[i].height/2 * even;
+
+            var yOffset = zeroHeight + middleHeight +finalHeight;
+            var xOffset = node.getSize().width + mindplot.nlayout.GridSorter.GRID_HORIZONTAR_SIZE;
+
+            $assert(!isNaN(xOffset), "xOffset can not be null");
+            $assert(!isNaN(yOffset), "yOffset can not be null");
+
+            result[heights[i].id] = {x:xOffset,y:yOffset};
+
+        }
+        return result;
+    },
+
     toString:function() {
         return "Grid Sorter";
     }
 
 });
 
-mindplot.nlayout.GridSorter.GRID_HORIZONTAR_SIZE = 50;
+mindplot.nlayout.GridSorter.GRID_HORIZONTAR_SIZE = 20;
 mindplot.nlayout.GridSorter.INTER_NODE_VERTICAL_DISTANCE = 50;