diff --git a/README.md b/README.md
index 6f7ccd0..143625c 100644
--- a/README.md
+++ b/README.md
@@ -140,59 +140,58 @@ The `draw()` function parses through all the items of the treemap. You could use
 ### Treemap
 
 Creates a new empty Treemap with position (x, y), width and height. 
-To specify drawing a bit more, you can give drawing options. `order` is "sort" or "shuffle".
-`direction` is either "horizontal", "vertical" or "both". With 'ignore', you can easily switch on and off branches of the Treemap. 
+To specify drawing a bit more, you can give drawing options. See method `setOptions()` for more information.
 Content may be added using `addData()` or `addItem()`.
 
 **Parameters**
 
--   `x` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** x position
--   `y` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** y position
--   `w` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** width
--   `h` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** height
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** drawing and sorting options {sort:true or false, direction:"horizontal", "vertical" or "both", ignore:["abc", "xyz"]}
+-   `x` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** – X position
+-   `y` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** – Y position
+-   `w` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** – Width
+-   `h` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** – Height
+-   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** – Drawing options
 
-Returns **[Treemap](#treemap)** the new empty Treemap
+Returns **[Treemap](#treemap)** – The new empty Treemap
 
 #### x
 
-x position of the rectangle.
+X position of the rectangle.
 
 #### y
 
-y position of the rectangle.
+Y position of the rectangle.
 
 #### w
 
-width of the rectangle.
+Width of the rectangle.
 
 #### h
 
-height of the rectangle.
+Height of the rectangle.
 
 #### minValue
 
-the minimum value of the items in the items array
+The minimum value of the items in the items array
 
 #### maxValue
 
-the maximum value of the items in the items array
+The maximum value of the items in the items array
 
 #### level
 
-level of the item; the root node has level 0
+Level of the item; the root node has level 0
 
 #### depth
 
-the depth of the branch; end nodes have depth 0
+The depth of the branch; end nodes have depth 0
 
 #### itemCount
 
-the number of items in the complete branch
+The number of items in the complete branch
 
 #### index
 
-index of the item in the sorted items array.
+Index of the item in the sorted items array.
 
 ### addData
 
@@ -227,7 +226,11 @@ Returns **[Treemap](#treemap)** – Returns the treemap where the data was added
 
 ### setOptions
 
-Set order, padding, ... for next calculation of the treemap.
+Set options for next calculation of the treemap. Currently there are the following options you might set:
+
+-   order: 'sort', 'shuffle' or 'keep'. Default is 'sort'. Attention: don't use 'keep' for the first calculation of the treemap.
+-   direction: 'both, 'horizontal' or 'vertical'. Default is 'both'.
+-   padding: 0 (default) or any positive number.
 
 **Parameters**
 
diff --git a/dist/Treemap.js b/dist/Treemap.js
index b0aad77..42be70d 100644
--- a/dist/Treemap.js
+++ b/dist/Treemap.js
@@ -6,21 +6,20 @@ var packageInfo = require('./package.json');
 
 /**
  * Creates a new empty Treemap with position (x, y), width and height. 
- * To specify drawing a bit more, you can give drawing options. `order` is "sort" or "shuffle".
- * `direction` is either "horizontal", "vertical" or "both". With 'ignore', you can easily switch on and off branches of the Treemap. 
+ * To specify drawing a bit more, you can give drawing options. See method `setOptions()` for more information.
  * Content may be added using `addData()` or `addItem()`.
  * 
  * @class Treemap
  * @constructor
- * @param  {Number} x         x position
- * @param  {Number} y         y position
- * @param  {Number} w         width
- * @param  {Number} h         height
- * @param  {Object} [options] drawing and sorting options {sort:true or false, direction:"horizontal", "vertical" or "both", ignore:["abc", "xyz"]}
- * @return {Treemap}          the new empty Treemap 
+ * @param  {Number} x         – X position
+ * @param  {Number} y         – Y position
+ * @param  {Number} w         – Width
+ * @param  {Number} h         – Height
+ * @param  {Object} [options] – Drawing options
+ * @return {Treemap}          – The new empty Treemap 
  */
 
-/**
+/*
  * @class Treemap
  * @ignore
  * @constructor (mainly for internal use)
@@ -30,7 +29,7 @@ var packageInfo = require('./package.json');
  * @return {Treemap}          the new Treemap that represents one item
  */
 
-/**
+/*
  * @class Treemap
  * @ignore
  * @constructor (mainly for internal use)
@@ -45,25 +44,25 @@ function Treemap() {
   this.items = [];
 
   /**
-   * x position of the rectangle.
+   * X position of the rectangle.
    * @property x
    * @type {Number}
    */
   this.x = 0;
   /**
-   * y position of the rectangle.
+   * Y position of the rectangle.
    * @property y
    * @type {Number}
    */
   this.y = 0;
   /**
-   * width of the rectangle.
+   * Width of the rectangle.
    * @property w
    * @type {Number}
    */
   this.w = 0;
   /**
-   * height of the rectangle.
+   * Height of the rectangle.
    * @property h
    * @type {Number}
    */
@@ -103,20 +102,20 @@ function Treemap() {
 
 
   /**
-   * the minimum value of the items in the items array
+   * The minimum value of the items in the items array
    * @property minValue
    * @type {Number}
    */
   this.minValue = 0;
   /**
-   * the maximum value of the items in the items array
+   * The maximum value of the items in the items array
    * @property maxValue
    * @type {Number}
    */
   this.maxValue = 0;
 
   /**
-   * level of the item; the root node has level 0
+   * Level of the item; the root node has level 0
    * @property level
    * @type {Number}
    */
@@ -124,21 +123,21 @@ function Treemap() {
   if (this.parent) this.level = this.parent.level + 1;
 
   /**
-   * the depth of the branch; end nodes have depth 0
+   * The depth of the branch; end nodes have depth 0
    * @property depth
    * @type {Number}
    */
   this.depth = 0;
 
   /**
-   * the number of items in the complete branch
+   * The number of items in the complete branch
    * @property itemCount
    * @type {Number}
    */
   this.itemCount = 1;
 
   /**
-   * index of the item in the sorted items array.
+   * Index of the item in the sorted items array.
    * @property index
    * @type {Number}
    */
@@ -266,7 +265,10 @@ function Treemap() {
 
 
   /**
-   * Set order, padding, ... for next calculation of the treemap.
+   * Set options for next calculation of the treemap. Currently there are the following options you might set:
+   * - order: 'sort', 'shuffle' or 'keep'. Default is 'sort'. Attention: don't use 'keep' for the first calculation of the treemap.
+   * - direction: 'both, 'horizontal' or 'vertical'. Default is 'both'.
+   * - padding: 0 (default) or any positive number.
    *
    * @method setOptions
    * @param {Object} options – Object in the form `{order: 'keep', padding: 4}`
@@ -661,7 +663,7 @@ module.exports = Treemap;
 },{"./package.json":2}],2:[function(require,module,exports){
 module.exports={
   "name": "Treemap.js",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "A javascript library for calculating a treemap.",
   "license": "MIT",
   "main": "index.js",
diff --git a/dist/Treemap.min.js b/dist/Treemap.min.js
index f6ad048..b1d7c94 100644
--- a/dist/Treemap.min.js
+++ b/dist/Treemap.min.js
@@ -1 +1 @@
-(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.Treemap=f()}})(function(){var define,module,exports;return function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r}()({1:[function(require,module,exports){"use strict";var packageInfo=require("./package.json");function Treemap(){this.parent;this.data;this.value=0;this.items=[];this.x=0;this.y=0;this.w=0;this.h=0;this.options={};if(arguments.length>=4){this.x=arguments[0];this.y=arguments[1];this.w=arguments[2];this.h=arguments[3];this.options=arguments[4]||{}}else{this.parent=arguments[0];this.data=arguments[1];this.value=arguments[2]||0;if(typeof this.value=="object"){Object.keys(this.value).forEach(function(k){var v=parseFloat(this.value[k]);v=isNaN(v)?0:v;this.value[k]=v}.bind(this))}else{var v=parseFloat(this.value);v=isNaN(v)?0:v;this.value=v}}this.x=this.x||0;this.y=this.y||0;this.w=this.w||0;this.h=this.h||0;this.minValue=0;this.maxValue=0;this.level=0;if(this.parent)this.level=this.parent.level+1;this.depth=0;this.itemCount=1;this.index=0;this.root=this;this.isRoot=true;if(this.parent){this.root=this.parent.root;this.isRoot=false}this.options=this.options||this.root.options;this.ignored=false;Treemap.prototype.addData=function(data,opts){opts=opts||{};if(opts.data)this.data=data[opts.data];else this.data=data;if(typeof data==="number"){this.value=data}else{if(Array.isArray(opts.value)){if(typeof this.value!="object"){this.value={}}opts.value.forEach(function(k){this.value[k]=data[k]||0}.bind(this))}else{this.value=data[opts.value]||0}}var children=data;if(opts.children)children=data[opts.children];if(Array.isArray(children)){children.forEach(function(child){var t=new Treemap(this);this.items.push(t);t.addData(child,opts)}.bind(this));return true}return false};Treemap.prototype.addItem=function(data,keys,value){value=value||1;if(keys){var currItem=this;for(var j=0;j<keys.length;j++){var k=keys[j];var i=currItem.items.findIndex(function(el){return el.data==data[k]});if(i>=0){if(j==keys.length-1)currItem.items[i].add(value);currItem=currItem.items[i]}else{var newItem=new Treemap(currItem,data[k],value);currItem.items.push(newItem);currItem=newItem}}return currItem}else{var i=this.items.findIndex(function(el){return el.data==data});if(i>=0){this.items[i].add(value);return false}else{var newItem=new Treemap(this,data,value);this.items.push(newItem)}return newItem}};Treemap.prototype.setOptions=function(opts){Object.keys(opts).forEach(function(k){this.options[k]=opts[k]}.bind(this));this.items.forEach(function(el){el.setOptions(opts)})};Treemap.prototype.addTreemap=function(data,value){var t=new Treemap(this,data,value);this.items.push(t);return t};Treemap.prototype.add=function(val){if(typeof val==="object"){if(typeof this.value!="object"){this.value={}}Object.keys(val).forEach(function(k){var v=parseFloat(val[k]);v=isNaN(v)?0:v;if(this.value[k]){this.value[k]+=v}else{this.value[k]=v}}.bind(this))}else{var v=parseFloat(val);this.value+=isNaN(v)?0:v}};Treemap.prototype.sumUpValues=function(valueKey){if(Array.isArray(this.options.ignore)){if(this.options.ignore.indexOf(this.data)>=0){this.ignored=true}else{this.ignored=false}}if(this.items.length==0){if(this.ignored)return valueKey?{}:0}else{this.minValue=Number.MAX_VALUE;this.maxValue=0;this.depth=0;this.itemCount=1;this.value=valueKey?{}:0;if(this.ignored)return valueKey?{}:0;for(var i=0;i<this.items.length;i++){var sum=this.items[i].sumUpValues(valueKey);this.add(sum);var val=valueKey?sum[valueKey]:sum;this.minValue=Math.min(this.minValue,val);this.maxValue=Math.max(this.maxValue,val);this.depth=Math.max(this.depth,this.items[i].depth+1);this.itemCount+=this.items[i].itemCount}}return this.value};Treemap.prototype.calculate=function(valueKey){if(this.items.length==0)return;if(this==this.root){this.sumUpValues(valueKey)}if(this.ignored){this.x=-1e5;this.y=0;this.w=0;this.h=0;return}if(this.root.options.order=="sort"||this.root.options.order==undefined){this.items.sort(function(a,b){if(valueKey){if(a.value[valueKey]<b.value[valueKey])return 1;if(a.value[valueKey]>b.value[valueKey])return-1}else{if(a.value<b.value)return 1;if(a.value>b.value)return-1}return 0})}else if(this.root.options.order=="shuffle"){shuffleArray(this.items)}for(var i=0;i<this.items.length;i++){this.items[i].index=i}var restSum=valueKey?this.value[valueKey]:this.value;var pad=this.root.options.padding||0;var restX=this.x+pad;var restY=this.y+pad;var restW=this.w-pad*2;var restH=this.h-pad*2;if(this.root.options.order=="keep"){for(var i=0;i<this.items.length;i++){var a=restW;var b=restH;if(!this.items[i].isHorizontal){a=restH;b=restW}var rowSum=0;for(var j=i;j<this.items.length;j++){rowSum+=valueKey?this.items[j].value[valueKey]:this.items[j].value;if(this.items[j].wrap)break}var startI=i;var endI=j;var percentage=rowSum/restSum;var bLen=b*percentage;var aPos=restX;var bPos=restY;var aLen=restW;if(!this.items[i].isHorizontal){aPos=restY;bPos=restX;aLen=restH}for(var j=startI;j<=endI;j++){var val=valueKey?this.items[j].value[valueKey]:this.items[j].value;var aPart=aLen*val/rowSum;if(this.items[i].isHorizontal){this.items[j].x=aPos;this.items[j].y=bPos;this.items[j].w=aPart;this.items[j].h=bLen}else{this.items[j].x=bPos;this.items[j].y=aPos;this.items[j].w=bLen;this.items[j].h=aPart}this.items[j].w=Math.max(this.items[j].w,0);this.items[j].h=Math.max(this.items[j].h,0);this.items[j].calculate(valueKey);aPos+=aPart}if(this.items[i].isHorizontal){restY+=bLen;restH-=bLen}else{restX+=bLen;restW-=bLen}restSum-=rowSum;i=endI}}else{var actIndex=0;while(actIndex<this.items.length){var isHorizontal=true;var a=restW;var b=restH;if(this.root.options.direction!="horizontal"){if(restW>restH||this.root.options.direction=="vertical"){isHorizontal=false;a=restH;b=restW}}var rowSum=0;var rowCount=0;var avRelPrev=Number.MAX_VALUE;for(var i=actIndex;i<this.items.length;i++){rowSum+=valueKey?this.items[i].value[valueKey]:this.items[i].value;rowCount++;var percentage=rowSum/restSum;var bLen=b*percentage;var avRel=a/rowCount/bLen;this.items[i].isHorizontal=isHorizontal;if(avRel<1||i==this.items.length-1){if(avRelPrev<1/avRel){rowSum-=valueKey?this.items[i].value[valueKey]:this.items[i].value;rowCount--;bLen=b*rowSum/restSum;i--}this.items[i].wrap=true;var aPos=restX;var bPos=restY;var aLen=restW;if(!isHorizontal){aPos=restY;bPos=restX;aLen=restH}for(var j=actIndex;j<=i;j++){var val=valueKey?this.items[j].value[valueKey]:this.items[j].value;var aPart=aLen*val/rowSum;if(isHorizontal){this.items[j].x=aPos;this.items[j].y=bPos;this.items[j].w=aPart;this.items[j].h=bLen}else{this.items[j].x=bPos;this.items[j].y=aPos;this.items[j].w=bLen;this.items[j].h=aPart}this.items[j].w=Math.max(this.items[j].w,0);this.items[j].h=Math.max(this.items[j].h,0);this.items[j].calculate(valueKey);aPos+=aPart}if(isHorizontal){restY+=bLen;restH-=bLen}else{restX+=bLen;restW-=bLen}restSum-=rowSum;break}avRelPrev=avRel}actIndex=i+1}}};Treemap.prototype.draw=function(drawItemFunction){if(!drawItemFunction){console.warn("You have to supply a drawing function to see something.");return}if(!this.ignored){drawItemFunction(this);for(var i=0;i<this.items.length;i++){this.items[i].draw(drawItemFunction)}}}}function shuffleArray(array){for(var i=array.length-1;i>0;i--){var j=Math.floor(Math.random()*(i+1));var temp=array[i];array[i]=array[j];array[j]=temp}}if(!Array.isArray){Array.isArray=function(obj){return Object.prototype.toString.call(obj)=="[object Array]"}}module.exports=Treemap},{"./package.json":2}],2:[function(require,module,exports){module.exports={name:"Treemap.js",version:"0.3.0",description:"A javascript library for calculating a treemap.",license:"MIT",main:"index.js",scripts:{bundle:"browserify index.js --standalone Treemap -o dist/Treemap.js",devbundle:"npm run bundle && copyfiles -u 1 dist/Treemap.js examples/lib/",dist:"npm run bundle && browserify index.js --standalone Treemap | uglifyjs > dist/Treemap.min.js && copyfiles -u 1 dist/Treemap.js examples/lib/",documentation:"documentation readme index.js --section=Reference",onchange:"onchange 'index.js' -- npm run devbundle"},repository:{type:"git",url:"https://github.com/bohnacker/Treemap.js"},keywords:["dataviz","graph","treemap","recursive"],author:"Hartmut Bohnacker <mail@hartmut-bohnacker.de>",bugs:{url:"https://github.com/bohnacker/Treemap.js/issues"},homepage:"https://github.com/bohnacker/Treemap.js",devDependencies:{browserify:"^14.4.0",documentation:"^5.2.2","uglify-js":"^3.0.28",watch:"1.0.2",onchange:"6.0.0"}}},{}]},{},[1])(1)});
+(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.Treemap=f()}})(function(){var define,module,exports;return function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r}()({1:[function(require,module,exports){"use strict";var packageInfo=require("./package.json");function Treemap(){this.parent;this.data;this.value=0;this.items=[];this.x=0;this.y=0;this.w=0;this.h=0;this.options={};if(arguments.length>=4){this.x=arguments[0];this.y=arguments[1];this.w=arguments[2];this.h=arguments[3];this.options=arguments[4]||{}}else{this.parent=arguments[0];this.data=arguments[1];this.value=arguments[2]||0;if(typeof this.value=="object"){Object.keys(this.value).forEach(function(k){var v=parseFloat(this.value[k]);v=isNaN(v)?0:v;this.value[k]=v}.bind(this))}else{var v=parseFloat(this.value);v=isNaN(v)?0:v;this.value=v}}this.x=this.x||0;this.y=this.y||0;this.w=this.w||0;this.h=this.h||0;this.minValue=0;this.maxValue=0;this.level=0;if(this.parent)this.level=this.parent.level+1;this.depth=0;this.itemCount=1;this.index=0;this.root=this;this.isRoot=true;if(this.parent){this.root=this.parent.root;this.isRoot=false}this.options=this.options||this.root.options;this.ignored=false;Treemap.prototype.addData=function(data,opts){opts=opts||{};if(opts.data)this.data=data[opts.data];else this.data=data;if(typeof data==="number"){this.value=data}else{if(Array.isArray(opts.value)){if(typeof this.value!="object"){this.value={}}opts.value.forEach(function(k){this.value[k]=data[k]||0}.bind(this))}else{this.value=data[opts.value]||0}}var children=data;if(opts.children)children=data[opts.children];if(Array.isArray(children)){children.forEach(function(child){var t=new Treemap(this);this.items.push(t);t.addData(child,opts)}.bind(this));return true}return false};Treemap.prototype.addItem=function(data,keys,value){value=value||1;if(keys){var currItem=this;for(var j=0;j<keys.length;j++){var k=keys[j];var i=currItem.items.findIndex(function(el){return el.data==data[k]});if(i>=0){if(j==keys.length-1)currItem.items[i].add(value);currItem=currItem.items[i]}else{var newItem=new Treemap(currItem,data[k],value);currItem.items.push(newItem);currItem=newItem}}return currItem}else{var i=this.items.findIndex(function(el){return el.data==data});if(i>=0){this.items[i].add(value);return false}else{var newItem=new Treemap(this,data,value);this.items.push(newItem)}return newItem}};Treemap.prototype.setOptions=function(opts){Object.keys(opts).forEach(function(k){this.options[k]=opts[k]}.bind(this));this.items.forEach(function(el){el.setOptions(opts)})};Treemap.prototype.addTreemap=function(data,value){var t=new Treemap(this,data,value);this.items.push(t);return t};Treemap.prototype.add=function(val){if(typeof val==="object"){if(typeof this.value!="object"){this.value={}}Object.keys(val).forEach(function(k){var v=parseFloat(val[k]);v=isNaN(v)?0:v;if(this.value[k]){this.value[k]+=v}else{this.value[k]=v}}.bind(this))}else{var v=parseFloat(val);this.value+=isNaN(v)?0:v}};Treemap.prototype.sumUpValues=function(valueKey){if(Array.isArray(this.options.ignore)){if(this.options.ignore.indexOf(this.data)>=0){this.ignored=true}else{this.ignored=false}}if(this.items.length==0){if(this.ignored)return valueKey?{}:0}else{this.minValue=Number.MAX_VALUE;this.maxValue=0;this.depth=0;this.itemCount=1;this.value=valueKey?{}:0;if(this.ignored)return valueKey?{}:0;for(var i=0;i<this.items.length;i++){var sum=this.items[i].sumUpValues(valueKey);this.add(sum);var val=valueKey?sum[valueKey]:sum;this.minValue=Math.min(this.minValue,val);this.maxValue=Math.max(this.maxValue,val);this.depth=Math.max(this.depth,this.items[i].depth+1);this.itemCount+=this.items[i].itemCount}}return this.value};Treemap.prototype.calculate=function(valueKey){if(this.items.length==0)return;if(this==this.root){this.sumUpValues(valueKey)}if(this.ignored){this.x=-1e5;this.y=0;this.w=0;this.h=0;return}if(this.root.options.order=="sort"||this.root.options.order==undefined){this.items.sort(function(a,b){if(valueKey){if(a.value[valueKey]<b.value[valueKey])return 1;if(a.value[valueKey]>b.value[valueKey])return-1}else{if(a.value<b.value)return 1;if(a.value>b.value)return-1}return 0})}else if(this.root.options.order=="shuffle"){shuffleArray(this.items)}for(var i=0;i<this.items.length;i++){this.items[i].index=i}var restSum=valueKey?this.value[valueKey]:this.value;var pad=this.root.options.padding||0;var restX=this.x+pad;var restY=this.y+pad;var restW=this.w-pad*2;var restH=this.h-pad*2;if(this.root.options.order=="keep"){for(var i=0;i<this.items.length;i++){var a=restW;var b=restH;if(!this.items[i].isHorizontal){a=restH;b=restW}var rowSum=0;for(var j=i;j<this.items.length;j++){rowSum+=valueKey?this.items[j].value[valueKey]:this.items[j].value;if(this.items[j].wrap)break}var startI=i;var endI=j;var percentage=rowSum/restSum;var bLen=b*percentage;var aPos=restX;var bPos=restY;var aLen=restW;if(!this.items[i].isHorizontal){aPos=restY;bPos=restX;aLen=restH}for(var j=startI;j<=endI;j++){var val=valueKey?this.items[j].value[valueKey]:this.items[j].value;var aPart=aLen*val/rowSum;if(this.items[i].isHorizontal){this.items[j].x=aPos;this.items[j].y=bPos;this.items[j].w=aPart;this.items[j].h=bLen}else{this.items[j].x=bPos;this.items[j].y=aPos;this.items[j].w=bLen;this.items[j].h=aPart}this.items[j].w=Math.max(this.items[j].w,0);this.items[j].h=Math.max(this.items[j].h,0);this.items[j].calculate(valueKey);aPos+=aPart}if(this.items[i].isHorizontal){restY+=bLen;restH-=bLen}else{restX+=bLen;restW-=bLen}restSum-=rowSum;i=endI}}else{var actIndex=0;while(actIndex<this.items.length){var isHorizontal=true;var a=restW;var b=restH;if(this.root.options.direction!="horizontal"){if(restW>restH||this.root.options.direction=="vertical"){isHorizontal=false;a=restH;b=restW}}var rowSum=0;var rowCount=0;var avRelPrev=Number.MAX_VALUE;for(var i=actIndex;i<this.items.length;i++){rowSum+=valueKey?this.items[i].value[valueKey]:this.items[i].value;rowCount++;var percentage=rowSum/restSum;var bLen=b*percentage;var avRel=a/rowCount/bLen;this.items[i].isHorizontal=isHorizontal;if(avRel<1||i==this.items.length-1){if(avRelPrev<1/avRel){rowSum-=valueKey?this.items[i].value[valueKey]:this.items[i].value;rowCount--;bLen=b*rowSum/restSum;i--}this.items[i].wrap=true;var aPos=restX;var bPos=restY;var aLen=restW;if(!isHorizontal){aPos=restY;bPos=restX;aLen=restH}for(var j=actIndex;j<=i;j++){var val=valueKey?this.items[j].value[valueKey]:this.items[j].value;var aPart=aLen*val/rowSum;if(isHorizontal){this.items[j].x=aPos;this.items[j].y=bPos;this.items[j].w=aPart;this.items[j].h=bLen}else{this.items[j].x=bPos;this.items[j].y=aPos;this.items[j].w=bLen;this.items[j].h=aPart}this.items[j].w=Math.max(this.items[j].w,0);this.items[j].h=Math.max(this.items[j].h,0);this.items[j].calculate(valueKey);aPos+=aPart}if(isHorizontal){restY+=bLen;restH-=bLen}else{restX+=bLen;restW-=bLen}restSum-=rowSum;break}avRelPrev=avRel}actIndex=i+1}}};Treemap.prototype.draw=function(drawItemFunction){if(!drawItemFunction){console.warn("You have to supply a drawing function to see something.");return}if(!this.ignored){drawItemFunction(this);for(var i=0;i<this.items.length;i++){this.items[i].draw(drawItemFunction)}}}}function shuffleArray(array){for(var i=array.length-1;i>0;i--){var j=Math.floor(Math.random()*(i+1));var temp=array[i];array[i]=array[j];array[j]=temp}}if(!Array.isArray){Array.isArray=function(obj){return Object.prototype.toString.call(obj)=="[object Array]"}}module.exports=Treemap},{"./package.json":2}],2:[function(require,module,exports){module.exports={name:"Treemap.js",version:"0.4.0",description:"A javascript library for calculating a treemap.",license:"MIT",main:"index.js",scripts:{bundle:"browserify index.js --standalone Treemap -o dist/Treemap.js",devbundle:"npm run bundle && copyfiles -u 1 dist/Treemap.js examples/lib/",dist:"npm run bundle && browserify index.js --standalone Treemap | uglifyjs > dist/Treemap.min.js && copyfiles -u 1 dist/Treemap.js examples/lib/",documentation:"documentation readme index.js --section=Reference",onchange:"onchange 'index.js' -- npm run devbundle"},repository:{type:"git",url:"https://github.com/bohnacker/Treemap.js"},keywords:["dataviz","graph","treemap","recursive"],author:"Hartmut Bohnacker <mail@hartmut-bohnacker.de>",bugs:{url:"https://github.com/bohnacker/Treemap.js/issues"},homepage:"https://github.com/bohnacker/Treemap.js",devDependencies:{browserify:"^14.4.0",documentation:"^5.2.2","uglify-js":"^3.0.28",watch:"1.0.2",onchange:"6.0.0"}}},{}]},{},[1])(1)});
diff --git a/examples/lib/Treemap.js b/examples/lib/Treemap.js
index b0aad77..42be70d 100644
--- a/examples/lib/Treemap.js
+++ b/examples/lib/Treemap.js
@@ -6,21 +6,20 @@ var packageInfo = require('./package.json');
 
 /**
  * Creates a new empty Treemap with position (x, y), width and height. 
- * To specify drawing a bit more, you can give drawing options. `order` is "sort" or "shuffle".
- * `direction` is either "horizontal", "vertical" or "both". With 'ignore', you can easily switch on and off branches of the Treemap. 
+ * To specify drawing a bit more, you can give drawing options. See method `setOptions()` for more information.
  * Content may be added using `addData()` or `addItem()`.
  * 
  * @class Treemap
  * @constructor
- * @param  {Number} x         x position
- * @param  {Number} y         y position
- * @param  {Number} w         width
- * @param  {Number} h         height
- * @param  {Object} [options] drawing and sorting options {sort:true or false, direction:"horizontal", "vertical" or "both", ignore:["abc", "xyz"]}
- * @return {Treemap}          the new empty Treemap 
+ * @param  {Number} x         – X position
+ * @param  {Number} y         – Y position
+ * @param  {Number} w         – Width
+ * @param  {Number} h         – Height
+ * @param  {Object} [options] – Drawing options
+ * @return {Treemap}          – The new empty Treemap 
  */
 
-/**
+/*
  * @class Treemap
  * @ignore
  * @constructor (mainly for internal use)
@@ -30,7 +29,7 @@ var packageInfo = require('./package.json');
  * @return {Treemap}          the new Treemap that represents one item
  */
 
-/**
+/*
  * @class Treemap
  * @ignore
  * @constructor (mainly for internal use)
@@ -45,25 +44,25 @@ function Treemap() {
   this.items = [];
 
   /**
-   * x position of the rectangle.
+   * X position of the rectangle.
    * @property x
    * @type {Number}
    */
   this.x = 0;
   /**
-   * y position of the rectangle.
+   * Y position of the rectangle.
    * @property y
    * @type {Number}
    */
   this.y = 0;
   /**
-   * width of the rectangle.
+   * Width of the rectangle.
    * @property w
    * @type {Number}
    */
   this.w = 0;
   /**
-   * height of the rectangle.
+   * Height of the rectangle.
    * @property h
    * @type {Number}
    */
@@ -103,20 +102,20 @@ function Treemap() {
 
 
   /**
-   * the minimum value of the items in the items array
+   * The minimum value of the items in the items array
    * @property minValue
    * @type {Number}
    */
   this.minValue = 0;
   /**
-   * the maximum value of the items in the items array
+   * The maximum value of the items in the items array
    * @property maxValue
    * @type {Number}
    */
   this.maxValue = 0;
 
   /**
-   * level of the item; the root node has level 0
+   * Level of the item; the root node has level 0
    * @property level
    * @type {Number}
    */
@@ -124,21 +123,21 @@ function Treemap() {
   if (this.parent) this.level = this.parent.level + 1;
 
   /**
-   * the depth of the branch; end nodes have depth 0
+   * The depth of the branch; end nodes have depth 0
    * @property depth
    * @type {Number}
    */
   this.depth = 0;
 
   /**
-   * the number of items in the complete branch
+   * The number of items in the complete branch
    * @property itemCount
    * @type {Number}
    */
   this.itemCount = 1;
 
   /**
-   * index of the item in the sorted items array.
+   * Index of the item in the sorted items array.
    * @property index
    * @type {Number}
    */
@@ -266,7 +265,10 @@ function Treemap() {
 
 
   /**
-   * Set order, padding, ... for next calculation of the treemap.
+   * Set options for next calculation of the treemap. Currently there are the following options you might set:
+   * - order: 'sort', 'shuffle' or 'keep'. Default is 'sort'. Attention: don't use 'keep' for the first calculation of the treemap.
+   * - direction: 'both, 'horizontal' or 'vertical'. Default is 'both'.
+   * - padding: 0 (default) or any positive number.
    *
    * @method setOptions
    * @param {Object} options – Object in the form `{order: 'keep', padding: 4}`
@@ -661,7 +663,7 @@ module.exports = Treemap;
 },{"./package.json":2}],2:[function(require,module,exports){
 module.exports={
   "name": "Treemap.js",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "A javascript library for calculating a treemap.",
   "license": "MIT",
   "main": "index.js",
diff --git a/index.js b/index.js
index 92bf1fe..207ac5d 100644
--- a/index.js
+++ b/index.js
@@ -5,21 +5,20 @@ var packageInfo = require('./package.json');
 
 /**
  * Creates a new empty Treemap with position (x, y), width and height. 
- * To specify drawing a bit more, you can give drawing options. `order` is "sort" or "shuffle".
- * `direction` is either "horizontal", "vertical" or "both". With 'ignore', you can easily switch on and off branches of the Treemap. 
+ * To specify drawing a bit more, you can give drawing options. See method `setOptions()` for more information.
  * Content may be added using `addData()` or `addItem()`.
  * 
  * @class Treemap
  * @constructor
- * @param  {Number} x         x position
- * @param  {Number} y         y position
- * @param  {Number} w         width
- * @param  {Number} h         height
- * @param  {Object} [options] drawing and sorting options {sort:true or false, direction:"horizontal", "vertical" or "both", ignore:["abc", "xyz"]}
- * @return {Treemap}          the new empty Treemap 
+ * @param  {Number} x         – X position
+ * @param  {Number} y         – Y position
+ * @param  {Number} w         – Width
+ * @param  {Number} h         – Height
+ * @param  {Object} [options] – Drawing options
+ * @return {Treemap}          – The new empty Treemap 
  */
 
-/**
+/*
  * @class Treemap
  * @ignore
  * @constructor (mainly for internal use)
@@ -29,7 +28,7 @@ var packageInfo = require('./package.json');
  * @return {Treemap}          the new Treemap that represents one item
  */
 
-/**
+/*
  * @class Treemap
  * @ignore
  * @constructor (mainly for internal use)
@@ -44,25 +43,25 @@ function Treemap() {
   this.items = [];
 
   /**
-   * x position of the rectangle.
+   * X position of the rectangle.
    * @property x
    * @type {Number}
    */
   this.x = 0;
   /**
-   * y position of the rectangle.
+   * Y position of the rectangle.
    * @property y
    * @type {Number}
    */
   this.y = 0;
   /**
-   * width of the rectangle.
+   * Width of the rectangle.
    * @property w
    * @type {Number}
    */
   this.w = 0;
   /**
-   * height of the rectangle.
+   * Height of the rectangle.
    * @property h
    * @type {Number}
    */
@@ -102,20 +101,20 @@ function Treemap() {
 
 
   /**
-   * the minimum value of the items in the items array
+   * The minimum value of the items in the items array
    * @property minValue
    * @type {Number}
    */
   this.minValue = 0;
   /**
-   * the maximum value of the items in the items array
+   * The maximum value of the items in the items array
    * @property maxValue
    * @type {Number}
    */
   this.maxValue = 0;
 
   /**
-   * level of the item; the root node has level 0
+   * Level of the item; the root node has level 0
    * @property level
    * @type {Number}
    */
@@ -123,21 +122,21 @@ function Treemap() {
   if (this.parent) this.level = this.parent.level + 1;
 
   /**
-   * the depth of the branch; end nodes have depth 0
+   * The depth of the branch; end nodes have depth 0
    * @property depth
    * @type {Number}
    */
   this.depth = 0;
 
   /**
-   * the number of items in the complete branch
+   * The number of items in the complete branch
    * @property itemCount
    * @type {Number}
    */
   this.itemCount = 1;
 
   /**
-   * index of the item in the sorted items array.
+   * Index of the item in the sorted items array.
    * @property index
    * @type {Number}
    */
@@ -265,7 +264,10 @@ function Treemap() {
 
 
   /**
-   * Set order, padding, ... for next calculation of the treemap.
+   * Set options for next calculation of the treemap. Currently there are the following options you might set:
+   * - order: 'sort', 'shuffle' or 'keep'. Default is 'sort'. Attention: don't use 'keep' for the first calculation of the treemap.
+   * - direction: 'both, 'horizontal' or 'vertical'. Default is 'both'.
+   * - padding: 0 (default) or any positive number.
    *
    * @method setOptions
    * @param {Object} options – Object in the form `{order: 'keep', padding: 4}`
diff --git a/package.json b/package.json
index 9fb845f..7d1259c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "Treemap.js",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "A javascript library for calculating a treemap.",
   "license": "MIT",
   "main": "index.js",