力导向默认关闭 worker, 布局比例调整
diff --git a/doc/doc.html b/doc/doc.html
index a9feee8..1bd92f1 100644
--- a/doc/doc.html
+++ b/doc/doc.html
@@ -2870,7 +2870,7 @@
                         </tr>

                         <tr>

                             <td> <b>{boolean}</b> useWorker </td>

-                            <td> true </td>

+                            <td> false </td>

                             <td> 是否在浏览器支持 web worker 的时候把布局计算放入 web worker 中 </td>

                         </tr>

                         <tr>

diff --git a/doc/example/force1.html b/doc/example/force1.html
index d8043b4..7571bfc 100644
--- a/doc/example/force1.html
+++ b/doc/example/force1.html
@@ -105,7 +105,7 @@
             minRadius : 15,

             maxRadius : 25,

             gravity: 1.1,

-            scaling: 1.2,

+            scaling: 1.1,

             linkSymbol: 'arrow',

             nodes:[

                 {category:0, name: '乔布斯', value : 10},

diff --git a/doc/example/webkit-dep.html b/doc/example/webkit-dep.html
index 7ffd5dc..e50a97d 100644
--- a/doc/example/webkit-dep.html
+++ b/doc/example/webkit-dep.html
@@ -77,6 +77,7 @@
             webkitDepData.scaling = 1.1;
             webkitDepData.steps = 20;
             webkitDepData.large = true;
+            webkitDepData.useWorker = true;
             webkitDepData.coolDown = 0.995;
             webkitDepData.itemStyle = {
                 normal : {
diff --git a/src/chart/force.js b/src/chart/force.js
index 08e07da..b259079 100644
--- a/src/chart/force.js
+++ b/src/chart/force.js
@@ -363,8 +363,8 @@
 

             var config = {

                 center: center,

-                width: width,

-                height: height,

+                width: serie.ratioScaling ? width : size,

+                height: serie.ratioScaling ? height : size,

                 scaling: serie.scaling || 1.0,

                 gravity: serie.gravity || 1.0,

                 barnesHutOptimize: serie.large

diff --git a/src/chart/forceLayoutWorker.js b/src/chart/forceLayoutWorker.js
index 9e67663..fae9aeb 100644
--- a/src/chart/forceLayoutWorker.js
+++ b/src/chart/forceLayoutWorker.js
@@ -642,13 +642,13 @@
             // vec2.sub(v, this._rootRegion.centerOfMass, node.position);
             // vec2.negate(v, node.position);
             vec2.sub(v, this.center, node.position);
-            // if (this.width > this.height) {
-            //     // Stronger gravity on y axis
-            //     v[1] *= this.width / this.height;
-            // } else {
-            //     // Stronger gravity on x axis
-            //     v[0] *= this.height / this.width;
-            // }
+            if (this.width > this.height) {
+                // Stronger gravity on y axis
+                v[1] *= this.width / this.height;
+            } else {
+                // Stronger gravity on x axis
+                v[0] *= this.height / this.width;
+            }
             var d = vec2.len(v) / 100;
             
             if (this.strongGravity) {
diff --git a/src/config.js b/src/config.js
index ed89f45..6240dce 100644
--- a/src/config.js
+++ b/src/config.js
@@ -796,13 +796,16 @@
             minRadius : 10,

             maxRadius : 20,

 

+            // 是否根据屏幕比例拉伸

+            ratioScaling: false,

+

             // 在 500+ 顶点的图上建议设置 large 为 true, 会使用 Barnes-Hut simulation

             // 同时开启 useWorker 并且把 steps 值调大

             // 关于Barnes-Hut simulation: http://en.wikipedia.org/wiki/Barnes–Hut_simulation

             large: false,

 

-            // 为 false 的时候强制关闭 web worker

-            useWorker: true,

+            // 是否在浏览器支持 worker 的时候使用 web worker

+            useWorker: false,

             // 每一帧 force 迭代的次数,仅在启用webworker的情况下有用

             steps: 1,