feat(doc): add doc for apache/echarts#16904

Author: Ovilia

en/option/series/graph.md

@@ -31,15 +31,15 @@ Graph is a diagram to represent [nodes](~series-graph.nodes) and the [links](~se
     calendar = true
 ) }}
 
-## center(Array)
+## center(Array.<number|string>)
 
 <ExampleUIControlVector default="0,0" dims="x,y" />
 
-Center of current view-port.
+Center of current view-port. It can be an arrary containing two `number`s in pixels or `string`s in percentage relative to the container width/height.
 
 Example:
 ```ts
-center: [115.97, 29.71]
+center: [115.97, '30%']
 ```
 
 ## zoom(number) = 1
@@ -698,4 +698,3 @@ Label position, options：
     prefix = "####",
     defaultShow = true
 ) }}
-

en/option/series/map.md

@@ -24,6 +24,15 @@ Series of same [map type](~series-map.map) will show in one map. At this point,
     inMap = true
 ) }}
 
+## center(Array.<number|string>)
+
+Center of current view-port. It can be an arrary containing two `number`s in pixels or `string`s in percentage relative to the container width/height.
+
+Example:
+```ts
+center: [115.97, '30%']
+```
+
 ## geoIndex(number) = null
 
 In default case, map series create exclusive `geo` component for themselves. But `geoIndex` can be used to specify an outer [geo component](~geo), which can be shared with other series like [pie](~series-pie). Moreover, the region color of the outer [geo component](~geo) can be controlled by the map series (via [visualMap](~visualMap)).
@@ -211,4 +220,3 @@ The color of the map area.
 {{ use: partial-label-line(
     prefix = '####'
 ) }}
-

en/option/series/tree.md

@@ -35,13 +35,13 @@ The tree diagram is mainly used to visualize the tree data structure, which is a
     defaultHeight = 'null'
 ) }}
 
-## center(Array)
+## center(Array.<number|string>)
 
-Center of current view-port.
+Center of current view-port. It can be an arrary containing two `number`s in pixels or `string`s in percentage relative to the container width/height.
 
 Example:
 ```ts
-center: [115.97, 29.71]
+center: [115.97, '30%']
 ```
 
 ## zoom(number) = 1
@@ -471,4 +471,3 @@ Defines the style of the tree edge.
     prefix = ${prefix},
     state = ${state}
 ) }}
-

zh/option/series/graph.md

@@ -40,15 +40,15 @@ option.series[0].data.forEach(function (item) {
     calendar = true
 ) }}
 
-## center(Array)
+## center(Array.<number|string>)
 
 <ExampleUIControlVector default="0,0" dims="x,y" />
 
-当前视角的中心点
+当前视角的中心点。可以是包含两个 `number` 类型（表示像素值）或 `string` 类型（表示相对容器的百分比）的数组。
 
 例如：
 ```ts
-center: [115.97, 29.71]
+center: [115.97, '30%']
 ```
 
 ## zoom(number) = 1
@@ -706,4 +706,3 @@ links: [{
     prefix = "####",
     defaultShow = true
 ) }}
-

zh/option/series/map.md

@@ -26,6 +26,15 @@
     inMap = true
 ) }}
 
+## center(Array.<number|string>)
+
+当前视角的中心点。可以是包含两个 `number` 类型（表示像素值）或 `string` 类型（表示相对容器的百分比）的数组。
+
+例如：
+```ts
+center: [115.97, '30%']
+```
+
 ## geoIndex(number) = null
 
 默认情况下，map series 会自己生成内部专用的 `geo` 组件。但是也可以用这个 `geoIndex` 指定一个 [geo](~geo) 组件。这样的话，map 和 其他 series（例如散点图）就可以共享一个 [geo](~geo) 组件了。并且，[geo](~geo) 组件的颜色也可以被这个 map series 控制，从而用 [visualMap](~visualMap) 来更改。
@@ -208,4 +217,3 @@
 {{ use: partial-label-line(
     prefix = '####'
 ) }}
-

zh/option/series/tree.md

@@ -78,13 +78,13 @@ const option = {
     defaultHeight = 'null'
 ) }}
 
-## center(Array)
+## center(Array.<number|string>)
 
-当前视角的中心点
+当前视角的中心点。可以是包含两个 `number` 类型（表示像素值）或 `string` 类型（表示相对容器的百分比）的数组。
 
 例如：
 ```ts
-center: [115.97, 29.71]
+center: [115.97, '30%']
 ```
 
 ## zoom(number) = 1
@@ -514,4 +514,3 @@ center: [115.97, 29.71]
     prefix = ${prefix},
     state = ${state}
 ) }}
-