docs:add page header

docs/guide/command-get.md

@@ -20,7 +20,7 @@ const {
   margins: IMargin;
   header?: IHeader;
   watermark?: IWatermark;
-  data: IElement[];
+  data: IEditorData;
 } = instance.command.getValue()
 ```
 

docs/guide/option.md

@@ -5,7 +5,7 @@
 ```javascript
 import Editor from "@hufe921/canvas-editor"
 
-new Editor(container, [], {
+new Editor(container, IEditorData | IElement[], {
   // 配置项
 })
 ```
@@ -49,6 +49,7 @@ interface IEditorOption {
   headerTop?: number; // 页眉距离上边距。默认：50
   header?: IHeader; // 页眉信息。{data:string; color?:string; size?:number; font?:string;}
   paperDirection?: PaperDirection; // 纸张方向：纵向、横向
+  inactiveAlpha?: number; // 正文内容失焦时透明度。默认值：0.6
   watermark?: IWatermark; // 水印信息。{data:string; color?:string; opacity?:number; size?:number; font?:string;}
   control?: IControlOption; // 控件信息。 {placeholderColor?:string; bracketColor?:string; prefix?:string; postfix?:string;}
   checkbox?: ICheckboxOption; // 复选框信息。{width?:number; height?:number; gap?:number; lineWidth?:number; fillStyle?:string; fontStyle?: string;}

docs/guide/start.md

@@ -24,7 +24,7 @@
 
 ## 待开发
 
-- 可编辑页眉
+- 可编辑页眉（待边界修复）
 - 计算性能
 - 控件规则
 - 表格分页
@@ -44,6 +44,7 @@ npm i @hufe921/canvas-editor --save
 
 ## Step. 3: 实例化编辑器
 
+- 仅包含正文内容
 ```javascript
 import Editor from "@hufe921/canvas-editor"
 
@@ -54,6 +55,21 @@ new Editor(document.querySelector(".canvas-editor"), [
   ], {})
 ```
 
+- 包含正文及页眉内容
+```javascript
+import Editor from "@hufe921/canvas-editor"
+
+new Editor(document.querySelector(".canvas-editor"), {
+  header: [{
+    value: "Header",
+    rowFlex: RowFlex.CENTER
+  }],
+  main: [{
+    value: "Hello World"
+  }]
+}, {})
+```
+
 ## Step. 4: 配置编辑器
 
 详见下一节