feat: paper background color option

src/editor/core/draw/frame/Background.ts

@@ -1,17 +1,22 @@
+import { DeepRequired } from '../../../interface/Common'
+import { IEditorOption } from '../../../interface/Editor'
 import { Draw } from '../Draw'
 
 export class Background {
   private draw: Draw
+  private options: DeepRequired<IEditorOption>
 
   constructor(draw: Draw) {
     this.draw = draw
+    this.options = draw.getOptions()
   }
 
   public render(ctx: CanvasRenderingContext2D, pageNo: number) {
+    const { backgroundColor } = this.options
     const width = this.draw.getCanvasWidth(pageNo)
     const height = this.draw.getCanvasHeight(pageNo)
     ctx.save()
-    ctx.fillStyle = '#ffffff'
+    ctx.fillStyle = backgroundColor
     ctx.fillRect(0, 0, width, height)
     ctx.restore()
   }

src/editor/index.ts

@@ -140,6 +140,7 @@ export default class Editor {
       height: 1123,
       scale: 1,
       pageGap: 20,
+      backgroundColor: '#FFFFFF',
       underlineColor: '#000000',
       strikeoutColor: '#FF0000',
       rangeAlpha: 0.6,

src/editor/interface/Editor.ts

@@ -39,6 +39,7 @@ export interface IEditorOption {
   height?: number
   scale?: number
   pageGap?: number
+  backgroundColor?: string
   underlineColor?: string
   strikeoutColor?: string
   rangeColor?: string