feat:add lazy render mode

cypress/integration/menus/print.spec.ts

@@ -10,16 +10,16 @@ describe('菜单-打印', () => {
 
   it('打印', () => {
 
-    cy.getEditor().then((editor: Editor) => {
+    cy.getEditor().then(async (editor: Editor) => {
-      const imageList2 = editor.command.getImage()
+      const imageList2 = await editor.command.getImage()
       expect(imageList2.length).to.eq(2)
 
       editor.command.executeSelectAll()
 
       editor.command.executeBackspace()
 
-      cy.wait(200).then(() => {
+      cy.wait(200).then(async () => {
-        const imageList1 = editor.command.getImage()
+        const imageList1 = await editor.command.getImage()
         expect(imageList1.length).to.eq(1)
       })
     })

src/editor/core/command/Command.ts

@@ -381,7 +381,7 @@ export class Command {
     return Command.changeImageDisplay(element, display)
   }
 
-  public getImage(): string[] {
+  public getImage(): Promise<string[]> {
     return Command.getImage()
   }
 

src/editor/core/command/CommandAdapt.ts

@@ -327,7 +327,10 @@ export class CommandAdapt {
     selection.forEach(el => {
       el.color = payload
     })
-    this.draw.render({ isSetCursor: false })
+    this.draw.render({
+      isSetCursor: false,
+      isCompute: false
+    })
   }
 
   public highlight(payload: string) {
@@ -338,7 +341,10 @@ export class CommandAdapt {
     selection.forEach(el => {
       el.highlight = payload
     })
-    this.draw.render({ isSetCursor: false })
+    this.draw.render({
+      isSetCursor: false,
+      isCompute: false
+    })
   }
 
   public rowFlex(payload: RowFlex) {
@@ -1173,7 +1179,8 @@ export class CommandAdapt {
     options.watermark.font = payload.font || font
     this.draw.render({
       isSetCursor: false,
-      isSubmitHistory: false
+      isSubmitHistory: false,
+      isCompute: false
     })
   }
 
@@ -1185,7 +1192,8 @@ export class CommandAdapt {
       options.watermark = { ...defaultWatermarkOption }
       this.draw.render({
         isSetCursor: false,
-        isSubmitHistory: false
+        isSubmitHistory: false,
+        isCompute: false
       })
     }
   }
@@ -1229,7 +1237,9 @@ export class CommandAdapt {
     if (index === null) return
     this.draw.render({
       isSetCursor: false,
-      isSubmitHistory: false
+      isSubmitHistory: false,
+      isCompute: false,
+      isLazy: false
     })
   }
 
@@ -1238,7 +1248,9 @@ export class CommandAdapt {
     if (index === null) return
     this.draw.render({
       isSetCursor: false,
-      isSubmitHistory: false
+      isSubmitHistory: false,
+      isCompute: false,
+      isLazy: false
     })
   }
 
@@ -1352,12 +1364,13 @@ export class CommandAdapt {
     })
   }
 
-  public print() {
+  public async print() {
     const { width, height, scale } = this.options
     if (scale !== 1) {
       this.draw.setPageScale(1)
     }
-    printImageBase64(this.draw.getDataURL(), width, height)
+    const base64List = await this.draw.getDataURL()
+    printImageBase64(base64List, width, height)
     if (scale !== 1) {
       this.draw.setPageScale(scale)
     }
@@ -1393,7 +1406,7 @@ export class CommandAdapt {
     })
   }
 
-  public getImage(): string[] {
+  public getImage(): Promise<string[]> {
     return this.draw.getDataURL()
   }
 

src/editor/core/draw/Draw.ts

@@ -49,6 +49,7 @@ import { IMargin } from '../../interface/Margin'
 import { BlockParticle } from './particle/block/BlockParticle'
 import { EDITOR_COMPONENT, EDITOR_PREFIX } from '../../dataset/constant/Editor'
 import { I18n } from '../i18n/I18n'
+import { ImageObserver } from '../observer/ImageObserver'
 
 export class Draw {
 
@@ -96,6 +97,7 @@ export class Draw {
   private workerManager: WorkerManager
   private scrollObserver: ScrollObserver
   private selectionObserver: SelectionObserver
+  private imageObserver: ImageObserver
 
   private rowList: IRow[]
   private pageRowList: IRow[][]
@@ -103,6 +105,7 @@ export class Draw {
   private painterOptions: IPainterOptions | null
   private visiblePageNoList: number[]
   private intersectionPageNo: number
+  private lazyRenderIntersectionObserver: IntersectionObserver | null
 
   constructor(
     rootContainer: HTMLElement,
@@ -154,6 +157,7 @@ export class Draw {
 
     this.scrollObserver = new ScrollObserver(this)
     this.selectionObserver = new SelectionObserver()
+    this.imageObserver = new ImageObserver()
 
     this.canvasEvent = new CanvasEvent(this)
     this.cursor = new Cursor(this, this.canvasEvent)
@@ -169,6 +173,7 @@ export class Draw {
     this.painterOptions = null
     this.visiblePageNoList = []
     this.intersectionPageNo = 0
+    this.lazyRenderIntersectionObserver = null
 
     this.render({ isSetCursor: false })
   }
@@ -412,6 +417,10 @@ export class Draw {
     return this.workerManager
   }
 
+  public getImageObserver(): ImageObserver {
+    return this.imageObserver
+  }
+
   public getI18n(): I18n {
     return this.i18n
   }
@@ -420,7 +429,14 @@ export class Draw {
     return this.rowList.length
   }
 
-  public getDataURL(): string[] {
+  public async getDataURL(): Promise<string[]> {
+    this.render({
+      isLazy: false,
+      isCompute: false,
+      isSetCursor: false,
+      isSubmitHistory: false
+    })
+    await this.imageObserver.allSettled()
     return this.pageList.map(c => c.toDataURL())
   }
 
@@ -1096,11 +1112,35 @@ export class Draw {
     }
   }
 
+  private _lazyRender() {
+    const positionList = this.position.getOriginalPositionList()
+    this.lazyRenderIntersectionObserver?.disconnect()
+    this.lazyRenderIntersectionObserver = new IntersectionObserver((entries) => {
+      entries.forEach(entry => {
+        if (entry.isIntersecting) {
+          const index = Number((<HTMLCanvasElement>entry.target).dataset.index)
+          this._drawPage(positionList, this.pageRowList[index], index)
+        }
+      })
+    })
+    this.pageList.forEach(el => {
+      this.lazyRenderIntersectionObserver!.observe(el)
+    })
+  }
+
+  private _immediateRender() {
+    const positionList = this.position.getOriginalPositionList()
+    for (let i = 0; i < this.pageRowList.length; i++) {
+      this._drawPage(positionList, this.pageRowList[i], i)
+    }
+  }
+
   public render(payload?: IDrawOption) {
     const {
       isSubmitHistory = true,
       isSetCursor = true,
-      isCompute = true
+      isCompute = true,
+      isLazy = true
     } = payload || {}
     let { curIndex } = payload || {}
     const innerWidth = this.getInnerWidth()
@@ -1118,30 +1158,22 @@ export class Draw {
         this.search.compute(searchKeyword)
       }
     }
-    // 清除光标
+    // 清除光标等副作用
+    this.imageObserver.clearAll()
     this.cursor.recoveryCursor()
-    // 绘制元素
+    // 创建纸张
     const positionList = this.position.getOriginalPositionList()
-    const { visiblePageNoList } = this.scrollObserver.getPageVisibleInfo()
-    const minPageNo = visiblePageNoList[0]
-    const maxPageNo = visiblePageNoList[visiblePageNoList.length - 1]
     for (let i = 0; i < this.pageRowList.length; i++) {
       if (!this.pageList[i]) {
         this._createPage(i)
       }
-      // 优先绘制可见页
-      if (i >= minPageNo && i <= maxPageNo) {
-        this._drawPage(positionList, this.pageRowList[i], i)
     }
+    // 绘制元素
+    if (isLazy) {
+      this._lazyRender()
+    } else {
+      this._immediateRender()
     }
-    // 渲染后续不可见页
-    nextTick(() => {
-      for (let i = 0; i < this.pageRowList.length; i++) {
-        if (i < minPageNo || i > maxPageNo) {
-          this._drawPage(positionList, this.pageRowList[i], i)
-        }
-      }
-    })
     // 移除多余页
     nextTick(() => {
       const curPageCount = this.pageRowList.length
@@ -1187,9 +1219,8 @@ export class Draw {
         self.render({ curIndex, isSubmitHistory: false })
       })
     }
-
     // 信息变动回调
-    setTimeout(() => {
+    nextTick(() => {
       // 页面尺寸改变
       if (this.listener.pageSizeChange) {
         this.listener.pageSizeChange(this.pageRowList.length)

src/editor/core/draw/interactive/Search.ts

@@ -261,7 +261,11 @@ export class Search {
       const searchMatchIndexList = this.getSearchNavigateIndexList()
       if (searchMatchIndexList.includes(s)) {
         ctx.fillStyle = searchNavigateMatchColor
+        // 是否是第一个字符，则移动到可视范围
+        const preSearchMatch = this.searchMatchList[s - 1]
+        if (!preSearchMatch || preSearchMatch.groupId !== searchMatch.groupId) {
           this.searchNavigateScrollIntoView(position)
+        }
       } else {
         ctx.fillStyle = searchMatchColor
       }

src/editor/core/draw/particle/ImageParticle.ts

@@ -4,14 +4,20 @@ import { Draw } from '../Draw'
 
 export class ImageParticle {
 
+  private draw: Draw
   protected options: Required<IEditorOption>
   protected imageCache: Map<string, HTMLImageElement>
 
   constructor(draw: Draw) {
+    this.draw = draw
     this.options = draw.getOptions()
     this.imageCache = new Map()
   }
 
+  protected addImageObserver(promise: Promise<unknown>) {
+    this.draw.getImageObserver().add(promise)
+  }
+
   public render(ctx: CanvasRenderingContext2D, element: IElement, x: number, y: number) {
     const { scale } = this.options
     const width = element.width! * scale
@@ -20,12 +26,19 @@ export class ImageParticle {
       const img = this.imageCache.get(element.id!)!
       ctx.drawImage(img, x, y, width, height)
     } else {
+      const imageLoadPromise = new Promise((resolve, reject) => {
         const img = new Image()
         img.src = element.value
         img.onload = () => {
           ctx.drawImage(img, x, y, width, height)
           this.imageCache.set(element.id!, img)
+          resolve(element)
         }
+        img.onerror = (error) => {
+          reject(error)
+        }
+      })
+      this.addImageObserver(imageLoadPromise)
     }
   }
 

src/editor/core/draw/particle/latex/LaTexParticle.ts

@@ -21,12 +21,19 @@ export class LaTexParticle extends ImageParticle {
       const img = this.imageCache.get(element.value)!
       ctx.drawImage(img, x, y, width, height)
     } else {
+      const laTexLoadPromise = new Promise((resolve, reject) => {
         const img = new Image()
         img.src = element.laTexSVG!
         img.onload = () => {
           ctx.drawImage(img, x, y, width, height)
           this.imageCache.set(element.value, img)
+          resolve(element)
         }
+        img.onerror = (error) => {
+          reject(error)
+        }
+      })
+      this.addImageObserver(laTexLoadPromise)
     }
   }
 

src/editor/core/observer/ImageObserver.ts

@@ -0,0 +1,21 @@
+export class ImageObserver {
+
+  private promiseList: Promise<unknown>[]
+
+  constructor() {
+    this.promiseList = []
+  }
+
+  public add(payload: Promise<unknown>) {
+    this.promiseList.push(payload)
+  }
+
+  public clearAll() {
+    this.promiseList = []
+  }
+
+  public allSettled() {
+    return Promise.allSettled(this.promiseList)
+  }
+
+}

src/editor/interface/Draw.ts

@@ -6,6 +6,7 @@ export interface IDrawOption {
   isSetCursor?: boolean;
   isSubmitHistory?: boolean;
   isCompute?: boolean;
+  isLazy?: boolean;
 }
 
 export interface IDrawImagePayload {