feat:优化渲染性能

src/editor/core/draw/Draw.ts

@@ -20,6 +20,7 @@ import { Strikeout } from "./richtext/Strikeout"
 import { Underline } from "./richtext/Underline"
 import { ElementType } from "../../dataset/enum/Element"
 import { ImageParticle } from "./particle/ImageParticle"
+import { TextParticle } from "./particle/TextParticle"
 
 export class Draw {
 
@@ -40,8 +41,9 @@ export class Draw {
   private highlight: Highlight
   private historyManager: HistoryManager
   private imageParticle: ImageParticle
+  private textParticle: TextParticle
 
-  private rowCount: number
+  private rowList: IRow[]
   private painterStyle: IElementStyle | null
   private searchMatchList: number[][] | null
 
@@ -68,6 +70,7 @@ export class Draw {
     this.strikeout = new Strikeout(ctx, options)
     this.highlight = new Highlight(ctx, options)
     this.imageParticle = new ImageParticle(canvas, ctx, options, this)
+    this.textParticle = new TextParticle(ctx)
 
     const canvasEvent = new CanvasEvent(canvas, this)
     this.cursor = new Cursor(canvas, this, canvasEvent)
@@ -75,7 +78,7 @@ export class Draw {
     const globalEvent = new GlobalEvent(canvas, this, canvasEvent)
     globalEvent.register()
 
-    this.rowCount = 0
+    this.rowList = []
     this.painterStyle = null
     this.searchMatchList = null
 
@@ -115,7 +118,7 @@ export class Draw {
   }
 
   public getRowCount(): number {
-    return this.rowCount
+    return this.rowList.length
   }
 
   public getDataURL(): string {
@@ -155,25 +158,13 @@ export class Draw {
     return `${el.italic ? 'italic ' : ''}${el.bold ? 'bold ' : ''}${el.size || defaultSize}px ${el.font || defaultFont}`
   }
 
-  public render(payload?: IDrawOption) {
-    let { curIndex, isSubmitHistory = true, isSetCursor = true } = payload || {}
-    // 清除光标等副作用
-    this.cursor.recoveryCursor()
-    this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height)
-    this.position.setPositionList([])
-    const positionList = this.position.getPositionList()
-    // 基础信息
+  private computeRowList() {
     const { defaultSize } = this.options
     const canvasRect = this.canvas.getBoundingClientRect()
-    // 绘制背景
-    this.background.render(canvasRect)
-    // 绘制页边距
     const { width } = canvasRect
     const { margins, defaultRowMargin, defaultBasicRowMarginHeight } = this.options
     const leftTopPoint: [number, number] = [margins[3], margins[0]]
     const rightTopPoint: [number, number] = [width - margins[1], margins[0]]
-    this.margin.render(canvasRect)
-    // 计算行信息
     const rowList: IRow[] = []
     if (this.elementList.length) {
       rowList.push({
@@ -213,13 +204,17 @@ export class Draw {
         this.ctx.font = this.getFont(element)
         const fontMetrics = this.ctx.measureText(element.value)
         metrics.width = fontMetrics.width
-        metrics.boundingBoxAscent = i === 0 ? defaultSize : fontMetrics.actualBoundingBoxAscent
+        metrics.boundingBoxAscent = element.value === ZERO ? defaultSize : fontMetrics.actualBoundingBoxAscent
         metrics.boundingBoxDescent = fontMetrics.actualBoundingBoxDescent
       }
       const ascent = metrics.boundingBoxAscent + rowMargin
       const descent = metrics.boundingBoxDescent + rowMargin
       const height = ascent + descent
-      const rowElement: IRowElement = { ...element, metrics }
+      const rowElement: IRowElement = {
+        ...element,
+        metrics,
+        style: this.ctx.font
+      }
       // 超过限定宽度
       if (curRow.width + metrics.width > innerWidth || (i !== 0 && element.value === ZERO)) {
         rowList.push({
@@ -243,12 +238,39 @@ export class Draw {
       }
       this.ctx.restore()
     }
+    this.rowList = rowList
+  }
+
+  public render(payload?: IDrawOption) {
+    let {
+      curIndex,
+      isSubmitHistory = true,
+      isSetCursor = true,
+      isComputeRowList = true
+    } = payload || {}
+    // 清除光标等副作用
+    this.cursor.recoveryCursor()
+    this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height)
+    this.position.setPositionList([])
+    const positionList = this.position.getPositionList()
+    // 基础信息
+    const canvasRect = this.canvas.getBoundingClientRect()
+    // 绘制背景
+    this.background.render(canvasRect)
+    // 绘制页边距
+    const { margins } = this.options
+    const leftTopPoint: [number, number] = [margins[3], margins[0]]
+    this.margin.render(canvasRect)
+    // 计算行信息
+    if (isComputeRowList) {
+      this.computeRowList()
+    }
     // 渲染元素
     let x = leftTopPoint[0]
     let y = leftTopPoint[1]
     let index = 0
-    for (let i = 0; i < rowList.length; i++) {
-      const curRow = rowList[i]
+    for (let i = 0; i < this.rowList.length; i++) {
+      const curRow = this.rowList[i]
       // 计算行偏移量（行居左、居中、居右）
       if (curRow.rowFlex && curRow.rowFlex !== RowFlex.LEFT) {
         const canvasInnerWidth = this.canvas.width - margins[1] - margins[3]
@@ -259,15 +281,8 @@ export class Draw {
         }
       }
       for (let j = 0; j < curRow.elementList.length; j++) {
-        this.ctx.save()
         const element = curRow.elementList[j]
         const metrics = element.metrics
-        if (!element.type || element.type === ElementType.TEXT) {
-          this.ctx.font = this.getFont(element)
-          if (element.color) {
-            this.ctx.fillStyle = element.color
-          }
-        }
         const offsetY = element.type === ElementType.IMAGE
           ? curRow.ascent - element.height!
           : curRow.ascent
@@ -301,9 +316,10 @@ export class Draw {
         }
         // 元素绘制
         if (element.type === ElementType.IMAGE) {
+          this.textParticle.complete()
           this.imageParticle.render(element, x, y + offsetY)
         } else {
-          this.ctx.fillText(element.value, x, y + offsetY)
+          this.textParticle.record(element, x, y + offsetY)
         }
         // 选区绘制
         const { startIndex, endIndex } = this.range.getRange()
@@ -312,11 +328,12 @@ export class Draw {
         }
         index++
         x += metrics.width
-        this.ctx.restore()
       }
+      this.textParticle.complete()
       x = leftTopPoint[0]
       y += curRow.height
     }
+
     // 搜索匹配绘制
     if (this.searchMatchList) {
       this.search.render()
@@ -336,9 +353,12 @@ export class Draw {
       const height = Math.ceil(leftBottom[1] + (leftBottom[1] - leftTop[1]) + margins[2])
       this.canvas.height = height
       this.canvas.style.height = `${height}px`
-      this.render({ curIndex, isSubmitHistory: false })
+      this.render({
+        curIndex,
+        isSubmitHistory: false,
+        isComputeRowList: false
+      })
     }
-    this.rowCount = rowList.length
     // 历史记录用于undo、redo
     if (isSubmitHistory) {
       const self = this

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

@@ -0,0 +1,59 @@
+import { IRowElement } from "../../../interface/Row"
+
+export class TextParticle {
+
+  private ctx: CanvasRenderingContext2D
+  private curX: number
+  private curY: number
+  private text: string
+  private curStyle: string
+  private curColor?: string
+
+  constructor(ctx: CanvasRenderingContext2D) {
+    this.ctx = ctx
+    this.curX = -1
+    this.curY = -1
+    this.text = ''
+    this.curStyle = ''
+  }
+
+  public complete() {
+    this.render()
+    this.text = ''
+  }
+
+  public record(element: IRowElement, x: number, y: number) {
+    // 主动完成的重设起始点
+    if (!this.text) {
+      this.setCurXY(x, y)
+    }
+    // 样式发生改变
+    if (
+      (this.curStyle && element.style !== this.curStyle) ||
+      (element.color !== this.curColor)
+    ) {
+      this.complete()
+      this.setCurXY(x, y)
+    }
+    this.text += element.value
+    this.curStyle = element.style
+    this.curColor = element.color
+  }
+
+  private setCurXY(x: number, y: number) {
+    this.curX = x
+    this.curY = y
+  }
+
+  private render() {
+    if (!this.text || !~this.curX || !~this.curX) return
+    this.ctx.save()
+    this.ctx.font = this.curStyle
+    if (this.curColor) {
+      this.ctx.fillStyle = this.curColor
+    }
+    this.ctx.fillText(this.text, this.curX, this.curY)
+    this.ctx.restore()
+  }
+
+}

src/editor/core/event/CanvasEvent.ts

@@ -82,7 +82,8 @@ export class CanvasEvent {
     // 绘制
     this.draw.render({
       isSubmitHistory: false,
-      isSetCursor: false
+      isSetCursor: false,
+      isComputeRowList: false
     })
   }
 
@@ -95,7 +96,12 @@ export class CanvasEvent {
     const isDirectHitImage = isDirectHit && isImage
     if (~index) {
       this.range.setRange(index, index)
-      this.draw.render({ curIndex: index, isSubmitHistory: false, isSetCursor: !isDirectHitImage })
+      this.draw.render({
+        curIndex: index,
+        isSubmitHistory: false,
+        isSetCursor: !isDirectHitImage,
+        isComputeRowList: false
+      })
     }
     // 图片尺寸拖拽组件
     this.imageParticle.clearResizer()
@@ -151,13 +157,21 @@ export class CanvasEvent {
       if (index > 0) {
         const curIndex = index - 1
         this.range.setRange(curIndex, curIndex)
-        this.draw.render({ curIndex, isSubmitHistory: false })
+        this.draw.render({
+          curIndex,
+          isSubmitHistory: false,
+          isComputeRowList: false
+        })
       }
     } else if (evt.key === KeyMap.Right) {
       if (index < position.length - 1) {
         const curIndex = index + 1
         this.range.setRange(curIndex, curIndex)
-        this.draw.render({ curIndex, isSubmitHistory: false })
+        this.draw.render({
+          curIndex,
+          isSubmitHistory: false,
+          isComputeRowList: false
+        })
       }
     } else if (evt.key === KeyMap.Up || evt.key === KeyMap.Down) {
       const { rowNo, index, coordinate: { leftTop, rightTop } } = cursorPosition
@@ -194,7 +208,11 @@ export class CanvasEvent {
         }
         const curIndex = maxIndex
         this.range.setRange(curIndex, curIndex)
-        this.draw.render({ curIndex, isSubmitHistory: false })
+        this.draw.render({
+          curIndex,
+          isSubmitHistory: false,
+          isComputeRowList: false
+        })
       }
     } else if (evt.ctrlKey && evt.key === KeyMap.Z) {
       this.historyManager.undo()
@@ -216,7 +234,11 @@ export class CanvasEvent {
       }
     } else if (evt.ctrlKey && evt.key === KeyMap.A) {
       this.range.setRange(0, position.length - 1)
-      this.draw.render({ isSubmitHistory: false, isSetCursor: false })
+      this.draw.render({
+        isSubmitHistory: false,
+        isSetCursor: false,
+        isComputeRowList: false
+      })
     }
   }
 
@@ -233,10 +255,16 @@ export class CanvasEvent {
     const inputData: IElement[] = data.split('').map(value => ({
       value
     }))
+    let start = 0
     if (isCollspace) {
-      elementList.splice(index + 1, 0, ...inputData)
+      start = index + 1
     } else {
-      elementList.splice(startIndex + 1, endIndex - startIndex, ...inputData)
+      start = startIndex + 1
+      elementList.splice(startIndex + 1, endIndex - startIndex)
+    }
+    // 禁止直接使用解构存在性能问题
+    for (let i = 0; i < inputData.length; i++) {
+      elementList.splice(start + i, 0, inputData[i])
     }
     const curIndex = (isCollspace ? index : startIndex) + inputData.length
     this.range.setRange(curIndex, curIndex)

src/editor/index.ts

@@ -47,12 +47,15 @@ export default class Editor {
         value: ZERO
       })
     }
-    elementList.forEach(el => {
+    for (let i = 0; i < elementList.length; i++) {
+      const el = elementList[i]
       if (el.value === '\n') {
         el.value = ZERO
       }
-      el.id = getUUID()
-    })
+      if (el.type === ElementType.IMAGE) {
+        el.id = getUUID()
+      }
+    }
     // 监听
     this.listener = new Listener()
     // 启动

src/editor/interface/Draw.ts

@@ -2,6 +2,7 @@ export interface IDrawOption {
   curIndex?: number;
   isSetCursor?: boolean;
   isSubmitHistory?: boolean;
+  isComputeRowList?: boolean;
 }
 
 export interface IDrawImagePayload {

src/editor/interface/Row.ts

@@ -2,7 +2,8 @@ import { RowFlex } from "../dataset/enum/Row"
 import { IElement, IElementMetrics } from "./Element"
 
 export type IRowElement = IElement & {
-  metrics: IElementMetrics
+  metrics: IElementMetrics;
+  style: string;
 }
 
 export interface IRow {