feat:optimize rich text render performance

src/editor/core/draw/Draw.ts

@@ -767,6 +767,13 @@ export class Draw {
     return rowList
   }
 
+  private _drawRichText(ctx: CanvasRenderingContext2D) {
+    this.underline.render(ctx)
+    this.strikeout.render(ctx)
+    this.highlight.render(ctx)
+    this.textParticle.complete()
+  }
+
   private _drawRow(ctx: CanvasRenderingContext2D, payload: IDrawRowPayload): IDrawRowResult {
     const { positionList, rowList, pageNo, startX, startY, startIndex, innerWidth } = payload
     const { scale, tdPadding } = this.options
@@ -823,10 +830,10 @@ export class Draw {
         positionList.push(positionItem)
         // 元素绘制
         if (element.type === ElementType.IMAGE) {
-          this.textParticle.complete()
+          this._drawRichText(ctx)
           this.imageParticle.render(ctx, element, x, y + offsetY)
         } else if (element.type === ElementType.LATEX) {
-          this.textParticle.complete()
+          this._drawRichText(ctx)
           this.laTexParticle.render(ctx, element, x, y + offsetY)
         } else if (element.type === ElementType.TABLE) {
           if (isCrossRowCol) {
@@ -836,16 +843,16 @@ export class Draw {
           }
           this.tableParticle.render(ctx, element, x, y)
         } else if (element.type === ElementType.HYPERLINK) {
-          this.textParticle.complete()
+          this._drawRichText(ctx)
           this.hyperlinkParticle.render(ctx, element, x, y + offsetY)
         } else if (element.type === ElementType.DATE) {
-          this.textParticle.complete()
+          this._drawRichText(ctx)
           this.dateParticle.render(ctx, element, x, y + offsetY)
         } else if (element.type === ElementType.SUPERSCRIPT) {
-          this.textParticle.complete()
+          this._drawRichText(ctx)
           this.superscriptParticle.render(ctx, element, x, y + offsetY)
         } else if (element.type === ElementType.SUBSCRIPT) {
-          this.textParticle.complete()
+          this._drawRichText(ctx)
           this.subscriptParticle.render(ctx, element, x, y + offsetY)
         } else if (element.type === ElementType.SEPARATOR) {
           this.separatorParticle.render(ctx, element, x, y)
@@ -857,24 +864,24 @@ export class Draw {
           element.type === ElementType.CHECKBOX ||
           element.controlComponent === ControlComponent.CHECKBOX
         ) {
-          this.textParticle.complete()
+          this._drawRichText(ctx)
           this.checkboxParticle.render(ctx, element, x, y + offsetY)
         } else if (element.type === ElementType.TAB) {
-          this.textParticle.complete()
+          this._drawRichText(ctx)
         } else {
           this.textParticle.record(ctx, element, x, y + offsetY)
         }
-        // 下划线绘制
+        // 下划线记录
         if (element.underline) {
-          this.underline.render(ctx, element.color!, x, y + curRow.height, metrics.width)
+          this.underline.recordFillInfo(ctx, x, y + curRow.height, metrics.width, 0, element.color)
         }
-        // 删除线绘制
+        // 删除线记录
         if (element.strikeout) {
-          this.strikeout.render(ctx, x, y + curRow.height / 2, metrics.width)
+          this.strikeout.recordFillInfo(ctx, x, y + curRow.height / 2, metrics.width)
         }
-        // 元素高亮
+        // 元素高亮记录
         if (element.highlight) {
-          this.highlight.render(ctx, element.highlight, x, y, metrics.width, curRow.height)
+          this.highlight.recordFillInfo(ctx, x, y, metrics.width, curRow.height, element.highlight)
         }
         // 选区记录
         const { startIndex, endIndex } = this.range.getRange()
@@ -937,7 +944,8 @@ export class Draw {
           y = tablePreY
         }
       }
-      this.textParticle.complete()
+      // 绘制富文本及文字
+      this._drawRichText(ctx)
       // 绘制选区
       if (rangeRecord.width && rangeRecord.height) {
         const { x, y, width, height } = rangeRecord

src/editor/core/draw/richtext/AbstractRichText.ts

@@ -0,0 +1,41 @@
+import { IElementFillRect } from '../../../interface/Element'
+
+export abstract class AbstractRichText {
+  public fillRect: IElementFillRect
+  public fillColor?: string
+
+  constructor() {
+    this.fillRect = this.clearFillInfo()
+  }
+
+  public clearFillInfo() {
+    this.fillColor = undefined
+    return this.fillRect = {
+      x: 0,
+      y: 0,
+      width: 0,
+      height: 0
+    }
+  }
+
+  public recordFillInfo(ctx: CanvasRenderingContext2D, x: number, y: number, width: number, height?: number, color?: string) {
+    const isFirstRecord = !this.fillRect.width
+    if (!isFirstRecord && this.fillColor && this.fillColor !== color) {
+      this.render(ctx)
+      this.clearFillInfo()
+      return
+    }
+    if (isFirstRecord) {
+      this.fillRect.x = x
+      this.fillRect.y = y
+    }
+    if (height && this.fillRect.height < height) {
+      this.fillRect.height = height
+    }
+    this.fillRect.width += width
+    this.fillColor = color
+  }
+
+  public abstract render(ctx: CanvasRenderingContext2D): void
+
+}

src/editor/core/draw/richtext/Highlight.ts

@@ -1,21 +1,26 @@
+import { AbstractRichText } from './AbstractRichText'
 import { IEditorOption } from '../../../interface/Editor'
 import { Draw } from '../Draw'
 
-export class Highlight {
+export class Highlight extends AbstractRichText {
 
   private options: Required<IEditorOption>
 
   constructor(draw: Draw) {
+    super()
     this.options = draw.getOptions()
   }
 
-  public render(ctx: CanvasRenderingContext2D, color: string, x: number, y: number, width: number, height: number) {
+  public render(ctx: CanvasRenderingContext2D) {
+    if (!this.fillRect.width) return
     const { highlightAlpha } = this.options
+    const { x, y, width, height } = this.fillRect
     ctx.save()
     ctx.globalAlpha = highlightAlpha
-    ctx.fillStyle = color
+    ctx.fillStyle = this.fillColor!
     ctx.fillRect(x, y, width, height)
     ctx.restore()
+    this.clearFillInfo()
   }
 
 }

src/editor/core/draw/richtext/Strikeout.ts

@@ -1,23 +1,29 @@
+import { AbstractRichText } from './AbstractRichText'
 import { IEditorOption } from '../../../interface/Editor'
 import { Draw } from '../Draw'
 
-export class Strikeout {
+export class Strikeout extends AbstractRichText {
 
   private options: Required<IEditorOption>
 
   constructor(draw: Draw) {
+    super()
     this.options = draw.getOptions()
   }
 
-  public render(ctx: CanvasRenderingContext2D, x: number, y: number, width: number) {
+  public render(ctx: CanvasRenderingContext2D) {
+    if (!this.fillRect.width) return
     const { strikeoutColor } = this.options
+    const { x, y, width } = this.fillRect
     ctx.save()
     ctx.strokeStyle = strikeoutColor
+    const adjustY = y + 0.5 // 从1处渲染，避免线宽度等于3
     ctx.beginPath()
-    ctx.moveTo(x, y)
-    ctx.lineTo(x + width, y)
+    ctx.moveTo(x, adjustY)
+    ctx.lineTo(x + width, adjustY)
     ctx.stroke()
     ctx.restore()
+    this.clearFillInfo()
   }
 
 }

src/editor/core/draw/richtext/Underline.ts

@@ -1,23 +1,29 @@
+import { AbstractRichText } from './AbstractRichText'
 import { IEditorOption } from '../../../interface/Editor'
 import { Draw } from '../Draw'
 
-export class Underline {
+export class Underline extends AbstractRichText {
 
   private options: Required<IEditorOption>
 
   constructor(draw: Draw) {
+    super()
     this.options = draw.getOptions()
   }
 
-  public render(ctx: CanvasRenderingContext2D, color: string, x: number, y: number, width: number) {
+  public render(ctx: CanvasRenderingContext2D) {
+    if (!this.fillRect.width) return
     const { underlineColor } = this.options
+    const { x, y, width } = this.fillRect
     ctx.save()
-    ctx.strokeStyle = color || underlineColor
+    ctx.strokeStyle = this.fillColor || underlineColor
+    const adjustY = y + 0.5 // 从1处渲染，避免线宽度等于3
     ctx.beginPath()
-    ctx.moveTo(x, y)
-    ctx.lineTo(x + width, y)
+    ctx.moveTo(x, adjustY)
+    ctx.lineTo(x + width, adjustY)
     ctx.stroke()
     ctx.restore()
+    this.clearFillInfo()
   }
 
 }