feat: store handwriting

src/components/questionStructure/Task/variants/HandwritingTask/Canvas.tsx

@@ -1,5 +1,6 @@
 import { Excalidraw, MainMenu } from '@excalidraw/excalidraw'
 import { ClipboardData } from '@excalidraw/excalidraw/types/clipboard'
+import { ExcalidrawElement } from '@excalidraw/excalidraw/types/element/types'
 import { AppState, ExcalidrawImperativeAPI } from '@excalidraw/excalidraw/types/types'
 import { Box } from '@radix-ui/themes'
 import React, {
@@ -13,6 +14,7 @@ import React, {
 
 import { ConfirmDialog } from '../../../../ConfirmDialog'
 import useLiveUpdates from './live-updates.hook'
+import { HandwritingAnswer } from './types'
 
 const stopEvent = (e: SyntheticEvent | Event) => {
   e.preventDefault()
@@ -22,6 +24,10 @@ const stopEvent = (e: SyntheticEvent | Event) => {
 interface CanvasProps {
   username: string
   onAnswerChange: (value: string) => void
+  initialData: {
+    elements?: readonly ExcalidrawElement[]
+    appState?: AppState
+  }
 }
 
 // Excalidraw keyboard shortcuts we allow in the canvas:
@@ -44,11 +50,25 @@ const ALLOWED_TOOL_SHORTCUTS = [
   'Digit7', // pen
 ]
 
-const Canvas: React.FC<CanvasProps> = ({ username, onAnswerChange }) => {
-  const { updateStrokes } = useLiveUpdates(username, onAnswerChange)
+const Canvas: React.FC<CanvasProps> = ({ username, onAnswerChange, initialData }) => {
   const [excalidrawAPI, setExcalidrawAPI] = useState<ExcalidrawImperativeAPI | null>(null)
   const [clearDialogOpen, setClearDialogOpen] = useState(false)
 
+  const updateHandwriting = useCallback(
+    (latex: string) => {
+      const result: HandwritingAnswer = {
+        latex,
+        excalidraw: {
+          elements: excalidrawAPI?.getSceneElements() ?? [],
+          appState: excalidrawAPI?.getAppState(),
+        },
+      }
+      onAnswerChange(JSON.stringify(result))
+    },
+    [excalidrawAPI, onAnswerChange]
+  )
+  const { updateStrokes } = useLiveUpdates(username, updateHandwriting)
+
   const clearCanvas = useCallback(() => {
     updateStrokes({ elements: [] })
     excalidrawAPI?.updateScene({ elements: [] })
@@ -128,7 +148,10 @@ const Canvas: React.FC<CanvasProps> = ({ username, onAnswerChange }) => {
         UIOptions={{ tools: { image: false } }}
         gridModeEnabled
         excalidrawAPI={setExcalidrawAPI}
-        // initialData={excalidrawData}
+        initialData={{
+          ...initialData,
+          appState: { ...initialData.appState, collaborators: new Map() },
+        }}
         onPaste={pasteHandler}
       >
         <MainMenu>

src/components/questionStructure/Task/variants/HandwritingTask/HandwritingEditor.tsx

@@ -5,27 +5,33 @@ import React from 'react'
 import Markdown from '../../../../Markdown'
 import Canvas from './Canvas'
 import './handwritingEditor.css'
+import { HandwritingAnswer } from './types'
 
 interface HandwritingEditorProps {
   username: string
-  latex: string
+  answer?: HandwritingAnswer
   onAnswerChange: (value: string) => void
 }
 
 const HandwritingEditor: React.FC<HandwritingEditorProps> = ({
   username,
-  latex,
+  answer,
   onAnswerChange,
 }) => {
   return (
     <Flex direction="column" flexGrow="1" align="center" gap="3">
       <Card className="mathjax-card">
         <Box p="3">
-          <MathJax>{`\\( ${latex} \\)`}</MathJax>
+          <MathJax>{`\\( ${answer?.latex} \\)`}</MathJax>
         </Box>
       </Card>
       <Card className="excalidraw-canvas-card">
-        <Canvas username={username} onAnswerChange={onAnswerChange} />
+        <Canvas
+          username={username}
+          onAnswerChange={onAnswerChange}
+          // @ts-expect-error: this is not just initialData
+          initialData={answer?.excalidraw ?? {}}
+        />
       </Card>
     </Flex>
   )

src/components/questionStructure/Task/variants/HandwritingTask/ViewOnlyCanvas.tsx

@@ -1,31 +1,38 @@
 import { Excalidraw } from '@excalidraw/excalidraw'
-import {
-  ExcalidrawImperativeAPI,
-  ExcalidrawInitialDataState,
-} from '@excalidraw/excalidraw/types/types'
+import { ExcalidrawElement } from '@excalidraw/excalidraw/types/element/types'
+import { ExcalidrawImperativeAPI } from '@excalidraw/excalidraw/types/types'
 import { Box, Card } from '@radix-ui/themes'
 import React, { useEffect, useState } from 'react'
 
 interface ViewOnlyCanvasProps {
-  initialData: ExcalidrawInitialDataState
+  initialData: readonly ExcalidrawElement[]
 }
 
 export const ViewOnlyCanvas: React.FC<ViewOnlyCanvasProps> = ({ initialData }) => {
   const [excalidrawAPI, setExcalidrawAPI] = useState<ExcalidrawImperativeAPI | null>(null)
 
   useEffect(() => {
+    if (excalidrawAPI && initialData) {
+      excalidrawAPI.updateScene({
+        elements: initialData,
+      })
+    }
     setTimeout(() => {
       excalidrawAPI?.scrollToContent(undefined, {
         fitToContent: true,
       })
     })
-  }, [excalidrawAPI])
+  }, [excalidrawAPI, initialData])
 
-  return initialData && initialData.elements?.length ? (
+  return (
     <Card>
       <Box className="excalidraw-view-container excalidraw-box">
-        <Excalidraw excalidrawAPI={setExcalidrawAPI} viewModeEnabled initialData={initialData} />
+        <Excalidraw
+          excalidrawAPI={setExcalidrawAPI}
+          viewModeEnabled
+          initialData={{ elements: initialData }}
+        />
       </Box>
     </Card>
-  ) : null
+  )
 }

src/components/questionStructure/Task/variants/HandwritingTask/index.tsx

@@ -1,6 +1,7 @@
 import { Pencil2Icon } from '@radix-ui/react-icons'
 import { Button, Card, Dialog, Flex } from '@radix-ui/themes'
 import { MathJax } from 'better-react-mathjax'
+import { isEmpty } from 'lodash'
 import { FC } from 'react'
 import { useParams } from 'react-router-dom'
 
@@ -10,8 +11,9 @@ import { TaskBaseProps } from '../../types'
 import HandwritingEditor from './HandwritingEditor'
 import { ViewOnlyCanvas } from './ViewOnlyCanvas'
 import './index.scss'
+import { HandwritingAnswer } from './types'
 
-export interface HandwritingTaskProps extends TaskBaseProps<string> {
+export interface HandwritingTaskProps extends TaskBaseProps<HandwritingAnswer> {
   type: TaskType.PROCESSED_HANDWRITING
 }
 
@@ -25,7 +27,9 @@ export const HandwritingTask: FC<HandwritingTaskProps> = ({
   return (
     <Dialog.Root>
       <Dialog.Trigger>
-        <ViewOnlyCanvas initialData={{}} />
+        {!isEmpty(answer?.excalidraw?.elements) && (
+          <ViewOnlyCanvas initialData={answer!.excalidraw.elements} />
+        )}
       </Dialog.Trigger>
       <Flex gap="3" align="center">
         <Card className="latex-preview">
@@ -42,11 +46,7 @@ export const HandwritingTask: FC<HandwritingTaskProps> = ({
 
       <Dialog.Content className="excalidraw-dialog-content">
         <Flex direction="column" height="100%" gap="3">
-          <HandwritingEditor
-            latex={answer ?? ''}
-            onAnswerChange={onAnswerUpdate}
-            username={username}
-          />
+          <HandwritingEditor answer={answer} onAnswerChange={onAnswerUpdate} username={username} />
           <Flex justify="end">
             <Dialog.Close>
               <Button>Save LaTeX</Button>

src/components/questionStructure/Task/variants/HandwritingTask/types.ts

@@ -0,0 +1,10 @@
+import { ExcalidrawElement } from '@excalidraw/excalidraw/types/element/types'
+import { AppState } from '@excalidraw/excalidraw/types/types'
+
+export interface HandwritingAnswer {
+  excalidraw: {
+    elements: readonly ExcalidrawElement[]
+    appState?: Omit<AppState, 'offsetTop' | 'offsetLeft' | 'width' | 'height'>
+  }
+  latex: string
+}

src/utils/answers.ts

@@ -26,6 +26,8 @@ export function parseAnswer(answer: string, targetTaskType: TaskType) {
       return answer === '' ? answer : Number(answer)
     case TaskType.MULTIPLE_CHOICE_SELECT_SEVERAL:
       return answer === '' ? [] : answer.split(',')
+    case TaskType.PROCESSED_HANDWRITING:
+      return answer === '' ? { excalidraw: null, latex: '' } : JSON.parse(answer)
     default:
       return answer
   }