spike(exam): tldraw 3.6.1 custom shape/tool proof (S4-9.spike)

Recovered from cc-worker WIP left uncommitted in the dev-centre clone (card
t_fbe15cad, marked done but never committed/pushed). Adds ExamMarkerSpikePage +
exam-marker-spike util/test proving custom box shape + tool + hit-testing on
tldraw 3.6.1. Isolated on this branch (NOT master); reference for S4-9a.
Includes incidental edits to S4-8 files made during the spike — review before reuse.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/AppRoutes.admin.test.tsx

@@ -35,6 +35,7 @@ vi.mock('./pages/exam', () => ({ ExamDashboardPage: () => <div>Exam Marker</div>
 vi.mock('./pages/user/calendarPage', () => ({ default: () => <div>Calendar</div> }));
 vi.mock('./pages/user/settingsPage', () => ({ default: () => <div>Settings</div> }));
 vi.mock('./pages/tldraw/devPlayerPage', () => ({ default: () => <div>TLDraw Dev</div> }));
+vi.mock('./pages/tldraw/ExamMarkerSpikePage', () => ({ default: () => <div>Exam Marker Spike</div> }));
 vi.mock('./pages/tldraw/devPage', () => ({ default: () => <div>Dev</div> }));
 vi.mock('./pages/react-flow/teacherPlanner', () => ({ default: () => <div>Teacher Planner</div> }));
 vi.mock('./pages/morphicPage', () => ({ default: () => <div>Morphic</div> }));

src/AppRoutes.tsx

@@ -16,6 +16,7 @@ import AdminDashboard from './pages/auth/adminPage';
 import PlatformAdminPage from './pages/auth/PlatformAdminPage';
 import TLDrawDevPage from './pages/tldraw/devPlayerPage';
 import DevPage from './pages/tldraw/devPage';
+import ExamMarkerSpikePage from './pages/tldraw/ExamMarkerSpikePage';
 import TeacherPlanner from './pages/react-flow/teacherPlanner';
 import MorphicPage from './pages/morphicPage';
 import NotFound from './pages/user/NotFound';
@@ -186,6 +187,7 @@ const AppRoutes: React.FC = () => {
             <Route path="/doc-intelligence/:fileId" element={<CCDocumentIntelligence />} />
             <Route path="/morphic" element={<MorphicPage />} />
             <Route path="/tldraw-dev" element={<TLDrawDevPage />} />
+            <Route path="/exam-marker-spike" element={<ExamMarkerSpikePage />} />
             <Route path="/dev" element={<DevPage />} />
             <Route path="/dev/upload-test" element={<SimpleUploadTest />} />
             <Route path="/single-player" element={<SinglePlayerPage />} />

src/pages/exam/ExamDashboardPage.tsx

@@ -46,6 +46,7 @@ const ExamDashboardPage: React.FC = () => {
   const [createOpen, setCreateOpen] = useState(false);
   const [title, setTitle] = useState('');
   const [subject, setSubject] = useState('');
+  const [sourcePdf, setSourcePdf] = useState<File | null>(null);
   const [saving, setSaving] = useState(false);
 
   const load = useCallback(async () => {
@@ -66,6 +67,18 @@ const ExamDashboardPage: React.FC = () => {
     void load();
   }, [load, instituteId]);
 
+  const handleOpenCreate = () => {
+    setCreateOpen(true);
+  };
+
+  const handleCloseCreate = () => {
+    if (saving) return;
+    setCreateOpen(false);
+    setTitle('');
+    setSubject('');
+    setSourcePdf(null);
+  };
+
   const handleCreate = async () => {
     if (!title.trim()) return;
     setSaving(true);
@@ -74,10 +87,12 @@ const ExamDashboardPage: React.FC = () => {
         title: title.trim(),
         subject: subject.trim() || undefined,
         institute_id: instituteId,
+        source_pdf: sourcePdf,
       });
       setCreateOpen(false);
       setTitle('');
       setSubject('');
+      setSourcePdf(null);
       navigate(`/exam-marker/${created.id}/setup`);
     } catch (e) {
       const msg = e instanceof Error ? e.message : String(e);
@@ -112,7 +127,7 @@ const ExamDashboardPage: React.FC = () => {
               Build a template for an exam paper, then run marking batches against your classes.
             </Typography>
           </Box>
-          <Button variant="contained" startIcon={<AddIcon />} onClick={() => setCreateOpen(true)}>
+          <Button variant="contained" startIcon={<AddIcon />} onClick={handleOpenCreate}>
             New template
           </Button>
         </Box>
@@ -134,7 +149,7 @@ const ExamDashboardPage: React.FC = () => {
             <Typography variant="body2" color="text.secondary" sx={{ mb: 2 }}>
               Create your first template to start mapping an exam paper.
             </Typography>
-            <Button variant="outlined" startIcon={<AddIcon />} onClick={() => setCreateOpen(true)}>
+            <Button variant="outlined" startIcon={<AddIcon />} onClick={handleOpenCreate}>
               New template
             </Button>
           </Paper>
@@ -144,8 +159,16 @@ const ExamDashboardPage: React.FC = () => {
               <Grid item xs={12} sm={6} md={4} key={t.id}>
                 <Paper
                   elevation={2}
-                  sx={{ p: 3, height: '100%', cursor: 'pointer', display: 'flex', flexDirection: 'column', gap: 1,
+                  sx={{
-                        transition: 'box-shadow 120ms', '&:hover': { boxShadow: 6 } }}
+                    p: 3,
+                    height: '100%',
+                    cursor: 'pointer',
+                    display: 'flex',
+                    flexDirection: 'column',
+                    gap: 1,
+                    transition: 'box-shadow 120ms',
+                    '&:hover': { boxShadow: 6 },
+                  }}
                   onClick={() => navigate(`/exam-marker/${t.id}/setup`)}
                 >
                   <Box sx={{ display: 'flex', alignItems: 'flex-start', justifyContent: 'space-between' }}>
@@ -175,7 +198,7 @@ const ExamDashboardPage: React.FC = () => {
         )}
       </Stack>
 
-      <Dialog open={createOpen} onClose={() => (saving ? null : setCreateOpen(false))} fullWidth maxWidth="sm">
+      <Dialog open={createOpen} onClose={handleCloseCreate} fullWidth maxWidth="sm">
         <DialogTitle>New exam template</DialogTitle>
         <DialogContent>
           <Stack spacing={2} sx={{ mt: 1 }}>
@@ -193,10 +216,24 @@ const ExamDashboardPage: React.FC = () => {
               onChange={(e) => setSubject(e.target.value)}
               fullWidth
             />
+            <Box>
+              <Button variant="outlined" component="label">
+                {sourcePdf ? 'Replace source PDF' : 'Attach source PDF'}
+                <input
+                  hidden
+                  type="file"
+                  accept="application/pdf"
+                  onChange={(e) => setSourcePdf(e.target.files?.[0] ?? null)}
+                />
+              </Button>
+              <Typography variant="body2" color="text.secondary" sx={{ mt: 1 }}>
+                {sourcePdf ? sourcePdf.name : 'Optional: upload a PDF source for this template.'}
+              </Typography>
+            </Box>
           </Stack>
         </DialogContent>
         <DialogActions>
-          <Button onClick={() => setCreateOpen(false)} disabled={saving}>Cancel</Button>
+          <Button onClick={handleCloseCreate} disabled={saving}>Cancel</Button>
           <Button variant="contained" onClick={handleCreate} disabled={saving || !title.trim()}>
             {saving ? 'Creating…' : 'Create'}
           </Button>

src/pages/tldraw/ExamMarkerSpikePage.tsx

@@ -0,0 +1,170 @@
+import React, { useMemo, useRef, useState } from 'react'
+import {
+  Tldraw,
+  createTLStore,
+  createTLSchemaFromUtils,
+  defaultBindingUtils,
+  defaultShapeUtils,
+  Editor,
+  TLAnyBindingUtilConstructor,
+  TLAnyShapeUtilConstructor,
+  DEFAULT_SUPPORT_VIDEO_TYPES,
+  DEFAULT_SUPPORTED_IMAGE_TYPES,
+} from '@tldraw/tldraw'
+import { allBindingUtils } from '../../utils/tldraw/bindings'
+import { allShapeUtils } from '../../utils/tldraw/shapes'
+import { customAssets } from '../../utils/tldraw/assets'
+import { getUiComponents, getUiOverrides } from '../../utils/tldraw/ui-overrides'
+import { HEADER_HEIGHT } from '../Layout'
+import { devTools } from '../../utils/tldraw/tools'
+import {
+  activateExamMarkerTool,
+  EXAM_MARKER_BOX_TYPE,
+  ExamMarkerBoxShapeUtil,
+  ExamMarkerBoxTool,
+  placeExamMarkerSpike,
+} from '../../utils/tldraw/exam-marker-spike'
+
+const spikeShapeUtils = [...allShapeUtils, ExamMarkerBoxShapeUtil] as TLAnyShapeUtilConstructor[]
+const spikeBindingUtils = allBindingUtils as TLAnyBindingUtilConstructor[]
+const spikeTools = [...devTools, ExamMarkerBoxTool]
+
+const spikeSchema = createTLSchemaFromUtils({
+  shapeUtils: [...defaultShapeUtils, ...spikeShapeUtils],
+  bindingUtils: [...defaultBindingUtils, ...spikeBindingUtils],
+})
+
+export default function ExamMarkerSpikePage() {
+  const editorRef = useRef<Editor | null>(null)
+  const [status, setStatus] = useState('Ready to insert an image and a custom exam-marker box.')
+
+  const store = useMemo(() => {
+    const nextStore = createTLStore({
+      schema: spikeSchema,
+      shapeUtils: spikeShapeUtils,
+      bindingUtils: spikeBindingUtils,
+    })
+    ;(nextStore as unknown as { ensureStoreIsUsable(): void }).ensureStoreIsUsable()
+    return nextStore
+  }, [])
+
+  const onMount = (editor: Editor) => {
+    editorRef.current = editor
+  }
+
+  const insertSpike = () => {
+    if (!editorRef.current) return
+    const { imageId, boxId } = placeExamMarkerSpike(editorRef.current)
+    const toolId = activateExamMarkerTool(editorRef.current)
+    setStatus(`Inserted image ${imageId} and custom box ${boxId}; active tool is ${toolId}.`)
+  }
+
+  const focusBox = () => {
+    if (!editorRef.current) return
+    const current = editorRef.current.getCurrentPageShapes().find((shape) => shape.type === EXAM_MARKER_BOX_TYPE)
+    if (!current) {
+      setStatus('No exam-marker box found yet.')
+      return
+    }
+    const bounds = editorRef.current.getShapePageBounds(current)
+    if (bounds) {
+      editorRef.current.zoomToBounds(bounds)
+      setStatus('Focused the camera on the exam-marker box using getShapePageBounds + zoomToBounds.')
+    }
+  }
+
+  const uiOverrides = getUiOverrides(false)
+  const uiComponents = getUiComponents(false)
+
+  return (
+    <div style={{ position: 'fixed', inset: 0, top: HEADER_HEIGHT, background: '#f8fafc' }}>
+      <div
+        style={{
+          position: 'absolute',
+          zIndex: 10,
+          top: 16,
+          left: 16,
+          display: 'flex',
+          gap: 12,
+          alignItems: 'center',
+          padding: '10px 12px',
+          borderRadius: 16,
+          background: 'rgba(15, 23, 42, 0.9)',
+          color: 'white',
+          boxShadow: '0 10px 30px rgba(15, 23, 42, 0.22)',
+          maxWidth: 880,
+        }}
+      >
+        <div style={{ display: 'grid', gap: 4 }}>
+          <strong style={{ fontSize: 14 }}>Exam-marker spike</strong>
+          <span style={{ fontSize: 12, opacity: 0.9 }}>{status}</span>
+        </div>
+        <button
+          onClick={insertSpike}
+          style={{
+            marginLeft: 'auto',
+            padding: '8px 12px',
+            borderRadius: 10,
+            border: 'none',
+            background: '#f59e0b',
+            color: '#111827',
+            fontWeight: 700,
+            cursor: 'pointer',
+          }}
+        >
+          Insert image + marker box
+        </button>
+        <button
+          onClick={() => {
+            if (!editorRef.current) return
+            const toolId = activateExamMarkerTool(editorRef.current)
+            setStatus(`Activated tool ${toolId}. Drag on the canvas to create another marker box.`)
+          }}
+          style={{
+            padding: '8px 12px',
+            borderRadius: 10,
+            border: '1px solid rgba(255,255,255,0.2)',
+            background: 'transparent',
+            color: 'white',
+            fontWeight: 700,
+            cursor: 'pointer',
+          }}
+        >
+          Activate box tool
+        </button>
+        <button
+          onClick={focusBox}
+          style={{
+            padding: '8px 12px',
+            borderRadius: 10,
+            border: '1px solid rgba(255,255,255,0.2)',
+            background: 'transparent',
+            color: 'white',
+            fontWeight: 700,
+            cursor: 'pointer',
+          }}
+        >
+          Focus marker
+        </button>
+      </div>
+
+      <Tldraw
+        store={store}
+        tools={spikeTools}
+        shapeUtils={spikeShapeUtils}
+        bindingUtils={spikeBindingUtils}
+        components={uiComponents}
+        overrides={uiOverrides}
+        assetUrls={customAssets}
+        autoFocus
+        hideUi={false}
+        inferDarkMode={false}
+        acceptedImageMimeTypes={DEFAULT_SUPPORTED_IMAGE_TYPES}
+        acceptedVideoMimeTypes={DEFAULT_SUPPORT_VIDEO_TYPES}
+        maxImageDimension={Infinity}
+        maxAssetSize={100 * 1024 * 1024}
+        onMount={onMount}
+      />
+    </div>
+  )
+}

src/services/exam/examRepository.ts

@@ -43,6 +43,24 @@ export const examRepository = {
 
   async createTemplate(payload: CreateTemplatePayload): Promise<ExamTemplate> {
     const headers = await authHeaders();
+
+    if (payload.source_pdf) {
+      const form = new FormData();
+      form.append('title', payload.title);
+      if (payload.subject) form.append('subject', payload.subject);
+      if (payload.exam_id) form.append('exam_id', payload.exam_id);
+      if (payload.exam_code) form.append('exam_code', payload.exam_code);
+      if (payload.source_file_id) form.append('source_file_id', payload.source_file_id);
+      if (payload.page_count !== undefined) form.append('page_count', String(payload.page_count));
+      if (payload.institute_id) form.append('institute_id', payload.institute_id);
+      form.append('source_pdf', payload.source_pdf);
+
+      const res = await axios.post<ExamTemplate>(`${EXAM_BASE}/templates`, form, {
+        headers,
+      });
+      return res.data;
+    }
+
     const res = await axios.post<ExamTemplate>(`${EXAM_BASE}/templates`, payload, { headers });
     return res.data;
   },

src/types/exam.types.ts

@@ -27,6 +27,7 @@ export interface CreateTemplatePayload {
   exam_id?: string;
   exam_code?: string;
   source_file_id?: string;
+  source_pdf?: File | null;
   page_count?: number;
   institute_id?: string;
 }

src/utils/tldraw/exam-marker-spike.test.ts

@@ -0,0 +1,91 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import {
+  Editor,
+  createTLStore,
+  createTLSchemaFromUtils,
+  defaultBindingUtils,
+  defaultShapeUtils,
+} from '@tldraw/tldraw'
+import {
+  EXAM_MARKER_BOX_TYPE,
+  ExamMarkerBoxShapeUtil,
+  ExamMarkerBoxTool,
+  activateExamMarkerTool,
+  buildExamMarkerSvgDataUrl,
+  getExamMarkerHitTestPoints,
+  insertExamMarkerBox,
+} from './exam-marker-spike'
+
+const spikeShapeUtils = [ExamMarkerBoxShapeUtil]
+const spikeSchema = createTLSchemaFromUtils({
+  shapeUtils: [...defaultShapeUtils, ...spikeShapeUtils],
+  bindingUtils: defaultBindingUtils,
+})
+
+if (typeof globalThis.matchMedia !== 'function') {
+  vi.stubGlobal('matchMedia', () => ({
+    matches: false,
+    media: '',
+    onchange: null,
+    addEventListener: () => {},
+    removeEventListener: () => {},
+    addListener: () => {},
+    removeListener: () => {},
+    dispatchEvent: () => false,
+  } as unknown as MediaQueryList))
+}
+
+function makeEditor() {
+  const store = createTLStore({
+    schema: spikeSchema,
+    shapeUtils: spikeShapeUtils,
+    bindingUtils: defaultBindingUtils,
+  })
+  ;(store as unknown as { ensureStoreIsUsable(): void }).ensureStoreIsUsable()
+
+  return new Editor({
+    shapeUtils: spikeShapeUtils,
+    bindingUtils: defaultBindingUtils,
+    tools: [ExamMarkerBoxTool],
+    store,
+    getContainer: () => document.body,
+  })
+}
+
+describe('exam-marker spike tldraw helpers', () => {
+  let editor: Editor
+
+  beforeEach(() => {
+    editor = makeEditor()
+  })
+
+  afterEach(() => {
+    editor.dispose()
+  })
+
+  it('creates a custom box shape and supports point hit-testing + page bounds', () => {
+    const boxId = insertExamMarkerBox(editor)
+    const box = editor.getShape(boxId)
+
+    expect(box?.type).toBe(EXAM_MARKER_BOX_TYPE)
+    expect(editor.getShapePageBounds(boxId)).toBeTruthy()
+
+    const boxPoint = getExamMarkerHitTestPoints(editor, boxId)
+    expect(boxPoint?.bounds).toBeTruthy()
+    expect(editor.getShapesAtPoint(boxPoint!.center).some((shape) => shape.id === boxId)).toBe(true)
+
+    const viewport = editor.getViewportPageBounds()
+    expect(viewport.w).toBeGreaterThan(0)
+    expect(viewport.h).toBeGreaterThan(0)
+    expect(() => editor.zoomToBounds(boxPoint!.bounds)).not.toThrow()
+  })
+
+  it('registers the custom BaseBoxShapeTool and emits a locked svg asset URL', () => {
+    expect(activateExamMarkerTool(editor)).toBe(EXAM_MARKER_BOX_TYPE)
+    expect(editor.getCurrentToolId()).toBe(EXAM_MARKER_BOX_TYPE)
+
+    const svgUrl = buildExamMarkerSvgDataUrl()
+    expect(svgUrl.startsWith('data:image/svg+xml;charset=utf-8,')).toBe(true)
+    expect(decodeURIComponent(svgUrl.split(',')[1])).toContain('Exam scan')
+  })
+})

src/utils/tldraw/exam-marker-spike.tsx

@@ -0,0 +1,197 @@
+import React from 'react'
+import {
+  BaseBoxShapeTool,
+  BaseBoxShapeUtil,
+  Editor,
+  HTMLContainer,
+  T,
+  TLBaseBoxShape,
+  TLShapeId,
+  createShapeId,
+  toDomPrecision,
+} from '@tldraw/tldraw'
+
+export const EXAM_MARKER_BOX_TYPE = 'exam-marker-box' as const
+
+export type ExamMarkerBoxShape = TLBaseBoxShape & {
+  type: typeof EXAM_MARKER_BOX_TYPE
+}
+
+export class ExamMarkerBoxShapeUtil extends BaseBoxShapeUtil<ExamMarkerBoxShape> {
+  static override type = EXAM_MARKER_BOX_TYPE
+  static override props = {
+    w: T.number,
+    h: T.number,
+  }
+
+  override getDefaultProps(): ExamMarkerBoxShape['props'] {
+    return {
+      w: 320,
+      h: 180,
+    }
+  }
+
+  override component(shape: ExamMarkerBoxShape) {
+    return (
+      <HTMLContainer
+        id={shape.id}
+        style={{
+          width: toDomPrecision(shape.props.w),
+          height: toDomPrecision(shape.props.h),
+          border: '2px solid #b91c1c',
+          borderRadius: 14,
+          background: 'linear-gradient(180deg, rgba(255, 251, 235, 0.96), rgba(254, 242, 242, 0.96))',
+          boxShadow: '0 12px 24px rgba(185, 28, 28, 0.18)',
+          boxSizing: 'border-box',
+          overflow: 'hidden',
+          pointerEvents: 'all',
+        }}
+      >
+        <div
+          style={{
+            display: 'flex',
+            flexDirection: 'column',
+            gap: 8,
+            padding: 12,
+            fontFamily: 'Inter, system-ui, sans-serif',
+            color: '#7f1d1d',
+            height: '100%',
+          }}
+        >
+          <div style={{ fontSize: 12, fontWeight: 700, textTransform: 'uppercase', letterSpacing: 0.8 }}>
+            Exam marker spike
+          </div>
+          <div style={{ fontSize: 14, lineHeight: 1.35 }}>
+            This custom box shape uses the app&apos;s tldraw schema + BaseBoxShapeTool path.
+          </div>
+          <div
+            style={{
+              marginTop: 'auto',
+              padding: '6px 8px',
+              borderRadius: 999,
+              alignSelf: 'flex-start',
+              background: 'rgba(185, 28, 28, 0.12)',
+              fontSize: 12,
+              fontWeight: 600,
+            }}
+          >
+            Drag to resize · use the spike tool to create more
+          </div>
+        </div>
+      </HTMLContainer>
+    )
+  }
+}
+
+export class ExamMarkerBoxTool extends BaseBoxShapeTool {
+  static override id = EXAM_MARKER_BOX_TYPE
+  static override initial = 'pointing'
+  shapeType = EXAM_MARKER_BOX_TYPE
+}
+
+export function buildExamMarkerSvgDataUrl(label = 'Exam scan') {
+  const svg = `
+    <svg xmlns="http://www.w3.org/2000/svg" width="960" height="720" viewBox="0 0 960 720">
+      <defs>
+        <linearGradient id="g" x1="0" x2="1" y1="0" y2="1">
+          <stop offset="0%" stop-color="#ffffff"/>
+          <stop offset="100%" stop-color="#f4f7fb"/>
+        </linearGradient>
+      </defs>
+      <rect width="960" height="720" rx="32" fill="url(#g)" stroke="#cbd5e1" stroke-width="6"/>
+      <rect x="72" y="56" width="816" height="88" rx="18" fill="#1f2937" opacity="0.92"/>
+      <text x="116" y="108" fill="#fff" font-size="42" font-family="Inter, Arial, sans-serif" font-weight="700">${label}</text>
+      <rect x="72" y="176" width="816" height="120" rx="16" fill="#eef2ff" stroke="#c7d2fe"/>
+      <text x="106" y="224" fill="#1e3a8a" font-size="30" font-family="Inter, Arial, sans-serif" font-weight="700">Question 1</text>
+      <text x="106" y="266" fill="#334155" font-size="24" font-family="Inter, Arial, sans-serif">Show your working and annotate the image.</text>
+      <rect x="72" y="332" width="816" height="250" rx="16" fill="#fff7ed" stroke="#fed7aa"/>
+      <text x="106" y="384" fill="#9a3412" font-size="30" font-family="Inter, Arial, sans-serif" font-weight="700">Answer space</text>
+      <rect x="106" y="420" width="700" height="18" rx="9" fill="#fdba74" opacity="0.75"/>
+      <rect x="106" y="470" width="640" height="18" rx="9" fill="#fdba74" opacity="0.55"/>
+      <rect x="106" y="520" width="570" height="18" rx="9" fill="#fdba74" opacity="0.4"/>
+      <text x="106" y="644" fill="#475569" font-size="20" font-family="Inter, Arial, sans-serif">Inserted as a built-in tldraw image shape.</text>
+    </svg>
+  `.trim()
+
+  return `data:image/svg+xml;charset=utf-8,${encodeURIComponent(svg)}`
+}
+
+function getViewportAnchor(editor: Editor) {
+  const bounds = editor.getViewportPageBounds()
+  return {
+    x: bounds.x + bounds.w / 2,
+    y: bounds.y + bounds.h / 2,
+  }
+}
+
+export function insertExamMarkerImage(editor: Editor) {
+  const anchor = getViewportAnchor(editor)
+  const imageId = createShapeId()
+
+  editor.createShape({
+    id: imageId,
+    type: 'image',
+    x: anchor.x - 320,
+    y: anchor.y - 240,
+    props: {
+      url: buildExamMarkerSvgDataUrl(),
+      w: 640,
+      h: 480,
+      name: 'exam-marker-sample.svg',
+    },
+  })
+
+  return imageId
+}
+
+export function insertExamMarkerBox(editor: Editor) {
+  const anchor = getViewportAnchor(editor)
+  const boxId = createShapeId()
+
+  editor.createShape<ExamMarkerBoxShape>({
+    id: boxId,
+    type: EXAM_MARKER_BOX_TYPE,
+    x: anchor.x + 180,
+    y: anchor.y - 120,
+    props: {
+      w: 320,
+      h: 180,
+    },
+  })
+
+  return boxId
+}
+
+export function placeExamMarkerSpike(editor: Editor) {
+  const imageId = insertExamMarkerImage(editor)
+  const boxId = insertExamMarkerBox(editor)
+
+  const box = editor.getShape(boxId)
+  if (box) {
+    const bounds = editor.getShapePageBounds(box)
+    if (bounds) editor.zoomToBounds(bounds)
+  }
+
+  return { imageId, boxId }
+}
+
+export function activateExamMarkerTool(editor: Editor) {
+  editor.setCurrentTool(EXAM_MARKER_BOX_TYPE)
+  return editor.getCurrentToolId()
+}
+
+export function getExamMarkerHitTestPoints(editor: Editor, shapeId: TLShapeId) {
+  const shape = editor.getShape(shapeId)
+  if (!shape) return null
+
+  const bounds = editor.getShapePageBounds(shape)
+  if (!bounds) return null
+
+  return {
+    center: {
+      x: bounds.x + bounds.w / 2,
+      y: bounds.y + bounds.h / 2,
+    },
+    bounds,
+  }
+}