Add camera scan-to-text for notes via on-device OCR

Lets a photo of a book page fill in the note text instead of typing
it out. OCR runs entirely client-side (tesseract.js, dynamically
imported so it doesn't bloat the main bundle) - no server changes, no
API keys, and the photo never leaves the device. Recognized text is
appended into the textarea for the user to review/edit before saving.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01C3DGg1pvmvf81zXs4pk1J7

README.md

@@ -1,6 +1,6 @@
 # Notes
 
-A small PWA for jotting down short notes while reading — e.g. an interesting sentence from a book. Each note can optionally be tagged with a book/topic (existing or new) and a page number. Notes are saved as markdown directly into pages of a Nextcloud **Collective**, one page per book/topic, nested under a parent page (default: "Reading Notes"). Untagged notes are appended to that parent page itself.
+A small PWA for jotting down short notes while reading — e.g. an interesting sentence from a book. Each note is tagged with a book/topic (existing or new) and can optionally include a page number. Notes are saved as markdown directly into pages of a Nextcloud **Collective**, one page per book/topic, nested under a parent page (default: "Reading Notes"). A note's text can be typed by hand or filled in by scanning a photo of the page (on-device OCR via `tesseract.js` — no image or text ever leaves the device for this step).
 
 ## Stack
 

client/package.json

@@ -12,7 +12,8 @@
     "@notes/shared": "*",
     "@tanstack/react-query": "^5.51.23",
     "react": "^18.3.1",
-    "react-dom": "^18.3.1"
+    "react-dom": "^18.3.1",
+    "tesseract.js": "^7.0.0"
   },
   "devDependencies": {
     "@types/react": "^18.3.3",

client/src/lib/ocr.ts

@@ -0,0 +1,23 @@
+let workerPromise: Promise<import("tesseract.js").Worker> | null = null;
+
+function getWorker() {
+  if (!workerPromise) {
+    workerPromise = import("tesseract.js").then(({ createWorker }) => createWorker("eng"));
+  }
+  return workerPromise;
+}
+
+function cleanUpText(raw: string): string {
+  return raw
+    .replace(/[ \t]+\n/g, "\n")
+    .replace(/\n{3,}/g, "\n\n")
+    .trim();
+}
+
+export async function recognizeText(file: File): Promise<string> {
+  const worker = await getWorker();
+  const {
+    data: { text }
+  } = await worker.recognize(file);
+  return cleanUpText(text);
+}

client/src/pages/NoteFormPage.tsx

@@ -1,8 +1,9 @@
-import { useState, type FormEvent } from "react";
+import { useRef, useState, type ChangeEvent, type FormEvent } from "react";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { fetchBooks } from "../api/books";
 import { saveNote } from "../api/notes";
 import { logout } from "../api/auth";
+import { recognizeText } from "../lib/ocr";
 
 const NEW_BOOK_OPTION = "__new__";
 
@@ -15,6 +16,9 @@ export function NoteFormPage({ onLoggedOut }: { onLoggedOut: () => void }) {
   const [newBookTitle, setNewBookTitle] = useState("");
   const [page, setPage] = useState("");
   const [text, setText] = useState("");
+  const [isScanning, setIsScanning] = useState(false);
+  const [scanError, setScanError] = useState<string | null>(null);
+  const fileInputRef = useRef<HTMLInputElement>(null);
 
   const saveNoteMutation = useMutation({
     mutationFn: saveNote,
@@ -41,6 +45,23 @@ export function NoteFormPage({ onLoggedOut }: { onLoggedOut: () => void }) {
     }
   }
 
+  async function handleImageSelected(e: ChangeEvent<HTMLInputElement>) {
+    const file = e.target.files?.[0];
+    if (!file) return;
+
+    setIsScanning(true);
+    setScanError(null);
+    try {
+      const recognized = await recognizeText(file);
+      setText((prev) => (prev.trim() ? `${prev}\n${recognized}` : recognized));
+    } catch {
+      setScanError("Couldn't recognize text in that photo. Try again with better lighting/focus.");
+    } finally {
+      setIsScanning(false);
+      e.target.value = "";
+    }
+  }
+
   function handleSubmit(e: FormEvent) {
     e.preventDefault();
     const trimmedBook = (isAddingNewBook ? newBookTitle : book).trim();
@@ -65,7 +86,25 @@ export function NoteFormPage({ onLoggedOut }: { onLoggedOut: () => void }) {
         </div>
 
         <label>
-          Note
+          <div className="header-row">
+            Note
+            <button
+              type="button"
+              className="link"
+              onClick={() => fileInputRef.current?.click()}
+              disabled={isScanning || saveNoteMutation.isPending}
+            >
+              📷 Scan
+            </button>
+          </div>
+          <input
+            ref={fileInputRef}
+            type="file"
+            accept="image/*"
+            capture="environment"
+            onChange={handleImageSelected}
+            style={{ display: "none" }}
+          />
           <textarea
             value={text}
             onChange={(e) => setText(e.target.value)}
@@ -73,6 +112,8 @@ export function NoteFormPage({ onLoggedOut }: { onLoggedOut: () => void }) {
             placeholder="An interesting sentence…"
             required
           />
+          {isScanning && <span className="hint">Recognizing text…</span>}
+          {scanError && <span className="error">{scanError}</span>}
         </label>
 
         <label>

client/src/styles.css

@@ -124,3 +124,8 @@ button.link {
   font-size: 0.9rem;
   margin: 0;
 }
+
+.hint {
+  color: var(--muted);
+  font-size: 0.85rem;
+}

package-lock.json

@@ -29,7 +29,8 @@
         "@notes/shared": "*",
         "@tanstack/react-query": "^5.51.23",
         "react": "^18.3.1",
-        "react-dom": "^18.3.1"
+        "react-dom": "^18.3.1",
+        "tesseract.js": "^7.0.0"
       },
       "devDependencies": {
         "@types/react": "^18.3.3",
@@ -3492,6 +3493,11 @@
         "node": ">=6.0.0"
       }
     },
+    "node_modules/bmp-js": {
+      "version": "0.1.0",
+      "resolved": "https://registry.npmjs.org/bmp-js/-/bmp-js-0.1.0.tgz",
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+    },
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       "dev": true
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+    },
     "node_modules/ignore": {
       "version": "5.3.2",
       "resolved": "https://registry.npmjs.org/ignore/-/ignore-5.3.2.tgz",
@@ -5782,6 +5793,11 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/is-url": {
+      "version": "1.2.4",
+      "resolved": "https://registry.npmjs.org/is-url/-/is-url-1.2.4.tgz",
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+    },
     "node_modules/is-weakmap": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/is-weakmap/-/is-weakmap-2.0.2.tgz",
@@ -6202,6 +6218,25 @@
         "node": "^18 || ^20 || >= 21"
       }
     },
+    "node_modules/node-fetch": {
+      "version": "2.7.0",
+      "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-2.7.0.tgz",
+      "integrity": "sha512-c4FRfUm/dbcWZ7U+1Wq0AwCyFL+3nt2bEw05wfxSz+DWpWsitgmSgYmy2dQdWyKC1694ELPqMs/YzUSNozLt8A==",
+      "dependencies": {
+        "whatwg-url": "^5.0.0"
+      },
+      "engines": {
+        "node": "4.x || >=6.0.0"
+      },
+      "peerDependencies": {
+        "encoding": "^0.1.0"
+      },
+      "peerDependenciesMeta": {
+        "encoding": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/node-gyp-build": {
       "version": "4.8.4",
       "resolved": "https://registry.npmjs.org/node-gyp-build/-/node-gyp-build-4.8.4.tgz",
@@ -6289,6 +6324,14 @@
         "wrappy": "1"
       }
     },
+    "node_modules/opencollective-postinstall": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/opencollective-postinstall/-/opencollective-postinstall-2.0.3.tgz",
+      "integrity": "sha512-8AV/sCtuzUeTo8gQK5qDZzARrulB3egtLzFgteqB2tcT4Mw7B8Kt7JcDHmltjz6FOAHsvTevk70gZEbhM4ZS9Q==",
+      "bin": {
+        "opencollective-postinstall": "index.js"
+      }
+    },
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       "resolved": "https://registry.npmjs.org/optionator/-/optionator-0.9.4.tgz",
@@ -6692,6 +6735,11 @@
         "node": ">=4"
       }
     },
+    "node_modules/regenerator-runtime": {
+      "version": "0.13.11",
+      "resolved": "https://registry.npmjs.org/regenerator-runtime/-/regenerator-runtime-0.13.11.tgz",
+      "integrity": "sha512-kY1AZVr2Ra+t+piVaJ4gxaFaReZVH40AKNo7UCX6W+dEwBo/2oZJzqfuN1qLq1oL45o56cPaTXELwrTh8Fpggg=="
+    },
     "node_modules/regexp.prototype.flags": {
       "version": "1.5.4",
       "resolved": "https://registry.npmjs.org/regexp.prototype.flags/-/regexp.prototype.flags-1.5.4.tgz",
@@ -7591,6 +7639,28 @@
         "node": ">=10"
       }
     },
+    "node_modules/tesseract.js": {
+      "version": "7.0.0",
+      "resolved": "https://registry.npmjs.org/tesseract.js/-/tesseract.js-7.0.0.tgz",
+      "integrity": "sha512-exPBkd+z+wM1BuMkx/Bjv43OeLBxhL5kKWsz/9JY+DXcXdiBjiAch0V49QR3oAJqCaL5qURE0vx9Eo+G5YE7mA==",
+      "hasInstallScript": true,
+      "dependencies": {
+        "bmp-js": "^0.1.0",
+        "idb-keyval": "^6.2.0",
+        "is-url": "^1.2.4",
+        "node-fetch": "^2.6.9",
+        "opencollective-postinstall": "^2.0.3",
+        "regenerator-runtime": "^0.13.3",
+        "tesseract.js-core": "^7.0.0",
+        "wasm-feature-detect": "^1.8.0",
+        "zlibjs": "^0.3.1"
+      }
+    },
+    "node_modules/tesseract.js-core": {
+      "version": "7.0.0",
+      "resolved": "https://registry.npmjs.org/tesseract.js-core/-/tesseract.js-core-7.0.0.tgz",
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+    },
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@@ -7662,6 +7732,11 @@
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       }
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+    "node_modules/tr46": {
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@@ -8589,6 +8664,25 @@
         "url": "https://github.com/sponsors/jonschlinkert"
       }
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+    "node_modules/wasm-feature-detect": {
+      "version": "1.9.0",
+      "resolved": "https://registry.npmjs.org/wasm-feature-detect/-/wasm-feature-detect-1.9.0.tgz",
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+      "integrity": "sha512-2JAn3z8AR6rjK8Sm8orRC0h/bcl/DqL7tRPdGZ4I1CjdF+EaMLmYxBHyXuKL849eucPFhvBoxMsflfOb8kxaeQ=="
+    },
+    "node_modules/whatwg-url": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/whatwg-url/-/whatwg-url-5.0.0.tgz",
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+      "dependencies": {
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@@ -9222,6 +9316,14 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
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+    "node_modules/zlibjs": {
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