Keep refactoring

examples/node/recognize.js

@@ -1,7 +1,8 @@
 #!/usr/bin/env node
 const path = require('path');
+const fs = require('fs');
 const {
-  createScheduler, createWorker, createJob, PSM,
+  Tesseract, createScheduler, createWorker,
 } = require('../../');
 
 const [,, imagePath] = process.argv;
@@ -15,16 +16,19 @@ console.log(`Recognizing ${image}`);
   await worker.load();
   await worker.loadLanguage('eng');
   await worker.initialize('eng');
-  await worker.setParameters({
-    tessedit_char_whitelist: 'ABCDEFGH',
-  });
   scheduler.addWorker(worker);
-  const { text: t1 } = await scheduler.addJob(createJob('recognize', { image }));
-  console.log(t1);
-  await worker.setParameters({
-    tessedit_char_whitelist: 'abcdefg',
-  });
-  const { text: t2 } = await scheduler.addJob(createJob('recognize', { image }));
-  console.log(t2);
-  scheduler.terminate();
+  console.log((await scheduler.addJob('recognize', image)).text);
+  const data = await worker.getPDF('ocr', 'Tesseract OCR');
+  fs.writeFileSync('test.pdf', Buffer.from(data));
+  await scheduler.terminate();
 })();
+
+//Tesseract.recognize(image, 'eng', { logger: m => console.log(m) })
+//  .then(({ text }) => {
+//    console.log(text);
+//  });
+
+//Tesseract.detect(image, { logger: m => console.log(m) })
+//  .then((data) => {
+//    console.log(data);
+//  });

package-lock.json

@@ -3558,9 +3558,9 @@
       }
     },
     "file-type": {
-      "version": "10.11.0",
-      "resolved": "https://registry.npmjs.org/file-type/-/file-type-10.11.0.tgz",
-      "integrity": "sha512-uzk64HRpUZyTGZtVuvrjP0FYxzQrBf4rojot6J65YMEbwBLB0CWm0CLojVpwpmFmxcE/lkvYICgfcGozbBq6rw=="
+      "version": "12.3.0",
+      "resolved": "https://registry.npmjs.org/file-type/-/file-type-12.3.0.tgz",
+      "integrity": "sha512-4E4Esq9KLwjYCY32E7qSmd0h7LefcniZHX+XcdJ4Wfx1uGJX7QCigiqw/U0yT7WOslm28yhxl87DJ0wHYv0RAA=="
     },
     "finalhandler": {
       "version": "1.1.1",
@@ -8565,6 +8565,11 @@
         "zlibjs": "^0.3.1"
       },
       "dependencies": {
+        "file-type": {
+          "version": "10.11.0",
+          "resolved": "https://registry.npmjs.org/file-type/-/file-type-10.11.0.tgz",
+          "integrity": "sha512-uzk64HRpUZyTGZtVuvrjP0FYxzQrBf4rojot6J65YMEbwBLB0CWm0CLojVpwpmFmxcE/lkvYICgfcGozbBq6rw=="
+        },
         "is-url": {
           "version": "1.2.4",
           "resolved": "https://registry.npmjs.org/is-url/-/is-url-1.2.4.tgz",

package.json

@@ -53,12 +53,16 @@
   },
   "dependencies": {
     "axios": "^0.18.0",
+    "bmp-js": "^0.1.0",
     "check-types": "^7.4.0",
+    "file-type": "^12.3.0",
+    "idb-keyval": "^3.2.0",
     "is-url": "1.2.2",
     "opencollective-postinstall": "^2.0.2",
     "resolve-url": "^0.2.1",
     "tesseract.js-core": "^2.0.0-beta.13",
-    "tesseract.js-utils": "^1.0.0-beta.8"
+    "tesseract.js-utils": "^1.0.0-beta.8",
+    "zlibjs": "^0.3.1"
   },
   "repository": {
     "type": "git",

src/Tesseract.js

@@ -0,0 +1,33 @@
+const createScheduler = require('./createScheduler');
+const createWorker = require('./createWorker');
+
+const recognize = async (image, langs, options) => {
+  const scheduler = createScheduler();
+  const worker = createWorker(options);
+  await worker.load();
+  await worker.loadLanguage(langs);
+  await worker.initialize(langs);
+  scheduler.addWorker(worker);
+  return scheduler.addJob('recognize', image)
+    .finally(() => {
+      scheduler.terminate();
+    });
+};
+
+const detect = async (image, options) => {
+  const scheduler = createScheduler();
+  const worker = createWorker(options);
+  await worker.load();
+  await worker.loadLanguage('osd');
+  await worker.initialize('osd');
+  scheduler.addWorker(worker);
+  return scheduler.addJob('detect', image)
+    .finally(() => {
+      scheduler.terminate();
+    });
+};
+
+module.exports = {
+  recognize,
+  detect,
+};

src/createJob.js

@@ -9,10 +9,10 @@ module.exports = (
   jobCounter += 1;
   const id = `Job-${jobCounter}-${Math.random().toString(16).slice(3, 8)}`;
 
-  const start = (worker) => {
-    console.log(`[${worker.id}]: Start ${id}, action=${action}`);
-    send(worker, {
-      workerId: worker.id,
+  const start = (w) => {
+    console.log(`[${w.id}]: Start ${id}, action=${action}`);
+    send(w.worker, {
+      workerId: w.id,
       jobId: id,
       action,
       payload,

src/createScheduler.js

@@ -1,13 +1,13 @@
 module.exports = () => {
   const workers = {};
-  const runningJobs = {};
+  const runningWorkers = {};
   let jobQueue = [];
 
   const dequeue = () => {
     if (jobQueue.length !== 0) {
       const wIds = Object.keys(workers);
       for (let i = 0; i < wIds.length; i += 1) {
-        if (typeof runningJobs[wIds[i]] === 'undefined') {
+        if (typeof runningWorkers[wIds[i]] === 'undefined') {
           jobQueue[0](workers[wIds[i]]);
           break;
         }
@@ -15,19 +15,19 @@ module.exports = () => {
     }
   };
 
-  const queue = job => (
+  const queue = (action, payload) => (
     new Promise((resolve, reject) => {
-      jobQueue.push((w) => {
-        const { action } = job;
+      jobQueue.push(async (w) => {
         jobQueue.shift();
-        w.setResolve(action, (data) => {
-          delete runningJobs[w.id];
+        runningWorkers[w.id] = true;
+        try {
+          resolve(await w[action].apply(this, payload));
+        } catch (err) {
+          reject(err);
+        } finally {
+          delete runningWorkers[w.id];
           dequeue();
-          resolve(data);
-        });
-        w.setReject(action, reject);
-        runningJobs[w.id] = job;
-        job.start(w);
+        }
       });
       dequeue();
     })
@@ -38,13 +38,13 @@ module.exports = () => {
     return w.id;
   };
 
-  const addJob = job => (
-    queue(job)
+  const addJob = (action, ...payload) => (
+    queue(action, payload)
   );
 
-  const terminate = () => {
-    Object.keys(workers).forEach((id) => {
-      workers[id].terminate();
+  const terminate = async () => {
+    Object.keys(workers).forEach(async (id) => {
+      await workers[id].terminate();
     });
     jobQueue = [];
   };

src/createTesseract.js

@@ -1,7 +0,0 @@
-module.exports = (options = {}, nWorkers = 1) => {
-  return {
-    init: () => {},
-    loadLanguauge: () => {},
-    recognize: () => {},
-  };
-};

src/createWorker.js

@@ -44,7 +44,7 @@ module.exports = (_options = {}) => {
   );
 
   const loadLanguage = (langs = 'eng') => (
-    doJob('load-language', { langs, options })
+    doJob('loadLanguage', { langs, options })
   );
 
   const initialize = (langs = 'eng', oem = defaultOEM) => (
@@ -52,32 +52,39 @@ module.exports = (_options = {}) => {
   );
 
   const setParameters = (params = {}) => (
-    doJob('set-parameters', { params })
+    doJob('setParameters', { params })
   );
 
-  const terminate = () => {
+  const recognize = (image, opts = {}) => (
+    doJob('recognize', { image, options: opts })
+  );
+
+  const getPDF = (title = 'Tesseract OCR Result', textonly = false) => (
+    doJob('getPDF', { title, textonly })
+  );
+
+  const detect = image => (
+    doJob('detect', { image })
+  );
+
+  const terminate = async () => {
     if (worker !== null) {
+      await doJob('terminate');
       terminateWorker(worker);
       worker = null;
     }
+    return Promise.resolve();
   };
 
-  onMessage(worker, (packet) => {
-    const { status, action, data } = packet;
+  onMessage(worker, ({ status, action, data }) => {
     if (status === 'resolve') {
-      if (action === 'load') {
-        resolves.load(data);
-      } else if (action === 'initialize') {
-        resolves.initialize({ id });
-      } else if (action === 'set-parameters') {
-        resolves['set-parameters'](data);
-      } else if (action === 'load-language') {
-        resolves['load-language'](data);
-      } else if (action === 'recognize') {
-        resolves.recognize(circularize(data));
-      } else if (action === 'detect') {
-        resolves.detect(data);
+      let d = data;
+      if (action === 'recognize') {
+        d = circularize(data);
+      } else if (action === 'getPDF') {
+        d = Array.from({ ...data, length: Object.keys(data).length });
       }
+      resolves[action](d);
     } else if (status === 'reject') {
       rejects[action](data);
       throw Error(data);
@@ -95,6 +102,9 @@ module.exports = (_options = {}) => {
     loadLanguage,
     initialize,
     setParameters,
+    recognize,
+    getPDF,
+    detect,
     terminate,
   };
 };

src/index.js

@@ -10,6 +10,7 @@
 const createScheduler = require('./createScheduler');
 const createWorker = require('./createWorker');
 const createJob = require('./createJob');
+const Tesseract = require('./Tesseract');
 const OEM = require('./constants/OEM');
 const PSM = require('./constants/PSM');
 
@@ -19,4 +20,5 @@ module.exports = {
   createScheduler,
   createWorker,
   createJob,
+  Tesseract,
 };

src/worker-script/browser/resolveURL.js

@@ -0,0 +1 @@
+module.exports = require('resolve-url');

src/worker-script/constants/defaultParams.js

@@ -6,6 +6,7 @@ const PSM = require('../../constants/PSM');
 module.exports = {
   tessedit_pageseg_mode: PSM.SINGLE_BLOCK,
   tessedit_char_whiltelist: '',
+  user_defined_dpi: '300',
   tessjs_create_pdf: '0',
   tessjs_create_hocr: '1',
   tessjs_create_tsv: '1',
@@ -17,8 +18,4 @@ module.exports = {
   tessjs_pdf_title: 'Tesseract.js OCR Result',
   tessjs_pdf_auto_download: true,
   tessjs_pdf_bin: false,
-  tessjs_image_rectangle_left: 0,
-  tessjs_image_rectangle_top: 0,
-  tessjs_image_rectangle_width: -1,
-  tessjs_image_rectangle_height: -1,
 };

src/worker-script/index.js

@@ -7,11 +7,12 @@
  * @author Guillermo Webster <gui@mit.edu>
  * @author Jerome Wu <jeromewus@gmail.com>
  */
-const { loadLang } = require('tesseract.js-utils');
+const fileType = require('file-type');
+const axios = require('axios');
+const isURL = require('is-url');
 const dump = require('./utils/dump');
 const isBrowser = require('../utils/getEnvironment')('type') === 'browser';
 const setImage = require('./utils/setImage');
-const getFiles = require('./utils/getFiles');
 const defaultParams = require('./constants/defaultParams');
 
 /*
@@ -26,18 +27,6 @@ let latestJob;
 let adapter = {};
 let params = defaultParams;
 
-
-/**
- * handleInit
- *
- * @name handleInit
- * @function handle initialization of TessModule
- * @access public
- * @param {object} req - job payload
- * @param {string} req.corePath - path to the tesseract-core.js
- * @param {object} res - job instance
- * @returns {Promise} A Promise for callback
- */
 const load = ({ workerId, jobId, payload: { options: { corePath } } }, res) => {
   if (!TessModule) {
     const Core = adapter.getCore(corePath, res);
@@ -53,35 +42,99 @@ const load = ({ workerId, jobId, payload: { options: { corePath } } }, res) => {
           progress: Math.max(0, (percent - 30) / 70),
         });
       },
-    })
-      .then((tessModule) => {
-        TessModule = tessModule;
-        res.progress({ workerId, status: 'initialized tesseract', progress: 1 });
-        res.resolve({ loaded: true });
-      });
+    }).then((tessModule) => {
+      TessModule = tessModule;
+      res.progress({ workerId, status: 'initialized tesseract', progress: 1 });
+      res.resolve({ loaded: true });
+    });
   } else {
     res.resolve({ loaded: true });
   }
 };
 
-/**
- * loadLanguage
- *
- * @name loadLanguage
- * @function load language from remote or local cache
- * @access public
- * @param {object} req - job payload
- * @param {string} req.langs - languages to load, ex: eng, eng+chi_tra
- * @param {object} req.options - other options for loadLang function
- * @param {object} res - job instance
- * @returns {Promise} A Promise for callback
- */
-const loadLanguage = ({ workerId, payload: { langs, options } }, res) => {
+const loadLanguage = async ({
+  workerId,
+  payload: {
+    langs,
+    options: {
+      langPath,
+      dataPath,
+      cachePath,
+      cacheMethod,
+      gzip = true,
+    },
+  },
+},
+  res) => {
+  const loadAndGunzipFile = async (_lang) => {
+    const lang = typeof _lang === 'string' ? _lang : _lang.code;
+    const readCache = ['refresh', 'none'].includes(cacheMethod)
+      ? () => Promise.resolve()
+      : adapter.readCache;
+    let data = null;
+
+    try {
+      const _data = await readCache(`${cachePath || '.'}/${lang}.traineddata`);
+      if (typeof _data !== 'undefined') {
+        data = _data;
+      } else {
+        throw Error('Not found in cache');
+      }
+    } catch (e) {
+      if (typeof _lang === 'string') {
+        let path = null;
+
+        if (isURL(langPath)) { /** When langPath is an URL */
+          path = langPath;
+        } else if (process.browser) { /** When langPath is not an URL in browser */
+          path = adapter.resolveURL(langPath);
+        }
+
+        if (path !== null) {
+          const { data: _data } = await axios.get(
+            `${path}/${lang}.traineddata${gzip ? '.gz' : ''}`,
+            { responseType: 'arraybuffer' },
+          );
+          data = _data;
+        } else {
+          data = await adapter.readCache(`${langPath}/${lang}.traineddata${gzip ? '.gz' : ''}`);
+        }
+      } else {
+        data = _lang.data; // eslint-disable-line
+      }
+    }
+
+    data = new Uint8Array(data);
+
+    const type = fileType(data);
+    if (typeof type !== 'undefined' && type.mime === 'application/gzip') {
+      data = adapter.gunzip(data);
+    }
+
+    if (TessModule) {
+      if (dataPath) {
+        try {
+          TessModule.FS.mkdir(dataPath);
+        } catch (err) {
+          res.reject(err.toString());
+        }
+      }
+      TessModule.FS.writeFile(`${dataPath || '.'}/${lang}.traineddata`, data);
+    }
+
+    if (['write', 'refresh', undefined].includes(cacheMethod)) {
+      await adapter.writeCache(`${cachePath || '.'}/${lang}.traineddata`, data);
+    }
+
+    return Promise.resolve(data);
+  };
+
   res.progress({ workerId, status: 'loading language traineddata', progress: 0 });
-  loadLang({ langs, TessModule, ...options }).then(() => {
+  try {
+    await Promise.all((typeof langs === 'string' ? langs.split('+') : langs).map(loadAndGunzipFile));
     res.progress({ workerId, status: 'loaded language traineddata', progress: 1 });
     res.resolve(langs);
-  }).catch((err) => {
+  } catch (err) {
     if (isBrowser && err instanceof DOMException) {
       /*
        * For some reason google chrome throw DOMException in loadLang,
@@ -91,7 +144,7 @@ const loadLanguage = ({ workerId, payload: { langs, options } }, res) => {
     } else {
       res.reject(err.toString());
     }
-  });
+  }
 };
 
 const setParameters = ({ payload: { params: _params } }, res) => {
@@ -109,7 +162,6 @@ const setParameters = ({ payload: { params: _params } }, res) => {
 
 const initialize = ({
   workerId,
-  jobId,
   payload: { langs: _langs, oem },
 }, res) => {
   const langs = (typeof _langs === 'string')
@@ -118,13 +170,13 @@ const initialize = ({
 
   try {
     res.progress({
-      workerId, jobId, status: 'initializing api', progress: 0,
+      workerId, status: 'initializing api', progress: 0,
     });
     api = new TessModule.TessBaseAPI();
     api.Init(null, langs, oem);
     setParameters({ payload: { params } });
     res.progress({
-      workerId, jobId, status: 'initialized api', progress: 1,
+      workerId, status: 'initialized api', progress: 1,
     });
     res.resolve();
   } catch (err) {
@@ -132,48 +184,35 @@ const initialize = ({
   }
 };
 
-/**
- * handleRecognize
- *
- * @name handleRecognize
- * @function handle recognition job
- * @access public
- * @param {object} req - job payload
- * @param {array} req.image - binary image in array format
- * @param {string} req.langs - languages to load, ex: eng, eng+chi_tra
- * @param {object} req.options - other options for loadLang function
- * @param {object} req.params - parameters for tesseract
- * @param {object} res - job instance
- */
-const recognize = ({ payload: { image } }, res) => {
+const recognize = ({ payload: { image, options: { rectangles = [] } } }, res) => {
   try {
-    const ptr = setImage(TessModule, api, image, params);
-    api.Recognize(null);
-    res.resolve({
-      files: getFiles(TessModule, api, adapter, params),
-      ...dump(TessModule, api, params),
+    const ptr = setImage(TessModule, api, image);
+    rectangles.forEach(({
+      left, top, width, height,
+    }) => {
+      api.SetRectangle(left, top, width, height);
     });
+    api.Recognize(null);
+    res.resolve(dump(TessModule, api, params));
     TessModule._free(ptr);
   } catch (err) {
     res.reject(err.toString());
   }
 };
 
-/**
- * handleDetect
- *
- * @name handleDetect
- * @function handle detect (Orientation and Script Detection / OSD) job
- * @access public
- * @param {object} req - job payload
- * @param {array} req.image - binary image in array format
- * @param {string} req.langs - languages to load, ex: eng, eng+chi_tra
- * @param {object} req.options - other options for loadLang function
- * @param {object} res - job instance
- */
+const getPDF = ({ payload: { title, textonly } }, res) => {
+  const pdfRenderer = new TessModule.TessPDFRenderer('tesseract-ocr', '/', textonly);
+  pdfRenderer.BeginDocument(title);
+  pdfRenderer.AddImage(api);
+  pdfRenderer.EndDocument();
+  TessModule._free(pdfRenderer);
+
+  res.resolve(TessModule.FS.readFile('/tesseract-ocr.pdf'));
+};
+
 const detect = ({ payload: { image } }, res) => {
   try {
-    const ptr = setImage(TessModule, api, image, params);
+    const ptr = setImage(TessModule, api, image);
     const results = new TessModule.OSResults();
 
     if (!api.DetectOS(results)) {
@@ -236,22 +275,16 @@ exports.dispatchHandlers = (packet, send) => {
   latestJob = res;
 
   try {
-    const { action } = packet;
-    if (action === 'load') {
-      load(packet, res);
-    } else if (action === 'load-language') {
-      loadLanguage(packet, res);
-    } else if (action === 'initialize') {
-      initialize(packet, res);
-    } else if (action === 'set-parameters') {
-      setParameters(packet, res);
-    } else if (action === 'recognize') {
-      recognize(packet, res);
-    } else if (action === 'detect') {
-      detect(packet, res);
-    } else if (action === 'terminate') {
-      terminate(packet, res);
-    }
+    ({
+      load,
+      loadLanguage,
+      initialize,
+      setParameters,
+      recognize,
+      getPDF,
+      detect,
+      terminate,
+    })[packet.action](packet, res);
   } catch (err) {
     /** Prepare exception to travel through postMessage */
     res.reject(err.toString());

src/worker-script/node/cache.js

@@ -0,0 +1,16 @@
+const util = require('util');
+const fs = require('fs');
+
+module.exports = {
+  readCache: util.promisify(fs.readFile),
+  writeCache: util.promisify(fs.writeFile),
+  deleteCache: path => (
+    util.promisify(fs.unlink)(path)
+      .catch(() => {})
+  ),
+  checkCache: path => (
+    util.promisify(fs.access)(path, fs.F_OK)
+      .then(err => (err === null))
+      .catch(() => false)
+  ),
+};

src/worker-script/node/exportFile.js

@@ -1,7 +0,0 @@
-const fs = require('fs');
-
-module.exports = (path, data) => {
-  fs.writeFile(path, data, (err) => {
-    if (err) throw err;
-  });
-};

src/worker-script/node/getCore.js

@@ -0,0 +1,13 @@
+let TesseractCore = null;
+/*
+ * getCore is a sync function to load and return
+ * TesseractCore.
+ */
+module.exports = (_, res) => {
+  if (TesseractCore === null) {
+    res.progress({ status: 'loading tesseract core', progress: 0 });
+    TesseractCore = require('tesseract.js-core');
+    res.progress({ status: 'loaded tesseract core', progress: 1 });
+  }
+  return TesseractCore;
+};

src/worker-script/node/gunzip.js

@@ -0,0 +1 @@
+module.exports = require('zlib').gunzipSync;

src/worker-script/node/index.js

@@ -9,9 +9,10 @@
  */
 
 const worker = require('../');
-const exportFile = require('./exportFile');
-
-let TesseractCore = null;
+const getCore = require('./getCore');
+const resolveURL = require('./resolveURL');
+const gunzip = require('./gunzip');
+const cache = require('./cache');
 
 /*
  * register message handler
@@ -20,20 +21,9 @@ process.on('message', (packet) => {
   worker.dispatchHandlers(packet, obj => process.send(obj));
 });
 
-/*
- * getCore is a sync function to load and return
- * TesseractCore.
- */
-const getCore = (_, res) => {
-  if (TesseractCore === null) {
-    res.progress({ status: 'loading tesseract core', progress: 0 });
-    TesseractCore = require('tesseract.js-core');
-    res.progress({ status: 'loaded tesseract core', progress: 1 });
-  }
-  return TesseractCore;
-};
-
 worker.setAdapter({
   getCore,
-  exportFile,
+  gunzip,
+  resolveURL,
+  ...cache,
 });

src/worker-script/node/resolveURL.js

@@ -0,0 +1 @@
+module.exports = s => s;

src/worker-script/utils/getFiles.js

@@ -1,39 +0,0 @@
-/**
- * handleOutput
- *
- * @name handleOutput
- * @function handle file output
- * @access private
- * @param {object} customParams - an object of params
- */
-module.exports = (TessModule, api, adapter, params) => {
-  let files = {};
-  const {
-    tessjs_create_pdf,
-    tessjs_textonly_pdf,
-    tessjs_pdf_name,
-    tessjs_pdf_title,
-    tessjs_pdf_auto_download,
-    tessjs_pdf_bin,
-  } = params;
-
-  if (tessjs_create_pdf === '1') {
-    const pdfRenderer = new TessModule.TessPDFRenderer(tessjs_pdf_name, '/', tessjs_textonly_pdf === '1');
-    pdfRenderer.BeginDocument(tessjs_pdf_title);
-    pdfRenderer.AddImage(api);
-    pdfRenderer.EndDocument();
-    TessModule._free(pdfRenderer);
-
-    const data = TessModule.FS.readFile(`/${tessjs_pdf_name}.pdf`);
-
-    if (tessjs_pdf_bin) {
-      files = { pdf: data, ...files };
-    }
-
-    if (tessjs_pdf_auto_download) {
-      adapter.exportFile(`${tessjs_pdf_name}.pdf`, data, 'application/pdf');
-    }
-  }
-
-  return files;
-};

src/worker-script/utils/getLangStr.js

@@ -1,5 +0,0 @@
-module.exports = langs => (
-  typeof langs === 'string'
-    ? langs
-    : langs.map(lang => (typeof lang === 'string' ? lang : lang.data)).join('+')
-);

src/worker-script/utils/setImage.js

@@ -1,4 +1,5 @@
-const { readImage } = require('tesseract.js-utils');
+const bmp = require('bmp-js');
+const fileType = require('file-type');
 
 /**
  * setImage
@@ -9,16 +10,43 @@ const { readImage } = require('tesseract.js-utils');
  * @param {array} image - binary array in array format
  * @returns {number} - an emscripten pointer of the image
  */
-module.exports = (TessModule, api, image, params) => {
-  const {
-    tessjs_image_rectangle_left: left,
-    tessjs_image_rectangle_top: top,
-    tessjs_image_rectangle_width: width,
-    tessjs_image_rectangle_height: height,
-  } = params;
-  const {
-    w, h, bytesPerPixel, data, pix,
-  } = readImage(TessModule, Array.from(image));
+module.exports = (TessModule, api, image) => {
+  const buf = Buffer.from(Array.from(image));
+  const type = fileType(buf);
+  let bytesPerPixel = 0;
+  let data = null;
+  let pix = null;
+  let w = 0;
+  let h = 0;
+
+  /*
+   * Although leptonica should support reading bmp, there is a bug of "compressed BMP files".
+   * As there is no solution, we need to use bmp-js for now.
+   * @see https://groups.google.com/forum/#!topic/tesseract-ocr/4mPD9zTxdxE
+   */
+  if (type && type.mime === 'image/bmp') {
+    const bmpBuf = bmp.decode(buf);
+    data = TessModule._malloc(bmpBuf.data.length * Uint8Array.BYTES_PER_ELEMENT);
+    TessModule.HEAPU8.set(bmpBuf.data, data);
+    w = bmpBuf.width;
+    h = bmpBuf.height;
+    bytesPerPixel = 4;
+  } else {
+    const ptr = TessModule._malloc(buf.length * Uint8Array.BYTES_PER_ELEMENT);
+    TessModule.HEAPU8.set(buf, ptr);
+    pix = TessModule._pixReadMem(ptr, buf.length);
+    if (TessModule.getValue(pix + (7 * 4), 'i32') === 0) {
+      /*
+       * Set a yres default value to prevent warning from tesseract
+       * See kMinCredibleResolution in tesseract/src/ccstruct/publictypes.h
+       */
+      TessModule.setValue(pix + (7 * 4), 300, 'i32');
+    }
+    [w, h] = Array(2).fill(0)
+      .map((v, idx) => (
+        TessModule.getValue(pix + (idx * 4), 'i32')
+      ));
+  }
 
   /*
    * As some image format (ex. bmp) is not supported natiely by tesseract,
@@ -31,11 +59,5 @@ module.exports = (TessModule, api, image, params) => {
   } else {
     api.SetImage(data, w, h, bytesPerPixel, w * bytesPerPixel);
   }
-  api.SetRectangle(
-    (left < 0) ? 0 : left,
-    (top < 0) ? 0 : top,
-    (width < 0) ? w : width,
-    (height < 0) ? h : height,
-  );
   return data === null ? pix : data;
 };

src/worker/node/send.js

@@ -46,7 +46,7 @@ const loadImage = (image) => {
  * @param {object} instance TesseractWorker instance
  * @param {object} iPacket data for worker
  */
-module.exports = ({ worker }, packet) => {
+module.exports = (worker, packet) => {
   const p = { ...packet };
   if (['recognize', 'detect'].includes(p.action)) {
     loadImage(p.payload.image)