Update rectangles to rectangle as only one region can be assigned, fix #378

Author: jeromewu

docs/api.md

@@ -179,7 +179,7 @@ Figures out what words are in `image`, where the words are in `image`, etc.
 
 - `image` see [Image Format](./image-format.md) for more details.
 - `options` a object of customized optons
-  - `rectangles` an array of objects to specify the region you want to recognized in the image, the object should contain top, left, width and height, see example below.
+  - `rectangle` an object to specify the region you want to recognized in the image, the object should contain top, left, width and height, see example below.
 - `jobId` Please see details above
 
 **Output:**
@@ -198,7 +198,7 @@ const { createWorker } = Tesseract;
 })();
 ```
 
-With rectangles
+With rectangle
 
 ```javascript
 const { createWorker } = Tesseract;
@@ -208,9 +208,7 @@ const { createWorker } = Tesseract;
   await worker.loadLanguage('eng');
   await worker.initialize('eng');
   const { data: { text } } = await worker.recognize(image, {
-    rectangles: [
-      { top: 0, left: 0, width: 100, height: 100 },
-    ],
+    rectangle: { top: 0, left: 0, width: 100, height: 100 },
   });
   console.log(text);
 })();

docs/examples.md

@@ -5,7 +5,7 @@ You can also check [examples](../examples) folder.
 ### basic
 
 ```javascript
-import { createWorker } from 'tesseract.js';
+const { createWorker } = require('tesseract.js');
 
 const worker = createWorker();
 
@@ -22,7 +22,7 @@ const worker = createWorker();
 ### with detailed progress 
 
 ```javascript
-import { createWorker } from 'tesseract.js';
+const { createWorker } = require('tesseract.js');
 
 const worker = createWorker({
   logger: m => console.log(m), // Add logger here
@@ -41,7 +41,7 @@ const worker = createWorker({
 ### with multiple languages, separate by '+'
 
 ```javascript
-import { createWorker } from 'tesseract.js';
+const { createWorker } = require('tesseract.js');
 
 const worker = createWorker();
 
@@ -57,7 +57,7 @@ const worker = createWorker();
 ### with whitelist char (^2.0.0-beta.1)
 
 ```javascript
-import { createWorker } from 'tesseract.js';
+const { createWorker } = require('tesseract.js');
 
 const worker = createWorker();
 
@@ -79,7 +79,7 @@ const worker = createWorker();
 Check here for more details of pageseg mode: https://github.com/tesseract-ocr/tesseract/blob/4.0.0/src/ccstruct/publictypes.h#L163
 
 ```javascript
-import { createWorker, PSM } from 'tesseract.js';
+const { createWorker, PSM } = require('tesseract.js');
 
 const worker = createWorker();
 
@@ -103,30 +103,105 @@ Please check **examples** folder for details.
 Browser: [download-pdf.html](../examples/browser/download-pdf.html)
 Node: [download-pdf.js](../examples/node/download-pdf.js)
 
-### with only part of the image (^2.0.0-beta.1)
+### with only part of the image (^2.0.1)
+
+**One rectangle**
 
 ```javascript
-import { createWorker } from 'tesseract.js';
+const { createWorker } = require('tesseract.js');
+
+const worker = createWorker();
+const rectangle = { left: 0, top: 0, width: 500, height: 250 };
+
+(async () => {
+  await worker.load();
+  await worker.loadLanguage('eng');
+  await worker.initialize('eng');
+  const { data: { text } } = await worker.recognize('https://tesseract.projectnaptha.com/img/eng_bw.png', { rectangle });
+  console.log(text);
+  await worker.terminate();
+})();
+```
+
+**Multiple Rectangles**
+
+```javascript
+const { createWorker } = require('tesseract.js');
 
 const worker = createWorker();
 const rectangles = [
-  { left: 0, top: 0, width: 500, height: 250 },
+  {
+    left: 0,
+    top: 0,
+    width: 500,
+    height: 250,
+  },
+  {
+    left: 500,
+    top: 0,
+    width: 500,
+    height: 250,
+  },
 ];
 
 (async () => {
   await worker.load();
   await worker.loadLanguage('eng');
   await worker.initialize('eng');
-  const { data: { text } } = await worker.recognize('https://tesseract.projectnaptha.com/img/eng_bw.png', 'eng', { rectangles });
-  console.log(text);
+  const values = [];
+  for (let i = 0; i < rectangles.length; i++) {
+    const { data: { text } } = await worker.recognize('https://tesseract.projectnaptha.com/img/eng_bw.png', { rectangle: rectangles[i] });
+    values.push(text);
+  }
+  console.log(values);
   await worker.terminate();
 })();
 ```
 
+**Multiple Rectangles (with scheduler to do recognition in parallel)**
+
+```javascript
+const { createWorker, createScheduler } = require('tesseract.js');
+
+const scheduler = createScheduler();
+const worker1 = createWorker();
+const worker2 = createWorker();
+const rectangles = [
+  {
+    left: 0,
+    top: 0,
+    width: 500,
+    height: 250,
+  },
+  {
+    left: 500,
+    top: 0,
+    width: 500,
+    height: 250,
+  },
+];
+
+(async () => {
+  await worker1.load();
+  await worker2.load();
+  await worker1.loadLanguage('eng');
+  await worker2.loadLanguage('eng');
+  await worker1.initialize('eng');
+  await worker2.initialize('eng');
+  scheduler.addWorker(worker1);
+  scheduler.addWorker(worker2);
+  const results = await Promise.all(rectangles.map((rectangle) => (
+    scheduler.addJob('recognize', 'https://tesseract.projectnaptha.com/img/eng_bw.png', { rectangle })
+  )));
+  console.log(results.map(r => r.data.text));
+  await scheduler.terminate();
+})();
+```
+
 ### with multiple workers to speed up (^2.0.0-beta.1)
 
 ```javascript
-import { createWorker, createScheduler } from 'tesseract.js';
+const { createWorker, createScheduler } = require('tesseract.js');
 
 const scheduler = createScheduler();
 const worker1 = createWorker();
@@ -143,7 +218,7 @@ const worker2 = createWorker();
   scheduler.addWorker(worker2);
   /** Add 10 recognition jobs */
   const results = await Promise.all(Array(10).fill(0).map(() => (
-    await scheduler.addJob('recognize', 'https://tesseract.projectnaptha.com/img/eng_bw.png')
+    scheduler.addJob('recognize', 'https://tesseract.projectnaptha.com/img/eng_bw.png')
   )))
   console.log(results);
   await scheduler.terminate(); // It also terminates all workers.

src/worker-script/index.js

@@ -187,14 +187,12 @@ const initialize = ({
   }
 };
 
-const recognize = ({ payload: { image, options: { rectangles = [] } } }, res) => {
+const recognize = ({ payload: { image, options: { rectangle: rec } } }, res) => {
   try {
     const ptr = setImage(TessModule, api, image);
-    rectangles.forEach(({
-      left, top, width, height,
-    }) => {
-      api.SetRectangle(left, top, width, height);
-    });
+    if (typeof rec === 'object') {
+      api.SetRectangle(rec.left, rec.top, rec.width, rec.height);
+    }
     api.Recognize(null);
     res.resolve(dump(TessModule, api, params));
     TessModule._free(ptr);

tests/recognize.test.js

@@ -69,11 +69,9 @@ describe('recognize()', () => {
         const { data: { text } } = await worker.recognize(
           `${IMAGE_PATH}/${name}`,
           {
-            rectangles: [
-              {
-                top, left, width, height,
-              },
-            ],
+            rectangle: {
+              top, left, width, height,
+            },
           },
         );
         expect(text).to.be(ans);