优化后端

2026-09-11 17:56:56 +08:00
parent 7eed11b774
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+# Tesseract.js Examples
+
+You can also check [examples](../examples) folder.
+
+### basic
+
+```javascript
+const { createWorker } = require('tesseract.js');
+
+const worker = await createWorker('eng');
+
+(async () => {
+  const { data: { text } } = await worker.recognize('https://tesseract.projectnaptha.com/img/eng_bw.png');
+  console.log(text);
+  await worker.terminate();
+})();
+```
+
+### with detailed progress 
+
+```javascript
+const { createWorker } = require('tesseract.js');
+
+const worker = await createWorker('eng', 1, {
+  logger: m => console.log(m), // Add logger here
+});
+
+(async () => {
+  const { data: { text } } = await worker.recognize('https://tesseract.projectnaptha.com/img/eng_bw.png');
+  console.log(text);
+  await worker.terminate();
+})();
+```
+
+### with multiple languages, separate by '+'
+
+```javascript
+const { createWorker } = require('tesseract.js');
+
+const worker = await createWorker(['eng', 'chi_tra']);
+
+(async () => {
+  const { data: { text } } = await worker.recognize('https://tesseract.projectnaptha.com/img/eng_bw.png');
+  console.log(text);
+  await worker.terminate();
+})();
+```
+### with whitelist char
+
+```javascript
+const { createWorker } = require('tesseract.js');
+
+const worker = await createWorker('eng');
+
+(async () => {
+  await worker.setParameters({
+    tessedit_char_whitelist: '0123456789',
+  });
+  const { data: { text } } = await worker.recognize('https://tesseract.projectnaptha.com/img/eng_bw.png');
+  console.log(text);
+  await worker.terminate();
+})();
+```
+
+### with different pageseg mode
+
+Check here for more details of pageseg mode: https://github.com/tesseract-ocr/tesseract/blob/4.0.0/src/ccstruct/publictypes.h#L163
+
+```javascript
+const { createWorker, PSM } = require('tesseract.js');
+
+const worker = await createWorker('eng');
+
+(async () => {
+  await worker.setParameters({
+    tessedit_pageseg_mode: PSM.SINGLE_BLOCK,
+  });
+  const { data: { text } } = await worker.recognize('https://tesseract.projectnaptha.com/img/eng_bw.png');
+  console.log(text);
+  await worker.terminate();
+})();
+```
+
+### with pdf output
+
+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 (^2.0.1)
+
+**One rectangle**
+
+```javascript
+const { createWorker } = require('tesseract.js');
+
+const worker = await createWorker('eng');
+const rectangle = { left: 0, top: 0, width: 500, height: 250 };
+
+(async () => {
+  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 = await createWorker('eng');
+const rectangles = [
+  {
+    left: 0,
+    top: 0,
+    width: 500,
+    height: 250,
+  },
+  {
+    left: 500,
+    top: 0,
+    width: 500,
+    height: 250,
+  },
+];
+
+(async () => {
+  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 = await createWorker('eng');
+const worker2 = await createWorker('eng');
+const rectangles = [
+  {
+    left: 0,
+    top: 0,
+    width: 500,
+    height: 250,
+  },
+  {
+    left: 500,
+    top: 0,
+    width: 500,
+    height: 250,
+  },
+];
+
+(async () => {
+  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
+
+```javascript
+const { createWorker, createScheduler } = require('tesseract.js');
+
+const scheduler = createScheduler();
+const worker1 = await createWorker('eng');
+const worker2 = await createWorker('eng');
+
+(async () => {
+  scheduler.addWorker(worker1);
+  scheduler.addWorker(worker2);
+  /** Add 10 recognition jobs */
+  const results = await Promise.all(Array(10).fill(0).map(() => (
+    scheduler.addJob('recognize', 'https://tesseract.projectnaptha.com/img/eng_bw.png')
+  )))
+  console.log(results);
+  await scheduler.terminate(); // It also terminates all workers.
+})();
+```