6. Bekijk hoe u een Computer Vision toevoegt aan de React app
Dit voorbeeld heeft alle TypeScript-code die nodig is om een Computer Vision aan de React app. In deze sectie van de zelfstudie worden de stappen en code bespreekt. U hoeft deze stappen niet uit te voeren voor deze zelfstudie.
- Voorbeeldcode
- Azure-services
Een Computer Vision toevoegen aan de lokale React app
Gebruik npm om een Computer Vision aan het bestand package.json toe te voegen.
npm install @azure/cognitiveservices-computervision
Code Computer Vision toevoegen als afzonderlijke module
De Computer Vision code is opgenomen in een afzonderlijk bestand met de naam ./src/azure-cognitiveservices-computervision.js . De hoofdfunctie van de module is gemarkeerd.
// ./src/azure-cognitiveservices-computervision.js
// Azure SDK client libraries
import { ComputerVisionClient } from '@azure/cognitiveservices-computervision';
import { ApiKeyCredentials } from '@azure/ms-rest-js';
// List of sample images to use in demo
import RandomImageUrl from './DefaultImages';
// Authentication requirements
const key = process.env.REACT_APP_COMPUTERVISIONKEY;
const endpoint = process.env.REACT_APP_COMPUTERVISIONENDPOINT;
console.log(`key = ${key}`)
console.log(`endpoint = ${endpoint}`)
// Cognitive service features
const visualFeatures = [
"ImageType",
"Faces",
"Adult",
"Categories",
"Color",
"Tags",
"Description",
"Objects",
"Brands"
];
export const isConfigured = () => {
const result = (key && endpoint && (key.length > 0) && (endpoint.length > 0)) ? true : false;
console.log(`key = ${key}`)
console.log(`endpoint = ${endpoint}`)
console.log(`ComputerVision isConfigured = ${result}`)
return result;
}
// Computer Vision detected Printed Text
const includesText = async (tags) => {
return tags.filter((el) => {
return el.name.toLowerCase() === "text";
});
}
// Computer Vision detected Handwriting
const includesHandwriting = async (tags) => {
return tags.filter((el) => {
return el.name.toLowerCase() === "handwriting";
});
}
// Wait for text detection to succeed
const wait = (timeout) => {
return new Promise(resolve => {
setTimeout(resolve, timeout);
});
}
// Analyze Image from URL
export const computerVision = async (url) => {
// authenticate to Azure service
const computerVisionClient = new ComputerVisionClient(
new ApiKeyCredentials({ inHeader: { 'Ocp-Apim-Subscription-Key': key } }), endpoint);
// get image URL - entered in form or random from Default Images
const urlToAnalyze = url || RandomImageUrl();
// analyze image
const analysis = await computerVisionClient.analyzeImage(urlToAnalyze, { visualFeatures });
// text detected - what does it say and where is it
if (includesText(analysis.tags) || includesHandwriting(analysis.tags)) {
analysis.text = await readTextFromURL(computerVisionClient, urlToAnalyze);
}
// all information about image
return { "URL": urlToAnalyze, ...analysis};
}
// analyze text in image
const readTextFromURL = async (client, url) => {
let result = await client.read(url);
let operationID = result.operationLocation.split('/').slice(-1)[0];
// Wait for read recognition to complete
// result.status is initially undefined, since it's the result of read
const start = Date.now();
console.log(`${start} -${result?.status} `);
while (result.status !== "succeeded") {
await wait(500);
console.log(`${Date.now() - start} -${result?.status} `);
result = await client.getReadResult(operationID);
}
// Return the first page of result.
// Replace[0] with the desired page if this is a multi-page file such as .pdf or.tiff.
return result.analyzeResult;
}
Catalogus met afbeeldingen toevoegen als afzonderlijke module
De app selecteert een willekeurige afbeelding uit een catalogus als de gebruiker geen afbeeldings-URL op geeft. De functie voor willekeurige selectie is gemarkeerd
const describeURL = 'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/celebrities.jpg';
const categoryURLImage = 'https://moderatorsampleimages.blob.core.windows.net/samples/sample16.png';
const tagsURL = 'https://moderatorsampleimages.blob.core.windows.net/samples/sample16.png';
const objectURL = 'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-node-sdk-samples/master/Data/image.jpg';
const brandURLImage = 'https://docs.microsoft.com/en-us/azure/cognitive-services/computer-vision/images/red-shirt-logo.jpg';
const facesImageURL = 'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/faces.jpg';
const printedTextSampleURL = 'https://moderatorsampleimages.blob.core.windows.net/samples/sample2.jpg';
const multiLingualTextURL = 'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/MultiLingual.png';
const adultURLImage = 'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/celebrities.jpg';
const colorURLImage = 'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/celebrities.jpg';
// don't use with picture analysis
// eslint-disable-next-line
const mixedMultiPagePDFURL = 'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/MultiPageHandwrittenForm.pdf';
const domainURLImage = 'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/landmark.jpg';
const typeURLImage = 'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-python-sdk-samples/master/samples/vision/images/make_things_happen.jpg';
const DefaultImages = [
describeURL,
categoryURLImage,
tagsURL,
objectURL,
brandURLImage,
facesImageURL,
adultURLImage,
colorURLImage,
domainURLImage,
typeURLImage,
printedTextSampleURL,
multiLingualTextURL,
//mixedMultiPagePDFURL
];
const RandomImageUrl = () => {
return DefaultImages[Math.floor(Math.random() * Math.floor(DefaultImages.length))];
}
export default RandomImageUrl;
Aangepaste module Computer Vision toevoegen aan React app
Voeg methoden toe aan de React app.js . De afbeeldingsanalyse en weergave van de resultaten zijn gemarkeerd.
// ./src/App.js
import React, { useState } from 'react';
import './App.css';
import { computerVision, isConfigured as ComputerVisionIsConfigured } from './azure-cognitiveservices-computervision';
function App() {
const [fileSelected, setFileSelected] = useState(null);
const [analysis, setAnalysis] = useState(null);
const [processing, setProcessing] = useState(false);
const handleChange = (e) => {
setFileSelected(e.target.value)
}
const onFileUrlEntered = (e) => {
// hold UI
setProcessing(true);
setAnalysis(null);
computerVision(fileSelected || null).then((item) => {
// reset state/form
setAnalysis(item);
setFileSelected("");
setProcessing(false);
});
};
// Display JSON data in readable format
const PrettyPrintJson = (data) => {
return (<div><pre>{JSON.stringify(data, null, 2)}</pre></div>);
}
const DisplayResults = () => {
return (
<div>
<h2>Computer Vision Analysis</h2>
<div><img src={analysis.URL} height="200" border="1" alt={(analysis.description && analysis.description.captions && analysis.description.captions[0].text ? analysis.description.captions[0].text : "can't find caption")} /></div>
{PrettyPrintJson(analysis)}
</div>
)
};
const Analyze = () => {
return (
<div>
<h1>Analyze image</h1>
{!processing &&
<div>
<div>
<label>URL</label>
<input type="text" placeholder="Enter URL or leave empty for random image from collection" size="50" onChange={handleChange}></input>
</div>
<button onClick={onFileUrlEntered}>Analyze</button>
</div>
}
{processing && <div>Processing</div>}
<hr />
{analysis && DisplayResults()}
</div>
)
}
const CantAnalyze = () => {
return (
<div>Key and/or endpoint not configured in ./azure-cognitiveservices-computervision.js</div>
)
}
function Render() {
const ready = ComputerVisionIsConfigured();
if (ready) {
return <Analyze />;
}
return <CantAnalyze />;
}
return (
<div>
{Render()}
</div>
);
}
export default App;