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| 1 | +<!DOCTYPE html> |
| 2 | +<html lang="en"> |
| 3 | +<head> |
| 4 | + <meta charset="UTF-8"> |
| 5 | + <meta name="viewport" content="width=device-width, initial-scale=1.0"> |
| 6 | + <title>Document</title> |
| 7 | +</head> |
| 8 | +<body> |
| 9 | + <video id="video" autoplay muted playsinline></video> |
| 10 | +</body> |
| 11 | +<script type="module"> |
| 12 | +import BarcodeDetector from "https://cdn.skypack.dev/[email protected]"; |
| 13 | + |
| 14 | +const adaptOldFormat = detectedCodes => { |
| 15 | + if (detectedCodes.length > 0) { |
| 16 | + const [ firstCode ] = detectedCodes; |
| 17 | + |
| 18 | + const [ |
| 19 | + topLeftCorner, |
| 20 | + topRightCorner, |
| 21 | + bottomRightCorner, |
| 22 | + bottomLeftCorner |
| 23 | + ] = firstCode.cornerPoints |
| 24 | + |
| 25 | + return { |
| 26 | + content: firstCode.rawValue, |
| 27 | + location: { |
| 28 | + topLeftCorner, |
| 29 | + topRightCorner, |
| 30 | + bottomRightCorner, |
| 31 | + bottomLeftCorner, |
| 32 | + |
| 33 | + // not supported by native API: |
| 34 | + topLeftFinderPattern: {}, |
| 35 | + topRightFinderPattern: {}, |
| 36 | + bottomLeftFinderPattern: {} |
| 37 | + }, |
| 38 | + imageData: null |
| 39 | + } |
| 40 | + } else { |
| 41 | + return { |
| 42 | + content: null, |
| 43 | + location: null, |
| 44 | + imageData: null |
| 45 | + } |
| 46 | + } |
| 47 | +} |
| 48 | + |
| 49 | +export const keepScanning = (videoElement, options) => { |
| 50 | + const barcodeDetector = new BarcodeDetector({ formats: ["qr_code"] }); |
| 51 | + |
| 52 | + const { detectHandler, locateHandler, minDelay } = options; |
| 53 | + |
| 54 | + const processFrame = state => async timeNow => { |
| 55 | + if (videoElement.readyState > 1) { |
| 56 | + console.log("scan") |
| 57 | + const { lastScanned, contentBefore, locationBefore } = state |
| 58 | + |
| 59 | + if (timeNow - lastScanned >= minDelay) { |
| 60 | + const detectedCodes = await barcodeDetector.detect(videoElement); |
| 61 | + const { content, location, imageData } = adaptOldFormat(detectedCodes) |
| 62 | + |
| 63 | + if (content !== null && content !== contentBefore) { |
| 64 | + detectHandler({ content, location, imageData }); |
| 65 | + } |
| 66 | + |
| 67 | + if (location !== null || locationBefore !== null) { |
| 68 | + locateHandler(detectedCodes); |
| 69 | + } |
| 70 | + |
| 71 | + window.requestAnimationFrame(processFrame({ |
| 72 | + lastScanned: timeNow, |
| 73 | + contentBefore: content ?? contentBefore, |
| 74 | + locationBefore: location |
| 75 | + })) |
| 76 | + } else { |
| 77 | + window.requestAnimationFrame(processFrame(state)) |
| 78 | + } |
| 79 | + } |
| 80 | + }; |
| 81 | + |
| 82 | + processFrame({ |
| 83 | + contentBefore: null, |
| 84 | + locationBefore: null, |
| 85 | + lastScanned: performance.now() |
| 86 | + })(); |
| 87 | +}; |
| 88 | + |
| 89 | +(async () => { |
| 90 | + const videoEl = document.querySelector('#video') |
| 91 | + |
| 92 | + const stream = await navigator.mediaDevices.getUserMedia({ video: true, audio: false }) |
| 93 | + |
| 94 | + videoEl.srcObject = stream |
| 95 | + |
| 96 | + videoEl.addEventListener("loadeddata", () => { |
| 97 | + keepScanning(videoEl, { minDelay: 40, detectHandler: console.log, locateHandler: console.log }) |
| 98 | + }) |
| 99 | + |
| 100 | +})() |
| 101 | +</script> |
| 102 | +</html> |
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