小程序解析二维码:jsQR
jsQR是一个用于解析二维码的JavaScript库。以下是使用jsQR解析二维码的基本步骤:
- 引入jsQR库。
- 访问用户的摄像头。
- 定期从摄像头捕获帧。
- 使用jsQR解析帧数据以获取二维码数据。
以下是一个简单的示例代码,展示了如何使用jsQR在网页上解析二维码:
<!DOCTYPE html>
<html>
<head>
<title>jsQR Demo</title>
</head>
<body>
<video id="video" width="300" height="200" style="display: block;"></video>
<canvas id="canvas" style="display: none;"></canvas>
<script src="https://cdn.jsdelivr.net/npm/jsqr@latest/dist/jsQR.js"></script>
<script>
const video = document.createElement("video");
const canvasElement = document.getElementById("canvas");
const canvas = canvasElement.getContext("2d");
let scanning = false;
video.setAttribute("autoplay", "");
video.setAttribute("playsinline", true); // iOS
function setUpScanner() {
navigator.mediaDevices.getUserMedia({ video: { facingMode: "environment" } })
.then(function(stream) {
video.srcObject = stream;
scanning = true;
})
.catch(function(err) {
console.error(err);
});
}
setUpScanner();
function scan() {
if (scanning) {
requestAnimationFrame(scan);
}
canvasElement.height = video.videoHeight;
canvasElement.width = video.videoWidth;
canvas.drawImage(video, 0, 0, canvasElement.width, canvasElement.height);
const imageData = canvas.getImageData(0, 0, canvasElement.width, canvasElement.height);
const code = jsQR(imageData.data, imageData.width, imageData.height, {
inversionAttempts: "dontInvert",
});
if (code) {
console.log("Decoded QR Code", code.data);
scanning = false;
video.srcObject.getTracks().forEach(track => track.stop());
}
}
setTimeout(() => scan(), 1000); // Delay for one second to allow the video stream to start.
</script>
</body>
</html>
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