时间：2021-07-11 08:40:52 | 栏目：JavaScript代码 | 点击：次
项目要求：
使用H5模仿微信扫一扫付款功能
经过一系列的查找最后发现可以使用 JS调用手机摄像头然后用画布把当前摄像头的数据转成Base64的png图片，经过QrCode直接再本地识别。
优点：
兼容大多数浏览器
本地识别不占用服务端资源
代码比较简单只有一个页面
<html lang="ZH-CN">
<head>
<meta charset="utf-8">
<title>Web QrCode Test</title>
<script type="text/javascript" src="jquery-1.8.3.min.js"></script>
<script type="text/javascript" src="jsqrcode/src/grid.js"></script>
<script type="text/javascript" src="jsqrcode/src/version.js"></script>
<script type="text/javascript" src="jsqrcode/src/detector.js"></script>
<script type="text/javascript" src="jsqrcode/src/formatinf.js"></script>
<script type="text/javascript" src="jsqrcode/src/errorlevel.js"></script>
<script type="text/javascript" src="jsqrcode/src/bitmat.js"></script>
<script type="text/javascript" src="jsqrcode/src/datablock.js"></script>
<script type="text/javascript" src="jsqrcode/src/bmparser.js"></script>
<script type="text/javascript" src="jsqrcode/src/datamask.js"></script>
<script type="text/javascript" src="jsqrcode/src/rsdecoder.js"></script>
<script type="text/javascript" src="jsqrcode/src/gf256poly.js"></script>
<script type="text/javascript" src="jsqrcode/src/gf256.js"></script>
<script type="text/javascript" src="jsqrcode/src/decoder.js"></script>
<script type="text/javascript" src="jsqrcode/src/qrcode.js"></script>
<script type="text/javascript" src="jsqrcode/src/findpat.js"></script>
<script type="text/javascript" src="jsqrcode/src/alignpat.js"></script>
<script type="text/javascript" src="jsqrcode/src/databr.js"></script>
</head>
<body>
<div class="booth">
<video id="video" width="400" height="400"></video>
<canvas id='canvas' width='400' height='400'></canvas>
<img id='img' src=''>
</div>
<div id="mmm"></div>
<canvas id="qr-canvas" width="640" height="480"></canvas>
<script>
//初始化媒体对象
var c=0;
var video = document.getElementById('video'),
canvas = document.getElementById('canvas'),
img = document.getElementById('img'),
vendorUrl = window.URL || window.webkitURL;
//媒体对象
navigator.getMedia = navigator.getUserMedia ||
navagator.webkitGetUserMedia ||
navigator.mozGetUserMedia ||
navigator.msGetUserMedia;
navigator.getMedia({
video: true, //使用摄像头对象
audio: false //不适用音频
}, function(strem){
console.log(strem);
video.src = vendorUrl.createObjectURL(strem);
video.play();
}, function(error) {
//error.code
console.log(error);
});
//启动定时器
setTimeout("actionP(null)","1000");
//定时器
function actionP(data){
if(data==null){
Screenshot()
}else{
if(data!=null & data!="error decoding QR Code"){//识别出数据
if(data.indexOf("http")!=-1){
window.location.href=data;
}else alert(data);
}else{//没有数据循环十次
c++;
if(c<10){
setTimeout("actionP(null)","1000");
}
}
}
}
function Screenshot(){//截取图像
canvas.getContext('2d').drawImage(video, 0, 0, 400, 400);
var imgData = canvas.toDataURL("image/png");
load(imgData);
img.src=imgData;
}
////////////////////////////////////////识别二维码////////////////////////////////////////////
function dragenter(e) {
e.stopPropagation();
e.preventDefault();
}
function dragover(e) {
e.stopPropagation();
e.preventDefault();
}
function drop(e) {
e.stopPropagation();
e.preventDefault();
var dt = e.dataTransfer;
var files = dt.files;
}
function load(name)
{
initCanvas(640,480);
//识别二维码并回调方法
qrcode.callback = actionP;
qrcode.decode(name);
}
function initCanvas(ww,hh)//创建画板
{
gCanvas = document.getElementById("qr-canvas");
gCanvas.addEventListener("dragenter", dragenter, false);
gCanvas.addEventListener("dragover", dragover, false);
gCanvas.addEventListener("drop", drop, false);
var w = ww;
var h = hh;
gCanvas.style.width = w + "px";
gCanvas.style.height = h + "px";
gCanvas.width = w;
gCanvas.height = h;
gCtx = gCanvas.getContext("2d");
gCtx.clearRect(0, 0, w, h);
imageData = gCtx.getImageData( 0,0,320,240);
}
</script>
</body>
</html>