为什么80%的码农都做不了架构师？>>>
但是navigator.getUserMediau已经从 Web 标准中删除，虽然部分浏览器可以使用，生产环境中还是要做好兼容。新的API更替为MediaDevices.getUserMedia。MediaDevices.getUserMedia可以通过video的facingMode属性指定调用手机的前置或后置摄像头
video:{ 'facingMode': "user" }//调用前置摄像头
video: { facingMode: { exact: "environment" } }//后置
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具体代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1.0,maximum-scale=1.0,minimum-scale=1.0,user-scalable=no">
<title>Document1</title>
<style type='text/css'>
* { margin: 0; padding: 0; }
html, body { height: 100%; }
.flex { display: flex; }
.flex-row { flex-direction: row; justify-content: space-around; align-items: center; }
.flex-column { flex-direction: column; justify-content: flex-start; align-items: center; }
body { overflow: auto; background: #fff; }
.title { width: 920px; padding: 30px; align-items: flex-end; }
.title h1 { padding-bottom: 20px; font-size: 38px; color: #ffffff; text-shadow: 0 1px 3px #222222; }
.title p { font-size: 18px; color: #f5f5f5; text-shadow: 0 1px 3px #565656; }
.wrap { width: 1220px; }
.wrap .reference { position: relative; padding: 10px; background-color: rgba(255, 255, 255, 0); border-radius: 10px; box-shadow: 0 0 20px #a1a19f; }
.wrap .reference img.face { display: block; width: 320px; height: auto; border-radius: 10px; }
.wrap .reference img.toggle { position: absolute; right: 10px; top: 10px; width: 50px; height: 50px; }
.wrap .scan video { background-color: rgba(0, 0, 0, .8); border-radius: 10px; }
.wrap .control { justify-content: space-around; height: 456px; padding: 0 20px; }
.wrap .control p { width: 160px; height: 60px; background-color: #f9f9f9; text-align: center; line-height: 60px; color: #ffffff; font-size: 24px; border-radius: 8px; cursor: pointer; box-shadow: -8px -8px 150px -8px #b2b3b5 inset, 0 0 5px #222222; text-shadow: 0 0 1px #222222; transition: .5s; }
.wrap .control p:hover { box-shadow: -8px -8px 150px -8px #50c4f1 inset, 0 0 5px #ffffff; }
.wrap .scan { position: relative; overflow: hidden; }
.wrap .scan .strainer { position: absolute; top: 10px; width: 320px; z-index: 999; height: 3px; }
.wrap .scan .capture { width: 320px; height: 456px; }
.wrap .scan .strainer.on { background: linear-gradient(to left, transparent, #0bffb2, transparent); animation: scan 1s linear infinite; }
@keyframes scan {
0% { top: 10px; }
50% { top: 456px; }
100% { top: 10px; }
}
</style>
<script type="text/javascript" src="vconsole.min.js"></script>
</head>
<body>
<div class="title flex flex-column">
</div>
<div class="wrap flex flex-row">
<div class="control flex flex-column">
<p class="open">开启摄像头</p>
<p class="recognition">显示到Canvas</p>
<p class="close">关闭摄像头</p>
</div>
<div class="scan reference">
<div class="strainer"></div>
<video class="capture" width="320" height="456" src=""></video>
</div>
</div>
<script type="text/javascript">
var buffer;
var oCapture = document.querySelector(".capture"),
open = document.querySelector(".open"),
recognition = document.querySelector(".recognition"),
close = document.querySelector(".close");
var control = document.querySelector(".control");
window.navigator.getUserMedia = navigator.getUserMedia || navigator.webKitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;
function invokingCarera(){
if(navigator.mediaDevices&&navigator.mediaDevices.getUserMedia){
navigator.mediaDevices.getUserMedia({
'audio':true,
'video':{ 'facingMode': "user" }//调用前置摄像头，后置摄像头使用video: { facingMode: { exact: "environment" } }
})
.then(function(mediaStream) {console.log(555);getVideoStream(mediaStream)})
.catch(function(error) { console.log(666);console.log(error) })
}else if(navigator.getUserMedia){
navigator.getUserMedia({
'video':true,
'audio':true
},getVideoStream,getFail)
}else{
alert('不支持摄像头调用！')
}
}
//调用成功
function getVideoStream(stream){
buffer = stream;
if(oCapture.mozSrcObject !== undefined){
oCapture.mozSrcObject = buffer;
}else{
oCapture.src = window.URL && window.URL.createObjectURL(buffer);
}
oCapture.play();
}
function getFail(){
}
recognition.onclick = function(){
}
control.addEventListener('click',function(e){
e = e || window.event;
var className = e.target.className;
switch(className){
case 'open':
invokingCarera();
break;
case 'close':
closeCamera();
break;
case 'recognition':
screenShot();
break;
default:
break;
}
})
function closeCamera(){
buffer&&buffer.getTracks()[1].stop();//关闭摄像头
}
window.requestAnimFrame = (function(){
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
function( callback ){
window.setTimeout(callback, 1000 / 60);
};
})();
function screenShot(){
var canvas = document.createElement('canvas');
canvas.width=320,canvas.height = 456;
document.querySelector(".wrap").appendChild(canvas);
var ctx = canvas.getContext('2d');
function drawVideo(){
ctx.drawImage(oCapture,0,0,320,456);
ctx.font = "30px sans-serif";
ctx.fillStyle = "blue";
ctx.fillText("请眨眼", 50, 50);
requestAnimationFrame(drawVideo);
}
window.requestAnimationFrame(drawVideo);
}
</script>
</body>
</html>
