ppReader-Web/text.html at master · CrashKingOrz/ppReader-Web · GitHub

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<!doctype html>
<html lang="en">
<head>
  <title>GET VIDEO</title>
  <meta charset="utf-8">
</head>
<body>
<input type="button" title="开启摄像头" value="开启摄像头" onclick="getMedia()" />
<video id="video" width="500px" height="500px" autoplay="autoplay"></video>
<canvas id="canvas" width="500px" height="500px"></canvas>
<button id="snap" onclick="takePhoto()">拍照</button>
<script>
  //获得video摄像头区域
  let video = document.getElementById("video");
  function getMedia() {
    let constraints = {
      video: {width: 500, height: 500},
      audio: true
    };
    /*
    这里介绍新的方法:H5新媒体接口 navigator.mediaDevices.getUserMedia()
    这个方法会提示用户是否允许媒体输入,(媒体输入主要包括相机,视频采集设备,屏幕共享服务,麦克风,A/D转换器等)
    返回的是一个Promise对象。
    如果用户同意使用权限,则会将 MediaStream对象作为resolve()的参数传给then()
    如果用户拒绝使用权限,或者请求的媒体资源不可用,则会将 PermissionDeniedError作为reject()的参数传给catch()
    */
    let promise = navigator.mediaDevices.getUserMedia(constraints);
    promise.then(function (MediaStream) {
      video.srcObject = MediaStream;
      video.play();
    }).catch(function (PermissionDeniedError) {
      console.log(PermissionDeniedError);
    })
  }
  function takePhoto() {
    //获得Canvas对象
    let canvas = document.getElementById("canvas");
    let ctx = canvas.getContext('2d');
    ctx.drawImage(video, 0, 0, 500, 500);
  }
</script>
</body>
</html>