<!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");
async 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()
try {
let MediaStream = await navigator.mediaDevices.getUserMedia(
constraints
);
console.log("返回对象", MediaStream);
video.srcObject = MediaStream;
video.play();
} catch (e) {
console.log(e);
}
}
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>
