<!DOCTYPE html>
<html>
<head>
<title>JS调用摄像头屏幕截图</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<style>
</style>
<script src="https://code.jquery.com/jquery-2.2.4.min.js" integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44="
crossorigin="anonymous"></script>
<script src="https://webrtc.github.io/adapter/adapter-latest.js"></script>
<script type="text/javascript">
var localVideo;
var localStream;
var aCanvas;
var ctx;
$(function(){
localVideo = document.querySelector('#localVideo');
aCanvas = document.getElementById('canvas');
ctx = aCanvas.getContext('2d');
navigator.mediaDevices.enumerateDevices()
.then(function(devices) {
devices.forEach(function(device) {
if(device.kind === "videoinput"){
if(device.label === ""){
$("#videoDevice").append("<option value='" + device.deviceId + "'>" + device.deviceId + "</option>");
}else{
$("#videoDevice").append("<option value='" + device.deviceId + "'>" + device.label + "</option>");
}
}
if(device.kind === "audioinput"){
if(device.label === ""){
$("#microphoneDevice").append("<option value='" + device.deviceId + "'>" + device.deviceId + "</option>");
}else{
$("#microphoneDevice").append("<option value='" + device.deviceId + "'>" + device.label + "</option>");
}
}
//console.log(device.kind + ": " + device.label + " id = " + device.deviceId);
});
})
.catch(function(err) {
console.log(err.name + ": " + err.message);
});
});
function View(){
let deviceType = $('input[name="deviceType"]:checked').val().toString();
if (deviceType === "1") {//摄像头
return new Promise(function (resolve, reject) {
navigator.mediaDevices.getUserMedia({
audio: {deviceId: $("#microphoneDevice").val()},
video: {deviceId: $("#videoDevice").val()}
//video: {mediaSource: 'screen'}//屏幕共享只支持火狐
}).then(function openLocalStream(stream) {
localVideo.srcObject = stream;
localStream = stream;
resolve('初始化本地视频成功！');
}).catch(function (e) {
console.log(e);
alert('getUserMedia() error: ' + e.name);
reject(e);
});
});
} else {//屏幕
return new Promise(function (resolve, reject) {
navigator.mediaDevices.getDisplayMedia({
video: {cursor: "never"},
audio: false //true时谷歌报错
}).then(function (stream) {
localVideo.srcObject = stream;
localStream = stream;
resolve('初始化本地视频成功！');
}).catch(function (e) {
console.log(e);
alert('getDisplayMedia() error: ' + e.name);
reject(e.name);
});
});
}
}
function Stop(){
//清空图像
localVideo.srcObject = null;
//关闭设备
localStream.getTracks().forEach(track => {
track.stop();
});
}
function Snap(){
ctx.drawImage(localVideo, 0, 0, 640, 480); //将获取视频绘制在画布上
}
</script>
</head>
<body>
<input type="radio" name="deviceType" value="1" checked>摄像头
<input type="radio" name="deviceType" value="2">屏幕
<button type="button" onclick="View()">显示</button>
<button type="button" onclick="Stop()">停止</button>
<button type="button" onclick="Snap()">截图</button>
视频:<select id="videoDevice"></select>
麦克风:<select id="microphoneDevice"></select>
<br>
<video id="localVideo" style="width: 600px; height:600px" autoplay></video>
<canvas id="canvas" width="600" height="600"></canvas>
</body>
</html>
在线代码:https://codepen.io/pen/?&editable=true
