# 移动端网页调用摄像头的 2 种方式
# WebRTC
navigator.mediaDevices.getUserMedia
// 这里还有一个旧有的 API Navigator.getUserMedia 已经被废弃掉了
1
2
2
<body>
<div>H5调前置摄像头DEMO</div>
<video id="video" width="480" height="320" muted controls autoplay="autoplay">
</video>
<div>
<button id="capture">拍照</button>
</div>
<canvas id="canvas" width="480" height="320"></canvas>
<script>
//访问用户媒体设备的兼容方法
function getUserMedia(constraints, success, error) {
if (navigator.mediaDevices.getUserMedia) {
//最新的标准API
navigator.mediaDevices.getUserMedia({
'audio':{ echoCancellation: false },
'video':{ 'facingMode': "user" }//调用前置摄像头，后置摄像头使用video: { facingMode: { exact: "environment" } }
})
.then(success)
.catch(error)
} else if (navigator.webkitGetUserMedia) {
//webkit核心浏览器
navigator.webkitGetUserMedia(constraints, success, error)
} else if (navigator.mozGetUserMedia) {
//firfox浏览器
navigator.mozGetUserMedia(constraints, success, error);
} else if (navigator.getUserMedia) {
//旧版API
navigator.getUserMedia(constraints, success, error);
}
}
let video = document.getElementById('video');
let canvas = document.getElementById('canvas');
let context = canvas.getContext('2d');
function success(stream) {
//兼容webkit核心浏览器
let CompatibleURL = window.URL || window.webkitURL;
//将视频流设置为video元素的源
console.log(stream);
//video.src = CompatibleURL.createObjectURL(stream);
video.srcObject = stream;
video.play();
}
function error(error) {
console.log(`访问用户媒体设备失败${error.name}, ${error.message}`);
}
if (navigator.mediaDevices.getUserMedia || navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia) {
//调用用户媒体设备, 访问摄像头
getUserMedia({ video: { width: 480, height: 320 } }, success, error);
} else {
alert('不支持访问用户媒体');
}
document.getElementById('capture').addEventListener('click', function () {
context.drawImage(video, 0, 0, 480, 320);
})
</script>
</body>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62