实时预览
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<title>Title</title>
</head>
<body>
<div>
<video id="video"></video>
<canvas id="canvas"></canvas>
<!-- <canvas id="canvas" style="display: none"></canvas>-->
<script>
const width = 480;
const height = 320;
const video = document.getElementById('video');
//访问摄像头
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, height: height } }, success, error);
} else {
alert('不支持访问用户媒体');
}
//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(constraints).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);
}
}
//成功回调
function success(stream) {
console.log('成功');
//兼容webkit核心浏览器
// const CompatibleURL = window.URL || window.webkitURL;
//将视频流设置为video元素的源
// video.src = CompatibleURL.createObjectURL(stream);
video.srcObject = stream;
video.play();
setInterval(drawCanvasImage, 10);
}
//失败回调
function error(error) {
console.log('失败');
console.log('访问用户媒体设备失败', error);
}
function drawCanvasImage() {
const canvas = document.getElementById('canvas');
canvas.width = width;
canvas.height = height;
const context = canvas.getContext('2d');
context.drawImage(video, 0, 0, width, height, 0, 0, width, height);
//获取图片，数据格式为base64
const imageData = canvas.toDataURL('image/png');
console.log(imageData);
}
</script>
</div>
</body>
</html>