学习记录1

人脸识别技术中js调用本地摄像头拍照，上传图片文字字符串的实现：

function getMedia() {
$("#mainDiv").empty();
let videoComp = " <video id='video' width='500px' height='500px' autoplay='autoplay' style='margin-top: 20px'></video><canvas id='canvas' width='500px' height='500px' style='display: none'></canvas>";
$("#mainDiv").append(videoComp);

let constraints = {
video: {width: 500, height: 500},
audio: true
};
//获得video摄像头区域
let video = document.getElementById("video");
//这里介绍新的方法，返回一个 Promise对象
// 这个Promise对象返回成功后的回调函数带一个 MediaStream 对象作为其参数
// then()是Promise对象里的方法
// then()方法是异步执行，当then()前的方法执行完后再执行then()内部的程序
// 避免数据没有获取到
let promise = navigator.mediaDevices.getUserMedia(constraints);
promise.then(function (MediaStream) {
video.srcObject = MediaStream;
video.play();
});

// var t1 = window.setTimeout(function() {
// takePhoto();
// },2000)
}
//拍照事件
function takePhoto() {
let mainComp = $("#mainDiv");
if(mainComp.has('video').length)
{
let userNameInput = $("#userName").val();
if(userNameInput == "")
{
alert("姓名不能为空!");
return false;
}
//获得Canvas对象
let video = document.getElementById("video");
let canvas = document.getElementById("canvas");
let ctx = canvas.getContext('2d');
ctx.drawImage(video, 0, 0, 500, 500);
var formData = new FormData();
var base64File = canvas.toDataURL();
var userName = $("#userName").val();
formData.append("file", base64File);
formData.append("name", userName);
formData.append("groupId", "101");
$.ajax({
type: "post",
url: "/faceAdd",
data: formData,
contentType: false,
processData: false,
async: false,
success: function (text) {
var res = JSON.stringify(text)
if (text.code == 0) {
alert("注册成功")
} else {
alert(text.message)
}
},
error: function (error) {
alert(JSON.stringify(error))
}
});
}
else{
var formData = new FormData();
let userName = $("#userName").val();
formData.append("groupId", "101");
var file = $("#file0")[0].files[0];
var reader = new FileReader();
reader.readAsDataURL(file);
reader.onload = function () {
var base64 = reader.result;
formData.append("file", base64);
formData.append("name",userName);
$.ajax({
type: "post",
url: "/faceAdd",
data: formData,
contentType: false,
processData: false,
async: false,
success: function (text) {
var res = JSON.stringify(text)
if (text.code == 0) {
alert("注册成功")
} else {
alert(text.message)
}
},
error: function (error) {
alert(JSON.stringify(error))
}
});
location.reload();
}
}

}