關於H5 和 畫布 調用本地攝像頭拍照功能的實現

1.代碼的實現（html部分）

<input type="button" title="開啟攝像頭" value="開啟攝像頭" onclick="getMedia();" /><br />

<video height="120px" autoplay="autoplay"></video><hr />

<input type="button" title="拍照" value="拍照" onclick="getPhoto();" /><br />

<canvas id="canvas1" height="120px" ></canvas><hr />

<input type="button" title="視頻" value="視頻" onclick="getVedio();" /><br />

<canvas id="canvas2" height="120px"></canvas>

2.js部分

<script type="text/javascript">
var video = document.querySelector(‘video‘);
var audio, audioType;
var canvas1 = document.getElementById(‘canvas1‘);
var context1 = canvas1.getContext(‘2d‘);
var canvas2 = document.getElementById(‘canvas2‘);
var context2 = canvas2.getContext(‘2d‘);
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;
window.URL = window.URL || window.webkitURL || window.mozURL || window.msURL;
var exArray = []; //存儲設備源ID
MediaStreamTrack.getSources(function (sourceInfos) {
for (var i = 0; i != sourceInfos.length; ++i) {
var sourceInfo = sourceInfos[i];
//這裏會遍歷audio,video，所以要加以區分
if (sourceInfo.kind === ‘video‘) {
exArray.push(sourceInfo.id);
}
}
});
function getMedia() {
if (navigator.getUserMedia) {
navigator.getUserMedia({
‘video‘: {
‘optional‘: [{
‘sourceId‘: exArray[1] //0為前置攝像頭，1為後置
}]
},
‘audio‘:true
}, successFunc, errorFunc); //success是獲取成功的回調函數
}
else {
alert(‘Native device media streaming (getUserMedia) not supported in this browser.‘);
}
}
function successFunc(stream) {
//alert(‘Succeed to get media!‘);
if (video.mozSrcObject !== undefined) {
//Firefox中，video.mozSrcObject最初為null，而不是未定義的，我們可以靠這個來檢測Firefox的支持
video.mozSrcObject = stream;
}
else {
video.src = window.URL && window.URL.createObjectURL(stream) || stream;
}
//video.play();
// 音頻
audio = new Audio();
audioType = getAudioType(audio);
if (audioType) {
audio.src = ‘polaroid.‘ + audioType;
audio.play();
}
}
function errorFunc(e) {
alert(‘Error！‘+e);
}
// 將視頻幀繪制到Canvas對象上,Canvas每60ms切換幀，形成肉眼視頻效果
function drawVideoAtCanvas(video,context) {
window.setInterval(function () {
context.drawImage(video, 0, 0,90,120);
}, 60);
}
//獲取音頻格式
function getAudioType(element) {
if (element.canPlayType) {
if (element.canPlayType(‘audio/mp4; codecs="mp4a.40.5"‘) !== ‘‘) {
return (‘aac‘);
} else if (element.canPlayType(‘audio/ogg; codecs="vorbis"‘) !== ‘‘) {
return ("ogg");
}
}
return false;
}
// vedio播放時觸發，繪制vedio幀圖像到canvas
// video.addEventListener(‘play‘, function () {
// drawVideoAtCanvas(video, context2);
// }, false);
//拍照
function getPhoto() {
context1.drawImage(video, 0, 0,90,120); //將video對象內指定的區域捕捉繪制到畫布上指定的區域，實現拍照。
}
//視頻
function getVedio() {
drawVideoAtCanvas(video, context2);
}
</script>

3.實現效果圖

4.瀏覽器部分

H5的拍照開啟攝像頭方法navigator.getUserMedia，測試適用於火狐，本地調用，和滿足https協議的瀏覽器調用，本地localhost和127.0.0.1可以訪問，然而發布到項目上面，通過其他頁面訪問，需要tomcat配置https協議，但是安全性很低，所以，只用於參考

調用本地攝像頭拍照（H5和畫布）