我正在尝试从网络摄像头随机捕获图像,然后将其保存到我的服务器上,现在我正在使用getUserMedia将网络摄像头传输到视频元素,然后我可以使用按钮将图像捕捉到画布,但我不知道如何将该图像从画布保存到我的服务器.
另一个问题是getUserMedia只适用于Chrome,Opera和Firefox,是否有任何替代的IE？
这是我目前正在使用的：
<video id="video" width="640" height="480" autoplay></video>
<button id="snap">Snap Photo</button>
<canvas id="canvas" width="640" height="480"></canvas>
<button id="getBase" onclick="getBase()">Get Base64</button>
<textarea id="textArea"></textarea>
<script>
// Put event listeners into place
window.addEventListener("DOMContentLoaded",function() {
// Grab elements,create settings,etc.
var canvas = document.getElementById("canvas"),context = canvas.getContext("2d"),video = document.getElementById("video"),videoObj = { "video": true },errBack = function(error) {
console.log("Video capture error: ",error.code);
};
// Put video listeners into place
if(navigator.getUserMedia) { // Standard
navigator.getUserMedia(videoObj,function(stream) {
video.src = stream;
video.play();
},errBack);
} else if(navigator.webkitGetUserMedia) { // WebKit-prefixed
navigator.webkitGetUserMedia(videoObj,function(stream){
video.src = window.webkitURL.createObjectURL(stream);
video.play();
},errBack);
}
// Trigger photo take
document.getElementById("snap").addEventListener("click",function() {
context.drawImage(video,640,480);
});
document.getElementByID("getBase").addEventListener("click",getBase());
},false);
function getBase(){
var imgBase = canvas.toDataURL("image/png");
document.getElementByID("textArea").value=imgBase;
}
</script>`
谢谢堆
解决方法
您可以使用canvas.toDataUrl获取一个base64编码的字符串,您可以将其作为参数发布到服务器上的脚本,该脚本将读取并存储为图像文件.
以下是这种方法的实际实现的缩写版本：
<script>
function saveImage(){
var xmlhttp;
xmlhttp=((window.XMLHttpRequest)?new XMLHttpRequest():new ActiveXObject("Microsoft.XMLHTTP"));
xmlhttp.onreadystatechange=function(){
if (xmlhttp.readyState==4){
if(xmlhttp.status==200){
//handle success
}
}
}
xmlhttp.open("POST",baseURL,true);
var oldCanvas = under.toDataURL("image/png");
var params=oldCanvas;
xmlhttp.setRequestHeader("Content-type","application/upload");
xmlhttp.setRequestHeader("Content-length",params.length);
xmlhttp.setRequestHeader("Connection","close");
xmlhttp.send(params);
}
</script>
这里是一个示例PHP脚本,接受base64字符串,转换为.png,给它一个随机的文件名,并保存：
<?PHP if((isset($GLOBALS["HTTP_RAW_POST_DATA"]))){ //some validation is necessary,this is just a proof of concept if(isset($GLOBALS["HTTP_RAW_POST_DATA"])){ $params=explode('&',$GLOBALS["HTTP_RAW_POST_DATA"]); $imgsrc=str_replace(' ','+',$params[0]); $im = imagecreatefrompng($imgsrc); } if($im){ $background = imagecolorallocatealpha($im,255,127); imagecolortransparent($im,$background); //random file name $m = rand(10e16,10e24); $filename=base_convert($m,10,36); //save image imagepng($im,'images/'.$filename.'.png'); imagedestroy($im); $size = getimagesize('images/'.$filename.'.png'); $iH=$size[1]; $iW=$size[0]; echo "{\"filename\":\"".$filename."\",\"width\":\"".$iW."\",\"height\":\"".$iH."\"}"; } } ?>
