问题描述
这是情况。
这是我当前的代码:
<div class="row">
<div class="col-md-6">
<video onclick="snapshot(this);" width=400 height=400 id="video" controller autoplay></video>
<button type="button" onclick="startWebcam();" style="background-color: #3c8dbc;border-color: #367fa9;color: #fff;border:0;height:30px;" >START WEBCAM</button>
<button type="button" onclick="stopWebcam();" style="background-color: #3c8dbc;border-color: #367fa9;color: #fff;border:0;height:30px;" >STOP WEBCAM</button>
<button type="button" onclick="snapshot();" id="snapShot" class="snapShot" style="background-color: #3c8dbc;border-color: #367fa9;color: #fff;border:0;height:30px;" >TAKE SNAPSHOT</button>
<!-- <button type="button" class="savePicture" style="background-color: #3c8dbc;border-color: #367fa9;color: #fff;border:0;height:30px;" >SAVE PICTURE</button> -->
</div>
<div class="col-md-6">
<canvas id="canvas" width="640" height="480"></canvas>
</div>
</div>
<div class="row">
<div id="container" style="overflow: hidden;width: 200px;">
<div id="inner" style=" overflow: hidden; width: 200px;">
</div>
</div>
</div>
这是我当前的JS代码:
<script type="text/javascript">
var video;
var webcamStream;
var clicks = 0;
function startWebcam() {
if (navigator.getUserMedia) {
navigator.getUserMedia (
// constraints
{
video: true,audio: false
},// successCallback
function(localMediaStream) {
video = document.querySelector('video');
//video.src = window.URL.createObjectURL(localMediaStream);
video.srcObject = localMediaStream;
webcamStream = localMediaStream;
video.play();
},// errorCallback
function(err) {
console.log("The following error occured: " + err);
}
);
} else {
console.log("getUserMedia not supported");
}
}
function snapshot() {
var canvas = document.getElementById("canvas");
var context = canvas.getContext('2d');
context.drawImage(video,640,480);
clicks += 1;
document.getElementById('inner').innerHTML = '';
for (x=0; x < clicks; x++)
{
$(document).ready(function() { $('#inner').append('<div id="div-'+x+'" style="background-color: #fff;float: left; width: 250px;height: 250px;"><canvas id="canvas'+x+'" width="640" height="480"></canvas></div>'); });
var canvasx = document.getElementById("canvas"+x);
var contextx = canvasx.getContext('2d');
contextx.drawImage(video,100,100);
console.log(contextx);
}
}
</script>
如何保留先前的图像,并在旧图像旁边显示新图像?现在,它显示不同的画布,但是,每次显示相同的图像。
谢谢, 凯文
解决方法
我找到了解决方法。
问题出在内部,画布不是数组。所以这就是我要做的。
首先,我必须将画布创建为数组:
var canvas = document.getElementById("canvas"),img,i,image_array = [];
然后我将画布放入URL:
var dataURL = canvas.toDataURL('image/jpg');
我将图片网址推入图片数组:
image_array.push(dataURL);
现在我创建了一个for循环:
for (i = 0; i < image_array.length; i++) {
img = new Image();
img.src = image_array[i];
img.onload = (function(img,i){
return function () {
$(document).ready(function() { $('#inner').append('<div id="divimage" style="background-color: #fff;float: left; width: 300px;height: 300px;"><img style="width:250px; height:250px;" src="'+img.src+'" /></canvas></div>'); });
}
})(img,i);
}
这解决了我的问题。