I am running a Apache Server . I have a simple screen capture set up using Html2canvas .The capture function is rendering a blank Image . I have tried numerous ways to configure the javascript using related articles from this site to no Avail . The code is all working and tested because I can capture the image prior to "google maps api being loaded . Thank you and any advice would be much appreciated .
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<head>
<title>Tester</title>
<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script type="text/javascript" src="html2canvas.js"></script>
<script type="text/javascript" src="jquery.plugin.html2canvas.js"></script>
<script src="http://www.google.com/jsapi?key=ABQIAAAAwbkbZLyhsmTCWXbTcjbgbRSzHs7K5SvaUdm8ua-Xxy_-2dYwMxQMhnagaawTo7L1FE1-amhuQxIlXw"></script>
<script>
google.load("earth", "1");
var ge = null;
function init() {
google.earth.createInstance("map_canvas", initCallback, failureCallback);
}
function initCallback(object) {
ge = object;
ge.getWindow().setVisibility(true);
}
function failureCallback(object) {
}
function capture() {
$('#target').html2canvas({
onrendered: function (canvas) {
//Set hidden field's value to image data (base-64 string)
$('#img_val').val(canvas.toDataURL("image/png"));
//Submit the form manually
document.getElementById("myForm").submit();
}
});
}
</script>
<style type="text/css">
#map_canvas {position: fixed; top: 60px;
left: 0px; right:0px; bottom:0px; }
#target {
border: 1px solid #CCC;
margin: 0px; padding:0px; position: absolute; left: 10px;top: 80px;height: 580px; width: 580px;
}
</style>
</head>
<body onload='init()' id='body'>
<form method="POST" enctype="multipart/form-data" action="save.php" id="myForm">
<input type="hidden" name="img_val" id="img_val" value="" />
</form>
<input type="submit" value="Take Screenshot Of Div Below" onclick="capture();" />
<div id="target">
<div id="map_canvas"> </div>
</div>
</body>
</html>
This is the php document renders to save.php
<?php
//Get the base-64 string from data
$filteredData=substr($_POST['img_val'], strpos($_POST['img_val'], ",")+1);
//Decode the string
$unencodedData=base64_decode($filteredData);
//Save the image
file_put_contents('img.png', $unencodedData);
?>
<h2>Save the image and show to user</h2>
<table>
<tr>
<td>
<a href="img.png" target="blank">
Click Here to See The Image Saved to Server</a>
</td>
<td align="right">
<a href="index.php">
Click Here to Go Back</a>
</td>
</tr>
<tr>
<td colspan="2">
<br />
<br />
<span>
Here is Client-sided image:
</span>
<br />
<?php
//Show the image
echo '<img src="'.$_POST['img_val'].'" />';
?>
</td>
</tr>
</table>
<style type="text/css">
body, a, span {
font-family: Tahoma; font-size: 10pt; font-weight: bold;
}
</style>
This sample works Correctly . I want to achieve this with above Code using "Google Earth"
Since I was just having a similar problem and I managed to solve it maybe this will help you too.
It turns out to be a problem with loading images from a different (external) domain. In our case the external domain is something like maps.googleapis.com.
html2canvas allows us to use a proxy to solve that problem so instead of directly trying to load the images cross-domain we use the local proxy to retrieve the images, save them and pass them on to html2canvas.
Just download it and then make sure to create the data directory that the proxy uses exists and is writable. By default the directory is called 'data' and it should be in your webroot.
Then change the piece of JavaScript to use the proxy:
html2canvas($('#googleMap'), {
proxy: 'html2canvasproxy.php',
useCORS: false,
onrendered: function (canvas) {
var dataUrl= canvas.toDataURL("image/png").replace("image/png", "image/octet-stream");
window.location.href = dataUrl;
}
});
Also make sure to set useCORS to false, because you can't use both a proxy and have useCORS enabled.
