<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>html2canvas example</title>
<script src="../../assets/gis/jquery/jquery-1.8.3.js"></script>
<script type="text/javascript" src="http://html2canvas.hertzen.com/dist/html2canvas.js"></script>
</head>
<script type="text/javascript">
function html2Image() {
console.log('test');
html2canvas(document.getElementById("view")).then(function (canvas) {
console.log(canvas);
var dataUrl = canvas.toDataURL();
document.getElementById("html2Image").src = dataUrl;
});
}
</script>
<script type="text/javascript">
$(document).ready(function () {
// canvas生成图片
$("#btn").on("click", function () {
var getPixelRatio = function (context) { // 获取设备的PixelRatio
var backingStore = context.backingStorePixelRatio ||
context.webkitBackingStorePixelRatio ||
context.mozBackingStorePixelRatio ||
context.msBackingStorePixelRatio ||
context.oBackingStorePixelRatio ||
context.backingStorePixelRatio || 0.5;
return (window.devicePixelRatio || 0.5) / backingStore;
};
//生成的图片名称 在html2canvas插件中，用jquery获取到DOM对象是无法读取的，因此需要用document.getElementById("pic")来获取原生js对象，图中是用jquery对象转化为js对象：$("#pic")[0]或者$("#pic").get(0)
var imgName = "@(webSiteName)@(weekName).jpg";
var shareContent = document.getElementsByTagName("canvas")[0]; // $(".mapboxgl-canvas-container").get(0) ; //document.getElementById("imgDiv");
var width = shareContent.offsetWidth;
var height = shareContent.offsetHeight;
var canvas = document.createElement("canvas");
var context = canvas.getContext('2d');
var scale = getPixelRatio(context); //将canvas的容器扩大PixelRatio倍，再将画布缩放，将图像放大PixelRatio倍。
canvas.width = width * scale;
canvas.height = height * scale;
canvas.style.width = width + 'px';
canvas.style.height = height + 'px';
context.scale(scale, scale);
var opts = {
scale: 1,
background: '#FFFFFF'
};
window.pageYoffset = 0;
document.documentElement.scrollTop = 0;
document.body.scrollTop = 0;
//html2canvas(shareContent, opts).then(function (canvas) {
html2canvas(shareContent, {dpi: window.devicePixelRatio, width: width, scale: 1, useCORS: true}).then(function (canvas) {
context.imageSmoothingEnabled = false;
context.webkitImageSmoothingEnabled = false;
context.msImageSmoothingEnabled = false;
context.imageSmoothingEnabled = false;
var dataUrl = canvas.toDataURL('image/jpeg', 1.0);
dataURIToBlob(imgName, dataUrl, callback);
});
});
})
// edited from https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toBlob#Polyfill
var dataURIToBlob = function (imgName, dataURI, callback) {
var binStr = atob(dataURI.split(',')[1]),
len = binStr.length,
arr = new Uint8Array(len);
for (var i = 0; i < len; i++) {
arr[i] = binStr.charCodeAt(i);
}
callback(imgName, new Blob([arr]));
}
var callback = function (imgName, blob) {
var triggerDownload = $("<a>").attr("href", URL.createObjectURL(blob)).attr("download", imgName).appendTo("body").on("click", function () {
if (navigator.msSaveBlob) {
return navigator.msSaveBlob(blob, imgName);
}
});
triggerDownload[0].click();
triggerDownload.remove();
};
</script>
<body>
<div style="float:right;"><input type="button" id="btn" class="k-button" value="保存为图片" /></div>
<div id="imgDiv" style="padding-top:30px;">
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
</div>
<div id="view" style="width: 600px; height: 400px;">
eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
</div>
<input type="button" value="截图" onclick="html2Image()" / >
<div>
<img id="html2Image" src="" alt="">
</div>
</body>
</html>
