Tat*_*ing 6 google-visualization
Google Visualization API可以使用javascript在网站上绘制饼图.图表可以输出为PNG图像文件吗？
谢谢.
是.Google Visualization API不再支持此功能,但它只需要几行JavaScript,如下所示.
该解决方案最初由Riccardo Govoni在精彩的战马教程中描述,将SVG转换为Canvas,然后转换为PNG,然后可以显示或保存.
教程代码不再有效,但我添加了两个修复:
chartArea变量设置为使用Google Visualization API版本1.32(2012年9月24日)及更高版本(源代码).
<html>
<head>
<script type="text/javascript" src="https://www.google.com/jsapi"></script>
<script type="text/javascript" src="http://canvg.googlecode.com/svn/trunk/rgbcolor.js"></script>
<script type="text/javascript" src="https://canvg.googlecode.com/svn-history/r157/trunk/canvg.js"></script>
<script>
function getImgData(chartContainer) {
var chartArea = chartContainer.getElementsByTagName('svg')[0].parentNode;
var svg = chartArea.innerHTML;
var doc = chartContainer.ownerDocument;
var canvas = doc.createElement('canvas');
canvas.setAttribute('width', chartArea.offsetWidth);
canvas.setAttribute('height', chartArea.offsetHeight);
canvas.setAttribute(
'style',
'position: absolute; ' +
'top: ' + (-chartArea.offsetHeight * 2) + 'px;' +
'left: ' + (-chartArea.offsetWidth * 2) + 'px;');
doc.body.appendChild(canvas);
canvg(canvas, svg);
var imgData = canvas.toDataURL("image/png");
canvas.parentNode.removeChild(canvas);
return imgData;
}
function saveAsImg(chartContainer) {
var imgData = getImgData(chartContainer);
// Replacing the mime-type will force the browser to trigger a download
// rather than displaying the image in the browser window.
window.location = imgData.replace("image/png", "image/octet-stream");
}
function toImg(chartContainer, imgContainer) {
var doc = chartContainer.ownerDocument;
var img = doc.createElement('img');
img.src = getImgData(chartContainer);
while (imgContainer.firstChild) {
imgContainer.removeChild(imgContainer.firstChild);
}
imgContainer.appendChild(img);
}
</script>
<script type="text/javascript">
google.load("visualization", "1", {packages:["corechart"]});
google.setOnLoadCallback(drawChart);
function drawChart() {
// Pie chart
var data = new google.visualization.DataTable();
data.addColumn('string', 'Task');
data.addColumn('number', 'Hours per Day');
data.addRows(5);
data.setValue(0, 0, 'Work');
data.setValue(0, 1, 11);
data.setValue(1, 0, 'Eat');
data.setValue(1, 1, 2);
data.setValue(2, 0, 'Commute');
data.setValue(2, 1, 2);
data.setValue(3, 0, 'Watch TV');
data.setValue(3, 1, 2);
data.setValue(4, 0, 'Sleep');
data.setValue(4, 1, 7);
var chart = new google.visualization.PieChart(document.getElementById('google_visualization_div'));
chart.draw(data, {width: 450, height: 300, title: 'My Daily Activities'});
}
</script>
</head>
<body>
<div id="google_visualization_div"></div>
<button onclick="saveAsImg(document.getElementById('google_visualization_div'));">Save as PNG Image</button>
<button onclick="toImg(document.getElementById('google_visualization_div'), document.getElementById('img_div'));">Convert to image</button>
<hr>
<div id="img_div">
Image will be placed here
</div>
</body>
</html>