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battlehorse/index.html

Created November 2, 2011 15:21
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Demo script to convert Google Chart Tools charts into PNG images.
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index.html
<html>
<head>
<script type="text/javascript" src="http://canvg.googlecode.com/svn/trunk/rgbcolor.js"></script>
<script type="text/javascript" src="http://canvg.googlecode.com/svn/trunk/canvg.js"></script>
<script>
function getImgData(chartContainer) {
var chartArea = chartContainer.getElementsByTagName('iframe')[0].
contentDocument.getElementById('chartArea');
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" src="https://www.google.com/jsapi"></script>
<script type="text/javascript">
google.load("visualization", "1", {packages:["corechart", "treemap", "geochart"]});
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('pie_div'));
chart.draw(data, {width: 450, height: 300, title: 'My Daily Activities'});
// Line chart
data = new google.visualization.DataTable();
data.addColumn('string', 'Year');
data.addColumn('number', 'Sales');
data.addColumn('number', 'Expenses');
data.addRows(4);
data.setValue(0, 0, '2004');
data.setValue(0, 1, 1000);
data.setValue(0, 2, 400);
data.setValue(1, 0, '2005');
data.setValue(1, 1, 1170);
data.setValue(1, 2, 460);
data.setValue(2, 0, '2006');
data.setValue(2, 1, 860);
data.setValue(2, 2, 580);
data.setValue(3, 0, '2007');
data.setValue(3, 1, 1030);
data.setValue(3, 2, 540);
var chart = new google.visualization.LineChart(document.getElementById('line_div'));
chart.draw(data, {width: 450, height: 300, title: 'Company Performance'});
// Treemap
data = new google.visualization.DataTable();
data.addColumn('string', 'Region');
data.addColumn('string', 'Parent');
data.addColumn('number', 'Market trade volume (size)');
data.addColumn('number', 'Market increase/decrease (color)');
data.addRows([
["Global",null,0,0],
["America","Global",0,0],
["Europe","Global",0,0],
["Asia","Global",0,0],
["Australia","Global",0,0],
["Africa","Global",0,0],
["Brazil","America",11,10],
["USA","America",52,31],
["Mexico","America",24,12],
["Canada","America",16,-23],
["France","Europe",42,-11],
["Germany","Europe",31,-2],
["Sweden","Europe",22,-13],
["Italy","Europe",17,4],
["UK","Europe",21,-5],
["China","Asia",36,4],
["Japan","Asia",20,-12],
["India","Asia",40,63],
["Laos","Asia",4,34],
["Mongolia","Asia",1,-5],
["Israel","Asia",12,24],
["Iran","Asia",18,13],
["Pakistan","Asia",11,-52],
["Egypt","Africa",21,0],
["S. Africa","Africa",30,43],
["Sudan","Africa",12,2],
["Congo","Africa",10,12],
["Zair","Africa",8,10]
]);
var tree = new google.visualization.TreeMap(document.getElementById('treemap_div'));
tree.draw(data, {
minColor: '#f00',
midColor: '#ddd',
maxColor: '#0d0',
headerHeight: 15,
fontColor: 'black',
showScale: true});
data = new google.visualization.DataTable();
data.addRows(6);
data.addColumn('string', 'Country');
data.addColumn('number', 'Popularity');
data.setValue(0, 0, 'Germany');
data.setValue(0, 1, 200);
data.setValue(1, 0, 'United States');
data.setValue(1, 1, 300);
data.setValue(2, 0, 'Brazil');
data.setValue(2, 1, 400);
data.setValue(3, 0, 'Canada');
data.setValue(3, 1, 500);
data.setValue(4, 0, 'France');
data.setValue(4, 1, 600);
data.setValue(5, 0, 'RU');
data.setValue(5, 1, 700);
var options = {};
var container = document.getElementById('map_div');
var geochart = new google.visualization.GeoChart(container);
geochart.draw(data, options);
data = new google.visualization.DataTable();
data.addColumn('number', 'Age');
data.addColumn('number', 'Weight');
data.addRows(6);
data.setValue(0, 0, 8);
data.setValue(0, 1, 12);
data.setValue(1, 0, 4);
data.setValue(1, 1, 5.5);
data.setValue(2, 0, 11);
data.setValue(2, 1, 14);
data.setValue(3, 0, 4);
data.setValue(3, 1, 4.5);
data.setValue(4, 0, 3);
data.setValue(4, 1, 3.5);
data.setValue(5, 0, 6.5);
data.setValue(5, 1, 7);
var chart = new google.visualization.ScatterChart(document.getElementById('scatter_div'));
chart.draw(data, {width: 400, height: 240,
title: 'Age vs. Weight comparison',
hAxis: {title: 'Age', minValue: 0, maxValue: 15},
vAxis: {title: 'Weight', minValue: 0, maxValue: 15},
legend: 'none'
});
}
</script>
</head>
<body>
<div id="img_div" style="position: fixed; top: 0; right: 0; z-index: 10; border: 1px solid #b9b9b9">
Image will be placed here
</div>
<button onclick="saveAsImg(document.getElementById('pie_div'));">Save as PNG Image</button>
<button onclick="toImg(document.getElementById('pie_div'), document.getElementById('img_div'));">Convert to image</button>
<div id="pie_div"></div>
<button onclick="saveAsImg(document.getElementById('line_div'));">Save as PNG Image</button>
<button onclick="toImg(document.getElementById('line_div'), document.getElementById('img_div'));">Convert to image</button>
<div id="line_div"></div>
<button onclick="saveAsImg(document.getElementById('treemap_div'));">Save as PNG Image</button>
<button onclick="toImg(document.getElementById('treemap_div'), document.getElementById('img_div'));">Convert to image</button>
<div id="treemap_div" style="width: 450px; height: 300px;"></div>
<button onclick="saveAsImg(document.getElementById('map_div'));">Save as PNG Image</button>
<button onclick="toImg(document.getElementById('map_div'), document.getElementById('img_div'));">Convert to image</button>
<div id="map_div" style="width: 500px; height: 300px"></div>
<button onclick="saveAsImg(document.getElementById('scatter_div'));">Save as PNG Image</button>
<button onclick="toImg(document.getElementById('scatter_div'), document.getElementById('img_div'));">Convert to image</button>
<div id="scatter_div"></div>
</body>
</html>
@irmela
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irmela commented Oct 29, 2015

Had the same problem. There was additional html markup inside of var svg. I fixed it by changing

var chartArea = chartContainer.getElementsByTagName('svg')[0].parentNode;
var svg = chartArea.innerHTML;

to

var chartArea = chartContainer.getElementsByTagName('svg')[0].parentNode;
var svg = '<svg>' + chartContainer.getElementsByTagName('svg')[0].innerHTML + '</svg>'

@GoutamTMS
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Uncaught ReferenceError: canvg is not defined
This error occurring..

@FGRibreau
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FGRibreau commented Oct 11, 2016 •
edited

If you don't want to host it, scale it yourself, and would like gif animation on top of it (nice for animated charts in emails!) you may want to give a try to https://image-charts.com !

No more server-side chart rendering pain, just 1 URL = 1 image chart.

a

One last thing, it's a drop-in replacement for the soon-to-be-shutdown Google Image Chart!

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