javascript - How to save an image of the chart on the server with highcharts?

Question

With highcharts, you have a built-in button to download the current chart (example: http://www.highcharts.com/demo/, this button: ). You can save it as PNG, JPEG, PDF or SVG.

What I'd like to do is to create a link that saves the image on the server, instead of downloading it. How could I do that ?

I suppose that I have to modify the exportChart function in the exporting.src.js file. It looks like this (but I don't know javascript enough to do that) :

exportChart: function (options, chartOptions) {
        var form,
            chart = this,
            svg = chart.getSVG(chartOptions);

        // merge the options
        options = merge(chart.options.exporting, options);

        // create the form
        form = createElement('form', {
            method: 'post',
            action: options.url
        }, {
            display: NONE
        }, doc.body);

        // add the values
        each(['filename', 'type', 'width', 'svg'], function (name) {
            createElement('input', {
                type: HIDDEN,
                name: name,
                value: {
                    filename: options.filename || 'chart',
                    type: options.type,
                    width: options.width,
                    svg: svg
                }[name]
            }, null, form);
        });

        // submit
        form.submit();

        // clean up
        discardElement(form);
    },

Answer 1

It could be done really easy with PhantomJS. You can render Highchart chart and save it to SVG, PNG, JPEG or PDF. The example below renders a demo Highcharts diagram to SVG and PDF at the same time:

var system = require('system');
var page = require('webpage').create();
var fs = require('fs');

// load JS libraries
page.injectJs("js/jquery.min.js");
page.injectJs("js/highcharts/highcharts.js");
page.injectJs("js/highcharts/exporting.js");

// chart demo
var args = {
    width: 600,
    height: 500
};

var svg = page.evaluate(function(opt){
    $('body').prepend('<div id="container"></div>');

    var chart = new Highcharts.Chart({
        chart: {
            renderTo: 'container',
            width: opt.width,
            height: opt.height
        },
        exporting: {
            enabled: false
        },
        title: {
            text: 'Combination chart'
        },
        xAxis: {
            categories: ['Apples', 'Oranges', 'Pears', 'Bananas', 'Plums']
        },
        yAxis: {
            title: {
                text: 'Y-values'
            }
        },
        labels: {
            items: [{
                html: 'Total fruit consumption',
                style: {
                    left: '40px',
                    top: '8px',
                    color: 'black'
                }
            }]
        },
        plotOptions: {
            line: {
                dataLabels: {
                    enabled: true
                },
                enableMouseTracking: false
            },
            series: {
                enableMouseTracking: false, 
                shadow: false, 
                animation: false
            }
        },
        series: [{
            type: 'column',
            name: 'Andrii',
            data: [3, 2, 1, 3, 4]
        }, {
            type: 'column',
            name: 'Fabian',
            data: [2, 3, 5, 7, 6]
        }, {
            type: 'column',
            name: 'Joan',
            data: [4, 3, 3, 9, 0]
        }, {
            type: 'spline',
            name: 'Average',
            data: [3, 2.67, 3, 6.33, 3.33],
            marker: {
                lineWidth: 2,
                lineColor: 'white'
            }
        }, {
            type: 'pie',
            name: 'Total consumption',
            data: [{
                name: 'Andrii',
                y: 13,
                color: '#4572A7'
            }, {
                name: 'Fabian',
                y: 23,
                color: '#AA4643'
            }, {
                name: 'Joan',
                y: 19,
                color: '#89A54E'
            }],
            center: [100, 80],
            size: 100,
            showInLegend: false,
            dataLabels: {
                enabled: false
            }
        }]
    });

    return chart.getSVG();
},  args);

// Saving SVG to a file
fs.write("demo.svg", svg);
// Saving diagram as PDF
page.render('demo.pdf');

phantom.exit();

If you save the code as demo.js, then just run bin/phantomjs demo.js to generate demo.svg and demo.pdf