dc.js: use image for the legend - dc.js

Question

I'd like to use images (icon or svg) instead of the default rectangles for the legend of the pie chart.
Would it be possible to do this in dc.js?
For example:
Many thanks.

Answer 1

This feature isn't built-in, but it's usually easy to "escape to d3" and customize your charts as you see fit.
In this case, we want to wait until the chart is rendered and then replace the rectangles with images:
chart.on('pretransition', function(chart) { // 1
var items = chart.selectAll('.dc-legend .dc-legend-item'); // 2
items.selectAll('rect').remove(); // 3
var images = items.selectAll('image').data(function(x) { // 4
return [x];
});
images.enter().append('image').attr({ // 5
width: 25,
height: 25,
href: function(leg) { return _icons[leg.name]; }
});
console.log('items', items.data());
});
Wait for chart render/redraw
Select the legend items
Remove any rect under each item (if it's a line chart you'll have to look for line instead
Select any existing images (the "trick" of returning a single-item array is so that we can cleanly replace anything which was there, and not keep adding more images)
And set up the image - in this example I'm using some the first SVG icons I could find on a CDN; we map stack names to SVG URLs using an object.
Finally, we also need to set the legend's item height to match the image height:
chart.legend(dc.legend().itemHeight(25));
Example output:
Example fiddle: https://jsfiddle.net/gordonwoodhull/Lss5wsz6/9/