c3js Multi color design - d3.js

Question

I've implementing barchart to denote my result set. I am trying to create this design using c3js. I referred the documentation but have not getting the shaded design. Please someone guide me to solve this.
My Code Snippet is,
var chart = c3.generate({
bindto: '#chart',
size : {
width: 600,
height: 200
},
data: {
columns: [
["data1", 40, 20, 20, 20],
["data2", 20, 10, 30, 30]
],
type: 'bar',
groups: [
['data1', 'data2']
],
order: null,
labels: {
format: function(v, id, i, j) {
return v;
}
}
},
bar: {
space: 0.2,
width: {
ratio: 0.2 // this makes bar width 50% of length between ticks
}
},
});
<link href="https://cdnjs.cloudflare.com/ajax/libs/c3/0.3.0/c3.min.css" rel="stylesheet" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/c3/0.3.0/c3.min.js"></script>
<div id="chart"></div>
My requirement is to design like below image in bars in barchart,
Thanks

Answer 1

The solution in the snippet introduces some d3 SVG manipulation which puts a region over the bars of each targeted series. The region has a hatched grey line and a semi-transparent fill. The function to do this is written to be portable i.e. outside of the C3 construtor params, and is invoked by the onrendered c3 event.
The doClone() function duplicates nodes in place which is useful to know, and the creation of the pattern and use as a colour via 'url(#patternid)' is also a potentially useful technique.
Also available at https://codepen.io/JEE42/pen/yRWbvq
function doClone(node){ // clone the given node
return d3.select(node.parentNode.insertBefore(node.cloneNode(true), node.nextSibling));
}
function hatchBars(hatchTargets){ // Place a hatching pattern over the target bars.
for (var i = 0; i < hatchTargets.length; i = i + 1){
d3.select('.c3-bars-' + hatchTargets[i]).each(function(d, i){
d3.select(this).selectAll('path').each(function(d, i){
var node = d3.select(this).node();
var daClone = doClone(node);
daClone
.style('fill', 'url(#hash4_4)')
.style('stroke', 'url(#hash4_4)');
});
})
}
}
c3.chart.internal.fn.afterInit = function () {
d3.select('defs')
.append('pattern')
.attr('id', "hash4_4") // use id to get handle in a moment
.attr('width', 14)
.attr('height', 14)
.attr('patternUnits', "userSpaceOnUse")
.attr('patternTransform', "rotate(45 0 0 )")
.append("rect")
.attr('width', 14)
.attr('height', 14)
.attr('fill', '#00000000') // transparent background
d3.select('#hash4_4') // get the pattenn
.append('line') // add a line
.attr('y2', 14)
.style('stroke', "#00000044") // semi-transparent bars
.attr('stroke-width', 14)
};
//
// Standard C3 chart render with one twist which is the onrendered event call at the end.
//
var chart = c3.generate({
bindto: '#chart',
data: {
columns: [
['data1', -30, 200, 200, 400, -150, 250],
['data2', 130, 100, -100, 200, -150, 50],
],
type: 'bar',
groups: [
['data1', 'data2']
]
},
grid: {
y: {
lines: [{value:0}]
}
},
onrendered: function () { // execute after drawn
hatchBars(['data2']); // Place a hatching pattern over the target bars.
}
});
<link href="https://cdnjs.cloudflare.com/ajax/libs/c3/0.6.7/c3.min.css" rel="stylesheet"/>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/c3/0.6.7/c3.min.js"></script>
<div class='chart-wrapper'>
<div class='chat' id="chart"></div>
</div>