How to decrease the chart opacity in highcharts - highcharts

Question

I am trying to decrease the opacity of charts instead of hiding when click the legend.
Example: When i click the Tokyo legend series blue color column hiding instead of hiding I want to decrease the opacity to 0.34 of blue color column. same for other legend when clicking. So, How to do it?
Highcharts.chart('container', {
chart: {
type: 'column'
},
title: {
text: 'Monthly Average Rainfall'
},
subtitle: {
text: 'Source: WorldClimate.com'
},
xAxis: {
categories: [
'Jan',
'Feb',
'Mar',
'Apr',
'May',
'Jun',
'Jul',
'Aug',
'Sep',
'Oct',
'Nov',
'Dec'
],
crosshair: true
},
yAxis: {
min: 0,
title: {
text: 'Rainfall (mm)'
}
},
tooltip: {
headerFormat: '<span style="font-size:10px">{point.key}</span><table>',
pointFormat: '<tr><td style="color:{series.color};padding:0">{series.name}: </td>' +
'<td style="padding:0"><b>{point.y:.1f} mm</b></td></tr>',
footerFormat: '</table>',
shared: true,
useHTML: true
},
plotOptions: {
column: {
pointPadding: 0.2,
borderWidth: 0
},
series: {
events: {
legendItemClick: function(event) {
var visibility = this.visible ? '0.35' : '';
alert(event);
}
}
},
},
series: [{
name: 'Tokyo',
data: [49.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4,
194.1, 95.6, 54.4]
}, {
name: 'New York',
data: [83.6, 78.8, 98.5, 93.4, 106.0, 84.5, 105.0, 104.3, 91.2, 83.5,
106.6, 92.3]
}, {
name: 'London',
data: [48.9, 38.8, 39.3, 41.4, 47.0, 48.3, 59.0, 59.6, 52.4, 65.2, 59.3,
51.2]
}, {
name: 'Berlin',
data: [42.4, 33.2, 34.5, 39.7, 52.6, 75.5, 57.4, 60.4, 47.6, 39.1, 46.8,
51.1]
}]
});
https://www.highcharts.com/demo/column-basic
Demo:
https://jsfiddle.net/4t6arfg8/

Answer 1

You used the correct event, the remaining thing is to change opacity of the proper SVG element and colorize the legend item.
series: {
events: {
legendItemClick: function(e) {
const series = this;
const chart = series.chart;
const hasChangedOpacity = series.hasChangedOpacity;
series.group.attr({
opacity: hasChangedOpacity ? 1 : 0.2
});
chart.legend.colorizeItem(series, hasChangedOpacity);
series.hasChangedOpacity = !hasChangedOpacity;
// prevent default behaviour
return false;
}
}
}
Also, to keep the default series states behaviour, you need to add the below small plugin:
(function(H) {
H.wrap(H.Series.prototype, 'setState', function(proceed) {
if (!this.hasChangedOpacity) {
proceed.apply(this, Array.prototype.slice.call(arguments, 1));
}
});
}(Highcharts));
Live demo: https://jsfiddle.net/BlackLabel/p1x6937f/
API Reference: https://api.highcharts.com/highcharts/series.column.events.legendItemClick
Docs: https://www.highcharts.com/docs/extending-highcharts/extending-highcharts