I need to change Chart.js tooltip template, so that only value part is displayed in bold. There is tooltipTemplate option, which should do exactly this. Default value of this option is:
tooltipTemplate: "<%if (label){%><%=label%>: <%}%><%= value %>%"
I tried editing it like this:
tooltipTemplate: "<%if (label){%><%=label%>: <%}%><strong><%= value %></strong>%"
But it displays strong
tags on screen as part of text, instead of rendering bold text. I tried moving them around <%
and %>
, but it still doesn't work. Any ideas?
The template does not recognize HTML. You have to use the customTooltips option. Below is an example adapted (but not optimized) from https://github.com/nnnick/Chart.js/blob/master/samples/line-customTooltips.html
HTML
<canvas id="myChart" width="400" height="200"></canvas>
<div id="chartjs-tooltip"></div>
CSS
#chartjs-tooltip {
opacity: 0;
position: absolute;
background: rgba(0, 0, 0, .7);
color: white;
padding: 3px;
border-radius: 3px;
-webkit-transition: all .1s ease;
transition: all .1s ease;
pointer-events: none;
-webkit-transform: translate(-50%, 0);
transform: translate(-50%, 0);
}
JS
var ctx = $("#myChart").get(0).getContext("2d");
var data = {
labels: ["January", "February", "March", "April", "May", "June", "July"],
datasets: [{
label: "My First dataset",
fillColor: "rgba(220,220,220,0.2)",
strokeColor: "rgba(220,220,220,1)",
pointColor: "rgba(220,220,220,1)",
pointStrokeColor: "#fff",
pointHighlightFill: "#fff",
pointHighlightStroke: "rgba(220,220,220,1)",
data: [65, 59, 80, 81, 56, 55, 40]
}]
};
var myLineChart = new Chart(ctx).Line(data, {
customTooltips: function (tooltip) {
var tooltipEl = $('#chartjs-tooltip');
if (!tooltip) {
tooltipEl.css({
opacity: 0
});
return;
}
tooltipEl.removeClass('above below');
tooltipEl.addClass(tooltip.yAlign);
// split out the label and value and make your own tooltip here
var parts = tooltip.text.split(":");
var innerHtml = '<span>' + parts[0].trim() + '</span> : <span><b>' + parts[1].trim() + '</b></span>';
tooltipEl.html(innerHtml);
tooltipEl.css({
opacity: 1,
left: tooltip.chart.canvas.offsetLeft + tooltip.x + 'px',
top: tooltip.chart.canvas.offsetTop + tooltip.y + 'px',
fontFamily: tooltip.fontFamily,
fontSize: tooltip.fontSize,
fontStyle: tooltip.fontStyle,
});
}
});
Fiddle - http://jsfiddle.net/6rxdo0c0/1/
I have an up-to-date answer using jquery and bootstrap 4 tooltips that creates the tooltip divs dynamically. Assume your html is
<canvas id="myPieChart" width="100" height="55"></canvas>
Then use this script:
<script>
$(document).ready(function() {
let canvas = $("#donutChart")[0];
let ctx = canvas.getContext("2d");
let donutChart = new Chart(ctx, {
type: 'doughnut',
data: data,
options: {
tooltips: {
callbacks: {
title: function(){
return null;
},
label: function(tooltipItem, data) {
var multiline = ['First Line', 'second line'];
return multiline;
},
},
enabled: false, // the builtin tooltips cannot extend beyond the canvas
custom: function(tooltip) {
var tooltipEl = $('#chartjs-tooltip');
if(tooltipEl.length == 0) { // if not exists, create it
tooltipEl = $('<div class="tooltip fade" id="chartjs-tooltip"></div>').appendTo('body');
}
if ( !tooltip.body ) { // Hide if no tooltip
tooltipEl.remove();
return;
}
tooltipEl.removeClass('bs-tooltip-top bs-tooltip-bottom');
tooltipEl.addClass( 'bs-tooltip-' + (tooltip.yAlign == "bottom" ? "top" : "bottom") ); // different naming in bootstrap
var innerHtml = '<div class="arrow" style="left: '+tooltip.caretX+'px;"></div>'
+ '<div class="tooltip-inner" style="max-width: none;">' + tooltip.body[0].join('<br>')
+ '</div>';
tooltipEl.html( innerHtml );
tooltipEl.css( {
opacity: 1,
left: $("#donutChart").offset().left + tooltip.x + 'px',
top: $("#donutChart").offset().top + tooltip.y + 'px'
} );
},
},
hover: {
mode: null,
},
}
});
});
</script>
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