Develop Reference

Chart.js: For tooltips, can we achieve something like "only-when-not-intersect: true"? (Touchscreen hover/click conflict)

In particular, is there a way to only trigger hover tips if we are NOT intersecting an element?
More background:
Trying to work out some touch screen compatibility issues. We have a custom onclick listener that renders a popup if we click on a data point; we also have a custom tooltip we render when we hover over the chart with intersect set to false currently. The issue is, on touch screens, if I click on a data point, both the tooltip and the popup shows up. I can use z-index and / or javascript in the onclick-listener to hide the tooltip, but both methods entail a slight delay: that is, the tooltip first shows for a split second, and then it's hidden. Is there any way to make this behave more elegantly? Thanks!
Edit:
Sorry for not being clear enough - this is particularly a question about Chart.js (v2), and to include some example:
const chartEl= document.getElementById('chartEl').getContext('2d');
[#chartEl is a canvas element: <canvas id="chartEl"></canvas>]
const justAChart = new Chart(chartEl,
{
data: {
datasets: someDataSet,
},
type: 'line',
responsive: true,
options: {
hover: {
mode: 'index',
intersect: false
},
tooltips: {
mode: 'index',
intersect: false,
// custom tooltip rendering
custom: someCustomTooltip,
}
}
};
);
// Onclick listener for popup when clicking on a datapoint
document.getElementById("chartEl").onclick = function(evt){
let points = justAChart.getElementsAtEventForMode(evt, 'point', justAChart.options);
if (points .length > 0) {
showThePopup()
}
}

How to create custom legend in ChartJS

I need to create custom legend for my donut chart using ChartJS library.
I have created donut with default legend provided by ChartJS but I need some modification.
I would like to have value above the car name. Also I don't like sticky legend I want to have it separate from donut so I can change the style for fonts, boxes (next to the text "Audi" for example)
I know there is some Legend generator but I'm not sure how to use it with VueJS - because I'm using VueJS as a framework
This is how my legend looks like now - http://imgur.com/a/NPUoi
My code:
From Vue component where I import a donut component:
<div class="col-md-6">
<div class="chart-box">
<p class="chart-title">Cars</p>
<donut-message id="chart-parent"></donut-message>
</div>
</div>
Javascript:
import { Doughnut } from 'vue-chartjs'
export default Doughnut.extend({
ready () {
Chart.defaults.global.tooltips.enabled = false;
Chart.defaults.global.legend.display = false;
this.render({
labels: ['Audi','BMW','Ford','Opel'],
datasets: [
{
label: 'Cars',
backgroundColor: ['#35d89b','#4676ea','#fba545','#e6ebfd'],
data: [40, 30, 20, 10]
}
]
},
{
responsive: true,
cutoutPercentage: 75,
legend: {
display: true,
position: "right",
fullWidth: true,
labels: {
boxWidth: 10,
fontSize: 14
}
},
animation: {
animateScale: true
}
})
}
});

I'm having the same problem trying to understand the documentation and this link might clarify the process of customize the legends:
https://codepen.io/michiel-nuovo/pen/RRaRRv
The trick is to track a callback to build your own HTML structure and return this new structure to ChartJS.
Inside the options object:
legendCallback: function(chart) {
var text = [];
text.push('<ul class="' + chart.id + '-legend">');
for (var i = 0; i < chart.data.datasets[0].data.length; i++) {
text.push('<li><span style="background-color:' +
chart.data.datasets[0].backgroundColor[i] + '">');
if (chart.data.labels[i]) {
text.push(chart.data.labels[i]);
}
text.push('</span></li>');
}
text.push('</ul>');
return text.join("");
}
Second, you need a container to insert the new html and using the method myChart.generateLegend() to get the customized html:
$("#your-legend-container").html(myChart.generateLegend());
After that, if you need, track down the events:
$("#your-legend-container").on('click', "li", function() {
myChart.data.datasets[0].data[$(this).index()] += 50;
myChart.update();
console.log('legend: ' + data.datasets[0].data[$(this).index()]);
});
$('#myChart').on('click', function(evt) {
var activePoints = myChart.getElementsAtEvent(evt);
var firstPoint = activePoints[0];
if (firstPoint !== undefined) {
console.log('canvas: ' +
data.datasets[firstPoint._datasetIndex].data[firstPoint._index]);
}
else {
myChart.data.labels.push("New");
myChart.data.datasets[0].data.push(100);
myChart.data.datasets[0].backgroundColor.push("red");
myChart.options.animation.animateRotate = false;
myChart.options.animation.animateScale = false;
myChart.update();
$("#your-legend-container").html(myChart.generateLegend());
}
}
Another solution that I found, if you don't need to change the HTMl structure inside the legend, you can just insert the same HTML in your legend container and customize it by CSS, check this another link:
http://jsfiddle.net/vrwjfg9z/
Hope it works for you.

You can extract the legend markup.
data () {
return {
legendMarkup: ''
}
},
ready () {
this.legendMarkup = this._chart.generateLegend()
}
And in your template you can output it.
<div class="legend" ref="legend" v-html="legendMarkup"></div>
this._chart is the internal chartjs instance in vue-chartjs. So you can call all chartjs methods which are not exposed by vue-chartjs api over it.
However you can also use the legend generator. The usage is the same in vue. You can pass in the options, use callbacks etc.

please check this documentation
.
Legend Configuration
The chart legend displays data about the datasets that area appearing on the chart.
Configuration options
Position of the legend. Options are:
'top'
'left'
'bottom'
'right'
Legend Item Interface
Items passed to the legend onClick function are the ones returned from labels.generateLabels. These items must implement the following interface.
{
// Label that will be displayed
text: String,
// Fill style of the legend box
fillStyle: Color,
// If true, this item represents a hidden dataset. Label will be rendered with a strike-through effect
hidden: Boolean,
// For box border. See https://developer.mozilla.org/en/docs/Web/API/CanvasRenderingContext2D/lineCap
lineCap: String,
// For box border. See https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/setLineDash
lineDash: Array[Number],
// For box border. See https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineDashOffset
lineDashOffset: Number,
// For box border. See https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineJoin
lineJoin: String,
// Width of box border
lineWidth: Number,
// Stroke style of the legend box
strokeStyle: Color
// Point style of the legend box (only used if usePointStyle is true)
pointStyle: String
}
Example
The following example will create a chart with the legend enabled and turn all of the text red in color.
var chart = new Chart(ctx, {
type: 'bar',
data: data,
options: {
legend: {
display: true,
labels: {
fontColor: 'rgb(255, 99, 132)'
}
}
}
});
Custom On Click Actions
It can be common to want to trigger different behaviour when clicking an item in the legend. This can be easily achieved using a callback in the config object.
The default legend click handler is:
function(e, legendItem) {
var index = legendItem.datasetIndex;
var ci = this.chart;
var meta = ci.getDatasetMeta(index);
// See controller.isDatasetVisible comment
meta.hidden = meta.hidden === null? !ci.data.datasets[index].hidden : null;
// We hid a dataset ... rerender the chart
ci.update();
}
Lets say we wanted instead to link the display of the first two datasets. We could change the click handler accordingly.
var defaultLegendClickHandler = Chart.defaults.global.legend.onClick;
var newLegendClickHandler = function (e, legendItem) {
var index = legendItem.datasetIndex;
if (index > 1) {
// Do the original logic
defaultLegendClickHandler(e, legendItem);
} else {
let ci = this.chart;
[ci.getDatasetMeta(0),
ci.getDatasetMeta(1)].forEach(function(meta) {
meta.hidden = meta.hidden === null? !ci.data.datasets[index].hidden : null;
});
ci.update();
}
};
var chart = new Chart(ctx, {
type: 'line',
data: data,
options: {
legend: {
}
}
});
Now when you click the legend in this chart, the visibility of the first two datasets will be linked together.
HTML Legends
Sometimes you need a very complex legend. In these cases, it makes sense to generate an HTML legend. Charts provide a generateLegend() method on their prototype that returns an HTML string for the legend.
To configure how this legend is generated, you can change the legendCallback config property.
var chart = new Chart(ctx, {
type: 'line',
data: data,
options: {
legendCallback: function(chart) {
// Return the HTML string here.
}
}
});

c3.js tooltip - make static and style

I have a c3.js stacked barchart that updates when you hover over a Leaflet map, and I need the tooltip to be static as otherwise the user will hover over other areas of the map and change the data in the barchart, before actually reaching it. However, I'm new to coding and especially new to C3 and I can't get around how to make the tooltip static. Also, does anyone know how to style the tooltip later? I have only found very complex examples online, but it feels like I should be able to do it somewhere after I generate the chart.
Any help would be much appreciated!
Here is my code:
function getMiniChartData(properties) {
var values = [
['rape', rape[properties['gss_code']]],
['other sexual', other_sexual[properties['gss_code']]]];
console.log(values);
return values;
}
var chart;
function drawMiniChart(properties) {
console.log('drawing mini chart');
var data = getMiniChartData(properties);
chart = c3.generate({
bindto: '#minichart',
color: {
pattern: ['#E31A1C', '#BD0026']
},
point: {
show: false
},
tooltip: {
show: true
},
data: {
columns: data,
type: 'bar',
groups: [
['rape', 'other sexual']
]
},
axis: {
y: {
max:60,
min:0
}
},
grid: {
y: {
lines: [{
value: 0
}]
}
}
});
}
function updateMiniChartData(properties) {
console.log('updating mini chart');
var data = getMiniChartData(properties);
chart.load({
columns: data
});
}

Just edit the position in the tooltip :
position: function () {
var position = c3.chart.internal.fn.tooltipPosition.apply(this, arguments);
position.top = 0;
return position;
}
This will set the tooltip to always be at the top of the point. So it stays at the same y coordinate (top:0) but follows the points x value. You could go further and set it to stay at one position on the page.
Check this fiddle I have put together : http://jsfiddle.net/thatOneGuy/owhxgaqm/185/
This question will help you out : C3 charts - contents of tooltip clickable
If you want it visible all the time just add this code :
var originalHideTooltip = chart.internal.hideTooltip
chart.internal.hideTooltip = function () {
setTimeout(originalHideTooltip, 100)
};

chart.js on animation end callback

Does the library chart.js support any sort of callbacks on specific events? I'm mostly interested in 'on animation end' event, but would be nice to know any other events if they're supported.
If this is not an option, do you know any workarounds? I'm using jQuery and vue.js and I just need to show some additional text on the page (completely outside of the chart itself) when chart.js finishes the animation of the chart.

For Chart.Js 2.6.0
options: {
cutoutPercentage: 90,
animation: {
duration: 2000,
onProgress: function(animation) {
$progress.attr({
value: animation.animationObject.currentStep / animation.animationObject.numSteps,
});
},
onComplete: function(animation) {
alert('onAnimationComplete')
}
}
},
See this codepen https://codepen.io/shivabhusal/pen/XaZQaW

There is an onAnimationComplete option you can specify to run stuff once the animation completes. See this section of the documentation.
Example
var ctx = document.getElementById("chart").getContext("2d");
var myLine1 = new Chart(ctx).Line(lineChartData1, {
onAnimationComplete: function() {
alert('animation complete')
}
});
Fiddle - http://jsfiddle.net/4vo72rLd/

Highcharts: Add a custom image button

I want to add and image button on highcharts.
So far, I have successfully created a image button and have attached a click event on it.
But problem is that, the image (sun.png) is on left side of chart and image button is right aligned ( the default position of toolbar). Any fix for this ?
exporting: {
buttons: {
popUpBtn: {
symbol: 'url(images/sun.png)',
_titleKey: 'popUpBtnTitle',
x: -10,
symbolFill: '#B5C9DF',
hoverSymbolFill: '#779ABF',
onclick: function () {
alert('ad');
popUpChart($(this));
}
},
exportButton: {
enabled: false
},
printButton: {
enabled: false
}
}
}
Also, if there are other methods to add an image in chart which have click event, those methods are welcomed too.

Finally, I figured it out like this.
May be it will help others.
function callback($this){
var img = $this.renderer.image('images/zoom_icon.png',$this.chartWidth-40,5,40,12);
img.add();
img.css({'cursor':'pointer'});
img.attr({'title':'Pop out chart'});
img.on('click',function(){
// prcessing after image is clicked
});
}
new Highcharts.Chart(charts.params,callback);
// where charts.params is object which contains options for chart