I'd like to conditionally add a strikethrough to tick labels. As far as I can tell, there's no option to natively do that through Chart.js. Is there a way to hook in through the axes callbacks to add that?
I don't know if that is possible because you are dealing with a canvas element, but you can customize the text in the labels by using the ticks callback as in this example:
new Chart(document.getElementById("bar-chart"), {
type: 'bar',
data: {
labels: ["One", "Two", "Three", "Four", "Five"],
datasets: [
{
label: "A chart",
backgroundColor: ["#3e95cd", "#8e5ea2", "#3cba9f", "#e8c3b9", "#c45850"],
data: [2478, 5267, 734, 784, 433]
}
]
},
options: {
legend: { display: false },
title: {
display: true,
text: 'A chart with columns and custom vertical labels'
},
scales: {
yAxes: [{
ticks: {
callback: function (value, index, values) {
return index % 2 == 0 ? value : '**' + value + '**';
}
}
}]
}
}
});
Note the callback funcion there, maybe you can use this to give some labels a distinctive text.
The chart of this example looks like this:
Related
I have some time based data I want a graphical representation of, and was hoping to use Chartjs to plot this.
The data looks something like the following:
Time State
--------------
7am up
9am down
10.45am out
17.35 up
Also, each "state" will have its own color, so I would use this as a bar color when using a bar graph
up = red
down = yellow
out = green
The end result I am after is a simple one row bar like the following...
I thought I may be able to use a Chartjs horizontal stacked bar chart (https://www.chartjs.org/docs/latest/charts/bar.html#horizontal-bar-chart) to do this somehow, but I just can't work out how to get this working.
Some (not working) experimental code is as follows:
private createChart(): void {
if (this.chart !== undefined) {
return;
}
Chart.register(BarController, PointElement, Tooltip, Legend, TimeScale, LinearScale, CategoryScale, LinearScale, BarElement);
const options: ChartOptions = {
plugins: {
legend: {
display: false,
},
title: {
display: false,
},
},
indexAxis: 'y',
responsive: true,
maintainAspectRatio: false,
scales: {
y: {
stacked: true,
type: 'time',
display: true,
// position: 'bottom',
time: {
unit: 'minute',
displayFormats: {
minute: 'h:mm a'
}
}
},
x: {
stacked: false,
}
}
};
this.chart = new Chart(this.canvasRef.nativeElement, {
type: 'bar',
data: this.chartData,
options
});
this.chart.config.options.scales.y.min = new Date('2023-02-13T06:19:31.842Z').getTime();
const labels = [
'up',
'down'
// 'Dataset 2'
];
const d1 = new Date('2023-02-13T06:20:32.842Z').getTime();
const d2 = new Date('2023-02-13T06:21:33.842Z').getTime();
this.chartData = {
labels,
datasets: [{
label: 'up',
data: [{x: 10, y: d1}],
backgroundColor: 'red',
},
{
label: 'down',
data: [{x: 20, y: d2}],
backgroundColor: 'green',
}
]
};
this.chart.update();
}
In the above I have tried various combinations of labels, x values, y values, data shapes, but I only even get an empty graph.
Perhaps this is not really possible (I am trying to use the wrong component).
How can I achieve this using chartjs?
Update
Using example from #winner_joiner below, I have put a copy of it at plunkr and have tried to use the time in the x axis, but can see it is still not plotting the bars using the dates as the length
Well your code basically works, here a slightly modified version of your code.
After your comments and updated question, I reworke the example (seen below). Although it is possible to do with chart.js the question is, maybe for this specific task a different library or solution would be better/more convenient.
Update Chart, with some similar values from your question:
(I'm using here momentjs, since it is recommend usually needed form date/time actions in chartjs, as mentioned in the documentation)
const d0 = moment.duration('07:00:00').asMinutes();
const d1 = moment.duration('09:00:00').asMinutes();
const d2 = moment.duration('10:45:00').asMinutes();
const d3 = moment.duration('17:35:00').asMinutes();
const d4 = moment.duration('19:00:00').asMinutes();
let values = [d0, d1, d2, d3, d4];
let data = {
labels: [''],
datasets: [{
label: 'up',
axis: 'y',
data: [d1],
backgroundColor: 'red',
},{
label: 'down',
axis: 'y',
data: [d2],
backgroundColor: 'yellow',
},{
label: 'out',
axis: 'y',
data: [d3],
backgroundColor: 'green',
},{
label: 'up',
axis: 'y',
data: [d4],
backgroundColor: 'red',
}
]
};
const config = {
data,
type: 'bar',
options:{
plugins: {
tooltip: {
mode: 'dataset',
callbacks: {
label: function(item){
return moment().startOf('day').add({ minute: item.raw}).format('HH:mm');
}
}
},
legend: {
display: false,
},
title: {
display: false,
},
},
indexAxis: 'y',
responsive: true,
maintainAspectRatio: false,
scales: {
x: {
min: d0,
ticks: {
callback: function(value, index, ticks) {
return moment().startOf('day').add({ minute: value}).format('HH:mm');
}
},
afterBuildTicks: axis => axis.ticks = values.map(v => ({ value: v }))
},
y: {
stacked: true
},
}
}};
new Chart(document.getElementById("chart"), config);
<script src="//cdn.jsdelivr.net/npm/chart.js"></script>
<script src="//cdn.jsdelivr.net/npm/moment#^2"></script>
<script src="//cdn.jsdelivr.net/npm/chartjs-adapter-moment#^1"></script>
<div class="chart" style="height:184px; width:350px;">
<canvas id="chart" ></canvas>
</div>
Is their a way to rotate the legend on the left side of a bar chart vertically (in chartjs)? I can't seem to find it in the documentation.
Current:
Wanted:
Code:
chartData is an array containing the char data where chartData["yas"] is equal to the "Samples" legend title
let myChart = new Chart(chart, {
type: 'bar',
data: {
labels: chartData['labels'],
datasets: [{
label: chartData["yas"],
data: chartData['values'],
backgroundColor: '#6FB98F'
}]
},
options: {
responsive: true,
plugins: {
legend: {
position: 'left'
}
},
scales: {
y: {
ticks: {
beginAtZero:true,
minRotation : 0
}
}
}
}
});
This is not possible with the current implementation of the legend in chart.js. You have 2 options, you can use a html legend and rotate that 90 degree with css. Or you can take the legend plugin as a basis and write the functionality yourself to rotate it and either use it or make a pr and get it into the main lib.
I have a chart containing data for each day of the year and I'm wanting to show the x-axis simply as months.
I've set up the following callback function which (crudely) grabs the month from the set of labels, checks to see whether it already exists and if not, returns it as an axis label
let rollingLabel;
...
function(label, index, labels) {
let _label = label.replace(/[0-9]/g, '');
if (rollingLabel != _label) {
rollingLabel = _label;
return rollingLabel;
}
}
However, it's only returning two of the expected four labels.
What's confusing me more is that if I add console.log(rollingLabel) within the conditional I can see that the variable is updating how I'd expect but it's not returning the value, or it is and the chart isn't picking it up for whatever reason. Even more confusing is that if I uncomment line 48 // return _label the chart updates with all the labels so I don't believe it's an issue with max/min settings for the chart.
If anyone has any ideas I'd be most grateful. I've been staring at it for hours now!
The expected output for the below snippet should have the following x-axis labels:
Aug | Sep | Oct | Nov
const canvas = document.getElementById('chart');
const ctx = canvas.getContext('2d');
let data = [
1,6,3,11,5,1,2,6,2,10,5,8,1,1,2,4,5,2,3,1
];
let labels = [
"Aug 1","Aug 2","Aug 3","Aug 4","Aug 5","Sep 1","Sep 2","Sep 3","Sep 4","Sep 5","Oct 1","Oct 2","Oct 3","Oct 4","Oct 5","Nov 1","Nov 2", "Nov 3","Nov 4","Nov 5"
];
let rollingLabel;
chart = new Chart(ctx, {
type: "line",
data: {
datasets: [
{
backgroundColor: '#12263A',
data: data,
pointRadius: 0
}
],
labels: labels,
},
options: {
legend: {
display: false
},
responsive: false,
scales: {
xAxes: [
{
gridLines: {
display: false
},
ticks: {
display: true,
autoSkip: true,
callback: function(label, index, labels) {
let _label = label.replace(/[0-9]/g, '');
if (rollingLabel != _label) {
rollingLabel = _label;
return rollingLabel;
}
// return _label;
}
}
}
]
},
tooltips: {
mode: "index",
intersect: false
},
hover: {
mode: "index",
intersect: false
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="chart"></canvas>
You need to define ticks.autoSkip: false on the x-axis to make it work as expected:
autoSkip: If true, automatically calculates how many labels can be shown and hides labels accordingly. Labels will be rotated up to maxRotation before skipping any. Turn autoSkip off to show all labels no matter what.
Please take a look at your amended code below:
let data = [
1,6,3,11,5,1,2,6,2,10,5,8,1,1,2,4,5,2,3,1
];
let labels = [
"Aug 1","Aug 2","Aug 3","Aug 4","Aug 5","Sep 1","Sep 2","Sep 3","Sep 4","Sep 5","Oct 1","Oct 2","Oct 3","Oct 4","Oct 5","Nov 1","Nov 2", "Nov 3","Nov 4","Nov 5"
];
let rollingLabel;
chart = new Chart('chart', {
type: "line",
data: {
datasets: [
{
backgroundColor: '#12263A',
data: data,
pointRadius: 0
}
],
labels: labels,
},
options: {
legend: {
display: false
},
responsive: false,
scales: {
xAxes: [
{
gridLines: {
display: false
},
ticks: {
display: true,
autoSkip: false,
callback: function(label, index, labels) {
let _label = label.replace(/[0-9]/g, '');
if (rollingLabel != _label) {
rollingLabel = _label;
return rollingLabel;
}
}
}
}
]
},
tooltips: {
mode: "index",
intersect: false
},
hover: {
mode: "index",
intersect: false
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="chart"></canvas>
I found a easy solution via the chart.js documentation.
const config = {
type: 'line',
data: data,
options: {
responsive: true,
plugins: {
title: {
display: true,
text: 'Chart with Tick Configuration'
}
},
scales: {
x: {
ticks: {
// For a category axis, the val is the index so the lookup via getLabelForValue is needed
callback: function(val, index) {
// Hide the label of every 2nd dataset
return index % 2 === 0 ? this.getLabelForValue(val) : '';
},
color: 'red',
}
}
}
},
};
The callback function decides what labels will be shown. Current setup shows every 2nd label, if you want to show every 3rd for example you would change:
return index % 2 === 0 ? this.getLabelForValue(val) : '';
to:
return index % 3 === 0 ? this.getLabelForValue(val) : '';
I'm trying to put data into chartJS and have it automatically scroll when it reaches the end
so like when it reaches here
it will keep adding data without the user having to scroll, is there any ways that I can do this without the scroll bar at the bottom?
Automatic scrolling without visible scroll bar would means that the user can never see data again that was scrolled out of the visible area. If this is what you want, you can simply remove outdated labels and dataset values once a certain limit is reached. This can be done using Array.shift(), which removes the first element from an array.
chart.data.labels.push(<new label>);
chart.data.datasets[0].data.push(<new value>);
if (chart.data.labels.length > maxValues) {
chart.data.labels.shift();
chart.data.datasets[0].data.shift();
}
chart.update();
Please have a look at the runnable code snippet below that allows up to 10 labels and values. Once this limit is reached, outdated labels and values are removed.
var chart = new Chart('canvas', {
type: "line",
responsive: true,
maintainAspectRatio: false,
data: {
labels: [],
datasets: [{
label: "Data",
data: [],
fill: true,
backgroundColor: "lightblue",
borderColor: "lightblue",
pointRadius: 0
}]
},
options: {
legend: {
display: true,
position: 'bottom'
},
scales: {
yAxes: [{
ticks: {
min: 0,
max: 20,
stepSize: 5
}
}]
}
}
});
var maxValues = 10;
var count = 0;
setInterval(() => {
chart.data.labels.push(++count);
chart.data.datasets[0].data.push(Math.floor((Math.random() * 20) + 1));
if (chart.data.labels.length > maxValues) {
chart.data.labels.shift();
chart.data.datasets[0].data.shift();
}
chart.update();
}, 1000);
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="canvas" height="100"></canvas>
I would like to update specific column background colour but I couldn't do this. Seem like it is very easy but all the solution I tried out from google doesn't work. The code is as below.
var ctx = document.getElementById("myChart");
var myChart = new Chart(ctx, {
type: 'bar',
data: {
labels : ["A","B","C","D","E"],
datasets: [{
data : [<?php echo $graph_data;?>],
backgroundColor: "rgba(0,0,220,0.5)",
borderColor: "rgba(0,0,220,1)",
borderWidth: 2
}]
}
});
//I would like to achieve something like this, let's say change the first and second bar's background color
myChart.datasets[0].bars[0].fillColor = "rgba(220,0,0,0.5)";
myChart.datasets[0].bars[1].fillColor = "rgba(220,0,0,0.5)";
myChart.update();
I had an old code which run succesfully under version 1.0.1-beta.4, but now I world like to use the latest version 2.5.0, and then I faced this issue.
Thanks for any helps!
You can just pass an array to the backgroundColor bar chart dataset property (instead of a single color) where the position in the array maps to the position in the data array.
For example, if you have 3 bars and want all 3 to be a different color, just pass an array to backgroundColor where all 3 elements have a different color value.
var ctx = document.getElementById("canvas").getContext("2d");
var myBar = new Chart(ctx, {
type: 'bar',
data: {
labels: ["Car", "Bike", "Walking"],
datasets: [{
label: 'Fuel',
backgroundColor: [
chartColors.red,
chartColors.blue,
chartColors.yellow],
data: [
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
]
}]
},
options: {
title: {
display: true,
text: "Chart.js - Different Bar Colors"
},
tooltips: {
mode: 'index',
intersect: false
},
legend: {
display: false,
},
responsive: true,
}
});
Here is a codepen example demonstrating this.