We use the Chart.js library in our codebase and I need to create a histogram, which is not one of their default chart types. So I'm attempting to override the x-axis tick marks on a bar chart so that they appear at the left and right corners of each bar instead of directly underneath.
In the below example I've gotten the x-axis how I want it by adding an extra item in the labels
array and displaying a second x-axis in the options
. But, because there's now an extra label, the bars are taking up 4/5ths of the width, leaving space for a non-existent data point.
Is there some way that I can specify to ignore the missing data point? Or offset the bars? Or am I barking up the wrong tree?
The documentation is a little hard to parse through, so I'm not sure if there's something simple I'm missing.
var ctx = document.getElementById("myChart").getContext('2d');
var myChart = new Chart(ctx, {
type: 'bar',
data: {
labels: [0, 1, 2, 3, 4],
datasets: [{
label: 'Group A',
data: [12, 19, 3, 5],
backgroundColor: 'rgba(255, 99, 132, 1)',
}]
},
options: {
scales: {
xAxes: [{
display: false,
barPercentage: 1.30,
}, {
display: true,
}],
yAxes: [{
ticks: {
beginAtZero:true
}
}]
}
}
});
canvas { max-width: 200px; }
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.2/Chart.min.js"></script>
<canvas id="myChart" width="20" height="20"></canvas>
Edit: I realize there are other libraries that could achieve something similar and I am looking into other options. But, I've posted this just in case someone out there knows of a solution via Chart.js, which would be ideal.
Here's an example of what the end result I'm going for is:
I believe you can get the result you want by using the
max
parameter on theticks
configuration of the x axes.By using 2 different x axes with different maximums you can label the bars differently from how they're drawn. Resulting in labeling the marks in between the bars without drawing an extra "empty" bar.