Decimal in x-axis - chart.js

I'm trying to create a line chart with chart.js where the data in a dataset contains points:
data: [{x:0,y:5},{x:2.1,y:4.3},{x:3.9,y:3}]
The x values of those points contain decimals. The resulting chart looks like this:
Instead of showing the second data point at (2.1 | 4.3) it is drawn at (1 | 4.3)!
Can someone point me into the right direction on this one?
The code to reproduce this behavior:
<body>
<div>
<canvas id="myChart" width="400" height="200"></canvas>
</div>
<script>
var ctx = document.getElementById('myChart');
var myChart = new Chart(ctx, {
type: 'line',
data: {
labels: [0.0, 1.0, 2.0, 3.0, 4.0, 5.0],
datasets: [{
label: 'some label',
data: [{x:0,y:5},{x:2.1,y:4.3},{x:3.9,y:3}],
borderColor: 'red',
fill: false,
lineTension: 0
}]
},
options: {
scales: {
xAxes: [{
ticks: {
max: 10,
min: 0,
stepSize: 0.1
}
}],
yAxes: [{
ticks: {
max: 6,
min: 0,
stepSize: 1
}
}]
}
}
});
</script>
</body>


For the y-axis, using the stepSize variable of the ticks option does the trick. Doing the same for the x-axis is a little more complex but not impossible.
The first issue is that your x-axis labels are at integer intervals so the chart has nowhere to position the decimal values than at the closest integer. This can be fixed by specifying all the values in the desired intervals (ie: 0.1, 0.2,...,3.0) in the labels.
Then, making use of the autoSkip and maxTicksLimit, you can hide the labels not needed and so create the chart seen in your image, but with the points in the correct position.
I made a working version of this using your code in this fiddle. Hope this helps!

Related

Add space Between Columns in Bar chart. chartjs

I'm creating graphs using chart js V 2.9.3.
When I create the graph with a small amount of data it renders data perfectly but when the amount of data is increasing, the chart becomes Crowded.
A graph has two columns in single label.
I'm also not able to set the labels without rotation.
var config = {
type: 'bar',
data: {
labels: _datesForLabel,
datasets: _chartDataWithOptions,
},
options: {
tooltips: {
},
plugins: {
colorschemes: {
scheme: 'office.Waveform6'
}
},
scales: {
yAxes: [{
ticks: {
min: 0,
}
}],
xAxes: [{
barThickness: 40,
maxBarThickness: 40,
barPercentage: 1.0,
categoryPercentage: 1.0,
ticks: {
min: 0,
},
}]
}
}
};
myBarChart = new Chart(ctx, config);
These are the options I used.
given is the screenshot of the output
output Image
can anyone help me with this.
thank you

Remove this barThickness: 40, (40 in pixels). In your case "No space/room" for such width = overlaps & broken layout.
https://www.chartjs.org/docs/latest/charts/bar.html#barthickness
Basic snippet (Base on your code) (change barThickness barPercentage barPercentage):
https://www.chartjs.org/docs/latest/charts/bar.html#barpercentage-vs-categorypercentage
var canvas = document.getElementById("myChart");
var ctx = canvas.getContext("2d");
var _datesForLabel = ["2020-02-10",
"2020-02-13",
"2020-02-17",
"2020-02-18",
"2020-02-19",
"2020-02-20",
"2020-02-21",
"2020-02-22",
"2020-02-23",
"2020-02-24",
"2020-02-25",
"2020-02-26",
"2020-02-27",
"2020-02-28",
"2020-02-29",
"2020-03-01",
"2020-03-02",
"2020-03-03",
"2020-03-04",
"2020-03-05",
"2020-03-07",
"2020-03-08",
"2020-03-09",
"2020-03-10","2020-02-10",
"2020-02-13",
"2020-02-17",
"2020-02-18",
"2020-02-19",
"2020-02-20",
"2020-02-21",
"2020-02-22",
"2020-02-23",
"2020-02-24",
"2020-02-25",
"2020-02-26",
"2020-02-27",
"2020-02-28",
"2020-02-29",
"2020-03-01",
"2020-03-02",
"2020-03-03",
"2020-03-04",
"2020-03-05",
"2020-03-07",
"2020-03-08",
"2020-03-09",
"2020-03-10"]
var _chartDataWithOptions =[];
_chartDataWithOptions.push({
label:"dataseries1",
data:[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24],
backgroundColor:"blue"
})
_chartDataWithOptions.push({
label:"dataseries2",
data:[2,3,4,5,6,7,8,9,10,12,13,11,10,19,14,12,11,18,26,23,21,28,24,2,3,4,6,9,1,2,1,11,12,13,14,15,16,17,18,19,20,21,22,23,11,22,4,6,3,6],
backgroundColor:"red"
})
var config = {
type: 'bar',
data: {
labels: _datesForLabel,
datasets: _chartDataWithOptions,
borderSkipped: 'top'
},
options: {
// responsive: true,
tooltips: {
// mode: ''
},
plugins: {
colorschemes: {
scheme: 'office.Waveform6'
}
},
scales: {
yAxes: [{
ticks: {
min: 0,
}
}],
xAxes: [{
// barThickness: 40, // number (pixels) or 'flex'
maxBarThickness: 40,
barPercentage: 1,/* change this */
categoryPercentage: 0.5,/* change this */
ticks: {
min: 0,
},
}]
}
}
};
myBarChart = new Chart(ctx, config);
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js" ></script>
<div style="height: 500px; width: 100%;">
<canvas id="myChart" ></canvas>
</div>
About "set labels without rotation" - again "no room" - by maxRotation: 0, - full answer + example her: Chart Js Change Label orientation on x-Axis for Line Charts
"To much points/data" issue:
For now "no way" to auto group data - one idea is to use
stacked: true ("save room") - or manually filter your data (Show fewer points - related StackOverflow Q: Chartjs 2 scaling lots of data points).
Related Github feature request: https://github.com/chartjs/Chart.js/issues/4053

Chart.js display x axis labels ON ticks in bar chart, not between

I have this chart:
...which is displaying exactly how I want it to with one exception... The data in the bars is for between the two times in the x axis... so all the labels need shifting to lie on the grid lines, not between them as default for a bar chart. So the red and blue bar is data between 8:00 and 9:00. I hope I've explained that clearly enough.
I'm trawling through the Chart.js docs and it just doesn't seem like this is possible! I know I could change my labels to be, for example, 8pm - 9pm, but that seems a much more visually clunky way of doing it. Is there a way anyone know of achieving this? Ideally there would be another '12am' on the last vertical grid line too.

You can draw the tick lables at the desired position directly on to the canvas using the Plugin Core API. It offers number of hooks that may be used for performing custom code. In below code snippet, I use the afterDraw hook to draw my own labels on the xAxis.
const hours = ['00', '01', '02', '03', '04', '05', '06'];
const values = [0, 0, 0, 0, 10, 6, 0];
const chart = new Chart(document.getElementById('myChart'), {
type: 'bar',
plugins: [{
afterDraw: chart => {
var xAxis = chart.scales['x-axis-0'];
var tickDistance = xAxis.width / (xAxis.ticks.length - 1);
xAxis.ticks.forEach((value, index) => {
if (index > 0) {
var x = -tickDistance + tickDistance * 0.66 + tickDistance * index;
var y = chart.height - 10;
chart.ctx.save();
chart.ctx.fillText(value == '0am' ? '12am' : value, x, y);
chart.ctx.restore();
}
});
}
}],
data: {
labels: hours,
datasets: [{
label: 'Dataset 1',
data: values,
categoryPercentage: 0.99,
barPercentage: 0.99,
backgroundColor: 'blue'
}]
},
options: {
responsive: true,
legend: {
display: false
},
scales: {
xAxes: [{
type: 'time',
time: {
parser: 'HH',
unit: 'hour',
displayFormats: {
hour: 'Ha'
},
tooltipFormat: 'Ha'
},
gridLines: {
offsetGridLines: true
},
ticks: {
min: moment(hours[0], 'HH').subtract(1, 'hours'),
fontColor: 'white'
}
}]
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="myChart" height="90"></canvas>

Angular Chart.js Bar Chart

I am using a bar chart of chart.js in angular 7.This chart shows the relationship between policies and their number of sales. If the maximum number of sales is 2 or 1 or a small number, the chart shows the values along the y-axis in points, starts from 1 and ends on the maximum value.Right now i have maximum 6 policies, hence the values do not have points in them, but when the number of maximum policies reduce to 2, the values are as 1.0, 1.1, 1.2, 1.3....2.0. I want the values to be non-decimal in the y-axis and also they should start from zero up to the maximum number as 0,1,2,3...,. Is it possible?
//component
chartData1 = [
{
label: 'Policies',
data: this.policies
},
];
chartOptions = {
responsive: true // THIS WILL MAKE THE CHART RESPONSIVE (VISIBLE IN ANY DEVICE).
}
//template
<canvas
baseChart
[chartType]="'bar'"
[datasets]="chartData"
[labels]="labels"
[options]="chartOptions"
[legend]="true"
height="80"
width="100"
[colors]="colors"
(chartClick)="onChartClick($event)">
</canvas>

Within your component, try to define chartOptions as follows:
chartOptions = {
responsive: true,
scales: {
yAxes: [{
ticks: {
beginAtZero: true,
stepSize: 1
}
}]
}
}

Chart.js How to make a sample math axis?

I want to have x, y-axis like the following image.
It is really sample, but the x,y across on (0,0). and I want the negative part always shows whatever there is a point or now.
Thanks

You can get a result close to your example image, but not exactly the same. You would probably need to create a custom axis to align the tick labels to the zero line.
let axisConfig = {
drawBorder: false,
gridLines: {
lineWidth: 0,
zeroLineWidth: 1
},
ticks: {
max: 6,
min: -6
}
};
new Chart(document.getElementById("chart"), {
type: "scatter",
options: {
scales: {
xAxes: [axisConfig],
yAxes: [axisConfig]
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.min.js"></script>
<canvas id="chart"></canvas>

How to remove numbering on PolarArea circles?

If you look at the example of PolarArea in the Chart.js documentation, you will see each circle has a number like 16, 14, 12, etc.
These numbers refer to the value of each segment.
Is it possible to remove these numbers so the chart displays with the segments and circles only?

These are the ticks on the linear radial axis. They can be removed by setting the scale.ticks.display option to false.
Example:
new Chart(document.getElementById("chart"), {
type: "polarArea",
data: {
labels: ["a", "b", "c"],
datasets: [{
data: [10, 20, 30]
}]
},
options: {
scale: {
ticks: {
display: false
}
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.min.js"></script>
<canvas id="chart"></canvas>