68๐
After looking into the Chart.Bar.js file Iโve managed to find the solution.
Iโve used this function to generate a random color:
function getRandomColor() {
var letters = '0123456789ABCDEF'.split('');
var color = '#';
for (var i = 0; i < 6; i++ ) {
color += letters[Math.floor(Math.random() * 16)];
}
return color;
}
Iโve added it to the end of the file and i called this function right inside the โfillColor:โ under
helpers.each(dataset.data,function(dataPoint,index){
//Add a new point for each piece of data, passing any required data to draw.
so now it looks like this:
helpers.each(dataset.data,function(dataPoint,index){
//Add a new point for each piece of data, passing any required data to draw.
datasetObject.bars.push(new this.BarClass({
value : dataPoint,
label : data.labels[index],
datasetLabel: dataset.label,
strokeColor : dataset.strokeColor,
fillColor : getRandomColor(),
highlightFill : dataset.highlightFill || dataset.fillColor,
highlightStroke : dataset.highlightStroke || dataset.strokeColor
}));
},this);
and it works I get different color for each bar.
105๐
As of v2, you can simply specify an array of values to correspond to a color for each bar via the backgroundColor
property:
datasets: [{
label: "My First dataset",
data: [20, 59, 80, 81, 56, 55, 40],
backgroundColor: ["red", "blue", "green", "blue", "red", "blue"],
}],
This is also possible for the borderColor
, hoverBackgroundColor
, hoverBorderColor
.
From the documentation on the Bar Chart Dataset Properties:
Some properties can be specified as an array. If these are set to an array value, the first value applies to the first bar, the second value to the second bar, and so on.
69๐
Solution: call the update method to set new values โโ:
var barChartData = {
labels: ["January", "February", "March"],
datasets: [
{
label: "My First dataset",
fillColor: "rgba(220,220,220,0.5)",
strokeColor: "rgba(220,220,220,0.8)",
highlightFill: "rgba(220,220,220,0.75)",
highlightStroke: "rgba(220,220,220,1)",
data: [20, 59, 80]
}
]
};
window.onload = function(){
var ctx = document.getElementById("mycanvas").getContext("2d");
window.myObjBar = new Chart(ctx).Bar(barChartData, {
responsive : true
});
//nuevos colores
myObjBar.datasets[0].bars[0].fillColor = "green"; //bar 1
myObjBar.datasets[0].bars[1].fillColor = "orange"; //bar 2
myObjBar.datasets[0].bars[2].fillColor = "red"; //bar 3
myObjBar.update();
}
26๐
If you take a look at the library โChartNewโ which builds upon Chart.js you can do this by passing the values in as an array like so:
var data = {
labels: ["Batman", "Iron Man", "Captain America", "Robin"],
datasets: [
{
label: "My First dataset",
fillColor: ["rgba(220,220,220,0.5)", "navy", "red", "orange"],
strokeColor: "rgba(220,220,220,0.8)",
highlightFill: "rgba(220,220,220,0.75)",
highlightStroke: "rgba(220,220,220,1)",
data: [2000, 1500, 1750, 50]
}
]
};
25๐
You can call this function which generates random colors for each bars
var randomColorGenerator = function () {
return '#' + (Math.random().toString(16) + '0000000').slice(2, 8);
};
var barChartData = {
labels: ["001", "002", "003", "004", "005", "006", "007"],
datasets: [
{
label: "My First dataset",
fillColor: randomColorGenerator(),
strokeColor: randomColorGenerator(),
highlightFill: randomColorGenerator(),
highlightStroke: randomColorGenerator(),
data: [20, 59, 80, 81, 56, 55, 40]
}
]
};
21๐
Here, I solved this issue by making two functions.
1. dynamicColors() to generate random color
function dynamicColors() {
var r = Math.floor(Math.random() * 255);
var g = Math.floor(Math.random() * 255);
var b = Math.floor(Math.random() * 255);
return "rgba(" + r + "," + g + "," + b + ", 0.5)";
}
2. poolColors() to create array of colors
function poolColors(a) {
var pool = [];
for(i = 0; i < a; i++) {
pool.push(dynamicColors());
}
return pool;
}
Then, just pass it
datasets: [{
data: arrData,
backgroundColor: poolColors(arrData.length),
borderColor: poolColors(arrData.length),
borderWidth: 1
}]
20๐
As of August 2019, Chart.js now has this functionality built in.
You simply need to provide an array to backgroundColor.
Example taken from https://www.chartjs.org/docs/latest/getting-started/
Before:
data: {
labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
datasets: [{
label: 'My First dataset',
backgroundColor: 'rgb(255, 99, 132)',
borderColor: 'rgb(255, 99, 132)',
data: [0, 10, 5, 2, 20, 30, 45]
}]
},
After:
data: {
labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
datasets: [{
label: 'My First dataset',
backgroundColor: ['rgb(255, 99, 132)','rgb(0, 255, 0)','rgb(255, 99, 132)','rgb(128, 255, 0)','rgb(0, 255, 255)','rgb(255, 255, 0)','rgb(255, 255, 128)'],
borderColor: 'rgb(255, 99, 132)',
data: [0, 10, 5, 2, 20, 30, 45]
}]
},
I just tested this method and it works. Each bar has a different color.
11๐
Generate random colors;
function getRandomColor() {
var letters = '0123456789ABCDEF'.split('');
var color = '#';
for (var i = 0; i < 6; i++) {
color += letters[Math.floor(Math.random() * 16)];
}
return color;
}
and call it for each record;
function getRandomColorEachEmployee(count) {
var data =[];
for (var i = 0; i < count; i++) {
data.push(getRandomColor());
}
return data;
}
finally set colors;
var data = {
labels: jsonData.employees, // your labels
datasets: [{
data: jsonData.approvedRatios, // your data
backgroundColor: getRandomColorEachEmployee(jsonData.employees.length)
}]
};
9๐
Hereโs a way to generate consistent random colors using color-hash
const colorHash = new ColorHash()
const datasets = [{
label: 'Balance',
data: _.values(balances),
backgroundColor: _.keys(balances).map(name => colorHash.hex(name))
}]
3๐
here is how I dealed:
I pushed an array โcolorsโ, with same number of entries than number of datas. For this I added a function โgetRandomColorโ at the end of the script.
Hope it helpsโฆ
for (var i in arr) {
customers.push(arr[i].customer);
nb_cases.push(arr[i].nb_cases);
colors.push(getRandomColor());
}
window.onload = function() {
var config = {
type: 'pie',
data: {
labels: customers,
datasets: [{
label: "Nomber of cases by customers",
data: nb_cases,
fill: true,
backgroundColor: colors
}]
},
options: {
responsive: true,
title: {
display: true,
text: "Cases by customers"
},
}
};
var ctx = document.getElementById("canvas").getContext("2d");
window.myLine = new Chart(ctx, config);
};
function getRandomColor() {
var letters = '0123456789ABCDEF'.split('');
var color = '#';
for (var i = 0; i < 6; i++) {
color += letters[Math.floor(Math.random() * 16)];
}
return color;
}
2๐
If youโre not able to use NewChart.js you just need to change the way to set the color using array instead.
Find the helper iteration inside Chart.js:
Replace this line:
fillColor : dataset.fillColor,
For this one:
fillColor : dataset.fillColor[index],
The resulting code:
//Iterate through each of the datasets, and build this into a property of the chart
helpers.each(data.datasets,function(dataset,datasetIndex){
var datasetObject = {
label : dataset.label || null,
fillColor : dataset.fillColor,
strokeColor : dataset.strokeColor,
bars : []
};
this.datasets.push(datasetObject);
helpers.each(dataset.data,function(dataPoint,index){
//Add a new point for each piece of data, passing any required data to draw.
datasetObject.bars.push(new this.BarClass({
value : dataPoint,
label : data.labels[index],
datasetLabel: dataset.label,
strokeColor : dataset.strokeColor,
//Replace this -> fillColor : dataset.fillColor,
// Whith the following:
fillColor : dataset.fillColor[index],
highlightFill : dataset.highlightFill || dataset.fillColor,
highlightStroke : dataset.highlightStroke || dataset.strokeColor
}));
},this);
},this);
And in your js:
datasets: [
{
label: "My First dataset",
fillColor: ["rgba(205,64,64,0.5)", "rgba(220,220,220,0.5)", "rgba(24,178,235,0.5)", "rgba(220,220,220,0.5)"],
strokeColor: "rgba(220,220,220,0.8)",
highlightFill: "rgba(220,220,220,0.75)",
highlightStroke: "rgba(220,220,220,1)",
data: [2000, 1500, 1750, 50]
}
]
2๐
Code based on the following pull request:
datapoint.color = 'hsl(' + (360 * index / data.length) + ', 100%, 50%)';
1๐
try this :
function getChartJs() {
**var dynamicColors = function () {
var r = Math.floor(Math.random() * 255);
var g = Math.floor(Math.random() * 255);
var b = Math.floor(Math.random() * 255);
return "rgb(" + r + "," + g + "," + b + ")";
}**
$.ajax({
type: "POST",
url: "ADMIN_DEFAULT.aspx/GetChartByJenisKerusakan",
data: "{}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (r) {
var labels = r.d[0];
var series1 = r.d[1];
var data = {
labels: r.d[0],
datasets: [
{
label: "My First dataset",
data: series1,
strokeColor: "#77a8a8",
pointColor: "#eca1a6"
}
]
};
var ctx = $("#bar_chart").get(0).getContext('2d');
ctx.canvas.height = 300;
ctx.canvas.width = 500;
var lineChart = new Chart(ctx).Bar(data, {
bezierCurve: false,
title:
{
display: true,
text: "ProductWise Sales Count"
},
responsive: true,
maintainAspectRatio: true
});
$.each(r.d, function (key, value) {
**lineChart.datasets[0].bars[key].fillColor = dynamicColors();
lineChart.datasets[0].bars[key].fillColor = dynamicColors();**
lineChart.update();
});
},
failure: function (r) {
alert(r.d);
},
error: function (r) {
alert(r.d);
}
});
}
1๐
This works for me in the current version 2.7.1
:
function colorizePercentageChart(myObjBar) {
var bars = myObjBar.data.datasets[0].data;
console.log(myObjBar.data.datasets[0]);
for (i = 0; i < bars.length; i++) {
var color = "green";
if(parseFloat(bars[i]) < 95){
color = "yellow";
}
if(parseFloat(bars[i]) < 50){
color = "red";
}
console.log(color);
myObjBar.data.datasets[0].backgroundColor[i] = color;
}
myObjBar.update();
}
1๐
Taking the other answer, here is a quick fix if you want to get a list with random colors for each bar:
function getRandomColor(n) {
var letters = '0123456789ABCDEF'.split('');
var color = '#';
var colors = [];
for(var j = 0; j < n; j++){
for (var i = 0; i < 6; i++ ) {
color += letters[Math.floor(Math.random() * 16)];
}
colors.push(color);
color = '#';
}
return colors;
}
Now you could use this function in the backgroundColor field in data:
data: {
labels: count[0],
datasets: [{
label: 'Registros en BDs',
data: count[1],
backgroundColor: getRandomColor(count[1].length)
}]
}
1๐
If you know which colors you want, you can specify color properties in an array, like so:
backgroundColor: [
'rgba(75, 192, 192, 1)',
...
],
borderColor: [
'rgba(75, 192, 192, 1)',
...
],
1๐
Following this answer: https://stackoverflow.com/a/48067347/931409, this is what I came up with to generate consistent colors, that donโt change with each refresh:
const generateColorHue = (colorI: number, totalColors: number) => {
const step = 360 / totalColors;
const hue = Math.round(colorI * step);
return hue;
};
// ...
datasets: this.platforms.map((platform, i) => {
const hue = generateColorHue(i, this.platforms.length);
return {
label: platform,
borderColor: "hsl(" + hue + ", 50%, 40%)",
backgroundColor: "hsla(" + hue + ", 50%, 90%, .2)",
};
}),
0๐
I have just got this issue recently, and here is my solution
var labels = ["001", "002", "003", "004", "005", "006", "007"];
var data = [20, 59, 80, 81, 56, 55, 40];
for (var i = 0, len = labels.length; i < len; i++) {
background_colors.push(getRandomColor());// I use @Benjamin method here
}
var barChartData = {
labels: labels,
datasets: [{
label: "My First dataset",
fillColor: "rgba(220,220,220,0.5)",
strokeColor: "rgba(220,220,220,0.8)",
highlightFill: "rgba(220,220,220,0.75)",
highlightStroke: "rgba(220,220,220,1)",
backgroundColor: background_colors,
data: data
}]
};
0๐
what Iโve done is create a random color generator as many here have suggested
function dynamicColors() {
var r = Math.floor(Math.random() * 255);
var g = Math.floor(Math.random() * 255);
var b = Math.floor(Math.random() * 255);
return "rgba(" + r + "," + g + "," + b + ", 0.5)";
}
and then coded this
var chartContext = document.getElementById('line-chart');
let lineChart = new Chart(chartContext, {
type: 'bar',
data : {
labels: <?php echo json_encode($names); ?>,
datasets: [{
data : <?php echo json_encode($salaries); ?>,
borderWidth: 1,
backgroundColor: dynamicColors,
}]
}
,
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
},
responsive: true,
maintainAspectRatio: false,
}
});
Notice there is no parantheses at the function call
This enables the code to call the function every time, instead of making an array
This also prevents the code from using the same color for all the bars
0๐
Pass a color parameter in dataPoints like below for each bar:
{y: your value, label: your value, color: your color code}
0๐
function getRandomColor() {
const colors = [];
var obj = @json($year);
const length = Object.keys(obj).length;
for(let j=0; j<length; j++ )
{
const letters = '0123456789ABCDEF'.split('');
let color = '#';
for (let i = 0; i < 6; i++ ) {
color += letters[Math.floor(Math.random() * 16)];
}
colors.push(color);
}
return colors;
}
use this function for different colors