Changing barplot color with a button in d3.js





This post describes how to build a button that changes the color of a barplot. You need to understand how to draw a basic barplot first. It is a good way to understand how to build a button in html, and how to build a simple function in Javascript. This example works with d3.js v4 and v6


Barplot section

Steps:

  • First of all, understand how to build a basic barplot.

  • Add a button in the html part. Note the onclick attribute: it means that the changeColor() function will be triggered when you click on it

  • Create the changeColor() function in the Javascript part. It basically select all the rectangles of the plot and change their fill attribute.
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<!DOCTYPE html>
<meta charset="utf-8">

<!-- Load d3.js -->
<script src="https://d3js.org/d3.v4.js"></script>

<!-- Add 2 buttons -->
<button onclick="changeColor('blue')">Get blue</button>
<button onclick="changeColor('red')">Get red</button>

<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>

<!DOCTYPE html>
<meta charset="utf-8">
          
<!-- Load d3.js -->
<script src="https://d3js.org/d3.v6.js"></script>

<!-- Add 2 buttons -->
<button onclick="changeColor('blue')">Get blue</button>
<button onclick="changeColor('red')">Get red</button>
          
<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>
      
<script>


// set the dimensions and margins of the graph
var margin = {top: 30, right: 30, bottom: 70, left: 60},
    width = 460 - margin.left - margin.right,
    height = 400 - margin.top - margin.bottom;

// append the svg object to the body of the page
var svg = d3.select("#my_dataviz")
  .append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform",
          "translate(" + margin.left + "," + margin.top + ")");

// Parse the Data
d3.csv("https://raw.githubusercontent.com/holtzy/data_to_viz/master/Example_dataset/7_OneCatOneNum_header.csv", function(data) {

// X axis
var x = d3.scaleBand()
  .range([ 0, width ])
  .domain(data.map(function(d) { return d.Country; }))
  .padding(0.2);
svg.append("g")
  .attr("transform", "translate(0," + height + ")")
  .call(d3.axisBottom(x))
  .selectAll("text")
    .attr("transform", "translate(-10,0)rotate(-45)")
    .style("text-anchor", "end");

// Add Y axis
var y = d3.scaleLinear()
  .domain([0, 13000])
  .range([ height, 0]);
svg.append("g")
  .call(d3.axisLeft(y));

// Bars
svg.selectAll("mybar")
  .data(data)
  .enter()
  .append("rect")
    .attr("x", function(d) { return x(d.Country); })
    .attr("y", function(d) { return y(d.Value); })
    .attr("width", x.bandwidth())
    .attr("height", function(d) { return height - y(d.Value); })
    .attr("fill", "#69b3a2")

})

// This function is called by the buttons on top of the plot
function changeColor(color){
  d3.selectAll("rect")
    .transition()
    .duration(2000)
    .style("fill", color)
}


</script>
<script>

  
// set the dimensions and margins of the graph
const margin = {top: 30, right: 30, bottom: 70, left: 60},
    width = 460 - margin.left - margin.right,
    height = 400 - margin.top - margin.bottom;

// append the svg object to the body of the page
const svg = d3.select("#my_dataviz")
  .append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", `translate(${margin.left},${margin.top})`);

// Parse the Data
d3.csv("https://raw.githubusercontent.com/holtzy/data_to_viz/master/Example_dataset/7_OneCatOneNum_header.csv").then( function(data) {

// X axis
const x = d3.scaleBand()
  .range([ 0, width ])
  .domain(data.map(d => d.Country))
  .padding(0.2);
svg.append("g")
  .attr("transform", `translate(0, ${height})`)
  .call(d3.axisBottom(x))
  .selectAll("text")
    .attr("transform", "translate(-10,0)rotate(-45)")
    .style("text-anchor", "end");

// Add Y axis
const y = d3.scaleLinear()
  .domain([0, 13000])
  .range([ height, 0]);
svg.append("g")
  .call(d3.axisLeft(y));

// Bars
svg.selectAll("mybar")
  .data(data)
  .join("rect")
    .attr("x", d => x(d.Country))
    .attr("y", d => y(d.Value))
    .attr("width", x.bandwidth())
    .attr("height", d => height - y(d.Value))
    .attr("fill", "#69b3a2")

})

// This function is called by the buttons on top of the plot
function changeColor(color){
  d3.selectAll("rect")
    .transition()
    .duration(2000)
    .style("fill", color)
}
</script>

Related blocks →

  • Simple bar graph in v4 - link

  • Let's make a bar chart - link