CODEWITHSUNDEEP
javascriptd3.js
pir
pir

Reputation: 5933

Adding value labels to D3 bar chart

I want to add value labels as a black text above each bar in my bar chart. The code is inspired from http://bl.ocks.org/mbostock/3885304. I've posted it below with the data file. I've attempted to add the code snippet at the end of index.html to create the value labels, but I don't get any text added to the graph.

Index.html

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.bar {
  fill: steelblue;
  shape-rendering: crispEdges;
}

.bar text {
  //fill: black;
  font: 11x sans-serif;
  stroke: black;
}

.bar:hover {
  fill: brown;
}

.axis {
  font: 11x sans-serif;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.x.axis path {
  display: none;
}

</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>

var margin = {top: 20, right: 20, bottom: 90, left: 55},
    width = 400 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], .1);

var y = d3.scale.linear()
    .range([height, 0]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left")
    .ticks(10, "%");

var svg = d3.select("body").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 + ")");

d3.tsv("data.tsv", type, function(error, data) {
  x.domain(data.map(function(d) { return d.group; }));
  //y.domain([0, d3.max(data, function(d) { return d.frequency; })]);
  y.domain([0, 1]);

  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis)
      .selectAll("text")  
        .style("text-anchor", "end")
        //.attr("dx", "-.8em")
        //.attr("dy", ".15em")
        .attr("dx", "-.6em")
        .attr("dy", ".35em")
        .attr("transform", function(d) {
            return "rotate(-45)" 
            });

  svg.append("g")
      .attr("class", "y axis")
      .call(yAxis)
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", ".71em")
      .style("text-anchor", "end")
      .text("Frequency");

  var bar = svg.selectAll(".bar")
      .data(data)
    .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { return x(d.group); })
      .attr("width", x.rangeBand())
      .attr("y", function(d) { return y(d.frequency); })
      .attr("height", function(d) { return height - y(d.frequency); });

   // A formatter for counts.
   var formatCount = d3.format(",.0f"); 

   // Add value labels
   valueLabels = bar.append("text")
    .attr("dy", ".75em")
    .attr("y", 6)
    .attr("x", function(d) { return x(d.group); })
    .attr("text-anchor", "middle")
    .text(function(d) { return formatCount(y(d.frequency)); });

});

function type(d) {
  d.frequency = +d.frequency;
  return d;
}

</script>

data.tsv

group   frequency
1-9 weeks   .036197
10-12 weeks .0457085
13 weeks    .0714285
14 weeks    .846666

Upvotes: 0

Views: 1158

Answers (1)

pir
pir

Reputation: 5933

Based on the reference by @Lars Kotthoff and the material at https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/ceil, I coded the following:

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.bar {
  fill: steelblue;
  shape-rendering: crispEdges;
}


.bar text {
  //fill: black;
  font: 8x sans-serif;
  stroke: black;
}

.datalabel {
  font-size: 10px;
  fill: white;
}

.bar:hover {
  fill: brown;
}

.axis {
  font: 11x sans-serif;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.x.axis path {
  display: none;
}

</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>

var margin = {top: 20, right: 20, bottom: 90, left: 55},
    width = 400 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], .1);

var y = d3.scale.linear()
    .range([height, 0]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left")
    .ticks(10, "%");

var svg = d3.select("body").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 + ")");

d3.tsv("interactions.tsv", type, function(error, data) {
  x.domain(data.map(function(d) { return d.group; }));
  //y.domain([0, d3.max(data, function(d) { return d.frequency; })]);
  y.domain([0, 1]);

  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis)
      .selectAll("text")  
        .style("text-anchor", "end")
        //.attr("dx", "-.8em")
        //.attr("dy", ".15em")
        .attr("dx", "-.6em")
        .attr("dy", ".35em")
        .attr("transform", function(d) {
            return "rotate(-45)" 
            });

  svg.append("g")
      .attr("class", "y axis")
      .call(yAxis)
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", ".71em")
      .style("text-anchor", "end")
      .text("Frequency");

    var bar = svg.selectAll(".bar")
      .data(data)
      .enter().append("g");

    bar.append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { return x(d.group); })
      .attr("width", x.rangeBand())
      .attr("y", function(d) { return y(d.frequency); })
      .attr("height", function(d) { return height - y(d.frequency); });

    bar.append("text")
    .attr("class", "datalabel")
    .attr("x", function(d) { return x(d.group) + x.rangeBand()/2; })
    .attr("y",  function(d) { return y(0) - 10; } )
    .attr("dy", ".35em")
    .attr("text-anchor", "middle")
    .text(function(d) { return Math.ceil10(d.frequency*100, -1) + "%"; });

   // A formatter for counts.
   var formatCount = d3.format(",.0f"); 
});

function type(d) {
  d.frequency = +d.frequency;
  return d;
}

(function () {
    /**
     * Decimal adjustment of a number.
     *
     * @param {String}  type  The type of adjustment.
     * @param {Number}  value The number.
     * @param {Integer} exp   The exponent (the 10 logarithm of the adjustment base).
     * @returns {Number} The adjusted value.
     */
    function decimalAdjust(type, value, exp) {
        // If the exp is undefined or zero...
        if (typeof exp === 'undefined' || +exp === 0) {
            return Math[type](value);
        }
        value = +value;
        exp = +exp;
        // If the value is not a number or the exp is not an integer...
        if (isNaN(value) || !(typeof exp === 'number' && exp % 1 === 0)) {
            return NaN;
        }
        // Shift
        value = value.toString().split('e');
        value = Math[type]( + (value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp)));
        // Shift back
        value = value.toString().split('e');
        return  + (value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp));
    }

    // Decimal round
    if (!Math.round10) {
        Math.round10 = function (value, exp) {
            return decimalAdjust('round', value, exp);
        };
    }
    // Decimal floor
    if (!Math.floor10) {
        Math.floor10 = function (value, exp) {
            return decimalAdjust('floor', value, exp);
        };
    }
    // Decimal ceil
    if (!Math.ceil10) {
        Math.ceil10 = function (value, exp) {
            return decimalAdjust('ceil', value, exp);
        };
    }
})();

</script>

Upvotes: 1

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