Histogram: grouped, stacked, normalized

<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-size: 13px;
    margin: auto;
    position: relative;
    width: 960px;
    color: #333;
}
text {
    font: 10px sans-serif;
    fill: #666;
}
.axis path,
.axis line {
    fill: none;
    stroke: #666;
    shape-rendering: crispEdges;
}
.form {
    position: relative;
    float: right;
    right: 10px;
    top: 10px;
    margin: 40px 40px 0 0;
}
label{
    margin: 6px;
}
</style>
<div class="form">
    <label><input type="radio" name="mode" value="grouped" checked> Grouped</label>
    <label><input type="radio" name="mode" value="stacked"> Stacked</label>
    <label><input type="radio" name="mode" value="normalized"> Normalized</label>
</div>
<div id="chart"></div>
<script src="https://d3js.org/d3.v3.min.js"></script>

var n = 5,  // number of layers
    m = 65; // number of samples per layer
var transitionDuration = 250; // transition duration

console.log(layers);

var margin = {top: 40, right: 10, bottom: 20, left: 30},
    width = 960 - margin.left - margin.right,
    height = 350 - margin.top - margin.bottom;

var color = d3.scale.linear()
    .domain([0, n - 1])
    .range(["#ffc014", "#990000"]);

var x = d3.scale.ordinal()
    .domain(d3.range(m))
    .rangeRoundBands([0, width], 0.1);

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

var xAxis = d3.svg.axis()
    .scale(x)
    .tickSize(0)
    .tickPadding(6)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .tickSize(0)
    .tickPadding(6)
    .orient("left");

var svg = d3.select("#chart").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 + ")");

var layer = svg.selectAll(".layer")
    .data(layers)
    .enter().append("g")
    .attr("class", "layer")
    .style("fill", function(d, i) { return color(i); });

var rect = layer.selectAll("rect")
    .data(function(d) { return d; })
    .enter().append("rect")
    .attr("x", function(d, i, j) { 
        return x(d.x) + x.rangeBand() / n * j; 
    })
    .attr("y", height)
    .attr("width", x.rangeBand() / n)
    .attr("height", 0);

rect.transition()
    .duration(transitionDuration)
    .attr("y", function(d) { return y(d.y); })
    .attr("height", function(d) { return height - y(d.y); });

svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + height + ")")
    .call(xAxis);

svg.append("g")
    .attr("class", "y axis")
    .call(yAxis);

d3.selectAll("input").on("change", change);

function transitionGrouped() {
    y.domain([0, yGroupMax]).nice();

rect.transition()
        .duration(transitionDuration)
        .attr("x", function(d, i, j) { 
            return x(d.x) + x.rangeBand() / n * j; 
        })
        .attr("width", x.rangeBand() / n)
        .transition()
        .attr("y", function(d) { 
            return y(d.y); 
        })
        .attr("height", function(d) { 
            return height - y(d.y); 
        });

// update the y-axis
    svg.select('g.y.axis')
        .transition()
        .duration(transitionDuration)
        .call(yAxis);
}

function transitionStacked() {
    y.domain([0, yStackMax]).nice();

rect.transition()
        .duration(transitionDuration)
        .attr("y", function(d) { 
            return y(d.y0 + d.y); 
        })
        .attr("height", function(d) { 
            return y(d.y0) - y(d.y0 + d.y); 
        })
        .transition()
        .attr("x", function(d) { 
            return x(d.x); 
        })
        .attr("width", x.rangeBand());

// update the y-axis
    svg.select('g.y.axis')
        .transition()
        .duration(transitionDuration)
        .call(yAxis);
}

function transitionNormalized() {

function total(i) {
        var t = 0;
        for (var j = 0; j < n; j++) {
            t = t + layers[j][i].y;
        }
        return t;
    }

y.domain([0, 100]);
    rect.transition()
        .duration(transitionDuration)
        .attr("y", function(d,i,j) { 
            var t = total(i);
            var yy = y((d.y0 + d.y)/t*100);
            return yy; 
        })
        .attr("height", function(d,i) { 
            var t = total(i);
            var hh = y(d.y0/t*100) - y((d.y0 + d.y)/t*100);
            return hh; 
        })
        .transition()
        .attr("x", function(d) { 
            return x(d.x); 
        })
        .transition()
        .attr("x", function(d) { 
            return x(d.x); 
        })
        .attr("width", x.rangeBand());

// update the y-axis
    svg.select('g.y.axis')
        .transition()
        .duration(transitionDuration)
        .call(yAxis);
}

// random data generator - inspired by Lee Byron's test data generator
function bumpLayer(n, o) {

function bump(a) {
        var x = 1 / ( 0.1 + Math.random() ),
            y = 2 * Math.random() - 0.5,
            z = 10 / ( 0.1 + Math.random() );
        for ( var i = 0; i < n; i++ ) {
            var w = ( i / n - y ) * z;
            a[i] += x * Math.exp(-w * w);
        }
    }

}

</script>

Modified http://d3js.org/d3.v3.min.js to a secure url

https://d3js.org/d3.v3.min.js