D3: Animating between scales
The purpose of this gist is two-fold:
-
Demonstrate how to animate between scales;
-
Show how data visualization depends on the chosen scale.
For example, we can see how some data clusters using the power scale. The datums
1and10are rendered on the same spot. If we had a lot of these points close to each other and performance was a concern, filtering out some of these points could prove valuable.
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<!DOCTYPE html>
<meta charset="utf-8">
<style>
html, body {
height: 100%;
margin: 0;
}
.controls {
position: absolute;
top: 1em;
left: 1em;
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}
.chart {
width: 100%;
height: 100%;
display: block;
}
.chart path,
.chart line,
.chart rect {
shape-rendering: crispEdges;
}
.chart .axis path,
.chart .axis line {
fill: none;
stroke: #000;
}
.chart .linear .point {
fill: steelblue;
}
.chart .pow .point {
fill: #CD4638;
}
</style>
<body>
<form class="controls">
Scale:
<label><input type="radio" name="x-scale" value="power2" checked>Power2</label>
<label><input type="radio" name="x-scale" value="linear">Linear</label>
<label><input type="radio" name="x-scale" value="sqrt">SquareRoot</label>
<label><input type="radio" name="x-scale" value="log2">Log2</label>
<label><input type="radio" name="x-scale" value="log10">Log10</label>
</form>
<svg class="chart js-chart"></svg>
<script src="https://d3js.org/d3.v5.min.js"></script>
<script type="text/javascript">
"use strict";
/* global d3, document */
var chart = {
margin: { top: 0, right: 25, bottom: 0, left: 25 },
animationDuration: 400,
scales: {
power2: d3.scalePow().exponent(2),
linear: d3.scaleLinear(),
sqrt: d3.scalePow().exponent(0.5),
log2: d3.scaleLog().base(2),
log10: d3.scaleLog().base(10)
},
init: function (options, data) {
this.el = d3.select(".js-chart")
.attr("viewBox", "0 0 " + options.width + " " + options.height);
this.width = options.width - this.margin.left - this.margin.right;
this.height = options.height - this.margin.top - this.margin.bottom;
this.adaptScales();
this.setXScale();
this.draw(data);
d3.selectAll(".controls input").on("click", this.changeXScale.bind(this));
},
draw: function (data) {
var mainGroup, series;
mainGroup = this.el.append("g")
.attr("transform", "translate(" + this.margin.left + "," + this.margin.top + ")");
series = mainGroup.selectAll(".series").data(data)
.enter().append("g")
.attr("class", function (d) { return "series " + d.name; });
this.points = series.selectAll(".point").data(function (d) { return d.points; })
.enter().append("circle")
.attr("class", "point")
.attr("cx", this.xScale)
.attr("cy", this.height / 3)
.attr("r", 6);
this.points.append("title")
.text(String);
this.xAxis = d3.axisBottom()
.scale(this.xScale);
this.domXAxis = mainGroup.append("g")
.attr("class", "axis axis--x")
.attr("transform", "translate(0," + this.height / 2 + ")")
.call(this.xAxis);
},
redraw: function () {
this.domXAxis.transition()
.duration(this.animationDuration)
.call(this.xAxis.scale(this.xScale));
this.points.transition()
.duration(this.animationDuration)
.attr("cx", this.xScale);
},
adaptScales: function () {
Object.keys(this.scales).forEach(function (scaleType) {
this.scales[scaleType]
.domain([1, 1000])
.range([0, this.width]);
}, this);
},
changeXScale: function () {
this.setXScale();
this.redraw();
},
setXScale: function () {
var scaleType;
scaleType = d3.select(".controls input:checked").node().value;
this.xScale = this.scales[scaleType];
}
};
var options = {
width: 800,
height: 400
};
var data = [
{
name: "linear",
points: [300, 400, 500, 600]
},
{
name: "pow",
points: [1, 10, 100, 1000]
}
];
chart.init(options, data);
</script>
</body>