An improvement of Average Price Histories by using constraint relaxation to position the labels, borrowed from the Dorling Cartogram example.
forked from syntagmatic‘s block: Average Price Histories II
<!DOCTYPE html>
<title>Constraint Relaxation - Prices</title>
<meta charset="utf-8">
<style>
body {
font: 10px sans-serif;
}
.axis path,
.axis line {
fill: none;
stroke: #000;
shape-rendering: crispEdges;
}
.x.axis path {
display: none;
}
.line {
fill: none;
stroke: steelblue;
stroke-width: 1.5px;
-webkit-transition: opacity 0.3s;
-moz-transition: opacity 0.3s;
-o-transition: opacity 0.3s;
transition: opacity 0.3s;
}
path.invisible {
fill: none;
stroke: rgba(0,0,0,0);
stroke-width: 8px;
}
text.label {
font-size: 12px;
font-weight: bold;
}
</style>
<script src="//mbostock.github.com/d3/d3.v2.js"></script>
<script src="//documentcloud.github.com/underscore/underscore.js"></script>
<body></body>
<script type="text/javascript">
var margin = {top: 20, right: 220, bottom: 30, left: 50},
width = 1000 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var format = d3.time.format("%b %Y");
var start = format.parse("Jan 1984");
var end = format.parse("Aug 2012");
var range = d3.time.months(start,end);
var x = d3.time.scale()
.range([0,width])
.domain([start,end]);
var y = d3.scale.linear()
.range([height, 0]);
var color = function(i) {
return d3.hcl(48*i,95,45).toString();
};
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left");
var line = d3.svg.line()
.interpolate("basis")
.defined(function(d) { return d != null; })
.x(function(d,i) { return x(range[i]); })
.y(function(d) { return y(d); });
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.csv("average-prices.csv", function(raw) {
var data = [];
var goods = _(raw).pluck("Name");
_(raw).each(function(series) {
var value = {};
data.push({
id: series["Series ID"],
name: series["Name"],
values: _(range).map(function(month) {
return parseFloat(series[format(month)]) || null;
})
});
});
var values = _(data).chain().pluck('values').flatten().value();
y.domain([
0,
d3.max(values)
]);
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
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")
.style("font-weight", "bold")
.text("Average Price");
var series = svg.selectAll(".series")
.data(data)
.enter().append("g")
.attr("class", "series");
series.append("path")
.attr("class", "line")
.attr("d", function(d) { return line(d.values); })
.style("stroke", function(d,i) { return color(i); });
series.append("path")
.attr("class", "invisible hover")
.attr("d", function(d) { return line(d.values); });
var labels = data.map(function(d) { return {name: d.name, y: y(d.values[d.values.length - 1])}});
series.append("text")
.attr("class", "label hover")
.data(labels)
.attr("transform", function(d) { return "translate(" + x(end) + "," + d.y + ")"; })
.attr("x", 3)
.attr("dy", ".35em")
.style("fill", function(d,i) { return color(i); })
.text(function(d) { return d.name; });
// constraint relaxation on labels
var alpha = 0.5;
var spacing = 12;
function relax() {
var again = false;
labels.forEach(function(a,i) {
labels.slice(i+1).forEach(function(b) {
var dy = a.y - b.y;
if (Math.abs(dy) < spacing) {
again = true;
var sign = dy > 0 ? 1 : -1;
a.y += sign*alpha;
b.y -= sign*alpha;
}
});
});
d3.selectAll(".label")
.attr("transform", function(d) { return "translate(" + x(end) + "," + d.y + ")"; });
if (again) setTimeout(relax,20);
};
relax();
series.selectAll(".hover")
.on("mouseover", function(d,i) {
d3.selectAll(".line")
.style("opacity", 0.12)
.filter(function(p) { return p.name == d.name; })
.style("opacity", 1)
.style("stroke-width", 2.5);
d3.selectAll(".series text")
.style("opacity", 0)
.filter(function(p) { return p.name == d.name; })
.style("opacity", 1);
})
.on("mouseout", function(d,i) {
d3.selectAll(".line")
.style("opacity", 1)
.style("stroke-width", null);
d3.selectAll(".series text")
.style("opacity", 1);
});
});
</script>