Multiline Pan & Zoom with voronoi mouseover

Multi-line chart with mouseover using voronoi tesselation to isolate the nearest series to the cursor, as seen here but with added pan & zoom capability.

forked from twlynch's block: Multiline Pan & Zoom with voronoi mouseover

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

<div id="chart"></div>
<style>
body {
    font: 10px Arial;
	
}

.axis path {
  display: none;
}

.axis line {
  stroke-opacity: 0.3;
}

.line {
    fill: none;
    stroke: steelblue;
    stroke-width: 1.5px;
}

.site--hover {
  stroke: #000;
  stroke-width: 4px;
}

button {
  position: absolute;
  top: 20px;
  left: 80px;
}

.voronoi path {
  fill: none;
  pointer-events: all;
}

.voronoi--show path {
  stroke: red;
  stroke-opacity: 0.2;
}

</style>
<body>
<button>Reset</button>
<label id="form" for="show-voronoi">
  Show Voronoi
  <input type="checkbox" id="show-voronoi" disabled>
</label>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var margin = {top: 20, right: 20, bottom: 50, left: 50},
    width = 1000 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var parseTime = d3.timeParse("%d/%m/%Y %H:%M");
	bisectDate = d3.bisector(function(d) { return d.dt; }).left;
	formatValue = d3.format(",.2f"),
    formatCurrency = function(d) { return "£" + formatValue(d); };
	
var x = d3.scaleTime()
		  .range([0, width]);

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

var z = d3.scaleOrdinal(d3.schemeCategory10);

var voronoi = d3.voronoi()
    .x(function(d) { return x(d.dt); })
    .y(function(d) { return y(d.price); })
    .extent([[-margin.left, -margin.top], [width + margin.right, height + margin.bottom]]);

svg = d3.select('#chart')
    .append("svg:svg")
    .attr('width', width + margin.left + margin.right)
    .attr('height', height + margin.top + margin.bottom)
    .append("svg:g")
	.attr("id","group")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

// Get the data
d3.csv("data_long.csv", function(error, data) {
	if (error) throw error;
	
	data.forEach(function(d,i) {
		d.dt = parseTime(d.dt);
		d.price = +d.price;
	});
	
	var nest=d3.nest()
		  .key(function(d) {return d.site;})
		  .sortKeys(d3.ascending)
		  .entries(data);
		  	
	sites = {};	
	d3.map(data, function(d){return d.site;})
	  .keys() // unique sites
	  .forEach(function(d,i) {sites[d] = nest[i].values});
	
	console.log("sites4:", sites);
		  
	// Scale the range of the data
	var date_max = d3.max(data, function(d) { return d.dt; });
	console.log("Date range: ", d3.extent(data, function(d) { return d.dt; }));
	x.domain(d3.extent(data, function(d) { return d.dt; }));
	y.domain(d3.extent(data, function(d) { return d.price; }));
	z.domain(d3.map(data, function(d){return d.site;}).keys());
	
	var zoom = d3.zoom()
		.scaleExtent([0.75, 15000])
		.translateExtent([[-100000, -100000], [100000, 100000]])
		.on("zoom", zoomed);	
	
	var xAxis = d3.axisBottom(x)
		.ticks((width + 2) / (height + 2) * 5)
		.tickSize(-height)
		.tickPadding(10);
		
	var yAxis = d3.axisRight(y)
		.ticks(5)
		.tickSize(width)
		.tickPadding(- 20 - width);
	
	svg.append("text")             
	  .attr("transform",
			"translate(" + (width/2) + " ," + (height + margin.top + 20) + ")")
	  .style("font-size","12px")
	  .style("font-family", "sans-serif")
	  .style("text-anchor", "middle")
	  .text("Date/Time");
	  
	svg.append("text")
		  .attr("transform", "rotate(-90)")
		  .attr("y", 0 - margin.left/1.2)
		  .attr("x",0 - (height / 2))
		  .attr("dy", "1em")
		  .style("font-size","12px")
		  .style("text-anchor", "middle")
		  .text("Price");

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

var voronoiGroup = svg.append("g")
	  .attr("class", "voronoiParent")
	  .append("g")
      .attr("class", "voronoi")
	  .attr("clip-path","url(#clip)");
	
	voronoiGroup.selectAll("path")
      .data(voronoi.polygons(data))
      .enter()
	  .append("path")
      .attr("d", function(d) { return d ? "M" + d.join("L") + "Z" : null; })
      .on("mouseover", mouseover)
      .on("mouseout", mouseout);
	  
	d3.select(".voronoiParent").call(zoom);
	
	d3.select("button").on("click", resetted);
	
	d3.select("#show-voronoi")
      .property("disabled", false)
      .on("change", function() { voronoiGroup.classed("voronoi--show", this.checked); });

chartBody.selectAll("path")
		       .attr("d", priceSeries2);
	  
	  focus.select("circle.y")
		   .attr('cx', function() {return t.applyX(x(x_date.dt)); })
		   .attr('cy', function() {return t.applyY(y(x_date.price)); });
	  
	  voronoiGroup
	    .attr("transform", d3.event.transform)

}

function resetted() {
	  d3.select(".voronoiParent").transition()
		  .duration(750)
		  .call(zoom.transform, d3.zoomIdentity);
	}
	
});

</script>
</body>

https://d3js.org/d3.v4.min.js