D3 Examples - Assignment 5 - Interaction in D3

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<!DOCTYPE html>
<meta charset="utf-8">
<style>
​
.axis--x path {
  display: none;
}
​
.line {
  fill: none;
  stroke: steelblue;
  stroke-width: 1.5px;
}
​
</style>
<svg width="960" height="500"></svg>
<script src="//d3js.org/d3.v4.min.js"></script>
<script>
​
//global active variable -- use for on click function
var active;
​
//create svg
var svg = d3.select("svg"),
    margin = {top: 20, right: 80, bottom: 30, left: 50},
    width = svg.attr("width") - margin.left - margin.right,
    height = svg.attr("height") - margin.top - margin.bottom,
    g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");
​
var parseTime = d3.timeParse("%Y%m%d");
​
//x and y scales, z defines categorical colors for 3 cities
var x = d3.scaleTime().range([0, width]),
    y = d3.scaleLinear().range([height, 0]),
    z = d3.scaleOrdinal(d3.schemeCategory10);
​
//create xAxis
var xAxis = d3.axisBottom(x);
​
//define line
var line = d3.line()
    .curve(d3.curveBasis)
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.temperature); });
​
//zoom function
var zoom = d3.zoom()
    .scaleExtent([1 / 4, 8])
    .translateExtent([[-width, -Infinity], [2 * width, Infinity]])
    .on("zoom", zoomed);
​
//zoomRect -- for detecting mouse events
var zoomRect= svg.append("rect")
    .attr("width", width)
    .attr("height", height)
    .attr("fill", "none")
    .attr("pointer-events", "all")
    .call(zoom);
​
g.append("clipPath")
    .attr("id", "clip")
    .append("rect")
    .attr("width", width + 100)
    .attr("height", height);
​
//used for zoom
var xGroup = g.append("g");
​
var yGroup = g.append("g");
    //.attr("transform", "translate(0," + height + ")");
​
​
d3.tsv("data.tsv", type, function(error, data) {
  if (error) throw error;
​
  var cities = data.columns.slice(1).map(function(id) {
    return {
      id: id,
      values: data.map(function(d) {
        return {date: d.date, temperature: d[id]};
      })
    };
  });
​
  x.domain(d3.extent(data, function(d) { return d.date; }));
​
  //zoom on the x axis
  var xExtent = d3.extent(data, function(d) { return d.date; });
  zoom.translateExtent([[x(xExtent[0]), -Infinity], [x(xExtent[1]), Infinity]]);
  //areaPath.datum(data);
  zoomRect.call(zoom.transform, d3.zoomIdentity);
​
  y.domain([
    d3.min(cities, function(c) { return d3.min(c.values, function(d) { return d.temperature; }); }),
    d3.max(cities, function(c) { return d3.max(c.values, function(d) { return d.temperature; }); })
  ]);
​
  z.domain(cities.map(function(c) { return c.id; }));
​
  xGroup.attr("class", "axis axis--x")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);
​
  yGroup.attr("class", "axis axis--y")
      .call(d3.axisLeft(y))
      .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", "0.71em")
      .attr("fill", "#000")
      .text("Temperature, ºF");
​
  var city = g.selectAll(".city")
    .data(cities)
    .enter().append("g")
      .attr("clip-path", "url(#clip)")
      .attr("class", "city");
  
  city.append("path")
      .attr("class", "line")
      .attr("id", function(d) {return d.id.substring(0,3).toUpperCase()})
      .attr("d", function(d) { return line(d.values); })
      .style("stroke", function(d) { return z(d.id); })
    ;
​
  city.append("text")
      .datum(function(d) { return {id: d.id, value: d.values[d.values.length - 1]}; })
      .attr("transform", function(d) { return "translate(" + x(d.value.date) + "," + y(d.value.temperature) + ")"; })
      .attr("x", 3)
      .attr("dy", "0.35em")
      .style("font", "10px sans-serif")
      .text(function(d) { return d.id; })
        .on("click", function(d) {
          //grab the substring
          var selected = d.id.substring(0,3).toUpperCase();
          //set active variable as true or false if it's clicked
          active = d.active ? false : true;
          //set opacity
          var newOpacity = active ? 0 : 1;
          d3.select("#" + selected).style("opacity", newOpacity);
          d.active = d.active ? false : true;
      })
      .on("mouseover", function(d) {
        //if the link is visible
        if(!active){
          var selected = d.id.substring(0,3).toUpperCase();
          d3.selectAll(".city path")
          //filter out the ones that aren't the line hovered over
            .filter(function(d) {
              var compare = d.id.substring(0,3).toUpperCase();
              return compare != selected;
          })
          .style("stroke", "gray")
​
        }
      })
  
      .on("mouseout", function(d) {
        //return the colors to the originals
        var selected = d.id.substring(0,3).toUpperCase();
        d3.selectAll(".city path")
        .filter(function(d) {
          var compare = d.id.substring(0,3).toUpperCase();
          return selected != compare;
        })
        .style("stroke", function(d) {
          return z(d.id)  
        }) 
      });
​
 
});
​
function type(d, _, columns) {
  d.date = parseTime(d.date);
  for (var i = 1, n = columns.length, c; i < n; ++i) d[c = columns[i]] = +d[c];
  return d;
}
​
function zoomed() {
  //zoomed function - scales everything
  var xz = d3.event.transform.rescaleX(x);
  xGroup.call(xAxis.scale(xz));
  line.x(function(d) {return xz(d.date);});
  g.selectAll(".line")
    .attr("d", function(d) {return line(d.values);});
}
​
</script>
​
    