Comparing Multi-Line Chart to Multi-Line Chart

Comparing

“Multi-Line Chart” (target)

“Multi-Line Chart” (base)

Toph Tucker

Workspace

Published unlisted

Edited

May 6, 2020

chart = {

const svg = d3.create("svg")

.attr("viewBox", [0, 0, width, height])

.style("overflow", "visible");

svg.append("g")

.call(xAxis);

svg.append("g")

.call(yAxis);

const path = svg.append("g")

.attr("fill", "none")

.attr("stroke", "steelblue")

.attr("stroke-width", 1.5)

.attr("stroke-linejoin", "round")

.attr("stroke-linecap", "round")

.selectAll("path")

.data(data.series)

.join("path")

.style("mix-blend-mode", "multiply")

.attr("d", d => line(d.values));

svg.call(hover, path);

return svg.node();

}

data = {

const data = d3.tsvParse(await FileAttachment("unemployment.tsv").text());

const columns = data.columns.slice(1);

return {

y: "% Unemployment",

series: data.map(d => ({

name: d.name.replace(/, ([\w-]+).*/, " $1"),

values: columns.map(k => +d[k])

})),

dates: columns.map(d3.utcParse("%Y-%m"))

};

}

Changed in target

function hover(svg, path) {
  
  if ("ontouchstart" in document) svg
      .style("-webkit-tap-highlight-color", "transparent")
      .on("touchmove", moved)
      .on("touchstart", entered)
      .on("touchend", left)
  else svg
      .on("mousemove", moved)
      .on("mouseenter", entered)
      .on("mouseleave", left);

  const dot = svg.append("g")
      .attr("display", "none");

  dot.append("circle")
      .attr("r", 2.5);

  dot.append("text")
      .attr("font-family", "sans-serif")
      .attr("font-size", 10)
      .attr("text-anchor", "middle")
      .attr("y", -8);

  function moved() {
    d3.event.preventDefault();
-
    const ym = y.invert(d3.event.layerY);
    const xm = x.invert(d3.event.layerX);
+
    const mouse = d3.mouse(svg.node())
    const ym = y.invert(mouse[1]);
    const xm = x.invert(mouse[0]);
    const i1 = d3.bisectLeft(data.dates, xm, 1);
    const i0 = i1 - 1;
    const i = xm - data.dates[i0] > data.dates[i1] - xm ? i1 : i0;
    const s = d3.least(data.series, d => Math.abs(d.values[i] - ym));
    path.attr("stroke", d => d === s ? null : "#ddd").filter(d => d === s).raise();
    dot.attr("transform", `translate(${x(data.dates[i])},${y(s.values[i])})`);
    dot.select("text").text(s.name);
  }

  function entered() {
    path.style("mix-blend-mode", null).attr("stroke", "#ddd");
    dot.attr("display", null);
  }

  function left() {
    path.style("mix-blend-mode", "multiply").attr("stroke", null);
    dot.attr("display", "none");
  }
}

height = 600

margin = ({top: 20, right: 20, bottom: 30, left: 30})

x = d3.scaleUtc()

.domain(d3.extent(data.dates))

.range([margin.left, width - margin.right])

y = d3.scaleLinear()

.domain([0, d3.max(data.series, d => d3.max(d.values))]).nice()

.range([height - margin.bottom, margin.top])

xAxis = g => g

.attr("transform", `translate(0,${height - margin.bottom})`)

.call(d3.axisBottom(x).ticks(width / 80).tickSizeOuter(0))

yAxis = g => g

.attr("transform", `translate(${margin.left},0)`)

.call(d3.axisLeft(y))

.call(g => g.select(".domain").remove())

.call(g => g.select(".tick:last-of-type text").clone()

.attr("x", 3)

.attr("text-anchor", "start")

.attr("font-weight", "bold")

.text(data.y))

line = d3.line()

.defined(d => !isNaN(d))

.x((d, i) => x(data.dates[i]))

.y(d => y(d))

d3 = require("d3@5", "d3-array@2")