Bullet Charts with automatic updating

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license: mit

README.md

This is a Bullet Chart example that allows the user to update the chart automatically by updating the bulletdata2.json file. This (online) example won't change, but if you download the file and read in conjunction with d3noob.org you will be able to impliment your own dynamic chart with it.

This is a follow on from the example that updated the charts with random data.

bullet.js

(function() {

// Chart design based on the recommendations of Stephen Few. Implementation
// based on the work of Clint Ivy, Jamie Love, and Jason Davies.
// http://projects.instantcognition.com/protovis/bulletchart/
d3.bullet = function() {
  var orient = "left", // TODO top & bottom
      reverse = false,
      duration = 0,
      ranges = bulletRanges,
      markers = bulletMarkers,
      measures = bulletMeasures,
      width = 380,
      height = 30,
      tickFormat = null;

  // For each small multiple…
  function bullet(g) {
    g.each(function(d, i) {
      var rangez = ranges.call(this, d, i).slice().sort(d3.descending),
          markerz = markers.call(this, d, i).slice().sort(d3.descending),
          measurez = measures.call(this, d, i).slice().sort(d3.descending),
          g = d3.select(this);

      // Compute the new x-scale.
      var x1 = d3.scale.linear()
          .domain([0, Math.max(rangez[0], markerz[0], measurez[0])])
          .range(reverse ? [width, 0] : [0, width]);

      // Retrieve the old x-scale, if this is an update.
      var x0 = this.__chart__ || d3.scale.linear()
          .domain([0, Infinity])
          .range(x1.range());

      // Stash the new scale.
      this.__chart__ = x1;

      // Derive width-scales from the x-scales.
      var w0 = bulletWidth(x0),
          w1 = bulletWidth(x1);

      // Update the range rects.
      var range = g.selectAll("rect.range")
          .data(rangez);

      range.enter().append("rect")
          .attr("class", function(d, i) { return "range s" + i; })
          .attr("width", w0)
          .attr("height", height)
          .attr("x", reverse ? x0 : 0)
        .transition()
          .duration(duration)
          .attr("width", w1)
          .attr("x", reverse ? x1 : 0);

      range.transition()
          .duration(duration)
          .attr("x", reverse ? x1 : 0)
          .attr("width", w1)
          .attr("height", height);

      // Update the measure rects.
      var measure = g.selectAll("rect.measure")
          .data(measurez);

      measure.enter().append("rect")
          .attr("class", function(d, i) { return "measure s" + i; })
          .attr("width", w0)
          .attr("height", height / 3)
          .attr("x", reverse ? x0 : 0)
          .attr("y", height / 3)
        .transition()
          .duration(duration)
          .attr("width", w1)
          .attr("x", reverse ? x1 : 0);

      measure.transition()
          .duration(duration)
          .attr("width", w1)
          .attr("height", height / 3)
          .attr("x", reverse ? x1 : 0)
          .attr("y", height / 3);

      // Update the marker lines.
      var marker = g.selectAll("line.marker")
          .data(markerz);

      marker.enter().append("line")
          .attr("class", "marker")
          .attr("x1", x0)
          .attr("x2", x0)
          .attr("y1", height / 6)
          .attr("y2", height * 5 / 6)
        .transition()
          .duration(duration)
          .attr("x1", x1)
          .attr("x2", x1);

      marker.transition()
          .duration(duration)
          .attr("x1", x1)
          .attr("x2", x1)
          .attr("y1", height / 6)
          .attr("y2", height * 5 / 6);

      // Compute the tick format.
      var format = tickFormat || x1.tickFormat(8);

      // Update the tick groups.
      var tick = g.selectAll("g.tick")
          .data(x1.ticks(8), function(d) {
            return this.textContent || format(d);
          });

      // Initialize the ticks with the old scale, x0.
      var tickEnter = tick.enter().append("g")
          .attr("class", "tick")
          .attr("transform", bulletTranslate(x0))
          .style("opacity", 1e-6);

      tickEnter.append("line")
          .attr("y1", height)
          .attr("y2", height * 7 / 6);

      tickEnter.append("text")
          .attr("text-anchor", "middle")
          .attr("dy", "1em")
          .attr("y", height * 7 / 6)
          .text(format);

      // Transition the entering ticks to the new scale, x1.
      tickEnter.transition()
          .duration(duration)
          .attr("transform", bulletTranslate(x1))
          .style("opacity", 1);

      // Transition the updating ticks to the new scale, x1.
      var tickUpdate = tick.transition()
          .duration(duration)
          .attr("transform", bulletTranslate(x1))
          .style("opacity", 1);

      tickUpdate.select("line")
          .attr("y1", height)
          .attr("y2", height * 7 / 6);

      tickUpdate.select("text")
          .attr("y", height * 7 / 6);

      // Transition the exiting ticks to the new scale, x1.
      tick.exit().transition()
          .duration(duration)
          .attr("transform", bulletTranslate(x1))
          .style("opacity", 1e-6)
          .remove();
    });
    d3.timer.flush();
  }

  // left, right, top, bottom
  bullet.orient = function(x) {
    if (!arguments.length) return orient;
    orient = x;
    reverse = orient == "right" || orient == "bottom";
    return bullet;
  };

  // ranges (bad, satisfactory, good)
  bullet.ranges = function(x) {
    if (!arguments.length) return ranges;
    ranges = x;
    return bullet;
  };

  // markers (previous, goal)
  bullet.markers = function(x) {
    if (!arguments.length) return markers;
    markers = x;
    return bullet;
  };

  // measures (actual, forecast)
  bullet.measures = function(x) {
    if (!arguments.length) return measures;
    measures = x;
    return bullet;
  };

  bullet.width = function(x) {
    if (!arguments.length) return width;
    width = x;
    return bullet;
  };

  bullet.height = function(x) {
    if (!arguments.length) return height;
    height = x;
    return bullet;
  };

  bullet.tickFormat = function(x) {
    if (!arguments.length) return tickFormat;
    tickFormat = x;
    return bullet;
  };

  bullet.duration = function(x) {
    if (!arguments.length) return duration;
    duration = x;
    return bullet;
  };

  return bullet;
};

function bulletRanges(d) {
  return d.ranges;
}

function bulletMarkers(d) {
  return d.markers;
}

function bulletMeasures(d) {
  return d.measures;
}

function bulletTranslate(x) {
  return function(d) {
    return "translate(" + x(d) + ",0)";
  };
}

function bulletWidth(x) {
  var x0 = x(0);
  return function(d) {
    return Math.abs(x(d) - x0);
  };
}

})();

bulletdata2.json

[
  {
    "title":"CPU Load",
    "subtitle":"GHz",
    "ranges":[1500,2250,3000],
    "measures":[2200],
    "markers":[2500]
  },
  {
    "title":"Memory Used",
    "subtitle":"MBytes",
    "ranges":[256,512,1024],
    "measures":[768],
    "markers":[900]
  }
]

index.html

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

body {
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  margin: auto;
  padding-top: 40px;
  position: relative;
  width: 800px;
}

.bullet { font: 10px sans-serif; }
.bullet .marker { stroke: #000; stroke-width: 2px; }
.bullet .tick line { stroke: #666; stroke-width: .5px; }
.bullet .range.s0 { fill: #eee; }
.bullet .range.s1 { fill: #ddd; }
.bullet .range.s2 { fill: #ccc; }
.bullet .measure.s0 { fill: steelblue; }
.bullet .title { font-size: 14px; font-weight: bold; }
.bullet .subtitle { fill: #999; }

</style>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.17/d3.min.js"></script>
<script src="bullet.js"></script>
<script>

var margin = {top: 5, right: 40, bottom: 20, left: 120},
    width = 800 - margin.left - margin.right,
    height = 50 - margin.top - margin.bottom;

var chart = d3.bullet()
    .width(width)
    .height(height);

d3.json("bulletdata2.json", function(error, data) {
  var svg = d3.select("body").selectAll("svg")
      .data(data)
    .enter().append("svg")
      .attr("class", "bullet")
      .attr("width", width + margin.left + margin.right)
      .attr("height", height + margin.top + margin.bottom)
    .append("g")
      .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
      .call(chart);

  var title = svg.append("g")
      .style("text-anchor", "end")
      .attr("transform", "translate(-6," + height / 2 + ")");

  title.append("text")
      .attr("class", "title")
      .text(function(d) { return d.title; });

  title.append("text")
      .attr("class", "subtitle")
      .attr("dy", "1em")
      .text(function(d) { return d.subtitle; });

  setInterval(function() {
    updateData();
	}, 1000);

});

function updateData() {
  d3.json("bulletdata2.json", function(error, data) {
		d3.select("body").selectAll("svg")
			.datum(function (d, i) {
				d.ranges = data[i].ranges;
				d.measures = data[i].measures;
				d.markers = data[i].markers;
				return d;
			})
			.call(chart.duration(1000));
	});
}

</script>
</body>

thumbnail.png