CPR Neighborhood Segregation Chart

by Anna Hazard

HTML

<script src="//d3js.org/d3.v3.min.js"></script>

<div id='chart1'>
  <svg style='height:500px;width:400px'> </svg>
</div>

CSS

body {
  font: 10px sans-serif;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.bar {
  fill: steelblue;
}

.x.axis path {
  display: none;
}

.d3-tip {
  line-height: 1;
  font-weight: bold;
  padding: 12px;
  background: rgba(0, 0, 0, 0.8);
  color: #739FB5;
  border-radius: 2px;
}

.d3-tip:after {
  box-sizing: border-box;
  display: inline;
  font-size: 10px;
  width: 100%;
  line-height: 1;
  color: rgba(0, 0, 0, 0.8);
  content: "\25BC";
  position: absolute;
  text-align: center;
}

/* Style northward tooltips differently */
.d3-tip.n:after {
  margin: -1px 0 0 0;
  top: 100%;
  left: 0;
}

JavaScript

// d3.tip
// Copyright (c) 2013 Justin Palmer
//
// Tooltips for d3.js SVG visualizations

// Public - contructs a new tooltip
//
// Returns a tip
d3.tip = function() {
  var direction = d3_tip_direction,
      offset    = d3_tip_offset,
      html      = d3_tip_html,
      node      = initNode(),
      svg       = null,
      point     = null,
      target    = null

  function tip(vis) {
    svg = getSVGNode(vis)
    point = svg.createSVGPoint()
    document.body.appendChild(node)
  }

  // Public - show the tooltip on the screen
  //
  // Returns a tip
  tip.show = function() {
    var args = Array.prototype.slice.call(arguments)
    if(args[args.length - 1] instanceof SVGElement) target = args.pop()

    var content = html.apply(this, args),
        poffset = offset.apply(this, args),
        dir     = direction.apply(this, args),
        nodel   = d3.select(node), i = 0,
        coords

    nodel.html(content)
      .style({ opacity: 1, 'pointer-events': 'all' })

    while(i--) nodel.classed(directions[i], false)
    coords = direction_callbacks.get(dir).apply(this)
    nodel.classed(dir, true).style({
      top: (coords.top +  poffset[0]) + 'px',
      left: (coords.left + poffset[1]) + 'px'
    })

    return tip
  }

  // Public - hide the tooltip
  //
  // Returns a tip
  tip.hide = function() {
    nodel = d3.select(node)
    nodel.style({ opacity: 0, 'pointer-events': 'none' })
    return tip
  }

  // Public: Proxy attr calls to the d3 tip container.  Sets or gets attribute value.
  //
  // n - name of the attribute
  // v - value of the attribute
  //
  // Returns tip or attribute value
  tip.attr = function(n, v) {
    if (arguments.length < 2 && typeof n === 'string') {
      return d3.select(node).attr(n)
    } else {
      var args =  Array.prototype.slice.call(arguments)
      d3.selection.prototype.attr.apply(d3.select(node), args)
    }

    return tip
  }

  // Public: Proxy style calls to the d3 tip container.  Sets or gets a style value.
 ...