D3 Brush and Tooltip IV

Example for Cooperative Brushing and Tooltips in D3.

Note that the brush layer lives behind the data points, and therefore a brush cannot be started on the data point itself, only in the background layer.

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

.point {
  fill: #2f225d;
  stroke: #afa2dc;
}

.selected {
  fill: #afa2dc;
  stroke: #2f225d;
}

.axis {
  font: 10px sans-serif;
}

p {
  font: 12px sans-serif;
  margin: 0 0 2px 0;
  padding: 0;
}

.clear-button {
  font: 14px sans-serif;
  cursor: pointer;
}

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

.brush .extent {
  stroke: #fff;
  fill-opacity: .125;
  shape-rendering: crispEdges;
}

</style>
<body>
<script src="https://d3js.org/d3.v3.min.js"></script>
<script>
d3.helper = {};

d3.helper = {};

d3.helper.tooltip = function(){
    var tooltipDiv;
    var bodyNode = d3.select('body').node();

function tooltip(selection){

selection.on('mouseover.tooltip', function(pD, pI){
            // Clean up lost tooltips
            d3.select('body').selectAll('div.tooltip').remove();
            // Append tooltip
            tooltipDiv = d3.select('body')
                           .append('div')
                           .attr('class', 'tooltip')
            var absoluteMousePos = d3.mouse(bodyNode);
            tooltipDiv.style({
                left: (absoluteMousePos[0] + 10)+'px',
                top: (absoluteMousePos[1] - 40)+'px',
                'background-color': '#d8d5e4',
                width: '65px',
                height: '30px',
                padding: '5px',
                position: 'absolute',
                'z-index': 1001,
                'box-shadow': '0 1px 2px 0 #656565'
            });

var first_line = '<p>X-Value: ' + pD.index + '</p>'
            var second_line = '<p>Y-Value: ' + pD.value + '</p>'

tooltipDiv.html(first_line + second_line)
        })
        .on('mousemove.tooltip', function(pD, pI){
            // Move tooltip
            var absoluteMousePos = d3.mouse(bodyNode);
            tooltipDiv.style({
                left: (absoluteMousePos[0] + 10)+'px',
                top: (absoluteMousePos[1] - 40)+'px'
            });
        })
        .on('mouseout.tooltip', function(pD, pI){
            // Remove tooltip
            tooltipDiv.remove();
        });

}

tooltip.attr = function(_x){
        if (!arguments.length) return attrs;
        attrs = _x;
        return this;
    };

tooltip.style = function(_x){
        if (!arguments.length) return styles;
        styles = _x;
        return this;
    };

return tooltip;
};

var data = [];
var values = [];
for (var i = 2; i <= 50; i++) {
    var val = Math.floor(Math.random() * (50 - 5 + 1) + 5);
    data.push({index: i, value: val});
    values.push(val);
}

var margin = {top: 20, right: 20, bottom: 60, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var x = d3.scale.linear()
    .range([0, width])
    .domain([0, 50]);

var y = d3.scale.linear()
    .range([height, 0])
    .domain([0, d3.max(values) + 5]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom")

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left")
    .ticks(11);

var brush = d3.svg.brush()
    .x(x)
    .on("brush", brushmove)
    .on("brushend", brushend);

var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

svg.append("g")
    .attr("class", "x axis")
    .attr("clip-path", "url(#clip)")
    .attr("transform", "translate(0," + height + ")")
    .call(xAxis);

svg.append("g")
    .attr("class", "y axis")
    .call(yAxis);

svg.append("g")
    .attr("class", "brush")
    .call(brush)
  .selectAll('rect')
    .attr('height', height);

svg.append("defs").append("clipPath")
    .attr("id", "clip")
  .append("rect")
    .attr("width", width)
    .attr("height", height + 20);

points = svg.selectAll(".point")
    .data(data)
  .enter().append("circle")
    .attr("class", "point")
    .attr("clip-path", "url(#clip)")
    .attr("r", function(d){return Math.floor(Math.random() * (20 - 5 + 1) + 5);})
    .attr("cx", function(d) { return x(d.index); })
    .attr("cy", function(d) { return y(d.value); })
    .call(d3.helper.tooltip());

function brushmove() {
  var extent = brush.extent();
  points.classed("selected", function(d) {
    is_brushed = extent[0] <= d.index && d.index <= extent[1];
    return is_brushed;
  });
}

function brushend() {
  get_button = d3.select(".clear-button");
  if(get_button.empty() === true) {
    clear_button = svg.append('text')
      .attr("y", 460)
      .attr("x", 825)
      .attr("class", "clear-button")
      .text("Clear Brush");
  }

x.domain(brush.extent());

transition_data();
  reset_axis();

points.classed("selected", false);
  d3.select(".brush").call(brush.clear());

clear_button.on('click', function(){
    x.domain([0, 50]);
    transition_data();
    reset_axis();
    clear_button.remove();
  });
}

function transition_data() {
  svg.selectAll(".point")
    .data(data)
  .transition()
    .duration(500)
    .attr("cx", function(d) { return x(d.index); });
}

function reset_axis() {
  svg.transition().duration(500)
   .select(".x.axis")
   .call(xAxis);
}

</script>

Modified http://d3js.org/d3.v3.min.js to a secure url

https://d3js.org/d3.v3.min.js