d3 Polybrush v4

This is a modified version of the polybrush plugin, originaly created by Geoffrey T. Bell, for d3.js to make it compatible with d3-4.x-api.

The d3-3.x based plugin is forked from: https://gist.github.com/gtb104/3667340

The changes include adapting to d3-4.x-api and a few minor fixes.

Now the plugin can be instantiated like d3.brush() in d3-4.x-api.

var brush = d3.polybrush()
  .x({x_scale})
  .y({y_scale});

d3.select("svg")
  .append("g")
  .call(brush);

Please keep in mind that the extent in the polybrush is very different from that in d3-brush. So, the working area of the brush can only be assigned by the range of the {x_scale} and {y_scale}.

Three events are dispatched, which are start, brush, and end, consistent with the events of d3-brush. The event names are a bit different in the d3-3.x based version.

The rest is the same as using the d3-3.x version of the plugin.

Usage:
Click to add an anchor point, double click to close the selection.
Drag the selection to reposition it.
Double click outside the selection to clear it.

Try it on bl.ocks.org