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Lasso Selection in JavaScript

How to bind callback functions to lasso selection in JavaScript D3.js-based charts.


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Plotly is a free and open-source graphing library for JavaScript. We recommend you read our Getting Started guide for the latest installation or upgrade instructions, then move on to our Plotly Fundamentals tutorials or dive straight in to some Basic Charts tutorials.

var graphDiv = document.getElementById('myDiv');
var N = 1000;
var color1 = '#7b3294';
var color1Light = '#c2a5cf';
var colorX = '#ffa7b5';
var colorY = '#fdae61';

function randomArray() {
  var out = new Array(N);
  for(var i = 0; i < N; i++) {
    out[i] = Math.random();
  }
  return out;
}
var x = randomArray();
var y = randomArray();

Plotly.newPlot(graphDiv, [{
  type: 'scatter',
  mode: 'markers',
  x: x,
  y: y,
  xaxis: 'x',
  yaxis: 'y',
  name: 'random data',
  marker: {color: color1, size: 10}
}, {
  type: 'histogram',
  x: x,
  xaxis: 'x2',
  yaxis: 'y2',
  name: 'x coord dist.',
  marker: {color: colorX}
}, {
  type: 'histogram',
  x: y,
  xaxis: 'x3',
  yaxis: 'y3',
  name: 'y coord dist.',
  marker: {color: colorY}
}], {
  title: 'Lasso around the scatter points to see sub-distributions',
  dragmode: 'lasso',
  xaxis: {
    zeroline: false,
  },
  yaxis: {
    domain: [0.55, 1],
  },
  xaxis2: {
    domain: [0, 0.45],
    anchor: 'y2',
  },
  yaxis2: {
    domain: [0, 0.45],
    anchor: 'x2'
  },
  xaxis3: {
    domain: [0.55, 1],
    anchor: 'y3'
  },
  yaxis3: {
    domain: [0, 0.45],
    anchor: 'x3'
  }
});

graphDiv.on('plotly_selected', function(eventData) {
  var x = [];
  var y = [];

  var colors = [];
  for(var i = 0; i < N; i++) colors.push(color1Light);

  console.log(eventData.points)

  eventData.points.forEach(function(pt) {
    x.push(pt.x);
    y.push(pt.y);
    colors[pt.pointNumber] = color1;
  });

  Plotly.restyle(graphDiv, {
    x: [x, y],
    xbins: {}
  }, [1, 2]);

  Plotly.restyle(graphDiv, 'marker.color', [colors], [0]);
});