Honeycomb (Hexagon Cells) in JavaScript

// Seeded PRNG so the honeycomb is identical on every load (stable snapshots).
var __seed = 0x51ab3c21
function rand() {
  __seed |= 0
  __seed = (__seed + 0x6d2b79f5) | 0
  var t = Math.imul(__seed ^ (__seed >>> 15), 1 | __seed)
  t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t
  return ((t ^ (t >>> 14)) >>> 0) / 4294967296
}

// Signal strength across the floor: distance falloff from two access points
// plus gentle noise, so the color bands form contiguous regions instead of
// random speckle.
var ROWS = 12
var COLS = 20
var accessPoints = [
  { col: 4, row: 3 },
  { col: 14, row: 8 },
]

function coverage(col, row) {
  var best = 0
  for (var k = 0; k < accessPoints.length; k++) {
    var dx = col - accessPoints[k].col
    var dy = (row - accessPoints[k].row) * 1.6
    var d = Math.sqrt(dx * dx + dy * dy)
    best = Math.max(best, 96 - d * 7.5)
  }
  return Math.max(8, Math.min(100, Math.round(best + (rand() - 0.5) * 10)))
}

// First series renders as the bottom row, so build L..A to read A..L top-down.
function generateFloor() {
  var series = []
  for (var r = ROWS - 1; r >= 0; r--) {
    var data = []
    for (var c = 0; c < COLS; c++) {
      data.push({ x: String(c + 1), y: coverage(c, r) })
    }
    series.push({ name: String.fromCharCode(65 + r), data: data })
  }
  return series
}

var options = {
  series: generateFloor(),
  chart: {
    height: 420,
    type: 'heatmap',
  },
  plotOptions: {
    heatmap: {
      shape: 'hexagon',
      enableShades: false,
      colorScale: {
        ranges: [
          {
            from: 0,
            to: 39,
            name: 'Weak',
            color: '#A7E0F4',
          },
          {
            from: 40,
            to: 59,
            name: 'Fair',
            color: '#64C6E8',
          },
          {
            from: 60,
            to: 79,
            name: 'Good',
            color: '#2296CB',
          },
          {
            from: 80,
            to: 100,
            name: 'Excellent',
            color: '#0B6E9E',
          },
        ],
      },
    },
  },
  stroke: {
    width: 2,
    colors: ['#fff'],
  },
  dataLabels: {
    enabled: false,
  },
  tooltip: {
    y: {
      title: {
        // The honeycomb offsets shift each row a quarter cell off its column
        // tick, so name both coordinates in the tooltip: "Zone 7 · Row D: 78"
        formatter: function (seriesName, opts) {
          return (
            'Zone ' +
            opts.w.globals.labels[opts.dataPointIndex] +
            ' · Row ' +
            seriesName +
            ':'
          )
        },
      },
    },
  },
  xaxis: {
    type: 'category',
  },
  title: {
    text: 'Office Wi-Fi Coverage by Floor Zone',
  },
}

var chart = new ApexCharts(document.querySelector('#chart'), options)
chart.render()