block by micahstubbs ad5ac2813a8edb04ab87e7e033515cb9

fisheye magnifier with fixed focus

Full Screen

This time with a fixed, hard-coded focus

a further iteration on the block Fisheye Magnifying Glass from @micahstubbs

an iteration on @fernoftheandes‘s bl.ock Encircling D3’s Fisheye Distortion that uses ES2015 syntax

Original README.md

Except for the code segments that render the magnifying glass (as circle or path), this is essentially a copy of Mike Bostock’s Fisheye Distortion example.

The motivation for this was largely aesthetical but also a bit functional. When using the Fisheye as an aid to viewing large datasets, I often find myself experimenting with the degree and radius of the distortion. In such cases, I find it helpful to see the exact reach of the distortion and then decide the best configuration for a particular dataset.

index.js

const width = 960
const height = 600

const color = d3.scale.category20()

const fisheye = d3.fisheye.circular().radius(100).distortion(5)

const force = d3.layout
  .force()
  .charge(-440)
  .linkDistance(60)
  .size([width, height])

const svg = d3.select('#chart1').append('svg').attr({
  width,
  height,
})

// magnifier as circle
const lens = svg
  .append('circle')
  .attr('class', 'lens')
  .attr('r', fisheye.radius())

// magnifier as path
const mag = svg.append('path').attr('class', 'mag')

// magnifier handle as path
const mag2 = svg.append('path').attr('class', 'mag2')
// magnifier handle as path
const mag3 = svg.append('path').attr('class', 'mag2')

/*
  svg.append('rect')
    .attr('class', 'background')
    .attr('width', width)
    .attr('height', height);
  */

d3.json('miserables.json', (data) => {
  const n = data.nodes.length

  force.nodes(data.nodes).links(data.links)

  // Initialize the positions deterministically, for better results.
  data.nodes.forEach((d, i) => {
    d.x = d.y = (width / n) * i
  })

  // Run the layout a fixed number of times.
  // The ideal number of times scales with graph complexity.
  // Of course, don't run too long—you'll hang the page!
  force.start()
  for (let i = n; i > 0; --i) force.tick()
  force.stop()

  // Center the nodes in the middle.
  let ox = 0
  let oy = 0
  data.nodes.forEach((d) => {
    ox += d.x
    oy += d.y
  })
  ox = ox / n - width / 2
  oy = oy / n - height / 2
  data.nodes.forEach((d) => {
    d.x -= ox
    d.y -= oy
  })

  const link = svg
    .selectAll('.link')
    .data(data.links)
    .enter()
    .append('line')
    .attr('class', 'link')
    .attr('x1', (d) => d.source.x)
    .attr('y1', (d) => d.source.y)
    .attr('x2', (d) => d.target.x)
    .attr('y2', (d) => d.target.y)
    .style('stroke-width', (d) => Math.sqrt(d.value))

  const node = svg
    .selectAll('.node')
    .data(data.nodes)
    .enter()
    .append('g')
    .attr('class', 'node')

  render('path')

  function render(shape) {
    node.selectAll('.link').remove()
    node.selectAll('.circle').remove()
    node.selectAll('.text').remove()

    lens.style('stroke-opacity', shape === 'circle' ? 1 : 0)
    mag.style('stroke-opacity', shape === 'path' ? 1 : 0)
    mag2.style('stroke-opacity', shape === 'path' ? 1 : 0)
    mag3.style('stroke-opacity', shape === 'path' ? 1 : 0)

    const nodeEnter = node
      .append('circle')
      .attr('class', 'circle')
      .attr('cx', (d) => d.x)
      .attr('cy', (d) => d.y)
      .attr('r', 6)
      .style('fill', (d) => color(d.group))
      .call(force.drag)

    const text = node
      .append('text')
      .attr('class', 'text')
      .attr('dy', (d) => d.y)
      .attr('dx', (d) => d.x)
      .text((d) => d.name)

    node.append('title').text((d) => d.name)

    // svg.on('mousemove', function () {
    //
    // here is where we add the fixed focus
    //
    const focus = { x: 380, y: 100 }
    fisheye.focus([focus.x, focus.y])
    // fisheye.focus(d3.mouse(this))

    const mouseX = focus.x // d3.mouse(this)[0]
    const mouseY = focus.y // d3.mouse(this)[1]
    const r = fisheye.radius()

    if (shape === 'circle') {
      // display magnifier as circle
      lens.attr('cx', mouseX).attr('cy', mouseY)
    } else {
      // path for magnifier
      const magPath = `M ${mouseX},${mouseY} m -${r}, 0 a ${r},${r} 0 1,0 ${
        r * 2
      },0 a ${r},${r} 0 1,0 -${r * 2},0`

      //
      // path for magnifier's handle
      //

      // specify angle where magnifier handle should 'attach' to body
      const omegaTop = 1.15 * Math.PI
      // point in circumference to attach top magnifier handle
      const xt1 = mouseX + r * Math.sin(omegaTop)
      const yt1 = mouseY + r * Math.cos(omegaTop)
      const magHandleTop = `M${xt1 - 10},${yt1 + 2} L60,${mouseY} + r}`

      // specify angle where magnifier handle should 'attach' to body
      const omegaBottom = 1.85 * Math.PI

      // point in circumference to attach bottom magnifier handle
      const xb1 = mouseX + r * Math.sin(omegaBottom)
      const yb1 = mouseY + r * Math.cos(omegaBottom)
      const magHandleBottom = `M${xb1 - 10},${yb1 + 2} L60,${+r}`

      // display magnifier as path
      mag.attr('d', magPath)

      // display magnifier handle as path
      mag2.attr('d', magHandleTop)

      // display magnifier handle as path
      mag3.attr('d', magHandleBottom)
    }

    nodeEnter
      .each((d) => {
        d.fisheye = fisheye(d)
      })
      .attr('cx', (d) => d.fisheye.x)
      .attr('cy', (d) => d.fisheye.y)
      .attr('r', (d) => d.fisheye.z * 4.5)

    text.attr('dx', (d) => d.fisheye.x).attr('dy', (d) => d.fisheye.y)

    link
      .attr('x1', (d) => d.source.fisheye.x)
      .attr('y1', (d) => d.source.fisheye.y)
      .attr('x2', (d) => d.target.fisheye.x)
      .attr('y2', (d) => d.target.fisheye.y)
    // }) // end svg.on('mousemove')
  }
  d3.select('#circle').on('click', () => {
    render('circle')
  })

  d3.select('#path').on('click', () => {
    render('path')
  })
})

index.html

<!DOCTYPE html>
<html xmlns="//www.w3.org/1999/xhtml" xml:lang="en" lang="en">
  <head>
    <title>Encircling D3 Fisheye Distortion</title>
    <script type="text/javascript" src="https://d3js.org/d3.v3.min.js"></script>
    <script src="https://npmcdn.com/babel-core@5.8.34/browser.min.js"></script>
    <script type="text/javascript" src="fisheye.js"></script>
    <style>
      .background {
        fill: none;
        pointer-events: all;
      }

      /*
			#chart1 {
				width: 960px;
				height: 600px;
				border: solid 1px #ccc;
			}
			*/

      #chart1 .circle {
        stroke: #fff;
        stroke-width: 1.5px;
      }

      #chart1 .link {
        stroke: #999;
        stroke-opacity: 0.6;
        stroke-width: 1.5px;
      }

      text {
        font: 12px sans-serif;
        pointer-events: none;
        text-anchor: start;
      }

      /* magnifier glass as circle */
      .lens {
        stroke: gray;
        stroke-width: 2px;
        stroke-opacity: 0;
        fill: none;
      }

      /* magnifier glass as path */
      .mag {
        stroke: gray;
        stroke-width: 2px;
        stroke-opacity: 0;
        fill: none;
      }

      /* magnifier handle as path */
      .mag2 {
        stroke: black;
        stroke-width: 6px;
        stroke-linecap: round;
        fill: none;
      }
    </style>
  </head>
  <body bgcolor="white">
    <form style="margin-left: 20px;">
      <input type="radio" name="wot" id="circle" value="one" />&nbsp;as
      circle<br />
      <input type="radio" name="wot" id="path" value="two" checked />&nbsp;as
      path
    </form>
    <div id="chart1"></div>
    <script src="./index.js"></script>
  </body>
</html>

fisheye.js

;(function() {
  d3.fisheye = {
    scale: function(scaleType) {
      return d3_fisheye_scale(scaleType(), 3, 0)
    },
    circular: function() {
      var radius = 200,
        distortion = 2,
        k0,
        k1,
        focus = [0, 0]

      function fisheye(d) {
        var dx = d.x - focus[0],
          dy = d.y - focus[1],
          dd = Math.sqrt(dx * dx + dy * dy)
        if (!dd || dd >= radius) return { x: d.x, y: d.y, z: 1 }
        var k = ((k0 * (1 - Math.exp(-dd * k1))) / dd) * 0.75 + 0.25
        return {
          x: focus[0] + dx * k,
          y: focus[1] + dy * k,
          z: Math.min(k, 10),
        }
      }

      function rescale() {
        k0 = Math.exp(distortion)
        k0 = (k0 / (k0 - 1)) * radius
        k1 = distortion / radius
        return fisheye
      }

      fisheye.radius = function(_) {
        if (!arguments.length) return radius
        radius = +_
        return rescale()
      }

      fisheye.distortion = function(_) {
        if (!arguments.length) return distortion
        distortion = +_
        return rescale()
      }

      fisheye.focus = function(_) {
        if (!arguments.length) return focus
        focus = _
        return fisheye
      }

      return rescale()
    },
  }

  function d3_fisheye_scale(scale, d, a) {
    function fisheye(_) {
      var x = scale(_),
        left = x < a,
        range = d3.extent(scale.range()),
        min = range[0],
        max = range[1],
        m = left ? a - min : max - a
      if (m == 0) m = max - min
      return ((left ? -1 : 1) * m * (d + 1)) / (d + m / Math.abs(x - a)) + a
    }

    fisheye.distortion = function(_) {
      if (!arguments.length) return d
      d = +_
      return fisheye
    }

    fisheye.focus = function(_) {
      if (!arguments.length) return a
      a = +_
      return fisheye
    }

    fisheye.copy = function() {
      return d3_fisheye_scale(scale.copy(), d, a)
    }

    fisheye.nice = scale.nice
    fisheye.ticks = scale.ticks
    fisheye.tickFormat = scale.tickFormat
    return d3.rebind(fisheye, scale, 'domain', 'range')
  }
})()

miserables.json

{
  "nodes":[
    {"name":"Myriel","group":1},
    {"name":"Napoleon","group":1},
    {"name":"Mlle.Baptistine","group":1},
    {"name":"Mme.Magloire","group":1},
    {"name":"CountessdeLo","group":1},
    {"name":"Geborand","group":1},
    {"name":"Champtercier","group":1},
    {"name":"Cravatte","group":1},
    {"name":"Count","group":1},
    {"name":"OldMan","group":1},
    {"name":"Labarre","group":2},
    {"name":"Valjean","group":2},
    {"name":"Marguerite","group":3},
    {"name":"Mme.deR","group":2},
    {"name":"Isabeau","group":2},
    {"name":"Gervais","group":2},
    {"name":"Tholomyes","group":3},
    {"name":"Listolier","group":3},
    {"name":"Fameuil","group":3},
    {"name":"Blacheville","group":3},
    {"name":"Favourite","group":3},
    {"name":"Dahlia","group":3},
    {"name":"Zephine","group":3},
    {"name":"Fantine","group":3},
    {"name":"Mme.Thenardier","group":4},
    {"name":"Thenardier","group":4},
    {"name":"Cosette","group":5},
    {"name":"Javert","group":4},
    {"name":"Fauchelevent","group":0},
    {"name":"Bamatabois","group":2},
    {"name":"Perpetue","group":3},
    {"name":"Simplice","group":2},
    {"name":"Scaufflaire","group":2},
    {"name":"Woman1","group":2},
    {"name":"Judge","group":2},
    {"name":"Champmathieu","group":2},
    {"name":"Brevet","group":2},
    {"name":"Chenildieu","group":2},
    {"name":"Cochepaille","group":2},
    {"name":"Pontmercy","group":4},
    {"name":"Boulatruelle","group":6},
    {"name":"Eponine","group":4},
    {"name":"Anzelma","group":4},
    {"name":"Woman2","group":5},
    {"name":"MotherInnocent","group":0},
    {"name":"Gribier","group":0},
    {"name":"Jondrette","group":7},
    {"name":"Mme.Burgon","group":7},
    {"name":"Gavroche","group":8},
    {"name":"Gillenormand","group":5},
    {"name":"Magnon","group":5},
    {"name":"Mlle.Gillenormand","group":5},
    {"name":"Mme.Pontmercy","group":5},
    {"name":"Mlle.Vaubois","group":5},
    {"name":"Lt.Gillenormand","group":5},
    {"name":"Marius","group":8},
    {"name":"BaronessT","group":5},
    {"name":"Mabeuf","group":8},
    {"name":"Enjolras","group":8},
    {"name":"Combeferre","group":8},
    {"name":"Prouvaire","group":8},
    {"name":"Feuilly","group":8},
    {"name":"Courfeyrac","group":8},
    {"name":"Bahorel","group":8},
    {"name":"Bossuet","group":8},
    {"name":"Joly","group":8},
    {"name":"Grantaire","group":8},
    {"name":"MotherPlutarch","group":9},
    {"name":"Gueulemer","group":4},
    {"name":"Babet","group":4},
    {"name":"Claquesous","group":4},
    {"name":"Montparnasse","group":4},
    {"name":"Toussaint","group":5},
    {"name":"Child1","group":10},
    {"name":"Child2","group":10},
    {"name":"Brujon","group":4},
    {"name":"Mme.Hucheloup","group":8}
  ],
  "links":[
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