source/anonymization/make-sliders.js

window.makeSliders = function(){
  var rv = {
    population: 144,
    headsProb: .5,
  }

  rv.updateHeadsProb = (headsProb) => {
    rv.headsProb = headsProb
    updateSliderPos()


    estimates.updateEstimates()
    estimates.render()
  }

  rv.updatePopulation = (population) => {
    rv.population = population
    updateSliderPos()


    var scale = d3.clamp(0, 13 / Math.sqrt(population), 1)
    sel.studentGroup.st({
      transformOrigin: 'top',
      transformOrigin: c.width/2 + 'px ' + 160 + 'px',
      transform: `scale(${scale})`
    })

    estimates.updateEstimates()
    estimates.render()

    sel.student.classed('inactive',(d, i) => i >= population)
  }

  rv.updatePopulationSlider = (val) => {
    rv.updatePopulation(val)
  }

  rv.updateNoiseSlider = (val) => {
    rv.updateHeadsProb(val)
  }

  var updateSliderPos = (function(){
    var width = d3.clamp(50, window.innerWidth/2 - 40, 145)
    var height = 30
    var color = '#007276'

    var sliderVals = {
      population: {
        key: 'population',
        textFn: d => rv.population + ' students' ,
        r: [144, 756],
        v: 144,
        stepFn: d => rv.updatePopulation(Math.round(d.v/2)*2),
      },
      headsProb: {
        key: 'headsProb',
        textFn: d => d3.format('.1%')(rv.headsProb) + ' chance of heads',
        r: [.2, .5],
        v: .5,
        stepFn: d => rv.updateHeadsProb(d.v),
      }
    }
    var sliders = [sliderVals.headsProb, sliderVals.population, sliderVals.headsProb]
    sliders.forEach(d => {
      d.s = d3.scaleLinear().domain(d.r).range([0, width])
    })

    var sliderSel = d3.selectAll('.slide-container-population,.slide-container-heads-prob').html('')
      .data(sliders)
      .classed('slider', true)
      .st({
        display: 'inline-block',
        width: width,
        paddingRight: (d, i) => i == 1 ? 40 : 0,
        marginTop: 20,
      })

    var textSel = sliderSel.append('div.slider-label-container')
      .st({marginBottom: -5})

    var svgSel = sliderSel.append('svg').at({width, height})
      .on('click', function(d){
        d.v = d.s.invert(d3.mouse(this)[0])
        d.stepFn(d)
      })
      .st({
        cursor: 'pointer'
      })
      .append('g').translate(height/2, 1)
    svgSel.append('rect').at({width, height, y: -height/2, fill: 'rgba(0,0,0,0)'})

    svgSel.append('path').at({
      d: `M 0 -.5 H ${width}`, 
      stroke: color,
      strokeWidth: 1
    })

    var leftPathSel = svgSel.append('path').at({
      d: `M 0 -.5 H ${width}`, 
      stroke: color,
      strokeWidth: 3
    })


    var drag = d3.drag()
      .on('drag', function(d){
        var x = d3.mouse(this)[0]
        d.v = d3.clamp(d3.min(d.r), d.s.invert(x), d3.max(d.r))
        d.stepFn(d)
      })

    var rectSel = svgSel.append('rect')
      .at({
        width: height/2 - 1,
        height: height/2 - 1,
        stroke: color, 
        strokeWidth: 3,
        fill: '#fff',
      })
      .translate([-height/4, -height/4])
      .call(drag)

    return isDrag => {
      rectSel.at({x: d => Math.round(d.s(rv[d.key]))})
      textSel.text(d => d.textFn(d))

      leftPathSel.at({d: d => `M 0 -.5 H ${d.s(rv[d.key])}`})
    }
  })()
  updateSliderPos()


  return rv
}




if (window.init) window.init()