@quartic/bokehjs/src/coffee/models/formatters/basic_tick_formatter.coffee

Interactive, novel data visualization

import {TickFormatter} from "./tick_formatter"
import * as p from "core/properties"
import {isNumber} from "core/util/types"

export class BasicTickFormatter extends TickFormatter
  type: 'BasicTickFormatter'

  @define {
    precision:        [ p.Any,    'auto' ] # TODO (bev) better
    use_scientific:   [ p.Bool,   true   ]
    power_limit_high: [ p.Number, 5      ]
    power_limit_low:  [ p.Number, -3     ]
  }

  @getters {
    scientific_limit_low: () -> Math.pow(10.0, @power_limit_low)
    scientific_limit_high: () -> Math.pow(10.0, @power_limit_high)
  }

  initialize: (attrs, options) ->
    super(attrs, options)
    @last_precision = 3

  doFormat: (ticks, loc) ->
    if ticks.length == 0
      return []

    zero_eps = 0
    if ticks.length >= 2
      zero_eps = Math.abs(ticks[1] - ticks[0]) / 10000

    need_sci = false
    if @use_scientific
      for tick in ticks
        tick_abs = Math.abs(tick)
        if (tick_abs > zero_eps and
            (tick_abs >= @scientific_limit_high or
            tick_abs <= @scientific_limit_low))
          need_sci = true
          break

    precision = @precision

    if not precision? or isNumber(precision)
      labels = new Array(ticks.length)
      if need_sci
        for i in [0...ticks.length]
          labels[i] = ticks[i].toExponential(precision or undefined)
      else
        for i in [0...ticks.length]
          labels[i] = ticks[i].toFixed(precision or undefined).replace(
            /(\.[0-9]*?)0+$/, "$1").replace(/\.$/, "")
      return labels

    else if precision == 'auto'
      labels = new Array(ticks.length)
      for x in [@last_precision..15]
        is_ok = true
        if need_sci
          for i in [0...ticks.length]
            labels[i] = ticks[i].toExponential(x)
            if i > 0
              if labels[i] == labels[i-1]
                is_ok = false
                break
          if is_ok
            break
        else
          for i in [0...ticks.length]
            labels[i] = ticks[i].toFixed(x).replace(
              /(\.[0-9]*?)0+$/, "$1").replace(/\.$/, "")
            if i > 0
              if labels[i] == labels[i-1]
                is_ok = false
                break
          if is_ok
            break

        if is_ok
          @last_precision = x
          return labels

    return labels