A logarithmic scale to map continuous numeric data to a plotting coordinate system.

This works like Contex.ContinuousLinearScale, and the settings are given as keywords.

  ContinuousLogScale.new(
        domain: {0, 100},
        tick_positions: [0, 5, 10, 15, 30, 60,  120,  240, 480, 960],
        log_base: :base_10,
        negative_numbers: :mask,
        linear_range: 1
      )

Logarithm

• log_base is the logarithm base. Defaults to 2. Can be set to :base_2, :base_e or :base_10.
• negative_numbers controls how negative numbers are represented. It can be:
  • :mask: always return 0
  • :clip: always returns 0
  • :sym: logarithms are drawn symmetrically, that is, the log of a number n when n < 0 is -log(abs(n))
• linear_range is a range -if any- where results are not logarithmical

Data domain

Unfortunately, a domain must be given for all custom scales. To make your life easier, you can either:

• domain: {0, 27} will set an explicit domain, or
• dataset and axis let you specify a Dataset and one or a list of axes, and the domain will be computed out of them all.

Ticks

• interval_count divides the interval in n linear slices, or
• tick_positions can receive a list of explicit possible ticks, that will be displayed ony if they are within the domain area.
• custom_tick_formatter is a function to be applied to the ticks.