Set minimum/maximum domain for circle packing

[bryanph]

Changes the current behavior, which is to select the minimum value in the data as the minimum domain.

This causes problems when data is close together, like for example consider the values: [90, 100, 110, 120]. In this case 90 would be drawn as the minimum circle size and 120 as the max circle size.

It might perhaps be useful to also add a custom parameter to change the minimum domain.

[davelandry]

I'm not a fan of changing this default behavior to zero. If you'd like to make a publically accessable variable to change the domain mins and max that's fine. What might help you in the interim is changing the default minimum radius of the size scale (it defaults to 3):

.size({"scale": {"min": 10}})

Additionally, if you'd like to make the minimum dependent on other things like the available size, reference the current default maximum: https://github.com/alexandersimoes/d3plus/blob/master/src/viz/methods/size.coffee#L13-L14

[bryanph]

I have revised the commit to make the domain min and max available as an option like so:

domain {
min:
max:
}

[bryanph]

@davelandry would you mind taking a look at this again? :)

[davelandry]

Getting close!

I don't think this warrants having it's own .domain( ) method, as it only applies specifically to sizing (whereas the x and y axis methods have their own domains).

I would nest it inside of the scale method, moving the current "min" and "max" keys under a new "range" key. The new size.coffee would look something like this:

filter = require "../../core/methods/filter.coffee"

module.exports =
  accepted:   [false, Function, Number, Object, String]
  dataFilter: true
  deprecates: ["value", "value_var"]
  mute:       filter(true)
  scale:
    accepted:   [Function]
    deprecates: "size_scale"
    domain:
      max:
        accepted: [false, Number]
        value:    false
      min:
        accepted: [false, Number]
        value:    false
    range:
      max:
        accepted: [Function, Number]
        value:    (vars) ->
          Math.floor d3.max [d3.min([vars.width.viz,vars.height.viz])/15, 6]
      min:
        accepted: [Function, Number]
        value:    3
    value:      d3.scale.sqrt()
  solo:       filter(true)
  threshold:
    accepted: [Boolean, Function, Number]
    value:    false
  value:      false

[bryanph]

@davelandry, I have amended it, thanks for your quick response.
Please let me know if this is sufficient :)

[davelandry]

Great work @bryanph, I've updated the documentation to clarify this new change: https://github.com/alexandersimoes/d3plus/wiki/Visualizations#size