draw line chart path in the order determined by ordering

[gordonwoodhull]

See this SO question:
http://stackoverflow.com/questions/23774871/dc-js-sort-ordinal-chart-by-y-axis-value

[mr23]

Gordon, I made an example Plunk showing how I implemented a workaround.
http://embed.plnkr.co/VItIQ4ZcW9abfzI13z64/

And I posted it on the StackOverflow entry.

[gordonwoodhull]

Also: http://stackoverflow.com/questions/33550410/dc-js-original-ordering-of-ordinal-scale-on-linechart

[gordonwoodhull]

Notes on the ordinal case:

1. Currently one must force the ordinal domain and the order of the values in the group to be the same.
2. _ordinalXDomain() does correctly use .ordering() but plotting does not
3. sort_group in the FAQ can help with the group ordering (since group.order() doesn't have any way to work with the keys, just the values).

Two methods for getting the ordinal domain right:

1. The domain can be specified manually, example: https://jsfiddle.net/gordonwoodhull/sjjnx72f/11/
2. One can use .ordering() just for that: https://jsfiddle.net/gordonwoodhull/sjjnx72f/15/

Seems pretty clear that we must adapt the stack mixin to use .ordering(), especially for line charts, but I don't know if there will be ill consequences.

[gordonwoodhull]

Another example:

 lineChart_addChurn
 .width(300)
.height(200)
.x(d3.scale.ordinal().domain(data.map(function (d) {return d.Month;})))
.xUnits(dc.units.ordinal)
.clipPadding(10)
.compose([
    dc.lineChart(lineChart_addChurn)
        .dimension(dim_line_month)
        .colors('red')
        .interpolate('step-after')
        .renderArea(false)
        .renderDataPoints(true)
        .group(group_line_adds, "Top Line"),
    dc.lineChart(lineChart_addChurn)
        .dimension(dim_line_month)
        .colors('blue')
        .interpolate('step-after')
        .renderArea(false)
        .renderDataPoints(true)
        .group(group_line_churn, "Bottom Line")
    ])
.brushOn(false)
.render();

http://stackoverflow.com/questions/37055306/dc-js-composite-line-chart-unexpected-behaviour