Legendrank attribute in traces

[nicolaskruchten]

A new attribute in all traces called legendrank which defaults to the index of the trace in the data array. The legend items will then be sorted by legendrank (ties broken by index in the data array) before being laid out.

As an example for:

data = [
{name: "A", legendrank: 2}
{name: "D", legendrank: 4, legendgroup: "G2"}
{name: "E", legendrank: 4, legendgroup: "G2"}
{name: "B", legendrank: 1, legendgroup: "G1"}
{name: "C", legendrank: 3, legendgroup: "G1"}
]

then I would expect the legend order to be: G1(B,C), A, G2(D,E).

Note that the group order matters in the example above, when this will be coupled with #5260 and/or legendgroupgap.

[nicolaskruchten]

Notes:

• should be a number (floats and negatives OK)
• default should be 1000
• tie breaker is trace order as modulated by legend.traceorder i.e. 'reverse' reverses the tie-break

[ryan-williams]

For future searchers: I couldn't get legendrank to work; turns out I was inadvertently using plotly.js 1.x. This feature landed somewhere in the 2.x line.

[gonthalo]

For future searchers: I couldn't get legendrank to work; turns out I was inadvertently using plotly.js 1.x. This feature landed somewhere in the 2.x line.

This worked for me, thanks!