box/violin vs bar positioning inconsistency

[nicolaskruchten]

Not sure we can fix it in the context of the fix for #3402, but logging for reference:

Violin/box auto-populates x-axis categories here:

Plotly.newPlot(
  document.getElementById("gd"),
  {
    data: [{
      type: "violin",
      y: [1]
    },{
      type: "violin",
      y: [1]
    }],
  }
)

But bar does not:

Plotly.newPlot(
  document.getElementById("gd"),
  {
    data: [{
      type: "bar",
      y: [1]
    },{
      type: "bar",
      y: [1]
    }],
  }
)

[etpinard]

Here's the block in question:

plotly.js/src/traces/box/calc.js

Lines 158 to 191 in 02e51d8

	// In vertical (horizontal) box plots:
	// if no x (y) data, use x0 (y0), or name
	// so if you want one box
	// per trace, set x0 (y0) to the x (y) value or category for this trace
	// (or set x (y) to a constant array matching y (x))
	function getPos(trace, posLetter, posAxis, val, num) {
	if(posLetter in trace) {
	return posAxis.makeCalcdata(trace, posLetter);
	}
	var pos0;
	if(posLetter + '0' in trace) {
	pos0 = trace[posLetter + '0'];
	} else if('name' in trace && (
	posAxis.type === 'category' || (
	isNumeric(trace.name) &&
	['linear', 'log'].indexOf(posAxis.type) !== -1
	) || (
	Lib.isDateTime(trace.name) &&
	posAxis.type === 'date'
	)
	)) {
	pos0 = trace.name;
	} else {
	pos0 = num;
	}
	var pos0c = posAxis.type === 'multicategory' ?
	posAxis.r2c_just_indices(pos0) :
	posAxis.d2c(pos0, 0, trace[posLetter + 'calendar']);
	return val.map(function() { return pos0c; });
	}

I guess we could add another attribute to optionally make things consistent between bar and box/violin traces and perhaps change the default in v2 (or v3 😏 ).

[nicolaskruchten]

I think we will need an attribute to disable this behaviour for 1.45.0 otherwise PX will likely have trouble using offsetgroup and alignmentgroup correctly.

[etpinard]

It shouldn't have any problems if x and y are set.

[etpinard]

or x0 / y0

[nicolaskruchten]

Yes, but PX doesn't require both to be set and I don't want to change that...

[etpinard]

Ok, but then setting x0 or y0 will solve the issue? How is that different from adding a new box/violin attribute?

[nicolaskruchten]

OK, fair enough.

[gvwilson]

Hi - this issue has been sitting for a while, so as part of our effort to tidy up our public repositories I'm going to close it. If it's still a concern, we'd be grateful if you could open a new issue (with a short reproducible example if appropriate) so that we can add it to our stack. Cheers - @gvwilson