Histogram does not scale to the range of new data on restyle

If you set up a histogram…

var data1 = [1, 2, 2, 3, 3, 3, 4, 4, 5];
var hist = document.getElementById('hist_div');
Plotly.plot(hist, [{x: data1, type: 'histogram' }]);

… and then update this histogram with wider data followed by a restyle…

var data2 = [10, 20, 20, 30, 30, 30, 40, 40, 50];
Plotly.restyle(hist, {x: [data2]});

… the histogram keeps the old range (in this case 1 to 5) and does not scale to the range of the new data (which is the case when using scatter style plot). Here is a codepen showing this: http://codepen.io/rasmusab/pen/megKOo

I have not found any documentation regarding whether this is the expected behavior. If it is, what would be the best practice for updating a histogram with new data?

[alexcjohnson]

Ha, for colorscales it turns out we already do what I was about to propose here: if you explicitly specify *auto: false, then it will fill in the auto values but leave it looking like *auto: false so that future changes will not re-invoke the autoscaling; but if you don’t specify an explicit *auto value it defaults to true since the explicit ranges are missing.

So for example:

var x1 = [1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4];
var y1 = [1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4];
Plotly.newPlot(gd, [{type: 'histogram2d', x: x1, y: y1, zauto: false}]);

and then:

// move the last point so we have one bin that gets 1 sample, another gets 3
Plotly.restyle(gd,'x', [[1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 3]])

range is still 1.5->2.5

But if you don’t specify zauto: false in the first place, the initial plot is identical but after restyle you get: recalculated autocolor: 1->3

So I think it’s only in the context of histogram bins that this is a change - and therefore I’d consider it an inconsistency, a bug, not a breaking change, and I should implement the same logic with explicit autobin*: false values in histograms.

[etpinard]

I would actually argue that in all of these cases the update should reset the derived attributes

This means that if a user wants the auto first view (e.g. say the cmin and cmax colorbar attribute) of the first Plotly.newPlot to remain after updates, they will need to set cmin and cmax to those value that they don’t know in advance, which is a little annoying in my mind.

I’m not sure how common this use case is for plotly.js users. Maybe it doesn’t matter. Maybe we need another auto mode (e.g. cauto would be an enumerated true, false or first-view). But at the very least I’d call what @alexcjohnson is proposing a breaking change.