Feature request: access to layers and subplots with stable API

Context

We want to display interactive SVG elements on a plotly plot in data coordinates. In order to do this, we currently use the _fullLayout "private" API in order to get a handle to

• subplots
• clipId
• top shape layer.

We then add a new layer for positioning interactive elements right above _fullLayout._shapeUpperLayer, as seen here:

import { select as d3_select } from 'd3-selection';

export function getInteractorLayer(plotlyPlot, plot='xy') {
  // plotlyPlot is a plotly plot object, e.g. from Plotly.newPlot() or Plotly.react()
  // plot is the subplot name, e.g. 'xy', 'x2y2'
  const subplot = plotlyPlot._fullLayout._plots[plot];
  const shapelayer = plotlyPlot._fullLayout._shapeUpperLayer;
  const layer_above = d3_select(shapelayer.node().parentNode);
  // create interactor layer, if not exists:
  layer_above.selectAll("g.interactorlayer")
    .data(["interactors"])
    .enter().append("g")
    .classed("interactorlayer", true);
  const interactorlayer = layer_above.selectAll("g.interactorlayer");
  const clipid = subplot.clipId.replace(/plot$/, '');
  return { interactorlayer, subplot, clipid };
}

Request

A public interface for getting handles to subplots, the clipId, and the top shape layer (or a simple API function for creating a new top layer!)

Once we have the items above, we can create interactors on top of a plotly plot and re-render them as needed with e.g.

  plotlyPlot.on('plotly_relayout', relayout);
  plotlyPlot.on('plotly_afterplot', relayout);
  plotlyPlot.on('plotly_relayouting', relayout);

as seen in this demo: https://bmaranville.github.io/plotly-interactors/demo.html (drag the interactors around and look at the console to see the callbacks being called with the updated state of the interactor)

Commencez par l’exemple getInteractorLayer et les points d’entrée plotly_relayout, plotly_afterplot et plotly_relayouting décrits dans l’issue. Définissez une alternative publique à l’accès privé à _fullLayout qui expose subplots, clipId et la couche supérieure de formes, ou qui crée une couche supérieure, puis vérifiez que les interacteurs peuvent être positionnés et rendus à nouveau via les callbacks présentés.