Add new icon (Add chart breakdown) to library

[patpscal]

From Logs+, we want to add an icon to the library.

As discussed here: elastic/kibana#192700 (comment: elastic/kibana#192700 (comment)), it represents a new functionality for Discover fields, conveying that executing the button will add the selected field as a breakdown to the main bar chart.

I used the "plus" symbol in a bar chart to clarify that we are adding the field to an existing visualization instead of opening a visualization builder.

• Followed style instructions
• Used Figma plugin for SVG export

Please let me know what you think. If you're OK with this addition, I'll prepare the PR :)

[MichaelMarcialis]

Thanks for opening this issue, @patpscal! I think this icon looks good. My only concern is that it may be interpreted as "add bar chart" instead of the desired "breakdown" action. Have you given any consideration to using our existing visBarVerticalStacked icon? I wonder if this might better convey the "breakdown" concept, as we use stacked bars to convey the breakdown on the data exploration histograms in Kibana. Thoughts?

CCing my fellow analytics nerds in the @elastic/platform-design team, in case they have any thoughts as well.

[ryankeairns]

Thanks for opening this issue, @patpscal! I think this icon looks good. My only concern is that it may be interpreted as "add bar chart" instead of the desired "breakdown" action. Have you given any consideration to using our existing visBarVerticalStacked icon? I wonder if this might better convey the "breakdown" concept, as we use stacked bars to convey the breakdown on the data exploration histograms in Kibana. Thoughts?

CCing my fellow analytics nerds in the @elastic/platform-design team, in case they have any thoughts as well.

I think using the existing icon (sans plus) makes sense for a couple of additional reasons:

• From the linked issue, it looks like we'll have remaining work to organize that set of 'add' actions. This could result in a yet-to-be-determined UI that may or may not necessitate this new icon (or others if you consider a singe 'Add' button with popover menu, for example).
• With the further integration of Lens and the evolution of ES|QL, there will be more visualization work potentially happening in Discover which makes this action/icon less clear (imagine you have the histogram and/or a visualization)

Given these considerations, even if hypothetical, we may as well save the extra work and roll with the visBarVerticalStacked icon until some of these other topics settle into place.

[patpscal]

Thank you for your insights, @MichaelMarcialis and @ryankeairns. Since the popover may change, we'll proceed with visBarVerticalStacked as you suggested rather than risk discarding the new icon in the future.

CC @mohamedhamed-ahmed