[EuiIcon] Add primitive shapes into the EUI icon set

[sbelastic]

Metaphor

The icons we need specifically are the circle and diamond shape (not filled) but I'd say any primitive shape makes sense being added.

Do alternative icon or workarounds exist?

I can get similar(ish) alternatives if:

• I use the dot icon with a 2x scale for the circle (but it's a 'filled' circle)
• If i use the stopFilled icon rotated 45 degrees for the diamond shape (but it's a 'filled' diamond')

Use Case

To add it as a Legend to the Service Map in APM, in observability, in Kibana (see image bellow)

Value / Impact

• These icons are going to be used in a legend, and the usefulness of a legend is pretty large for new users
• I'd say primitive shapes are useful for everyone (and even if we don't need it right now, consider adding the filled alternatives)

Urgency

The feature is somewhat urgent but because these are basic shapes it can be 'circumvented' easily with SVG's

Related code or customizations

It's in this PR, the workarounds mentioned above (might change it to an SVG or keep the filled alternatives, will confirm with team about this)

Additional context (Optional)

It's in photo above.

Design proposal (Optional)

It's also in photo above.

[JasonStoltz]

@JoseLuisGJ If there is no current plans to use these anywhere else, should we add these to EUI or just advise they add them directly in Kibana as custom icons?

[JoseLuisGJ]

This is the only requester for now. I'd like to get @MichaelMarcialis and @bpotselastic thoughts on this.

[JoseLuisGJ]

Hey @sbelastic we've been discussing wether we should add these primitives icons to EUI. And there are some reasons why we shouldn't:

• We're avoiding to introduce new icons that can be perceived as generic artefacts that might be related to different usages. Because the same visual reference might be potentially be useed in many places with completely different contexts. And these primitive shapes might trigger this scenario.
• Related to the first point we recently made a clean up for the icons library removing the most abstract glyphs and using a more specific icon glyphs instead that better represent these elements. So we don't want to end up in the same situation.
• Usually we aim to get at least 2 or more use cases for the same committed icon to think about to move it the the general EUI library.
  So that for now we are not moving forward adding these icons to EUI. If there is a new related request with the triangle or circle shapes we'll reconsidere it. And thanks for the proposal.

[MichaelMarcialis]

Apologies for the late reply (PTO + EAH). I agree with @JoseLuisGJ's assessment. If these generic shape icons were more limited in use (such as be assigned by users in visualization annotations) I wouldn't mind. But making them available for wide usage would likely introduce a lot of inconsistency in their usage and meaning, which is something we're trying to avoid when possible.

That said, would it be possible to use something like our wrench and database icons for your needs (or any of our other existing icons)? If not, then perhaps the custom icon route would be best.

[sbelastic]

I mean, this was the legend for the service map, those are the shapes used for those specific service types in the UI, but the reasons you gave makes sense, we for now have some SVG's there and we currently don't plan to use those icons in more places, so, if it's really decided we won't have primitive shapes, I understand :)