[Kibana Lens] possibility to color cells of a table based on the value of another field and not the displayed field

[Danouchka]

Describe the feature:
In Lens table, the cells can be colored only according the displayed metrics and colors can be set only against positive numbers or percentages
In this feature requests, my customer would like to have cells colored against a secondary metric and allow coloration according values of secondary metrics including negative values.

Describe a specific use case for the feature:
We have the following dataset

POST mytestindex/_doc
{
    "name":"TOTO1",
    "@timestamp":"2024-12-14T23:23:00.000Z",
    "nb_alerts":59,
    "nb_alerts_ref":60
}
POST mytestindex/_doc
{
    "name":"TOTO1",
    "@timestamp":"2024-12-14T23:24:00.000Z",
    "nb_alerts":60,
    "nb_alerts_ref":60
}
POST mytestindex/_doc
{
    "name":"TOTO1",
    "@timestamp":"2024-12-14T23:25:00.000Z",
    "nb_alerts":61,
    "nb_alerts_ref":60
}
POST mytestindex/_doc
{
    "name":"TOTO1",
    "@timestamp":"2024-12-14T23:26:00.000Z",
    "nb_alerts":2,
    "nb_alerts_ref":60
}

In Lens we can represent this with the following table

Imagine we add a diff runtime fields with the formula

if (doc['nb_alerts'].size()>0 && doc['nb_alerts'].value > 0) {
    emit((double)(doc['nb_alerts'].value - doc['nb_alerts_ref'].value));
}

The goal is to color

• the cell with 59 in red because diff=-1<0
• the cell with 60 in green because diff=0>=0
• the cell with 61 in darker green because diff=1
• the cell with 2 in stronger red because diff=-58 ..etc

Thank you

[Danouchka]

cc @teresaalvarezsoler @ghudgins

[elasticmachine]

Pinging @elastic/kibana-visualizations (Team:Visualizations)