Revamp color use for numerical columns

[alexsb]

Numerical columns should not get a color by default. Instead, we give them a color in two conditions:

• Manual Labeling: Users can label a column with a color if they desire. The corresponding column identifier should then also be colored in all other views.
• Grouping: when we group two or more columns, they are assigned a color, since we need it for the stacked bar chart.

[alexsb]

Consider coloring for sorted columns.

[sgratzl]

So far LineUp doesn't enforce using colors for numerical colors. There is deriveColors in the builder if you don't do it, all will be gray.

The corresponding column identifier should then also be colored in all other views.

can you clarify that?

regarding automatic colors for grouping:

• personally not a fan of magic changes, since it complicates the tracking of the user action. i.e in this case. the move operation into a stacked/reduce column automatically triggers a set color operation on the column.
• what should happen if you ungroup the columns again?

[alexsb]

Re

The corresponding column identifier should then also be colored in all other views.

That means that if a numerical column in lineup is given a color, then this change should also be visible in all associated views. For LineUp standalone, that would be just the histogram in the side panel, I guess, but other views should receive an event notifying them of the color change, which LineUp would have to trigger.

Re colors for grouping:

• yes, magic is tricky. We should try it in original colors and see how it looks. Maybe we can get it to work with a nice separator. Or just light variations in darkness?
• Yeah, that would be a problem. If we do it, they should probably go back to the original, human-set color.