Editor: Dependent values

[kkaefer]

In TileMill/CartoCSS, we have variables that we can refer to to create derivative values. It's unclear how this looks in a no-code environment. Maybe we can use drag/dropping color swatches onto another layer to make that layer's color the same/dependent upon the dropped color.

/cc @samanpwbb @tristen

[tristen]

Do you mean this kind of operation that you want to represent in a nice way from a UI?

@land: #78d757;
polygon-fill: darken(@land, 0.5);

Where a color has been established that you can create derivative values off of?

[kkaefer]

Exactly. It doesn't necessarily have to be transformed; the easiest example would be the same color being used in two layers.

[tristen]

It seems like you would want two different paths to choosing color:

1. That is free-form color picker
2. That is dependent on an existing swatch. You would then get a different dialog like one with color operations to perform

So when you select a layer that hasn't been styled you have to make a choice on which path you take.

Another thought here: In TileMill I personally, (and see other folks) define my color palettes for a map at the top of the first stylesheet. I think a UI that represented this same workflow would work well - where you can build a color palette at the top of the page and your layers just reference them - you don't actually select colors from the layers