line-color should be related to polygon-fill for most if not all polygon features

[ian29]

This would simplify both the visual style and the code base considerably. Ideally we do this by establishing a convention like

polygon-fill: @some_color;
line-color: darken(@some_color, 10%)

although I imagine there will need to be considerable tweaking

[matthijsmelissen]

@floscher is this issue solved, or is there more that needs to be done?

[matthijsmelissen]

This has been resolved in the meanwhile.

[matkoniecz]

No, see https://github.com/gravitystorm/openstreetmap-carto/blob/master/landcover.mss#L33 and https://github.com/gravitystorm/openstreetmap-carto/blob/master/landcover.mss#L30 (maybe also something else)

[matthijsmelissen]

Why you think they are not related? They have the same hue, at least.

[matkoniecz]

I think that these are related, that is why this ticket applies to them and is not fixed (I replied to "This has been resolved in the meanwhile.")

[matthijsmelissen]

I don't follow you. If color and fill are related, the issue is solved, isn't it?

[matkoniecz]

I thought that replacing direct color definitions by darken(@color, something%) was part of this ticket ("Ideally we do this by").

I also think that it is a good idea, as it makes later changes of colours easier.

[matthijsmelissen]

Darken works on rgb, here basically the same has been done in Lch. I think Lch is preferable, even though Carto does not support it natively.

[matkoniecz]

OK, so with this part rejected I also think that this is solved.

[HolgerJeromin]

I think Lch is preferable, even though Carto does not support it natively.

which is btw issue:
mapbox/carto#354

[pnorman]

Yes - the basic problem with darken(@color, something%) is that it not only darkens, but also changes the perceptual hue and chroma. With the old colours, that's not too serious an issue because they were chosen sloppily enough, but when you're working out all the colours in a perceptual colour space, it makes sense to do them all there.