[josm-dev] MapCSS

Sebastian Klein bastikln at googlemail.com
Wed Mar 2 12:09:04 GMT 2011


André Riedel wrote:
> 1. Are relative width values only be supported by JOSM or is it a main
> feature of MapCSS 0.1 or 0.2?

No, it's not an official feature of MapCSS. I've suggested it on the
MapCSS mailing list [1].

> - relative values only be supported for a separate layer
> - no support for cascading relative values (see big_bridge)

At the moment, declarations are static properties: You can repeat them 
as often as you like and nothing changes. +6 basically means to have a 
margin of 3 on both sides.

What you propose would change this principle and move the language into 
an imperative direction - i'm not convinced this is a good idea.

In the mean time, you can make it explicit and write

  width: eval(prop(width) - 2);

> - no support for negative relative values

Will be fixed.

> 3. Why are there different definitions of casing-width?
> 
> JOSMCSS [1]:
>  absolute value -> absolute width of the casing
>  relative value -> refers to width
> MapCSS 0.1 [2]:
>  -> absoulte width
> MapCSS 0.2 [3]:
>  -> relative width

I took the liberty to suggest an improvement to the standard. :)
When the MapCSS community finally decides on something else, I will 
accept that. But what is written in the wiki is not necessarily the 
community consensus. In fact it was changed by RichardF, but Potlatch 2 
still seems to use absolute casing-width, so it is compatible at the 
moment...

Also note that MapCSS 0.1 is final, but MapCSS 0.2 is still a draft.

[1]
<http://lists.openstreetmap.org/pipermail/mapcss/2010-October/000124.html>

Sebastian



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