[Mapcss] multi-strokes and subparts

[Sebastian Spaeth]

On Tue, 13 Jul 2010 23:09:53 +0200, Sebastian Klein <bastikln at googlemail.com> wrote:
> E.g. you have a large and nice standard style file. But then you simply 
> want to show motorways on half transparent map:
> 
> [...] standard styles [...]
> node::*, way::*, relation::* { opacity: eval(0.1 * prop(opacity)); }
> way[highway=motorway] { opacity: 1; width: eval(1.4 * prop(width)); 
> z-index: 100; }
> (The example is a little artificial, but maybe you get the idea.)

Yes, I agree that ::* should probably be able to override
things. However in your example you say:
        way::* { a; } 
        way::A { b; } 

is equivalent to way::A {a;b;}.

So ::* works even on subparts that are not yet specified in the style
sheet? Or would it only apply to subparts that have been created before?
As in:
        way::A { b; } 
        way::* { a; } 
        way::B { c; } 
===>way::A { a; b;} 
    way::B { c;}

> I implemented it a little different. The approach is described on the wiki:
> http://wiki.openstreetmap.org/wiki/Talk:MapCSS/0.2

I agree with your approach of having ::* override stuff, but I don't get
this:

>   way[highway=footway] { width: 2; z-index: 3; } 
>   way[fixme]::fixme_highlight { width: 10; z-index: 2; color: red; text: "fixme"; font-size: 12; } 

> draws footways with width 2 and highlights all ways if they have the
> FIXME key.

So this draws 2 things? How do you specify generic styles that can be
overridden in specific subparts? With ::* rules at the beginning of a file?

>   way[highway=footway] { width: 2; z-index: 3; } 
>   way[fixme]::fixme_highlight { width: 10; ...text: "fixme";} 
>  Otherwise [::default] is just an ordinary subpart.

This way
  way[highway=footway] 
is NOT a superset of
  way[highway=footway]::centerline

which is what I argued for earlier. I do believe that the relationship
between "way" and "way::centerline" should be the same as for "way" and
"way[highway]".

Sebastian