[Mapcss] Development of MapCSS?

Tom Davie tom.davie at gmail.com
Wed Mar 6 09:37:43 UTC 2013

On 6 Mar 2013, at 09:32, Peter Wendorff <wendorff at uni-paderborn.de> wrote:

> Am 06.03.2013 10:06, schrieb Tom Davie:
>> On 6 Mar 2013, at 08:49, Martin Vonwald <imagic.osm at gmail.com> wrote:
>>> Here we have a problem. Lets look at my situation: I'm writing a style
>>> for JOSM. Actually it is my second style after some playing around
>>> with another minimalistic one, so I don't have much idea of the
>>> situation. I encounter some problems while implementing and so I ask
>>> on the josm-dev if something was possible or not. Shortly after that
>>> some new functions are implemented in JOSM.
>>> So who's the "bad guy" now? Is it me, because I shouldn't ask on
>>> josm-dev but on this mailing list? I had no clue about this mailing
>>> list. Is it the josm developer, because he implemented something
>>> without discussing it on this mailing list? He just provided some
>>> valuable features.
>>> And while we try to figure out who's to "blame" we have a short look
>>> at the number of participants on this discussion. It's me and you.
>>> Maybe that's the real problem - lack of interest. A short look at the
>>> history of http://wiki.openstreetmap.org/wiki/MapCSS/0.2 and its talk
>>> page seems to confirm this.
>> Hopefully that should indicate that I have been involved in the discussion too.  Personally, I'm of the opinion that MapCSS is in *very* early stages of development, and we're still discovering all the ways in which current MapCSS can't style things we want to style.  Because of that, I think it's entirely reasonable for individual implementers to experiment with ways of supporting styling these features.
> Probably here you/we (I prefer you here as I'm following the mapcss mailinglist and am interested in the topic, but not implementing anything like that currently) should learn from the CSS folks here; not in the way how mapcss should work and to do the same design decisions, but in the way how css evolves currently.
> Every few weeks or months browser vendors create new css features and implement these in their browsers, but usually they do this prefixed by a vendor-specific prefix at first: -moz-... -webkit-...-properties of CSS come to mind.

I'm not convinced that the CSS developers have come up with a better solution than we have to be honest.  The reason being simply that the -webkit prefix is already causing significant problems for other renderers.  Microsoft for example complained that while IE's engine supports many of the things that were webkit extensions and are now CSS3, they do not actually end up rendering because all the web devs in the world originally used the -webkit version, and never updated their CSS.

> I fear, this model of development is not possible for the selector stuff, but for the rendering rules and function names we/you should probably adapt it.

Indeed, I don't see a way that it can be adapted to new matching structures.  While I would be happy to adopt it in OSP, I don't really see it solving any significant problem - we would still end up with stylesheets that can only be rendered correctly by one renderer, and worse, when other renderers do support it in the future, no one will update the stylesheets to work with the other renderers.


Tom Davie

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