add {r} format to url, which returns @2x when retina detected and enabled

[urbaniak]

you can use {r} in tileLayer url, to serve different tiles (2x ones) for retina screens, cause the current detectRetina implementation makes the labels in tiles too small

[mourner]

Thanks! @tmcw what do you think? Is "@2x" a common convention for tiles?

[tmcw]

I'm not sure - it's Apple's recommendation of a prefix/postfix, but there are providers like CloudMade that do something entirely different, and it's not always upscaled 256 tiles but sometimes 512 tiles. Seems a bit tricky / potentially not ready for a future standard.

[mourner]

@tmcw CloudMade also uses @2x postfix, although not at the end but after style id: http://cloudmade.com/documentation/map-tiles

It doesn't take too much code so we could include it just for convenience, even if it's not a standard.

[mourner]

@jieter @calvinmetcalf what are your thoughts on this guys?

[calvinmetcalf]

add options for retinaFlag defaulting to '@2xandnonRetinaFlag` defaulting to an empty string ?

[mourner]

@calvinmetcalf looks a bit verbose, do you know any tile provider that utilizes non-@2x convention for retina?

[calvinmetcalf]

I should have more clearly pointed out that those were top of my head names I thought were terrible, as far as I know nobody does use anything else or sets a flag for non retina etc, but hard coding it without adding an option to change it from the default seems like the kind of thing which we might regret latter

[mourner]

Well, I think it's better to add it later than prematurely solve non-existing problems with more code. So good to merge then?

[calvinmetcalf]

my bad I didn't notice it was a pull request and not an issue so thought we were brainstorming, yeah that's fine

[mourner]

@calvinmetcalf that kind of input is always good in any case, be it pull or issue.