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Re: [css4-images] possible error in <image-set-decl> syntax

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Fri, 19 Oct 2012 12:56:08 -0700
Message-ID: <CAAWBYDApGtohkE_WLCyNBjxjuHg1YLMvSxbH24M4t6ZXRwT3ig@mail.gmail.com>
To: Glenn Adams <glenn@skynav.com>
Cc: W3C Style <www-style@w3.org>
On Fri, Oct 19, 2012 at 9:26 AM, Glenn Adams <glenn@skynav.com> wrote:
> should <image-set-decl> be
>
> <image-set-decl> = [ <image> | <string> ] <resolution>
>
> or
>
> <image-set-decl> = ( <image> | <string> ) <resolution>
>
> in other words, can one merely specify a <resolution> without <image> or
> <string>? if so, then the prose should define what this means

I think you're mistaken over the exact grammar syntax we use in CSS.
() has no special meaning, and [] is just a grouping construct, not an
optionality indicator.  The grammar for CSS properties and values is
documented in Values & Units.

> also, in regard to
>
> Every <image-set-decl> in a given ‘image-set()’ must have a different
> <resolution>, or else the function is invalid.
>
> what is the definition of 'different'? e.g., is 1dppx different from 96dpi?

This is a genuine omission - I should say "computed resolution".

~TJ
Received on Friday, 19 October 2012 19:56:56 GMT

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