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Re: UAWG action 729 re: stylesheet defn

From: Greg Lowney <gcl-0039@access-research.org>
Date: Fri, 25 May 2012 11:09:29 -0800
Message-ID: <4FBFD8E9.4040600@access-research.org>
To: "Richards, Jan" <jrichards@ocadu.ca>
CC: WAI-ua <w3c-wai-ua@w3.org>
Hi Jan,

A few changes were made to these SC during this week's call, which would have to be reconciled with yours.

Your definitions look pretty good , except that they don't explicitly define the terms "user style sheet" and "author style sheet" even though they're used and bolded. That means for example that it's unclear whether your 1.7.1 applies to user agents that support author style properties (e.g. inline styles) but not author style sheets as such.

(As an aside, I think the conceit that style property settings are "separate from other information and properties conveyed by the content" is exaggerated. I don't see any fundamental difference between an <i> element and a <span> element with the style attribute, and one can't really say that one is fundamentally different or more separated from content than the other, or that <i> is more separated from content than <p>. Similarly, I disagree with claims that style properties only affect presentation, because generated content defined by styles would certainly be considered content by the vast majority of users. It sometimes seems that the real difference is that style properties are those things adjusted by style mechanisms.)

Very minor, but if you define *style sheet* as "a mechanism...", and then use the phrase "a style sheet mechanism", it means you're really referring to a mechanism mechanism. Not as important here as in other standards where definitions are written as substitutable phrases.

It also appears that the wording of 1.7.2 could be read as mandating that user style sheets be supported, despite the fact that that contradicts 1.7.1.


-------- Original Message  --------
Subject: UAWG action 729 re: stylesheet defn
From: Richards, Jan <jrichards@ocadu.ca>
To: WAI-ua <w3c-wai-ua@w3.org>
Date: 5/25/2012 7:22 AM
> On the last call, I took an action to "Write definition of stylesheet." (https://www.w3.org/WAI/UA/tracker/actions/729)
> In doing so, I noticed some existing older definitions that perhaps could be used if they were made more clear...and also some opportunities to simplify the SCs we are working on. So I propose:
> 1.7.1 Support User Style Sheets: If the user agent supports an *author style sheet* mechanism, then *user style sheets* are also supported. (Level A)
> 1.7.2 Scope of User Style Sheets: The user can turn on the use of *user style sheets* so that they are applied to any of the following: (Level A)
>      (a) the current page, and
>      (b) all pages on specified web sites, and
>      (c) all pages.
> 1.7.3 Author Style Sheet Toggle: The user can turn off any *author style sheet* for both of the following: (Level A)
>      (a) the current page; and
>      (b) all pages that reference the style sheet.
> 1.7.4 Save Author Style Sheets: The user can save *author style sheets* to modify them for use as *user style sheets*. (Level AA)
> Style Properties:
> Properties whose values determine the presentation (e.g., font, color, size, location, padding, volume, synthesized speech prosody) of content elements as they are rendered (e.g. onscreen, via loudspeaker, via braille display) by user agents. Style properties can have several origins:
> *user agent default styles*: The default style property values applied in the absence of any author or user styles. Some *web content technologies* specify a default rendering; others do not.
> *author styles*: Style property values that are set by the author as part of the content (e.g., in-line styles, author style sheets).
> *user styles*: Style property values that are set by the user of a user agent (e.g., via user agent interface settings, user style sheets).
> Style Sheets:
> A mechanism for communicating *style property* settings for web content, in which the style property settings are separate from other information and properties conveyed by the content (e.g., structural markup). Style sheet *web content technologies* include Cascading Style Sheets (CSS) and Extensible Stylesheet Language (XSL).
> CURRENT SC wordings http://www.w3.org/WAI/UA/2012/ED-UAAG20-20120517/#gl-style-sheets-config) - NOTE: some words appear to be missing:
> Older Existing defns:
> ==============
> author styles:
> Style property values that are set by the author as part of the content.
> properties, values, and defaults:
> A user agent renders a document by applying formatting algorithms and style information to the document's elements. Formatting depends on a number of factors, including where the document is rendered (e.g. on screen, on paper, through loudspeakers, on a braille display, on a mobile device). Style information (e.g. fonts, colors, synthesized speech prosody) may come from the elements themselves (e.g. certain font and phrase elements in HTML), from style sheets, or from user agent settings. For the purposes of these guidelines, each formatting or style option is governed by a property and each property may take one value from a set of legal values. Generally in UAAG 2.0, the term "property" has the meaning defined in CSS 2 ([CSS2], section 3). A reference to "styles" in UAAG 2.0 means a set of style-related properties. The value given to a property by a user agent at installation is the property's default value.
> user agent default styles:
> User agent default styles are style property values applied in the absence of any author or user styles. Some markup languages specify a default rendering for content in that markup language; others do not. For example, XML 1.0 [XML] does not specify default styles for XML documents. HTML 4 [HTML4] does not specify default styles for HTML documents, but the CSS 2 [CSS2] specification suggests a sample default style sheet for HTML 4 based on current practice.
> user styles
> User styles are style property values that come from user interface settings, user style sheets, or other user interactions.
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Received on Friday, 25 May 2012 18:10:24 UTC

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