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Re: [MathML3-PR] Alignment with display="block"

From: Sam Dooley <sam@integretechpub.com>
Date: Thu, 02 Sep 2010 09:05:59 -0600
Message-Id: <201009021504.o82F4S6H003128@aragorn.integretechpub.com>
To: Alex Milowski <alex@milowski.org>, www-math@w3.org

It seems to me a user agent has leeway to supply default style rules
that support the preference for centered/indented block math elements,
despite the general default for other block elements, in the same way
legacy HTML attributes are given behaviors in terms of CSS properties.

I think the intent of 2.2.1 is simply to recommend that the user agent
take the display attribute into account when it produces a rendering,
without over-constraining what that rendering should look like.

So if a user agent centers the block math elements by default, and if
users must supply style rules to achieve other behaviors, that for me
would be one possible conforming behavior.

[speaking personally, not for the working group]

At 08:30 AM 9/2/2010, Alex Milowski wrote:
>While looking into what a user agent such as WebKit should do by
>default for when math elements have display="block", we've read
>through Section 2.2.1 where it says:
>"Moreover, when the math element is embedded in a larger document,
>a block math element should be treated as a block element as
>appropriate for the document type (typically as a new vertical block),
>whereas an inline math element should be treated as inline (typically
>exactly as if it were a sequence of words in normal text)."
>The default user agent behavior for a block in XHTML/HTML5 is
>to rendered a block left aligned (or writing start direction aligned).
>As such, I would interpret the correct default behavior by a user agent
>rendering a 'math' element with display="block" to be the same.
>There is a great preference out there for block level Mathematics
>to be centered.  The second preference would be for it to be
>at least indented from the normal block flow.
>Is it the intention of MathML3 for block level Mathematics to default
>to left or writing direction start alignment?
>If so, that would require users to add additional rules to their CSS
>to change to centered or indented block Mathematics.
>--Alex Milowski
>"The excellence of grammar as a guide is proportional to the paucity of the
>inflexions, i.e. to the degree of analysis effected by the language
>Bertrand Russell in a footnote of Principles of Mathematics
Received on Thursday, 2 September 2010 15:08:41 UTC

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