W3C home > Mailing lists > Public > www-math@w3.org > April 2010

Alignment and Embellished Operators

From: Frédéric WANG <fred.wang@free.fr>
Date: Fri, 09 Apr 2010 20:23:47 +0200
Message-ID: <4BBF70B3.2000402@free.fr>
To: "www-math@w3.org" <www-math@w3.org>
Hi all,

I would like to mention an issue about embellished operators that was 
reported ten years ago in Bugzilla. Consider the files given as 
attachment. In the XHTML page, two embellished operators are used as 
scripts of a <underover/>. The screenshot shows a sample rendering: the 
two arrows are correctly stretched to the size of the base of the 
<underover/>. However, the center of the children are aligned and, 
because of the size added by the embellishments, the arrows do not cover 
the base of the <underover/>. I suppose you agree that the expected 
rendering would be to align the arrows with the base, using some kind of 
automatic positioning for the scripts?

Now, MathML3 introduces a new attribute "align" for munderover (and 
under/over), that can only takes three values: "left" | "right" | 
"center". In the example I give, none of these values will give the 
expected result. It seems to me that either a new default value "auto" 
should be added or say that automatic alignment of embellished operator 
overrides the value of the align attribute. I think the latter is 
better: auto would be redundant with center in all the other cases, I 
don't see why one would refuse to align the stretched symbol with the 
base and (for munderover) this will allow to apply automatic positioning 
to only one of the two scripts.

Frédéric Wang


screenshot_alignment_embellished_operators.png
(image/png attachment: screenshot_alignment_embellished_operators.png)

Received on Friday, 9 April 2010 18:21:23 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Friday, 9 April 2010 18:21:23 GMT