W3C home > Mailing lists > Public > www-style@w3.org > March 2011

RE: box tree terminology

From: Alex Mogilevsky <alexmog@microsoft.com>
Date: Thu, 31 Mar 2011 18:44:35 +0000
To: fantasai <fantasai.lists@inkedblade.net>, "www-style@w3.org" <www-style@w3.org>
Message-ID: <D51C9E849DDD0D4EA38C2E539856928411F0F5DD@TK5EX14MBXC213.redmond.corp.microsoft.com>
So we are trying to give a name to something that doesn't really exist, but could be useful as imaginary concept to help understand reality...

Border I guess is a good example. When we see a  border that looks like this

    +++++++++++++++++
    +...............+
    +...............+
    +...............+
-------------------------- end of page 

We can *think* about it as if we were looking at top part of a bordered box which ends elsewhere. What we *actually* see is manifestation of a bordered element on this particular page. It lacks bottom border merely because it is a traditional way to communicate that something didn't fit...

Understandably we want to write phrases like "when a box is rendered in paged media it produces zero or more boxes" and then refer to those two kind of boxes separately.

But in reality it is not what is happening. Actually an *element* can have more than one boxes, each representing the element in context of its page. All boxes taken together don't make one continuous box, and if that virtual box existed it wouldn't really help build these partial boxes.

So what kind of text are you trying to write that would benefit from defining separate two kinds of boxes?

-----Original Message-----
From: www-style-request@w3.org [mailto:www-style-request@w3.org] On Behalf Of fantasai
Sent: Tuesday, March 29, 2011 11:28 PM
To: www-style@w3.org
Subject: Re: box tree terminology

On 03/29/2011 08:38 PM, Alex Mogilevsky wrote:
> Exactly as you say, line breaking and pagination can create multiple 
> rendering things for one element.
>
> When it is in fact broken between pages, is there any reason to refer 
> as a separate singular concept to whatever thing would have been there 
> if there weren't a page break?

It's not the thing that would have been there that needs a term, it's the rendering object itself. An anonymous block box, for example, can be broken across pages just like a regular block box. It's still one box, and you can't reflow lines across its boundary, but it's multiple boxes now that we've broken it.. The top of a block box has a border, as does the bottom, but if it breaks across pages the first box of the box has the top border and the last box of the box has the bottom border. The containing block is formed by the padding edges of the block box, not by the padding edges of the boxes that make up the block box when it is paginated.

Etc.

It gets kindof awkward. :)

~fantasai
Received on Thursday, 31 March 2011 18:45:10 GMT

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