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Re: [CSS21] Overconstrained fixed table layout

From: Gérard Talbot <www-style@gtalbot.org>
Date: Tue, 15 Jan 2013 15:01:08 -0500
Message-ID: <065c242bce385942afe329b610992214.squirrel@ed-sh-cp3.entirelydigital.com>
To: "fantasai" <fantasai.lists@inkedblade.net>
Cc: "www-style@w3.org" <www-style@w3.org>

Le Jeu 10 janvier 2013 19:13, "Gérard Talbot" a écrit :
>
> Le Jeu 10 janvier 2013 17:12, fantasai a écrit :
>> Gérard pointed out to me that the spec for fixed table layout
>> seems to have some problems in the area of overconstrained
>> fixed table layout. The relevant test cases are:
>>
>> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/fixed-table-layout-025.htm
>> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/fixed-table-layout-026.htm
>> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/fixed-table-layout-027.htm
>> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/fixed-table-layout-028.htm
>> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/fixed-table-layout-029.htm
>> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/fixed-table-layout-030.htm
>> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/fixed-table-layout-031.htm
>>
>
> 2 other tests:
>
> http://www.gtalbot.org/BrowserBugsSection/css21testsuite/border-spacing-percentage-cell-001.html
>
> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/fixed-table-layout-003e08.htm
> and the width of the cell in first column is -16px, that is minus 16px.
>


The computed width of 3rd cell in 3rd column of the following test is
minus 16px:

http://test.csswg.org/suites/css2.1/nightly-unstable/html4/fixed-table-layout-003e10.htm

Gérard


>
>> Specifically, the issue is how padding and borders factor into
>> the initial column width calculations. The algorithm says that
>> you only account for the width of cells with specified widths.
>>    http://www.w3.org/TR/CSS21/tables.html#fixed-table-layout
>>
>> We don't have interop on this.
>>
>> The problems I see so far are:
>>    * A column element's 'width' property sets the column's width.
>>      That's fine. But if it's width is 'auto', you take the 'width'
>>      of the first cell. But the 'width' typically does not include
>>      the cell's borders/padding -- shouldn't this be 'width' plus
>>      horizontal borders/padding?
>>    * When calculating a column width from the cell, the cell's
>>      parameters are ignored when its width is 'auto'. Shouldn't
>>      borders/padding factor into the table's width; and shouldn't
>>      they be subtracted from the remaining width before distributing
>>      to 'auto' columns?
>>    * Fixed table layout can result in table cells with negative
>>      widths. It's not specified what that means in terms of layout,
>>      since layout generally assumes that containing blocks are
>>      non-negative.
>>
>> ~fantasai
>>
>>
>
>
>
>
> "(...) the column width is set to the width of the cell plus its left
> padding plus its right padding plus half its left border plus half its
> right border in the collapsing border model, and the same but using full
> border widths in the separated border model. (...) we should
> probably just make it explicit what it means for a cell to 'determine' a
> column width." Boris Zbarsky
>
> coming from
> http://lists.w3.org/Archives/Public/www-style/2011Apr/0743.html
>
> Gérard
> --
> CSS 2.1 Test suite RC6, March 23rd 2011
> http://test.csswg.org/suites/css2.1/20110323/html4/toc.html
>
> Contributions to CSS 2.1 test suite
> http://www.gtalbot.org/BrowserBugsSection/css21testsuite/
>
> Web authors' contributions to CSS 2.1 test suite
> http://www.gtalbot.org/BrowserBugsSection/css21testsuite/web-authors-contributions-css21-testsuite.html
>
>
>


-- 
CSS 2.1 Test suite RC6, March 23rd 2011
http://test.csswg.org/suites/css2.1/20110323/html4/toc.html

Contributions to CSS 2.1 test suite
http://www.gtalbot.org/BrowserBugsSection/css21testsuite/

Web authors' contributions to CSS 2.1 test suite
http://www.gtalbot.org/BrowserBugsSection/css21testsuite/web-authors-contributions-css21-testsuite.html
Received on Tuesday, 15 January 2013 20:01:39 GMT

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