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Re: Comments on 'line-height'-related tests for Quirks Mode

From: Alan Gresley <alan@css-class.com>
Date: Fri, 23 Nov 2012 22:44:48 +1100
Message-ID: <50AF61B0.1010509@css-class.com>
To: "Kang-Hao (Kenny) Lu" <kanghaol@oupeng.com>
CC: Simon Pieters <simonp@opera.com>, W3C CSS Test Suite <public-css-testsuite@w3.org>
On 23/11/2012 9:07 PM, Kang-Hao (Kenny) Lu wrote:
> (12/11/23 17:25), Simon Pieters wrote:
>>>    # span { padding:1px 0 }
>>>    # <div id=test><span></span></div>
>>>    # <div id=ref></div><div id=s_ref></div>
>>>
>>> This is a bit puzzling, in particular about "<div id=s_ref></div>". I
>>> think what this test runs into is this part of CSS 2.1 9.4.2:
>>>
>>>    # Line boxes are created as needed to hold inline-level content
>>>    # within an inline formatting context. Line boxes that contain no
>>>    # text, no preserved white space, no inline elements with non-zero
>>>    # margins, padding, or borders, and no other in-flow content (such as
>>>    # images, inline blocks or inline tables), and do not end with a
>>>    # preserved newline must be treated as zero-height line boxes for the
>>>    # purposes of determining the positions of any elements inside of
>>>    # them, and must be treated as not existing for any other purpose.
>>>
>>> While the condition "no inline elements with non-zero margins, padding,
>>> or borders" probably has quirks-mode difference too (and should be
>>> specced), if you are testing the current prose to see if the above
>>> <span> contributes to line height, I'd suggest the test be written in
>>> this way:
>>>
>>>    | div { line-height: 0} span { padding:1px 0; line-height: normal }
>>>    | <div id=test>x<span></span></div><div id=ref>x</div>
>>>    | <div id=s_ref>x<span>x</span></div>
>>>
>>> The 'x' at the beginning ensures that the tests don't go into the
>>> "zero-height line boxes" situation.
>>>
>>> Ditto for all others.
>>
>> I think this is intentional. We could add tests with "x" in as well,
>> though, if that still makes the quirk kick in.
>>
>> Do you have a test case demonstrating quirks-mode differences in "no
>> inline elements with non-zero margins, padding, or borders"?
>
> (By the way, the CSS 2.1 propose here should really be "non-zero
> horizontal margins/paddings/borders/" as you have observed.)
>
> Well, your test case:
>
>    # span { margin:0 1px }
>    # <div id=test><span></span></div>
>    # <div id=ref></div><div id=s_ref>x</div>
>
> shows that :) (whether non-zero margins matter only in standards mode).
>
> What I am saying here is that if you compare this test with
>
>    | div { line-height: 0;} span { margin:0 1px; line-height: normal; }
>    | <div id=test>x<span></span></div>
>    | <div id=ref>x</div><div id=s_ref>x<span>x</span></div>
>
> you'll see that Firefox passes the former but not the latter. That is,
> the <span> in "<div id=test>x<span></span></div>" does contribute to
> line height (in a buggy way). This is probably an edgy bug Gecko has,
> but the point is that the result could be differnt.
>
> In other words, I guess the best option is to spec the quirk about
> "zero-height line boxes" and include both test cases.
>
>
>
> Cheers,
> Kenny

So are there any links to any testcase?




-- 
Alan Gresley
http://css-3d.org/
http://css-class.com/
Received on Friday, 23 November 2012 11:45:24 GMT

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