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Re: [css3-flexbox] make 'visibility: collpase' items more stable for multi-line flex container

From: Kang-Hao (Kenny) Lu <kennyluck@csail.mit.edu>
Date: Thu, 05 Jul 2012 08:31:50 +0800
Message-ID: <4FF4E076.2070901@csail.mit.edu>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: WWW Style <www-style@w3.org>
(12/07/05 7:51), Tab Atkins Jr. wrote:
> On Wed, Jul 4, 2012 at 9:02 AM, Kang-Hao (Kenny) Lu
> <kennyluck@csail.mit.edu> wrote:
>>   # 9. Collapse ‘visibility:collapse’ items. If any flex items have
>>   #   ‘visibility: collapse’, note the cross size of the line they're
>>   #     in as the item's strut size, and restart layout from the
>>   #     beginning.
>>
>> I am not sure why this need to go back to the beginning, why can't we
>> just make collapsed + uncollapsed items fixed in any flex line. That is,
>> just jump to right after
>>
>>   # 5. Resolve the flexible lengths of all the flex items to find their
>>   #    used main size, and determine their hypothetical cross size from
>>   #    this main size.
> 
> Because then you can have either ragged or uneven lines.  In many
> cases, I think it will be better to rerun line-breaking, which is why
> I specified it that way.

I think with the current specced behavior the condition for 'visibility:
collapse' to be useful for a multi-line flex container is significantly
complex to be worth written down. The condition, as far as I can tell is,

either

  * The collapsed item has a bigger cross-size than most of other items.

or

  * The collapsed item doesn't go into another line (it shouldn't bring
the strut size of one line to another) and an item with the biggest
cross-size in a flex line doesn't go into another line if there's an
item to be collapsed in the same line.

Am I right here?


Not rerunning line-breaking would have a easier condition for
'visibility: collapse' to be useful: the lines with items to be
collapsed are positively flexible.

I can't tell if this condition is often met though.


Cheers,
Kenny
Received on Thursday, 5 July 2012 00:32:19 GMT

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