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Re: [css-flexbox] rationale for definite size conditions

From: Christian Biesinger <cbiesinger@google.com>
Date: Mon, 4 Apr 2016 17:58:52 -0400
Message-ID: <CAPTJ0XGR8kdyzVQFqRBxX4R1p4PoeF8o=QN7wH+vfXKUgdwf7g@mail.gmail.com>
To: fantasai <fantasai.lists@inkedblade.net>
Cc: Daniel Holbert <dholbert@mozilla.com>, www-style list <www-style@w3.org>
On Mon, Apr 4, 2016 at 5:44 PM, fantasai <fantasai.lists@inkedblade.net> wrote:
> On 04/04/2016 05:23 PM, Daniel Holbert wrote:
>>
>> On 04/04/2016 01:57 PM, fantasai wrote:
>>>
>>> (Fwiw, we did clarify that if an item with a definite flex basis
>>> is inflexible, it is considered definite. [1])
>>> [1] https://hg.csswg.org/drafts/rev/fbcbe170c119
>>
>>
>> Two concerns about this -- so, the new language here is:
>>    # Note: An inflexible item with a definite flex basis
>>    # is, by definition, definite.
>>
>> CONCERN #1: "definite" is a term that applies to lengths, not to items.
>> So, the "item ... is ... definite" language doesn't make any sense here.
>>   This really wants to say that the item's main size is definite, I think?
>
>
> Yes, good point. Fixed.
>
>> CONCERN #2: This Note might need to be promoted to an actual listed case
>> here (alongside the other flex-specific special cases for "definite").
>> I don't think it's covered by any of the other cases, nor is it covered
>> by the CSS3-SIZING definition of "definite". (please correct me if I'm
>> missing the language that covers it, though).
>
>
> The definition in CSS Sizing *does* cover it:
>
> https://drafts.csswg.org/css-sizing-3/#definite
>   # A size that can be determined without measuring content;
>   # that is, a <length>, a size of the initial containing block,
>   # or a <percentage> or other formula (such the “fill-available”
>   # sizing of non-replaced blocks [CSS21]) that is resolved solely
>   # against definite sizes.
>
> If the flex basis is definite, and the item is inflexible, then
> the item's flexed flexed size is also definite.

I get that for each individual case this can eventually be deduced
from the definition but it really seems like such a generic definition
seems to make it harder for implementors and thus for
interoperability, as compared to an exhaustive list.

Also I'm not entirely sure that requiring a definite size for the
flexbox is required for this purpose but I need to think through this
more.

-Christian
Received on Monday, 4 April 2016 21:59:39 UTC

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