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Re: [css3-flexbox] question about calculating "hypothetical main size"

From: fantasai <fantasai.lists@inkedblade.net>
Date: Mon, 16 Jul 2012 22:21:46 -0400
Message-ID: <5004CC3A.2070005@inkedblade.net>
To: "Kang-Hao (Kenny) Lu" <kennyluck@csail.mit.edu>
CC: WWW Style <www-style@w3.org>
On 06/28/2012 10:18 AM, Kang-Hao (Kenny) Lu wrote:
> I am having trouble understanding the algorithm here, and I'll
> appreciate some help, for example, a pointer to a previous discussion.
>
>
> 9.2. Line Length Determination
>
>    # 3. Determine the flex base size and hypothetical main size of each
>    # item:
>    #
>    # ...
>    #    Otherwise, if the flex container's main-axis is parallel to the
>    # item's inline-axis, lay out the item using the available space and
>    # its flex basis if the item is inflexible,
>
> Question 1: What does use the available space *and* its flex basis mean?
> Using its flex basis as the available space? Using the maximum of
> available space from the flex container and the flex basis?

We've rewritten this part of the algorithm, hopefully it's clearer now:
   http://dev.w3.org/csswg/css3-flexbox/#line-sizing

> Question 2: What is the flex base size of
>
> <div style="display: flex; width: fit-content"><!--floated container-->
>   <div style="flex: 0 0 50%;">
>   </div>
> </div>
>
> The flex item is inflexible and the percentage is resolved against an
> flex container with indefinite width and hence indefinite by definition.
> How do you resolve 50% at this point?

As Tab says, that's undefined. It's now clearly specified as such, though. :)

> Question 3: What does "sized under a min-content or max-content
> main-size constraint" mean? What are the examples besides "width:
> min-content" and "width: max-content" on the flex container?

Another example would be 'min-content' or 'max-content' on an
ancestor of the flex container while the flex container is auto.

The most common case, however, is shrinkwrapping an ancestor: it
needs to size its content under both min and max constraints in
order to know what values to put into the fit-content expression.

Does that help?

~fantasai
Received on Tuesday, 17 July 2012 05:22:19 GMT

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