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Re: [css-flexbox] Different behaviour in FF and Chrome regarding flex-basis

From: Daniel Holbert <dholbert@mozilla.com>
Date: Mon, 18 Aug 2014 17:25:46 -0700
Message-ID: <53F2998A.4010500@mozilla.com>
To: www-style@w3.org
CC: Hubert SABLONNIERE <hubert.sablonniere@gmail.com>
On 07/23/2014 11:45 AM, Daniel Holbert wrote:
> In Firefox, when the height is indefinite, we establish it using the sum
> of the hypothetical main sizes of its children.  (I thought this was in
> the spec, but I can't find it at the moment; it's possible it was in an
> older version, or just that I'm misrememebering.)

Following up on this -- this behavior ^ is indeed correct per the spec:

  # The max-content main size of a flex container
  # is the sum of the flex container’s items' max-content
  # contributions in the main axis"
  [...]
  # The main-size min-content/max-content contribution of
  # a flex item is its outer hypothetical main size when
  # sized under a min-content/max-content constraint
  # (respectively).
  http://dev.w3.org/csswg/css-flexbox/#intrinsic-sizes

Also, here's a modified version of the original codepen, to demonstrate
the key difference here:
  http://codepen.io/anon/pen/JfHdE

Firefox and IE11 render this collapsed. Chrome renders it non-collapsed,
because it seems to be using the items' auto-heights instead of their
flex base sizes to establish the container's height.

I think Firefox & IE11 are correct.

The only things I changed in the codepen (w.r.t. the original one on
this thread) are:
  - I added "min-height:0", since otherwise Firefox Nightly honors the
default "min-height:auto" which saves it from collapsing.
  - I changed "flex: 1 1 0" to "1 1 0px", since IE incorrectly rejects
"1 1 0", as I noted in [1].

~Daniel
[1] http://lists.w3.org/Archives/Public/www-style/2014Jul/0442.html
Received on Tuesday, 19 August 2014 00:26:13 UTC

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