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Re: [CSS3] Flexible Flow Module, proposal.

From: Zack Weinberg <zweinberg@mozilla.com>
Date: Sun, 12 Apr 2009 19:05:18 -0700
To: robert@ocallahan.org
Cc: Andrew Fedoniouk <news@terrainformatica.com>, David Hyatt <hyatt@apple.com>, www-style <www-style@w3.org>
Message-ID: <20090412190518.22a16ab7@mozilla.com>
"Robert O'Callahan" <robert@ocallahan.org> wrote:
> Hacking calc() to allow mixing of flex and specified widths seems
> problematic to me because of the time-of-evaluation issue. 

We could just specify that at em-unit-calculation-time, calc()
reassociates as necessary to put its argument in a canonical form of
<fixed> +/- <flex>, and then the <flex> gets processed at layout time.

Alternatively, borrowing even more from TeX:

  glue(size, plus)
  glue(size, plus, minus)

where each of the three arguments can be a calc-expression, but flex
units and non-flex units may not be combined within a single expression.

I'm not fond of the box-flex idea because it's not obvious which
dimension, or even which *axis*, it applies to.  Keep it around for XUL
back compat, sure, but not the recommended way forward.

As a side issue, what's the rationale for restricting flex units to
some subset of the box dimension properties?  I would think it would be
useful in any length property.

Received on Monday, 13 April 2009 02:06:00 UTC

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