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Re: [css-grid] Using automatic (instead of min-content) minimums for 'auto' tracks

From: Sergio Villar Senin <svillar@igalia.com>
Date: Thu, 05 Mar 2015 17:11:23 +0100
Message-ID: <54F8802B.8010204@igalia.com>
To: www-style@w3.org
CC: fantasai <fantasai.lists@inkedblade.net>
On 12/01/15 21:43, fantasai wrote:
> The Grid spec, for 'auto' sized columns, uses the min-content size of
> the items
> to find the base size of the track. After some discussion, Tab, Rossen,
> Greg and
> I think it makes more sense to use the specified minimum size (via
> 'min-width'
> and 'min-height'). To get sensible behavior by default, we'll honor
> 'min-size: auto'
> as 'min-size: min-content' just like in Flexbox.

I've started to implement this for Blink and WebKit and I have found
some issues that I'd like to expose here:

1) It's about setting the initial value of min-size as 'auto' for grid
items. IMHO referring to the behavior in flexbox is a bit suboptimal. I
know that the spec editors are the same and that the development of both
layout systems is a bit entangled but for a guy with a reasonably good
knowledge of the grid specs like me, reading the description of 'auto'
in flexbox[1] is kind of alien language (full of flexbox jargon).

2) From the above quoted fantasai's email I've understood that by
default min-size: 'auto' is equivalent to min-size: min-content,
something which is nice because it's backwards compatible with
implementations. But the thing is that apparently in some cases
(according to the same email) it could be 0px. Which are those cases?
Could we explicitly mention them in the specs?

3) I think there is something missing in the track sizing algorithm. The
new 'auto' value adds a new step before resolving the content-based
minimums which is called intrinsic minimums (which includes
min-content,max-content and auto). That's fine, the problem is that
there isn't any correspondent new step in step 3 of the distribute extra
space algorithm[2]. That step describes which tracks should be selected
to grow beyond grow limits depending on which sizes we're currently
handling. For base sizes it only considers min-content and max-content
but not auto.

BR

[1] http://dev.w3.org/csswg/css-flexbox-1/#valdef-min-width-auto
[2] http://dev.w3.org/csswg/css-grid/#distribute-extra-space
Received on Thursday, 5 March 2015 16:11:51 UTC

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