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Re: [css3-images] Probably editorial: 'object-fit' values 'cover' and 'contain' contain redundant definition

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Thu, 2 Feb 2012 04:12:57 -0800
Message-ID: <CAAWBYDCM_8MkyVBHGMpiDz4UU_USicMHAUpN+ndG=sQVDcmHEg@mail.gmail.com>
To: Leif Arne Storset <lstorset@opera.com>
Cc: "www-style@w3.org" <www-style@w3.org>
On Wed, Feb 1, 2012 at 7:07 AM, Leif Arne Storset <lstorset@opera.com> wrote:
> In section 5.4, both 'contain' and 'cover' seem to be defined twice. For
> example, 'contain' says
>
> | Determine the used ‘height’ and ‘width’ of the element as usual, except:
> | If both ‘height’ and ‘width’ are ‘auto’, and the used value of at least
> | one of ‘max-width’ and ‘max-height’ is not ‘none’, then compute the
> | element's used width and used height as though the intrinsic dimensions
> | of the contents were infinitely large numbers whose ratio is the actual
> | intrinsic ratio of the contents. This will proportionally scale the used
> | width and height up to the given maximum constraints.
> |
> | Set the concrete object size to the largest width and height that has
> | the same aspect ratio as the object's intrinsic aspect ratio, and
> | additionally has neither width nor height larger than the replaced
> | element's used width and height, respectively.
>
> These seem redundant to me. I suspect the first definition, written in
> 2007, hails from a time when '(max|min)-(width|height)' were underdefined
> in level 2, and "as usual" wasn't sufficient. [0] Determining used values
> for 'width' and 'height' seems out of scope for this property and this
> spec, as implied by the introduction to 5.4:
>
> | The ‘object-fit’ property specifies how the contents of a replaced
> | element should be scaled relative to the box established by its used
> | height and width.
>
> I could be wrong: my head is spinning from trying to calculate
> some examples according to both the specs. If I am wrong, and some
> situation does require all the infinity math, I feel we could phrase it
> more simply and/or state the covered cases more clearly.
>
> My primary suggestion, however, is to delete the first paragraph, both
> under 'contain' and 'cover', so that both consist only of a paragraph
> starting with "Set the concrete object size…".
>
> [0] At the moment I can't find old versions of CSS 2.1, but CSS 2 does not
> define it as well as CSS 2.1.
> CSS 2:
> http://www.w3.org/TR/2008/REC-CSS2-20080411/visudet.html#min-max-widths
> CSS 2.1: http://www.w3.org/TR/CSS21/visudet.html#min-max-widths

Nope, it's not redundant.  Those first paragraphs have the effect of
forcing the size of the element itself to the min/max constraint.

I agree that this is out-of-scope for this property.  Fantasai does not.

~TJ
Received on Thursday, 2 February 2012 12:13:44 GMT

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