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Re: [css-sizing] Intrinsic Sizes of Replaced Elements ignores 'width' and 'height'?

From: Simon Sapin <simon.sapin@exyr.org>
Date: Fri, 14 Nov 2014 14:49:41 +0000
Message-ID: <54661685.1010208@exyr.org>
To: "L. David Baron" <dbaron@dbaron.org>
CC: www-style@w3.org
On 13/11/14 19:32, L. David Baron wrote:
> On Thursday 2014-11-13 14:58 +0000, Simon Sapin wrote:
>> The "Intrinsic Sizes of Replaced Elements" section of the ED
>> currently reads:
>>
>> http://dev.w3.org/csswg/css-sizing/#replaced-intrinsic
>>> For replaced elements, the min-content size and max-content size are
>>> equivalent and correspond to the appropriate dimension of the
>>> concrete object size returned by the default sizing algorithm
>>> [CSS3-IMAGES] of the element, calculated with an unconstrained
>>> specified size.
>>
>> css-images-3 defines "specified size" as given (for replaced
>> elements) by the 'width' and 'height' properties.
>>
>> So css-sizing says to ignore these properties for the intrinsic size
>> of an image? That sounds wrong.
>
> I think that's right in general:  we want the concept of intrinsic
> size not to be affected by height, width, etc., properties, so that
> we can have values of those properties that specify the intrinsic
> size.
>
> There's still a concept that css-sizing calls the min/max-content
> size contribution that should be affected by these.

I was not aware of this difference. How does it relate to what 
css-sizing calls the {min,max}-content contribution?

Whatever the terminology, I don’t see the specified size of images being 
accounted for anywhere in the current css-sizing ED.


>> I was looking for what should happen to images with the percentage
>> specified width. A possible solution would be to do like for blocks:
>> resolve the percentage if it is definite, or ignore it otherwise.
>>
>> However, browsers seem to interoperably do something more
>> complicated, at least when tables are involved, and I don’t know
>> what the algorithm is here.
>>
>> Compare the document below with and without the style="width: 50%".
>> (The behavior without is explained by tables always getting at least
>> their min-content size, even when the specified size is smaller, per
>> "shrink-to-fit".)
>>
>> <table style="width: 200px">
>> <td style="border: solid">
>> <img style="width: 50%"
>>       src="data:image/svg+xml,<svg width='1000'
>>            xmlns='http://www.w3.org/2000/svg'/>">
>
> In Gecko, the image has an intrinsic width of 1000px.  What differs
> with and without the width:50px is its intrinsic width contribution
> to its parent:  the presence of width: 50% makes that 0 for
> min-width only, since the min-content contribution for any element
> with a percentage width is 0.

Interesting. That last part doesn’t seem to be specified in css-sizing.

-- 
Simon Sapin
Received on Friday, 14 November 2014 14:50:10 UTC

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