'object-fit' values 'cover' and 'contain' contain redundant definition from Leif Arne Storset on 2012-02-01 (www-style@w3.org from February 2012) (original) (raw)

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

-- Leif Arne Storset Core Technology Developer, Opera Software Oslo, Norway

Received on Wednesday, 1 February 2012 15:08:27 UTC