ddbeck
commented
1 month ago https://github.com/mdn/browser-compat-data/pull/23631 purports to resolve this, but it does so in an unclear way for object-position and it does not resolve the issue for object-fit. It has also produced a problem for web-features, to compute an unambiguous support status for object-position. cc: @queengooborg @caugner.
And now there's a conflicting story:
- The spec (going back at least a decade) says that
object-positionapplies to replaced elements. css.properties.object-positionsays thatobject-positionworking with only<img>is a partial implementation.css.properties.object-position.applies_to_iframe_elementssays thatobject-positionnot working with<iframe>is not a partial implementation forcss.properties.object-position.
Taken together, this suggests there's some set of replaced elements that are required and some that are optional. Nowhere does BCD say which are optional and which are required. The only thing I'm certain of is that object-position works with <img> elements across browsers and not with <iframe> elements.
I'd prefer to see one of the following things happen:
- Revert https://github.com/mdn/browser-compat-data/pull/23631. Add subfeatures to
css.properties.object-positionenumerating compatibility for all the replaced elements (e.g., createcss.properties.object-position.{embed,iframe,img,…}). Setcss.properties.object-positionsupport to the earliest supported element whatever it happens to be (probably<img>). - Revert https://github.com/mdn/browser-compat-data/pull/23631. Set
css.properties.object-positiontopartial_implementation: truefor all the browsers that don't supportobject-positionwith iframes. In other words, treat it like Edge was treated previously and use notes and partial implementation to show that not all replaced elements can be positioned withobject-position.
Whatever happens, I'd like to see symmetrical changes to object-fit, which has similar limitations reported in a different way, so that they can make sense together. It would also alleviate the need for MDN to have several admonitions regarding which elements are and are not supported for object-fit.
See also https://github.com/web-platform-dx/web-features/pull/1972/.
OnkarRuikar
jamesnw
What type of issue is this?
Missing compatibility data
What information was incorrect, unhelpful, or incomplete?
Related to https://github.com/mdn/content/issues/32474#issuecomment-2182407633
The property doesn't work on iframes in Chromium-based browsers and Safari. But it does work in Firefox. In the OWD weekly meeting, it was decided that BCD needs to cover the iframe entry for the
object-positionproperty.What browsers does this problem apply to, if applicable?
Chromium (Chrome, Edge 79+, Opera, Samsung Internet), Safari
What did you expect to see?
In the
object-fitBCD entry, showiframeis supported in Firefox and not in other browsers. Or in theiframeBCD entry, showobject-fitis supported only in Firefox.Did you test this? If so, how?
Run the following playground demo in various browsers. https://developer.mozilla.org/en-US/play?id=M%2BIuRXx6jXT3WN%2FzFjlc5FQ1p%2B8VB0qGSpBnv%2F4B8bTvJRCQtdgRm9Qi%2BaXMV3jGMLkxAnciNkCPtL9a
Can you link to any release notes, bugs, pull requests, or MDN pages related to this?
No response
Do you have anything more you want to share?
No response
MDN URL
https://developer.mozilla.org/en-US/docs/Web/CSS/object-position
MDN metadata
MDN page report details
* Query: `css.properties.object-position` * Report started: 2024-07-01T06:25:22.629Z