CSS overflow for replaced elements

[marcoscaceres]

Request for position on an emerging web specification

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• WebKittens who can provide input:

Information about the spec

• Spec Title:
• Spec URL:
• GitHub repository:
• Issue Tracker (if not the repository's issue tracker):
• Explainer (if not README.md in the repository):

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• TAG Design Review:
• Mozilla standards-positions issue:

Bugs tracking this feature

• WebKit Bugzilla:
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Anything else we need to know

On WebKit-dev, @khushalsagar wrote:

Hello WebKit!

This is a follow up to previous RFP which introduced the object-overflow property to allow replaced elements to paint with ink overflow. Based on feedback in the CSSWG, the proposal has been updated to use the existing overflow property to provide the same functionality.

The issue capturing the discussion is here. We'd appreciate your feedback on the updated proposal.

Thanks. Khushal Sagar Google Chrome team

[khushalsagar]

Thanks for filing the issue for this RFP. The filled in template is below.

• WebKittens who can provide input: @smfr. They had input in the CSSWG discussion captured on the issue.

Information about the spec

• Spec Title: css-overflow-3
• Spec URL: The edits to the spec for this change are: define overflow on replaced elements and new UA CSS.
• GitHub repository: csswg-drafts.
• Issue Tracker (if not the repository's issue tracker):
• Explainer (if not README.md in the repository): explainer

Design reviews and vendor positions

• TAG Design Review: Issue
• Mozilla standards-positions issue: Issue

Bugs tracking this feature

• WebKit Bugzilla: none
• Radar: none

Anything else we need to know

This issue has relevant context for the motivation to introduce this functionality for replaced elements. The first resolution was to introduce a new property (object-overflow) but we pivoted to use the existing overflow property based on feedback here.

[hober]

I'm pretty sure this is fine; I'll close this as position: support in a week unless anybody objects.

[annevk]

While triaging I noticed that https://github.com/whatwg/html/pull/8028 still hasn't landed.

[khushalsagar]

The exact detail for how this is implemented is being revisited. There is consensus on enabling replaced element contents to overflow their bounds as ink overflow. We resolved on an approach to use UA styles so replaced elements continue to clip by default here.

But use-cases have since been highlighted where an element may or may not render as a replaced element. So a UA style rule which relies on the element tag to decide whether its replaced or not doesn't work.

There's 2 options being considered to address this properly here. We're waiting for a resolution there before spec-ing it.

[annevk]

Thanks @khushalsagar. I'll reopen this so we can evaluate if we want to change our position.

[khushalsagar]

Thanks! Since the group is still evaluating 2 options, feedback on the issue would also help: https://github.com/w3c/csswg-drafts/issues/7144.