Update overlay step function in cover block

[akasunil]

What?

Fixes #51625

Why?

Currently, we can set overlay in multiple of 10 in cover block.

How?

I have updated steps to enable any number from 1 to 100 to be set as overlay value.

Testing Instructions

1. Add cover block
2. Change overlay
3. Notice opacity

Screenshots or screencast

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

If you're merging code through a pull request on GitHub, copy and paste the following into the bottom of the merge commit message.

Co-authored-by: akasunil <sunil25393@git.wordpress.org>
Co-authored-by: aaronrobertshaw <aaronrobertshaw@git.wordpress.org>
Co-authored-by: Mamaduka <mamaduka@git.wordpress.org>
Co-authored-by: stokesman <presstoke@git.wordpress.org>
Co-authored-by: carolinan <poena@git.wordpress.org>
Co-authored-by: ndiego <ndiego@git.wordpress.org>
Co-authored-by: richtabor <richtabor@git.wordpress.org>
Co-authored-by: ramonjd <ramonopoly@git.wordpress.org>
Co-authored-by: t-hamano <wildworks@git.wordpress.org>
Co-authored-by: hanneslsm <hanneslsm@git.wordpress.org>

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[akasunil]

Hi @Mamaduka, need your help with PR review here.

[Mamaduka]

Hi, @sunil25393

It's been a while since I worked on the Cover block, and I might miss some of the pre-requestions needed for this change. I would recommend contacting folks who worked on the overlay feature "recently". cc @t-hamano, @stokesman

P.S. Removing the has-background-dim-{unit} class can be considered a breaking change, though I don't have any data about their usage in real-world sites.

[akasunil]

Removing the has-background-dim-{unit} class can be considered a breaking change,

I have kept the css for backward compatibility. We can deprecate it in future version of gutenberg i guess.

[stokesman]

I have kept the css for backward compatibility.

Yes but George was referring to its corresponding class in the markup. There could be instances of CSS written using it in their selectors. Here’s what can be found in themes from wpdirectory. Most of the usage seems odd to me and I'd like to think we can not worry about breakage but I think that’d be against policy.

Otherwise, I gave this a test drive and it worked well. I only tested a basic Cover block created from trunk before switching to this branch and the block updates successfully. I'm not sure how else these types of changes need to be tested.

[akasunil]

There could be instances of CSS written using it in their selectors.

Thank you for your reply. I see it now. However, if we leave the class selectors, opacity will be applied twice. There is no significance to it. Is there a workaround for this? We can always update the changelog, though.

[stokesman]

I took a closer look at the selectors used in the themes from that search and all of them that I saw are written for older cover block versions which had the has-background-dim-{unit} class directly on the block’s root element. So those styles wouldn’t be applying to more recent cover block versions anyway. I.e. this change won’t break those styles.

Yet I didn’t examine all the results because they are many (though it appears they are all repetitions of what I did examine). I wanted to try a more exacting regex to find results that aren’t paired up with wp-cover-block classes but didn’t see a way to do it that’s supported by WP Directory’s regex interpreter.

I've also ran the search on plugins. There are some results though it appears that they are for custom blocks that adopted the use of the class and so should be unaffected by this change. For example, I tested the most installed plugin in the results (WooCommerce) and the class is used on their Featured Product block that has nothing to do with Cover.

My feeling is that this should be safe to ship as is but I don’t know the level of caution others might think is warranted.

[akasunil]

Thank you for investing @stokesman, @t-hamano can we get your view on this ?

[akasunil]

@WordPress/outreach Need this PR to be reviewed.

[carolinan]

Hi @akasunil You need to update the PR with the latest files from Gutenberg trunk, and make sure that the tests pass.

[carolinan]

Change to 6.5 compatibility files need to be moved, I assume since we are in RC already, this needs to be in a 6.7 compatibility file, not 6.6.

[akasunil]

Hi @carolinan, I have updated PR. Could use review.

[aaronrobertshaw]

Thank you for all the hard work on this PR @akasunil 👍

I'm still in the process of giving the code a thorough review and test but thought it important to share a few early thoughts.

Backwards Compatibilty

As has already been discussed on this PR, the removal of the dim ratio CSS class from the block will cause existing blocks to be flagged as invalid due to the saved markup no longer matching what is generated in the editor.

If the dim ratio CSS class is to be removed in favour of an inline opacitiy style, the Cover block will need a deprecation to migrate the old versions' markup.

A lot of the block fixtures that are updated in this PR are related to past deprecations. Changing them means they don't match the markup those deprecated versions of the block actually have so are now incorrect.

The non-__deprecated fixtures could be updated with the proposed inline opacity styles but we would also need new fixtures covering the deprecation of the dim ratio class.

Alternative Approach

There are also a number of open issues currently to update the Cover block such that it's overlay is configurable via theme.json and Global Styles. The primary issue for this is:

• Cover Block: allow the overlay color and height default values to be changed by theme.json #27809

The general idea is that the background color block support could be used to provide the color for a Cover block's overlay. This block support also allows defining opactity via the color's alpha channel.

It's been on my radar for a while but I haven't had the bandwidth in the lead up to 6.6 to explore too deeply. I believe @ramonjd has also started working on this too.

I'm not sure yet whether the UI for the Cover block's overlay opacity would be removed so we rely solely on the background color control or whether it would be left in place as a convenience until it can be deprecated.

With the release of the Section Styles feature, the ability to style the Cover block's overlay via theme.json is getting more attention. I'd go so far as to say it's a must-have. (cc/ @richtabor)

As this PR won't address the above need and the alternative approach would also solve the main concern this PR addresses (i.e. finer control over opacity). I'd like to propose we avoid introducing the inline opacity style which would require yet another deprecation once the overlay is switched to use the background color block support.

I really do appreciate the huge amount of work that has gone into this PR. FWIW it might still help inform the direction we ultimately go in.

If you are open to it, perhaps we can collaborate on the alternative approach?

[ndiego]

With the release of the #57908 feature, the ability to style the Cover block's overlay via theme.json is getting more attention. I'd go so far as to say it's a must-have.

Agreed.

[richtabor]

As this PR won't address the above need and the alternative approach would also solve the may concern this PR addresses (i.e. finer control over opacity). I'd like to propose we avoid introducing the inline opacity style which would require yet another deprecation once the overlay is switched to use the background color block support.

I tend to agree. With this effort in flux yet I don't think we should push forward on too many changes with the opacity control. I think perhaps it coexists, but I'd like to push that work forward first.

[akasunil]

Thank you for the detailed feedback on this PR. I appreciate the time you're putting into reviewing.

I agree that we should minimize the deprecation as much possible, If we have better way to improve functionality, we should discuss that. Coming to the alternative approach you proposed, which involves updating the Cover block such that its overlay is configurable via theme.json and Global Styles, is definitely better solution then the inline styles this PR add into block.

The general idea is that the background color block support could be used to provide the color for a Cover block's overlay.

Just for the clarity, Does it mean we add a new setting for overlay color under block color support?

I'm open to collaborate on the alternative approach. It sounds like a more flexible solution for the Cover block's styling capabilities.

I really do appreciate the huge amount of work that has gone into this PR. FWIW it might still help inform the direction we ultimately go in.

Thank you again for your valuable insights and for recognizing the work put into this PR.

[aaronrobertshaw]

Just for the clarity, Does it mean we add a new setting for overlay color under block color support?

Ideally, we'd reuse the background color support as is, if possible. From the UI side, I think the difficulty would be labelling the "background" control as "overlay" so its purpose is still clear.

I'm open to collaborate on the alternative approach.

That sounds great, thanks 👍

As that work progresses, I'll add you to any issues and PRs as they're created.

[richtabor]

Ideally, we'd reuse the background color support as is, if possible. From the UI side, I think the difficulty would be labelling the "background" control as "overlay" so its purpose is still clear.

It's probably fine with the first iteration to just use "Background" even. There's a few ideas floating around about consolidating background color and image into one PanelBody, it may be that we don't need to change the label if that's the case.

[ramonjd]

I believe @ramonjd has also started working on this too.

Nothing recently, but it's worth highlighting the proposal to merge background controls in the UI.

#63096

#60100 (comment)

This wouldn't affect the way the background values are read and stored in theme.json, but would eventually make controls consistent across blocks that have background image and background color supports enabled, the Cover block (hopefully one day) included.