Cover block: Enable focal point picker for fixed background

[JosVelasco]

What problem does this address?

The focal point picker disappears when you activate the fixed background toggle in the Media settings.

What is your proposed solution?

I understand it doesn't make much sense for desktop to preserve this setting, but for mobile, it could be fantastic to use this UI to deal with backgrounds converted from fixed to scroll, to select more relevant parts of the image.

[t-hamano]

Thanks for the suggestion.

Personally, I think it's fine to always enable the focal point picker UI (background-position) regardless of whether the fixed background setting (background-attachment: fixed) is enabled. For example, for background image support, we can use the focal picker even when the fixed background is enabled:

This is also useful on other platforms, such as iOS, that don't support the fixed background, because we can still use the focal picker to adjust the horizontal or vertical position even when the fixed background is enabled.

In the video below, the focal point picker is operated while the fixed background is enabled in a Group block that supports the background image:

6a054ed0eba2dd4eea1735f190768da8.mp4

cc @WordPress/gutenberg-design @ramonjd

[ramonjd]

Sounds like a good idea. It might be good to also keep @ajlende in the loop. The Cover block resets the background-position value to background-position: 50% 50%; when you toggle the fixed background, and it looks like this is related to a couple of Duotone bug fixes (?)

• https://github.com/WordPress/gutenberg/pull/40554/files#diff-98e8fbed8e10d45fee8dfcb0373d733aa1335f7cbf0a5dd883739b86fae0fd7eR27
• https://github.com/WordPress/gutenberg/pull/65929/files#diff-4518dd019994a649b1d4def5459d5a5899d93543145bff074d531327730fef92R68

The latter relates to parallex, but I'm not sure how to enable that setting.