Consider providing a "white background" variation for Gallery captions

[kjellr]

The dark gradient background behind gallery captions can look pretty muddy when applied to a light image:

We should consider allowing folks to choose a light variant of that background:

[kjellr]

It took a quick pass at this in #24897, but it would be cool if this color were user-adjustable (and would provide an accessibility warning if the contrast wasn't strong enough).

[mtias]

cc @nosolosw @jorgefilipecosta on ideas on how best to handle this. Also consider that links contained there can cause issues when they inherit color.

[oandregal]

We can add text & link color controls to the gallery block and then use the presence/absence of has-text-color to set the caption's color: inherit or white/black. Would be this in line with what you're thinking?

We need to adjust how we generate the UI controls for colors, as of today text and background colors are coupled. #24927

[richtabor]

Do we know if this a real problem that needs solving? I'm not convinced adding this much more complexity to the Gallery block (a new styles panel, colors panel, or both would be worth the end result.

If it is a real problem that we have feedback on, what if we lean towards an automated black/white solution that works based on the darkness level detected per each image?

[mtias]

It might be interesting to use @ItsJonQ work on #22564 to maybe generate a bg color matching the dominant color of the image automatically.

[kjellr]

Do we know if this a real problem that needs solving? I'm not convinced adding this much more complexity to the Gallery block (a new styles panel, colors panel, or both would be worth the end result.

I think at the core of it, this is really just meant to solve help address situations where the caption awkwardly overlaps the image. To that end, I'm still hoping we eventually get a version where captions do not overlap the images at all: #8030