[RNMobile] Ensure font is scaled on iOS when accessibility settings are changed

[SiobhyB]

Note There are times where the font appears overly large when used with custom fonts and block-based themes, this will be addressed in a separate Gutenberg PR for both platforms. The scope of this specific PR is to enable support for Dynamic Type on iOS.

Related PRs

• Gutenberg Mobile: [RNMobile] Ensure font is scaled on iOS when accessibility settings are changed wordpress-mobile/gutenberg-mobile#6492
• WPiOS: [TESTING] Installable build for Dynamic Type support wordpress-mobile/WordPress-iOS#22272

What?

With this PR, we ensure that font in the editor is changed when users change their accessibility settings on iOS.

Why?

At the moment, Dynamic Type is not supported in the editor's RichText component for iOS. This is because the refreshFont() function here is 'undoing' the scaling that takes place elsewhere in Aztec's codebase.

How?

We ensure scaling is applied to the new font when it's set here within the applyFontConstraints() function.

Testing Instructions

An installable build to test these changes can be found here.

• Navigate to the Accessibility section in the Settings app.
• Select Display & Text Size then Larger Accessibility Sizes to on.
• Select a larger accessibility size.
• Next, open the WordPress app and select a site with a block-based theme.
• Navigate to the editor in the app.
• Either add a heading block or begin typing into a paragraph block.
• Select the block's cog/gear icon to open its settings and select a larger font size.
• Experiment with typing more text and adding more heading or paragraph blocks.
• Verify that the font has been scaled in accordance with your device and block settings.

Screenshots or screencast

Before and after ⤵️

Before	After

Android comparison ⤵️

Android	iOS

[github-actions]

Flaky tests detected in d98f0b7.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/7303326923
📝 Reported issues:

• [Flaky Test] Should show Columns block only if selected blocks are between limits (1-6) #40369 in specs/editor/various/block-switcher.test.js

[SiobhyB]

@geriux, @twstokes, I know you have some upcoming AFK, and I do too, so don't expect that this will be prioritised. Just wanted to get it on your radar for when you're back!

[twstokes]

Worked great for me @SiobhyB! 🚀

As a future enhancement it would be nice if the editor responded to Dynamic Type changes without needing to be closed and reopened. That's not nearly as important, though, as supporting it in the first place.

[SiobhyB]

@twstokes, thank you so much for the review! 🙌

As a future enhancement it would be nice if the editor responded to Dynamic Type changes without needing to be closed and reopened. That's not nearly as important, though, as supporting it in the first place.

This makes sense, I've created a new issue at #57354 listing some of the remaining tasks left to make Dynamic Type support better overall. I've made a note to shape a pitch around accessibility fixes in the New Year which would include this. 🙇‍♀️

[geriux]

TIL about scaledValue 👏