Remove percentage unit from letter spacing

[iamtakashi]

% is not a valid unit for letter spacing. I've seen users confused because the setting doesn't do anything when they choose % for letter spacing. Can we remove that?

[Mayank-Tripathi32]

We can implement solution is to filter out the % unit in the letter spacing control, similar to how the Spacer block does it. 🤔

	const [ spacingUnits ] = useSettings( 'spacing.units' );
	// In most contexts the spacer size cannot meaningfully be set to a
	// percentage, since this is relative to the parent container. This
	// unit is disabled from the UI.
	const availableUnits = spacingUnits
		? spacingUnits.filter( ( unit ) => unit !== '%' )
		: [ 'px', 'em', 'rem', 'vw', 'vh' ];

I will open up PR for the same.

[t-hamano]

Thanks for the report.

% is not a valid unit for letter spacing.

The percentage values ​​should be correct according to the CSS Text Module Level 4 specs.

This appears to be a bug in Chrome. I'm not sure in which version it will be released, but it seems to have been fixed already.

See https://chromium-review.googlesource.com/c/chromium/src/+/6651574

[Mayank-Tripathi32]

I was looking at this https://developer.mozilla.org/en-US/docs/Web/CSS/letter-spacing

tried to change values in % but it gave out warning 🤔

However, applying % values does work in safari

Should we still disable the "%" as alot of users are on chromium based browsers and letter spacing not working may break websites?

[t-hamano]

The percentage value ​​is defined in CSS Text Module Level 4, so tit may still be considered not officially supported.

That being said, I haven't had any issues outside of Chrome so far. The issue should be fixed in Chrome version 139 as well:

https://chromiumdash.appspot.com/commit/1c2b5b25c398cc2223a602fe5bcccd80767a4059?

With that in mind, I personally prefer not to remove this unit.

[iamtakashi]

@t-hamano, thank you so much for letting me know about that. It does look like just Chrome doesn't support it. I agree, let's leave it. Thank you all!