`$[fg ]` and `$[bg ]` should allow color property in 8bpc RGBA, as well as 4bpc RGBA.

[MineCake147E]

💡 Summary

The $[fg ] and $[bg ] MFM tags currently allow 4bpc RGBA color.

$[fg.color=f0f9 Magenta Semitransparent]
$[bg.color=f0f9 Magenta Semitransparent]

The text is clearly affected by the theme behind them.

But they don't allow 8bpc RGBA color.

$[fg.color=00ff0099 Green Semitransparent]
$[bg.color=00ff0099 Green Semitransparent]

Not only does it appear opaque, it also appears red.

🥰 Expected Behavior

The text

$[fg.color=00ff0099 Green Semitransparent]
$[bg.color=00ff0099 Green Semitransparent]

Gets rendered identically as:

$[fg.color=0f09 Green Semitransparent]
$[bg.color=0f09 Green Semitransparent]

Like:

🤬 Actual Behavior

📝 Steps to Reproduce

1. Open any instance of Misskey in any browser.
2. Type the text in the note form:

   $[fg.color=00ff0099 Green Semitransparent]
   $[bg.color=00ff0099 Green Semitransparent]

3. View the note preview.
4. You'll see what happens.

📌 Environment

Misskey version: 13.11.3 Your OS: Windows 10 Home 22H2 Build 19045.2846 Your browser: Mozilla Firefox 112.0.1

[MineCake147E]

Potential sources of this issue are: https://github.com/misskey-dev/misskey/blob/87ff004c736bef9e8d3a6ccc90242ffade977b2e/packages/frontend/src/components/mfm.ts#L232 https://github.com/misskey-dev/misskey/blob/87ff004c736bef9e8d3a6ccc90242ffade977b2e/packages/frontend/src/components/mfm.ts#L238 Which only allows hex number up to 24bit, not 32bit.