Fix / Renovate SpecialChars plugin

[WebCoder49]

Query

Please let me know here if you have any idea for how to get the width of a character in a textarea element, for use in rendering the character below in the highlighted section with the same width. A canvas solution is already being used, but some arbitrary checks are in place to make it more cross-browser compatible and this is becoming very messy. The code for this is in the special-chars plugin.

Testing

To test the special character view for every character, like in the screenshot below, use new codeInput.plugins.SpecialChars(true, true, /./g).

Status when Writing

• It doesn't get the right width with Unicode characters like emojis, but it appears fine with all ASCII characters except for Tab (0009):
  
• It never highlights newlines - maybe this should be made clear / fixed?
• The rather messy canvas method used to find character width may be the problem.
• The RegEx for special characters should probably be changed - perhaps it should just match zero-width (­) and �-like characters?

[WebCoder49]

This is truly broken - I tried the same tests on an X11/Ubuntu machine on Chromium and Firefox and it gave different character widths to on a Windows 11 machine.