If I reformat the second example with a mono-spaced ideographic font (PCMyungjo on macOS) I get the same alignment as the first example.

Don't we have a similar miss-alignment when switching from monospaced fonts to proportional fonts for pure ascii, aligned, text?

From: SG16 <sg16-bounces@lists.isocpp.org> on behalf of Peter Brett via SG16 <sg16@lists.isocpp.org>
Date: Thursday, December 2, 2021 at 5:38 AM
To: sg16@lists.isocpp.org <sg16@lists.isocpp.org>
Cc: Peter Brett <pbrett@cadence.com>
Subject: [SG16] Use of U+3000 IDEOGRAPHIC SPACE is common practice

Hi all,

Alignment with U+3000 IDEOGRAPHIC SPACE (the full-width space character) is common practice in Han text.

Consider the following text typed using the Microsoft Japanese IME in its default Hiragana configuration:

おはようございます

　　こんにちは

　おやすみなさい

Note that (1) pressing the space keyboard key inserts U+3000 IDEOGRAPHIC SPACE and (2) that U+3000 takes up exactly one ideographic square, allowing the text to be perfectly aligned.

The same text with each U+3000 IDEOGRAPHIC SPACE replaced with two U+0020 SPACE characters:

おはようございます

こんにちは

おやすみなさい

The ability to specify U+3000 as padding for formatting alignment is highly desirable in Han environments, especially for any text that may be copied and pasted from a terminal emulator into another environment (e.g. a programming text editor such as VS Code or Emacs).

Best regards,

                 Peter