Some members of the Unicode Consortium appear to have been doing some work in this area. The following paper was recently added to the UTC document register.

L2/23-107: Proper Complex Script Support in Text Terminals

Those interested in std::format and formatting textual displays might also find Will McGugan's work on Rich interesting. Rich is a Python library for text formatting. (I'm guessing Victor is aware of it and I wouldn't be surprised to hear that there has already been some cross-pollination of ideas).

Tom.

On 4/3/23 12:22 AM, Tom Honermann via SG16 wrote:

The adoption of P2675 (LWG3780: The Paper: format's width estimation is too approximate and not forward compatible) prompted me to file an enhancement request for ICU to consider providing an interface to query EGC display width for monospace applications.

ICU-22344: Support for estimating the monospace display width of a sequence of EGCs in a terminal or console

Please feel free to take a look and offer corrections or additional comments.

Tom.