Eli Zaretskii <e...@gnu.org> writes: >> From: Nicolas Goaziou <m...@nicolasgoaziou.fr> >> Cc: shingo....@gmail.com, 48...@debbugs.gnu.org >> Date: Sun, 02 May 2021 14:18:24 +0200 >> >> My problem is that I have some string, _which is not displayed anywhere_ >> yet. I need to obtain its real width along with the width of a single >> character in order to compute the length argument in `make-string'. > > The width of any text on display is meaningless unless you also tell > in what window will it be displayed. That's because some of the > factors that affect the display width depend on the window and the > buffer shown by that window.
I understand. More than the width of the text, I'm interested in the ratio between the width of the text and the width of an underline character (assuming monospace). > So assuming the string you have will eventually be displayed in some > window -- and most strings in Emacs are of that kind -- you should use > that window up front. Otherwise, the value you get from other methods > can only be an approximation, which will sometimes be close, and > sometimes quite far from the truth. The string may not be displayed at all. Since it is the output of an export process, it could, e.g., be written to a file. I applied Shingo Tanaka's suggestion using `string-width', which is the best we can do considering our requirements. Thank you for your answer, and to Shingo Tanaka for the report an the patch. Regards,
