> 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. 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.