Hello org mode users!

I recently looked into getting org mode tables to properly align cell borders and table border, when using Chinese characters in them.

I found out, that there is valign mode [1] and was happy with it for a few days. But then I opened a document with lots of tables and some of those tables bigger than what I had before in other documents. Scrolling inside that document became quite laggy. So teeth-gnashingly I deactivated valign mode, already suspecting it to be the culprit. And I was right. After deactivating it, I could scroll perfectly fine again.

So I returned to the second alternative I had found out about, when searching for a solution: Finding a font, which renders Chinese characters at exactly double the width of latin/ASCII characters. I found a font named "Sarasa" [2] and experimented a bit with setting the font globally, then setting it only when opening an org mode buffer. Now it looks like that font does character widths almost correctly (see attached screenshot, see slightly wider 4 ASCII characters than 2 Chinese characters).

My settings for org mode regarding fonts/faces are:

~~~~
(add-hook 'org-mode-hook
          (function
           (lambda ()
             ;; Only do the following in graphical mode, as it will
             ;; break when using emacs in terminal mode.
             (when (display-graphic-p)
               ;; Sarasa font is from https://github.com/be5invis/Sarasa-Gothic.
               (setq buffer-face-mode-face
                     '(:family "Sarasa Mono CL"
                       :weight normal
                       :height 110))
               (buffer-face-mode)))))
~~~~

However, it seems, that now org mode does not align tables correctly, even though an ASCII character is half the width of a Chinese character in the tables. Org mode seems to add too few or too many spaces, which are displayed as spaces of various width.—Is that because of the 1 pixel width difference?

Do I need to look for another font, which does things truly exactly, no 1 pixel too wide funny business? Maybe someone knows a more exact font?

Ultimately: How can I make tables align correctly?

My Emacs version is: GNU Emacs 28.2

My org mode version is: 9.6.1

[1]: https://github.com/casouri/valign

[2]: https://github.com/be5invis/Sarasa-Gothic

I have tried something else today:

I looked at how the font is rendered in Libre Office. There it seems, that the characters align perfectly (see attached screenshot). So maybe this is an Emacs in general issue of font rendering, which adds a pixel to ASCII characters or takes one away from CJK characters?

-- 
repositories: https://notabug.org/ZelphirKaltstahl