Align columns in Org mode table with Japanese fonts

Question

How can I mix Japanese and English in the same org-mode table (that uses fixed-width fonts)? Something like:

| m m m   m m m |      |
| はどう  デシウ |       |
| ﾊｰﾌ           | ﾊｰﾌ   |

won't align. Emacs simply counts the Japanese characters as one, when indeed they are more like 10% bigger.

Could the width of a column be set in pixels? I know that <10> would set the width, but that does not help, since it counts in terms of fixed-width letters.

The problem is basically how emacs aligns columns (using the font width).

Answer 1

This depends on the fonts you are using. And I don't think Elisp has pixel level alignment capability.

Org calculate width of string with string-width instead of length. string-width returns 1 for ASCII and Half width CJK chars or 2 for Full width chars. Evaluate the following code will show you that:

(string-width "m")
1
(string-width "ﾊ")
1
(string-width "は")
2

Now, even though Org mode got the right answer from the sting property, and added pads around strings, it is the Emacs display engine's job to place where those bits go on the screen.

Emacs display engine gets font information from the underlying OS. To make the complex problem simple, let's say that, with your configuration, m's width is 5 pixels and "は" is 10. In this case they will be perfectly aligned because Org mode's assumption ("は" takes twice the width of "m") matches with the actual pixels on your screen.

Instead, if your fonts configuration has 7 pixel for "m" and 10 pixel for "は", the things won't match up. And there is nothing Org mode nor the Display engine can do. They did what they told, by your configuration, to do.

Answer 2

You need to prepare the monospace font with 1:2 height-width aspect ratio, so called "narrow" font, such as Inconsolata. Most programmer's fonts have the aspect ratio of 3:5, or so called "wide" font, that can not be fit with Japanese font when used with org-mode tables.

Also, you must set your font height to be an even number. Otherwise, its width (half of height) wouldn't be an integer and would also cause problem on org-mode table alignment.