Hello. Let's discuss about follows.
When we use a combination font-setting of over two fonts in
emacs, it may be due to the multi-language editing
support. Those different fonts have varieties in their size,
e.g. many Asian glyphs occupy double width space of an
alphabet. (Even though the wide font is not perfectly double
wide space of one alphabet, many users want that the occupied
size of one wide character such as Asian character to be exactly
same with two alphabet characters, namely fixed font setting)
However, we must consider the line spacing, I mean the height of
the fonts. Although the width between different fonts have
variation along each other, the height (or line spacing) should
keep same, or, it would be better to allow user to be able to
set the base height, IMO.
If it's not, to keep the consistency in the height spacing with
various widths (size settings) of fonts, emacs needs to check the
largest height value along each specified
charset (i.e. fontset). Currently, emacs seems to set the base
height to the value of the default fontset. Then, if the height
value of other user-specified charset's font is larger, for line
having those fonts, it may cause inconsistent result in line
spacing. (This is exactly now happening.)
So, how can user specify different fontsets with different sizes
for each, but with consistent height? As you all already know,
users can set the line-spacing value to control the space between
lines. But this works only for the space between lines, not for
the height of a line itself.
Here is one case with the problem:
(set-face-font 'default (font-spec :family "terminus" :size 14))
(set-fontset-font nil 'korean-ksc5601
(font-spec :family "Guseul" :registry "unicode-
bmp" :lang "ko" :size 16)))
Thanks.
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