Re: char-displayable-p returns t for undisplayable characters

[Miles Bader]

Jonathan Yavner <address@hidden> writes:
> For utf8 locale, the character '…' (ellipsis) displays as a blank.  A
> call to (char-displayable-p ?…) returns t, but this character is not
> displayable.  The character 'é' (e-acute) displays properly.

I see the same behavior; I suspect it's a problem with the way xterm
displays utf8 (i.e., emacs thinks it can display any utf8 character,
because the terminal claims to support utf8, but the terminal doesn't
follow through).

> For iso88591 and iso885915 locales, 'é' (e-acute) displays as a blank while
> '…' (ellipsis) displays reasonably as a question mark.  In this case,
> char-displayable-p returns t for the e-acute that displays a blank, but
> returns nil for the ellipsis that displays as a question mark.

I see different behavior under xterm (started with LANG=ISO8859-1):

'é' (e-acute) displays properly, and char-displayable-p returns t
(however of course ellipsis displays as a question-mark and returns nil
from char-displayable-p).

> Note: xterm in locale iso88591 *can* display an e-acute, but not when running
> Emacs.  Why?

I don't know; it works here.

> Under X11, the e-acute and ellipsis characters both display properly
> in Emacs, while '√' (square root) displays as a white rectangle.
> char-displayable-p returns non-nil for the square-root character, and
> other programs on my computer (such as kmail) can display that
> character.

As I mentioned in an earlier post, this all works properly for me under
x11.

Perhaps the general problem is that you don't have proper fonts
installed (something which is always an issue with unicode -- many
fonts claiming to be unicode fonts aren't really...)

-Miles
-- 
自らを空にして、心を開く時、道は開かれる