> From: Kenichi Handa <handa@m17n...>
> Date: Mon, 01 Nov 2010 17:15:13 +0900
> Cc: emacs-bidi@gnu...., emacs-devel@gnu....
>
> Actually, glyphless-char-control should be a customizable
> variable with proper set: function.  But, I don't know how
> to write the correct 'defcustom' form.  Could someone DTRT?

I didn't do this; volunteers are welcome.

> (2) For Windows port:
>
> I wrote x_draw_glyphless_glyph_string_foreground (in
> w32term.c) by referring to x_draw_glyph_string_foreground in
> the same file.  But, it doesn't draw acronym nor hexa-code.
> I couldn't figure out what is wrong.  Please someone who
> knows Windows code fix it.

I fixed this.  The problem was that w32_draw_rectangle wiped out what
was drawn inside it; I switched the order, so the box is drawn before
the glyphs inside it.  Jason, could you please take a look and see if
I did everything right?

Assuming that on X the order doesn't matter (does it?), perhaps we
should switch the order there as well, for uniformity.

> (3) For mac port:
>
> As I have no idea how to write a code for mac, the 'case
> GLYPHLESS_GLYPH:' part in ns_draw_glyph_string (in nsterm.m)
> is not finished.  Please fill in the correct code by
> referring to x_draw_glyph_string_foreground in xterm.c.

Not done; I have no idea how to do this.

In addition, I did this:

. renamed glyphless-char-control to glyphless-char-display-control

. renamed hexa-code to hex-code.

. changed TTY display top enclose U+nnnn and "empty box" displays in
   "[]", to simulate a box and make the display easier to read.

. documented this feature in NEWS and in the manual.

There are a few issues with TTY display, see my other mail.