bug#15273: 24.3.50; Combining character sequences are displayed weirdly

["Jan Djärv" <jan.h.d@swipnet.se>]

Hi.

5 sep 2013 kl. 19:12 skrev Eli Zaretskii <eliz@gnu.org>:

>> From: Jan Djärv <jan.h.d@swipnet.se>
>> Date: Thu, 5 Sep 2013 18:48:43 +0200
>> Cc: 15273@debbugs.gnu.org
>> 
>> 
>>> emacs -Q
>>> !                      ;; input an exclamation mark (#x21)
>>> C-x 8 RET 2 0 E 4 RET  ;; COMBINING ENCLOSING UPWARD POINTING TRIANGLE
>>> RET                    ;; Newline
>>> C-x 8 2 6 A 0 RET      ;; WARNING SIGN
>>> 
>> 
>> I assume you mean C-x 8 RET 2 6 A 0 RET.
>> 
>>> I tried many fonts, but all results look weird (the first line is
>>> incomplete and too large).
>>> 
>>> (I haven't tried it on other platforms yet, so I'm not sure whether it's
>>> NS-port specific.)
>> 
>> On Fedora 19, the first does not combine, I just get ! followed by an upward pointing triangle.
>> The second is very small, see screen shot.
>> 
>> The NS one looks better, but when moving the cursor over the first row, it redraws funny.  And metrics are off, the distance between the first triangle and the aaa to the right is actually only one space.  The aaa to the left is also followed by a space, but there the distance is too short, and the source of the redraw error.
>> 
>> W32 anyone?
> 
> On w32, the Uniscribe font driver does not compose these two
> characters.  So I guess this composition is done by the driver used by
> NS, and perhaps the composition information Emacs gets is incorrect.
> 
> Once again, please show the full output of "C-u C-x =" on the composed
> character, the pixel-level data of the composition shown there will
> probably tell us what is wrong.


I don't know if it says anything.  In Emacs the square is actually a triangle, displayed too far to the left, i.e. covering half the letter to the left.  The mailer I use can't display it.

             position: 4 of 4 (75%), column: 3
            character: ⃤ (displayed as ⃤) (codepoint 8420, #o20344, #x20e4)
    preferred charset: unicode (Unicode (ISO10646))
code point in charset: 0x20E4
               script: symbol
               syntax: w 	which means: word
             to input: type "C-x 8 RET HEX-CODEPOINT" or "C-x 8 RET NAME"
          buffer code: #xE2 #x83 #xA4
            file code: #xE2 #x83 #xA4 (encoded by coding system utf-8-unix)
              display: by this font (glyph code)
    nil:-apple-STIXGeneral-medium-normal-normal-*-12-*-*-*-p-0-iso10646-1 (#x359)

Character code properties: customize what to show
  name: COMBINING ENCLOSING UPWARD POINTING TRIANGLE
  general-category: Me (Mark, Enclosing)
  decomposition: (8420) ('⃤')

There are text properties here:
  fontified            t

	Jan D.