Problem with rendering Combining Diacritics, using DejaVuSansMono in
MacVim/gvim


I use MacVim/gvim with either

1. DejaVuSansMono.ttf , currently 2.29, or
2. BrighamVuSansMono.ttf (my modification of DejaVuSansMono.ttf
2.22 that I augmented, using FontForge, with Deseret Alphabet glyphs)

With input sequences involving combining diacritics, and having
nothing to do with the added Deseret Alphabet glyphs, I somehow have
better results with BrighamVuSansMono.ttf (based on DejaVuSansMono.ttf
2.22) than with DejaVuSansMono.ttf 2.29.

For example, if, using DejaVuSansMono.ttf 2.29, I enter (in MacVim/
gvim) the sequence

0 0061 LATIN SMALL LETTER A
1 0328 COMBINING OGONEK
2 0301 COMBINING ACUTE ACCENT
3 0020 SPACE
4 0061 LATIN SMALL LETTER A
5 0301 COMBINING ACUTE ACCENT
6 0328 COMBINING OGONEK
7 0020 SPACE
8 000a

the gvim rendering is garbled. (I should see two instances of 'a'
with ogonek below and an acute accent above.)
The 'a's are not displayed, and there are some floating accents.
Here's a picture of the result in my gvim window:


--~--~---------~--~----~------------~-------~--~----~
You received this message from the "vim_multibyte" maillist.
For more information, visit http://www.vim.org/maillist.php
-~----------~----~----~----~------~----~------~--~---

I dumped the buffer to file, and the sequence of characters is as
shown above. So it's a rendering (or font) problem.
I downloaded the old DejaVuSansMono.ttf v. 2.22 and got the same
results.

***********************

If, however, I use my BrighamVuSansMono.ttf (based on
DejaVuSansMono.ttf 2.22), and enter the same sequence above,
the rendering is very different. In either case, I see an acceptably
rendered 'a' with a ogonek below and an acute accent above.
Voila:

The only change was this. In the first (garbled) example, I specified

set anti guifont=DejaVu\ Sans\ Mono.h14

in my .gvimrc file. In the second (successful) example, I specific
instead

set anti guifont=BrighamVu\ Sans\ Mono.h14

As far as I can remember, BrighamVuSansMono.ttf was created by adding
glyphs to DejaVuSansMono.ttf version 2.22. These glyphs are in the
supplementary area, so perhaps I increased the encoding (in FontForge)
of the resulting font to cover all of Unicode. But I'm sure I did
nothing directly to the combining diacritics.

I know that the rendering is being done by MacVim/gvim, but can anyone
tell me why it might work better with my modified v. 2.22 than with
2.29 or the unmodified 2.22?

(My MacVim is 7.2.148, snapshot 45)

Thanks,

Ken


******************************
Kenneth R. Beesley, D.Phil.
P.O. Box 540475
North Salt Lake, UT
84054 USA