[poppler] Why TrueType vertical glyphs for Adobe-CNS1, -GB1, -Korea1 use "kana" script tag?

[suzuki toshiya]

Dear Otani-san,

During the testing for GlobalParamsWin.cc improvement with MinGW,
I found that the vertical glyphs for Adobe-CNS1, -GB1, -Korea1
with external (non-embedded) TrueType fonts do not work well with
Chinese/Korean TrueType fonts bundled to Microsoft Windows; SimSun,
MingLiU and Batang.

The reason is very clear; FoFiTrueType::setupGSUB() prepares the
vert or vrt2 GSUB features for default language system and specified
script. In current poppler, "kana" script tag is used in all cases
of Adobe-CNS1, -GB1, -Korea1. But SimSun, MingLiU, and Batang fonts
have no layout features for "kana" script tag (furthermore, these
fonts do not know anything about "kana" script).
The reason why "kana" is used always is because of your patch applied
on 2007:

commit 14a8361039d708661b8699b2e7c4496135021a85
Author: Albert Astals Cid <aacid at kde.org>
Date:   Fri Jul 13 22:18:05 2007 +0000

            * fofi/FoFiTrueType.cc
            * fofi/FoFiTrueType.h
            * poppler/CairoFontEngine.cc
            * poppler/CharCodeToUnicode.cc
            * poppler/CharCodeToUnicode.h
            * poppler/GfxFont.cc
            * poppler/GfxFont.h
            * poppler/SplashOutputDev.cc: Patch by
            Koji Otani <sho at bbr.jp> to fix several problems with Japanese fonts.
            Fixes bug 11413

Could you explain the background why you used "kana" for all cases?
Or, you can list the fonts that you used for testing your patch in 2007.

I think using "hani" for Chinese, "hang" for Korean is safer, but
if there are many Chinese/Korean fonts using "kana" script tag (and
not using "hani" or "hang" tags for vertical shaping), more enhancement
for vertical glyphs is needed. I will work for it.

Regards,
mpsuzuki