[Fontconfig] Improving Latin font selection for CJK locales

[Qianqian Fang]

Behdad Esfahbod wrote:
> Hi Pat,
>
> Note that the request here is to allow such a behavior.  Qianqian has
> been looking for a way to force Pango to use the bitmap Latin glyphs in
> the Chinese font for Latin.  That's what Pango currently can't be
> instructed to do without changing the default Latin font for en_US
> locales too.
>   
while, not exactly. I think my purpose is almost the identical as Pat:

1) avoid using the Latin/Common glyphs from Chinese fonts, instead,
   using system preferred Latin fonts (Bitstream for exp.)

2) particularly, in mono environment, if the default font is Latin mono
   font (say Courier), do not use contextual propagation for the Common 
(digits etc)
   char. near Chinese text, because it will use Chinese fonts to render
   and mess up with the alignment with the Latin mono font.
   Even for sans/serif environments, to keep digits (and punctuations)
   as close as Latin is preferred.

Same as the Pat, we achieved the first purpose using Fontconfig,
that's the whole point of the wqy-bitmap-fonts fontconfig file review, see

http://www.redhat.com/archives/fedora-fonts-list/2007-December/msg00002.html

the second point currently is not possible, because Pango labels the Common
scripts (digits) near Chinese text as Chinese, and in fontconfig, we never
know if it is a common-script or Chinese Hanzi. This caused porblems 
like this:

https://www.redhat.com/archives/fedora-fonts-list/2007-December/pngsBGtUJxMgD.png

Seems to me that the proposed methods will still assign lang=zh for Common
scripts between Chinese Hanzi if locale=zh. So, it may still not likely
that we can force to use smooth Latin fonts for Common via fontconfig,
is my understanding correct?


>   
>> --Pat
>>