[Fontconfig] Support emoji fonts

[suzuki toshiya]

Dear Tagoh-san,

One of the recognizable subset would be the set to
interchange original "emoji" used by legacy Japanese
cellarphone. However, I don't think recent emoji
pushers do not care about this subset.

To consider other new emojis, should we ask for the
comments from Unicode (or ISO/IEC JTC1/SC2/WG2) experts,
to define the subset to judge whether the font is
sufficient to use to display emojis.

Also I'm interested in that fontconfig is expected
to pick the font supporting color glyphs, and/or,
supporting VS to display existing symbols with emoji-
style.

Regards,
mpsuzuki

Akira TAGOH wrote::
> Well, you may misunderstood my question. let me rephrase. the question 
> is, is a font required to contain all of them to say "our fonts support 
> emoji" or to indicate that in fontconfig? and how many emoji fonts has 
> supported all of them at this moment? in other words, if a font is more 
> or less missing them, it won't be recognized as emoji-aware.
> I don't see any mention about it there at least. .orth files in 
> fontconfig doesn't contain all of Unicode code points which is used in 
> those languages because some of them isn't often used and may not be 
> implemented for priority etc.
> 
> On Wed, Sep 7, 2016 at 8:30 PM, Guo Yunhe <guoyunhebrave at gmail.com 
> <mailto:guoyunhebrave at gmail.com>> wrote:
> 
>     Here is the official define of emoji characters. (Opening this page
>     may hang your browser for a while!!!)
>     http://unicode.org/emoji/charts/full-emoji-list.html
>     <http://unicode.org/emoji/charts/full-emoji-list.html>
> 
>     Hope it would be helpful.
> 
>     在 2016年09月07日 14:21, Akira TAGOH 写道:
>>     The problem on that idea is how to figure out what the minimal
>>     coverage in emoji block. at this point, the minimal glyph coverage
>>     for langs are defined in fc-lang/*.orth and cache files contains
>>     lang property only which fonts satisfies the coverage for. if
>>     there are any specs defining a must or an optional to have, that
>>     may be helpful otherwise we may need to think about another idea
>>     for that.
>>
>>     maybe good to have a property in a cache to indicate if a font has
>>     an emoji or not, and we could leave the way to use it to
>>     applications perhaps.
>>
>>     On Wed, Sep 7, 2016 at 4:28 PM, Guo Yunhe <guoyunhebrave at gmail.com
>>     <mailto:guoyunhebrave at gmail.com>> wrote:
>>
>>         Hi, I recently studied some emoji fonts. These emoji fonts
>>         have fontconfig difficulties when packaging. They try to set
>>         the font as default emoji font but do not affect others.
>>         Usually the font has a separated configure file.
>>
>>         <match>
>>           <test name="family">
>>             <string>sans-serif</string>
>>           </test>
>>           <edit binding="strong" name="family">
>>             <string>Nimbus Sans L</string>
>>             <string>EmojiOne Color</string>
>>           </edit>
>>         </match>
>>
>>         However, this will affect sans-serif font settings of other
>>         font packages or users' setting, because the package do not
>>         know which sans-serif font users want to use.
>>
>>         I suggest maybe we can map the Unicode emoji block as test
>>         condition. Just like when we set a Japanese font, it won't
>>         affect English and Arabic fonts.
>>
>>         <match>
>>           <test name="family">
>>             <string>sans-serif</string>
>>           </test>
>>           <test name="lang">
>>             <string>emoji</string>
>>           </test>
>>           <edit binding="strong" name="family">
>>             <string>EmojiOne Color</string>
>>           </edit>
>>         </match>
>>
>>
>>
>>         -- 
>>         Guo Yunhe
>>         _______________________________________________
>>         Fontconfig mailing list
>>         Fontconfig at lists.freedesktop.org
>>         <mailto:Fontconfig at lists.freedesktop.org>
>>         https://lists.freedesktop.org/mailman/listinfo/fontconfig
>>         <https://lists.freedesktop.org/mailman/listinfo/fontconfig>
>>
>>
>>
>>
>>     -- 
>>     Akira TAGOH
> 
>     -- 
>     Guo Yunhe
> 
> 
> 
> 
> -- 
> Akira TAGOH
>