Re: [ft-devel] Contribution to freetype

[Nikolay Sivov]

On 3/18/2018 12:05 PM, Werner LEMBERG wrote:
> 
>> Higher level would make use of ranges/language mapping for fallback.
>> DirectWrite fallback is modeled very close if not identical to how
>> this data is defined in .compositefont xml format.  When using
>> DirectWrite layout API, application can rely on implicit fonts being
>> selected for different script ranges, and you can set specific
>> language per range to get more accurate results.  Newer versions
>> allow user-defined fallback data, and API-wise it's very close to
>> what those files provide.
> 
> If I understand you correctly, an application that uses DirectWrite
> doesn't need `.compositeFont' files at all, right?  What happens with
> applications that don't use DirectWrite?

No, I don't think they have any value for DirectWrite. If application is
not using DirectWrite the only option left is GDI paired with Uniscribe,
or .NET (WPF is also working through DirectWrite in modern versions).

>  AFAIK, Windows offers
> composite fonts in its font selection menu like normal fonts...

Where do you see this, and under what names are they listed? Standard
Win32 font selection dialog is GDI-based, Wordpad does not list anything
called "Global User Interface" or "Global Sans Serif", DirectWrite
system font enumeration does not include anything obscure like that
either. It's possible those files are for WPF/.NET stuff that I'm not
familiar with.

> 
>> You can certainly parse and discard information irrelevant to
>> freetype, but that will create ambiguity because same script ranges
>> could be mapped to different fonts, and only differ in language.
> 
> We are miscommunicating, I think.  I talk about taking a
> `.compositeFont' file and use it as a font.  You are talking about
> configurability of `.compositeFont' files, effectively overriding its
> contents.

I'm talking about data such files provide. Assuming the idea was for
freetype to read them directly, and interpret one way or another.

> 
> 
>     Werner
>