Re: [ft-devel] WOFF2 support update and questions

[Werner LEMBERG]

> I have implemented functionality to read the WOFF2 header, table
> directory and collection directory (if the font is a TTC), including
> most of the checks (given in the specification) in `sfwoff2.c' on
> the `GSoC-2019-nikhil' branch.

Nice!

> It would be *great* if you could review (and also test with a few
> font files :-) ) the code and provide feedback!

Will do that today or tomorrow, hopefully.

> * The code in function `woff2_open_font' is already (almost) 300
>   lines.  I believe it would be better to split it up into smaller
>   functions (for instance, one for reading the table directory).
>   Any thoughts?

This is up to you.  If you can split the stuff into logical chunks
that are easier to understand, please do so.  However, this is not a
necessity.

> * For TTC fonts, the `Collection Directory' specifies the index of
>   tables that are part of each font in the collection. The
>   `face_index' parameter in `FT_New_Face' specifies which face to
>   load, so does that mean I can use that to directly extract and
>   load only those tables that belong to the font on that index?

I think so, yes.

>   Do I have to decompress each table and load the whole collection
>   as an SFNT? I'm not sure...

Me neither, sorry.  I have never worked with WOFF.  Please report any
unclear issues to the WOFF2 standard team so that they can improve the
documentation.

> * I have written a few macros in `sfwoff2.c' to help with basic
>   calculation and to allow implicit variables.  Should I `#undef'
>   these macros towards the end?

Well, I guess `sfwoff2.c' gets included with other .c files in
`sfnt.c', so it probably makes sense to undefine them, yes.

> * Is the code, in general, acceptable? Am I using the FT_* typedefs
> and macros correctly?

After a quick inspection, everything looks good, thanks!  Don't worry
too much, you will get a better feeling for that stuff soon :-)


    Werner