[Cairo] Text API proposal

[Carl Worth]

On Jul 30, Thorsten Behrens wrote:
 > No idea about that. How about an API that deals exactly with the
 > functionality needed by Cairo? Makes porter's life much more easy.

The problem is that Cairo doesn't need much. It just draws glyphs at
specified locations, and that's pretty easy.

However, applications that compute the glyph positions are going to
need a lot more information from the backend text engine. Rather than
implementing all of that API in Cairo, I'm currently just passing up
an FT_Face.

The more I think about it, the more I realize that wrapping a native
text engine to conform to a yet-to-be-proposed Cairo text API would be
substantially the same effort as wrapping it to conform to the FT_Face
APIs, (though it would add an extra layer within Cairo itself).

So, the question is, would most of the API in Freetype be used? Is it
basically what users want? Or is there a substantially smaller subset
that would simplify the backend wrapping effort enough to justify more
complexity in Cairo?

I need feedback from potential users of Cairo text functionality in
order to decide that.

 > Generally speaking, I have the impression that we're theorizing here. The
 > thing Cairo will benefit the most are actual ports to Windows and
 > OSX.

There is a Windows port in progress, so we'll be able to look at that
soon. The other datapoint that can be useful is from people that have
experience wrapping text engines from various platforms.

-Carl