[ft-devel] colored glyph layer support in ftview

[Werner LEMBERG]

Folks,


ftview now supports colored glyph layers (see attached image)!  This
is mainly a proof of concept; there are still some bits missing here
and there.

While working on this I found flaws in the original code contribution
for handling COLR tables: The per-glyph data was stored and allocated
in `FT_GlyphSlot', making it quite inconvenient if you are going to
handle colored glyph layers manually.  For this reason I implemented a
completely different API which uses an iterator object that works on
the `FT_Face' level and avoids allocation altogether.

There is also a new API to blend two bitmaps.

Please comment!  Maybe the APIs (and its documentation) can be further
improved.

Alexei, you suggested to handle sub-pixel shifts in blending bitmaps.
This is not implemented yet.  Admittedly, I have no idea how to do
that gracefully.  Can you work on that?  Similarly, there is still no
support for bitmaps with a different flow direction; I would be glad
if you could add this also.


    Werner