cut from my mail.
hi,
  I vote for adding embeddedbitmap option to official fontconfig.
  Several distros have shiped patched version of fontconfig which adds
an option like rh_prefer_bitmap or embeddedbitmap. Because we need a way
to explictly tell Xft/Cairo to load bitmaps embedded in fonts or not.
And for cairo, if i want to cairo transform a font to pretend as an
oblique one, and when i disable antialias for the font, then cairo will
always load embedded bitmaps if available, latter cairo(exactly to say
it's freetype) will be unable to transform the font glyphs because they
are bitmaps. If option embeddedbitmap is available, we can tell freetype
to load outlines rather than embedded bitmaps by set embeddedbitmap to
false and then can transform font glyphs as expected. Xft is smart
enough in this case, it add FC_LOAD_NO_BITMAP to load flags when loading
glyphs. But that is not easily to implement in cairo, because cairo
doesn't handle FC_MATRIX itself.