[Freetype] sub-pixel translations?

[Dan Maas]

Hi all - I'm using Freetype to render text titles in a video-editing system.
It has been working great so far. However:

Is there a way to specify a sub-pixel x/y offset when rasterizing a TrueType
character?

I need this capability for animating text whose size is changing over time.
I can get individual characters to resize very smoothly, using a scaling
transformation matrix. However, I must also maintain sub-pixel accuracy for
the intervals between characters (obtained from the "advance" values). I
need to be able to tell the rasterizer that the left edge of a character
lies not on a pixel boundary, but on some fraction of a pixel.

I have been able to achieve good results by asking for a monochrome bitmap
from FreeType, and then down-sampling to grayscale with my own code.
However, I'd like to know if there is some way to achieve sub-pixel offsets
with FreeType's own anti-aliasing rasterizer. (I have tried specifying an
x/y offset to FT_Glyph_Transform and FT_Glyph_To_Bitmap, but it seems to
have no effect on the rendered pixels).

Regards,
Dan