[ft] rounding char widths

[Anthony Feick]

We updated from 2.0.9 to 2.1.9 some time ago, and we just noticed that
we're not getting correct character widths for fractional font sizes
(at smaller sizes).  We had "fixed" this in 2.0.x by removing the
rounding done in FT_Set_Char_Size (src/base/ftobjs.c line 1658, now
line 2008).

It took me a while to realize that the rounding was now being done in
Set_Char_Sizes (src/truetype/ttdriver.c at line 222).  My question is
about a comment in that function:

     /* we need to use rounding in the following computations. Otherwise,
      * the resulting hinted outlines will be very slightly distorted
      */

How much distortion are we talking about here?  We _need_ to be able
to use small fractional font sizes, but I don't want to have distorted
text either.  Is there any other possible workaround?