Re: [Devel] FIX? [was: Non-integer bbox for T1 font?]

[Tom Kacvinsky]

The FontBBox is is set up to take 16.16 fixed values.  However, the code (w/o my
patch) was taking in 16 bit shorts.  This is because T1_ToCoordArray typescasts
(resulting in a demotion -- ugh!) the results of t1_tofixed to a 16 bit short.
Changing the code to use T1_ToFixedArray bypasses this typecast and uses the
full 16.16 fixed numbers returned by t1_tofixed.  So that is the fix, I think.

As an aside:

I think that if T1_ToCoordArray is going to fill in arrays of 16 bit shorts, the
code where the assignment is made should take the results of t1_tofixed, shift
right 16 bits, and with 0xFFFF, cast the result to a 16 bit short and then make
the assignment...

But I need to investigate more and see exactly how T1_ToCoordArray is used.

On Tue, 6 Mar 2001, Werner LEMBERG wrote:

>
> > Attached is patch fro t1load.c that places 16.16 fixed numbers (16
> > bits of integer, 16 bits of fraction) into the font bbox array.  To
> > get the integer part in your code, just shift right 16 bits.  There
> > will be some rounding errors (rounding up/down when it should be
> > vice versa), but i imagine you can get around that...
> >
> > Let me know if that fixes your problem.  I would appreciate comments
> > from others as well.
>
> You say that non-integer bboxes are valid, so I think it would be a
> good idea to have that in FreeType also...  Feel free to fix that :-)
>