Re: [ft-devel] state of the diagnostics patch b68+6.5, last two error codes, and undocumented engine behaviors

[Werner LEMBERG]

> FreeType does not seem to check 16-bit overflows on ADD/SUB/MUL/DIV,

16bit overflows?  What are you talking about?  All those arithmetic
operations use 32bit integers, in 26.6 format.

You are right that FreeType doesn't check them, since it is not
necessary for normal operation.

> I am unlikely to spend time adding that, but if somebody else adds
> the check to FreeType, I'll hook it up...

Hmm, this is unlikely, since such tests are specific to a font
validator (which FreeType is not).

> E6040 is an interesting one - it is about using real (non-twilight)
> zones in pre-programs.  [...]
> 
> Werner: what does FreeType do exactly, in this case?

Nothing in normal mode, setting an error if pedantic hinting is on,
since it checks whether the requested point index is smaller than the
number of available points – and we don't have any outline points in
the pre-programs.


    Werner