Re: [ft-devel] Curb the scaling

[Alexei Podtelezhnikov]

>> As per our discussion I propose the following patch to limit the
>> outline scaling so that ppem values do not exceed 65535.  As far as
>> I can see, no such limits are currently in place, ppem values are
>> simply truncated while the scaling factors are not limited.
>
> Looks good.

I am hesitating with the ppem-limiting patch. It turns out that the
fuzzer requests just 20 ppem, yet it overflows. So the glyphs spread
far beyond the EM and FT_Face->bbox too. Checking for reasonable size
by calling FT_Outline_Get_CBox may seem excessive, but we do call it
twice anyway when we enter FT_Render_Glyph. We do not need much, a lot
of overflows will be avoided if we only limit actual CBox to, say, 4
times EM.