Re: [ft-devel] Severe rendering bug

[Tobias Ringström]

On 2012-01-02 22:40, Werner LEMBERG wrote:
> BUT: Right now I've tried the Windows binary, and it works on my 
> GNU/Linux box :-) 

Note that there's even a debugger built-in where you can step through 
all instructions, and you can even step backwards. I didn't find the 
debugger immediately because the controls didn't fit inside the window. 
I managed to get to them by increasing the size of the glyph window 
before clicking on the Debug button.

> > Looking at the Freetype TrueType interpreter implementation, the
> > projection vector is in pixel space, meaning that the 300%
> > horizontal stretch that I use in my example has been applied.
> >
> > The problem is that in Ins_IP, the projections are calculated using
> > orus coordinate vectors, which are in em-space (NOT stretched).
> >
> > If I change from using orus to org, the instruction behaves as I
> > would expect it to from reading the TrueType specification, and
> > there are no artefacts.
> Can you prepare a patch, please?  I currently don't have the time to
> really delve into this issue, but maybe `orus' is correct, but should
> be scaled properly...

I'll continue to look at this tomorrow.

/Tobias