[Devel] Re: Font transforms and autohinter...

[Tom Kacvinsky]

Hi (again),

On Thu, 21 Dec 2000, Tom Kacvinsky wrote:

>
> But looking at the PLRM and/or Type 1 spec., it is not clear that these 
> matrices
> need to be invertible.  Hmmm...
>

I stand corrected.  There is some information in the PLRM about this. See
section 4.3.3 in the PLRM 3rd edition.  It is after the last note, at the
end of the section.  The PLRM does not explicitly state that non-invertible
matrices are a no-no, it just states that the interpreter often internally
inverts matrices, and this can lead an --undefinedresult-- error.  So, the
PLRM implicitly states that non-invertible matrices are a no-no!!

It will be interesting to see what the PDF Reference Manual has to say about
this.

Anyway, I think I'll try to cook up a test in FT2 to make sure we don't call
FT_Matrix_Invert for a non-invertible matrix.  If the matrix in question is
non-invertible, make the glyph loader fail, or some such.

Tom