Re: [Devel] Re: FIXED: Problems with oblique fonts

[David Turner]

Hi Tom,

> 
> I have a new fix ready for commiting, but I can't access the cvs server.
> Anyway, I now understand in more depth as to what is going on, and have a 
> fairly
> good idea why the patch works (I am still hung up on applying the inverse of 
> the
> font matrix to the translation vector).
> 
> Tom
> 
The CVS server is now up and running, please commit your patch. Note that
I probably need to adjust the hardware clock though.. :-(

Regarding the transformn here's a quick note:

  - a transform is made of a 2x2 matrix and a 2d translation.
    where the matrix is typically applied _before_ the translation

  - the auto-hinter normally works on un-transformed glyphs, then
    applies the transform on the result. Unfortunately, this tends
    to ruin the grid alignment when the translation vector is not
    in integer pixel positions

  - so, instead, un-transformed glyphs are loaded, then translated
    by a special vector before being hinter (this ensure grid-alignment).
    finally, the 2x2 matrix is applied.

      instead of computing:   G' = T*M*G

      we compute something like:   G' = M*T'*G

    where T' = inv(M)*T*M

Hope this clarifies,

- David