Re: [Devel] Getting accurate advances

[Werner LEMBERG]

> > Do you mean this (y components omitted)?
> > 
> >   FT_Set_Pixel_Sizes( FT_Face  face,
> >                       FT_UInt  pixel_width,  
> >                       FT_UInt  pixel_height )
> 
> However, I think your responses explain why I'm unwilling to change
> the calculation of x_scale.  I don't know why x_scale is set to
> different values in different contexts or what uses are made of it
> after it is set.

I've now rechecked the use of x_scale and I think that my last
comments were correct.  David, can you have a look too?

> So, I don't know why you think FT_Set_Pixel_Sizes() is correct,

Because `pixel_width' (which is set equal to the ppem value) as a
function argument of FT_Set_Pixel_Sizes() is always an integer,
contrary to FT_Set_Char_Size() which can produce a fractional value
for the pixel width (which is then rounded to an integer ppem value).

> or why ttdrivr doesn't need changing,

The TrueType module already contains two distinct sets of metrics; one
for hinting and one without hinting.  The former is rounded to integer
values if the TTF needs that, while the latter is always unrounded.

> or why you guess that the pfrdrivr code should be changed (though I
> can't actually see how it could be changed).

Because only the native TrueType hinter needs integer values, contrary
to FreeType's autohinter which is used for fonts in PFR format.


    Werner