Re: [ft-devel] discussion of truetype glyph loading code

[Werner LEMBERG]

Sorry for the late response.

> The original code translates the points so that the origin (pp1) has
> integral coordinates and rounds pp2 and pp4, before hinting.  I
> think the translation is not necessary.  When bytecode interpreter
> is enabled, we move points relative to reference point or to itself.
> Thus the translation has no effect.  When disabled, the translation
> doesn't help make other points having integral coordinates.
>
> And for rounding pp2 and pp4, doesn't it make the result of hinting
> inaccurate?  Plus, pp2 and pp4 are rounded when calculating metrics
> later.

Whether this improves the rendering process can only be decided in
direct comparison with the Windows hinting engine.  Whether it becomes
worse is hopefully visible immediately...

> ==================================================================
> @@ -1479,7 +1465,7 @@
>                int  n = c > d ? c : d;
>
>
> -              if ( a - b <= 33 && a - b >= -33 )
> +              if ( a - c <= 33 && a - c >= -33 )
>                  m *= 2;
>                if ( c - d <= 33 && c - d >= -33 )
>                  n *= 2;
> ==================================================================
>
> This snippet is in deciding the mac scale of component offsets.  It
> is commented out because the result is bad.  But in this page
> http://developer.apple.com/fonts/TTRefMan/RM06/Chap6glyf.html, the
> algorithm described is slightly different (typo?) from what we use
> here.

I have no idea whether this makes any difference.  George?


    Werner