Re: [ft-devel] [GSoC] Extending the CF2 interpreter

[Ewald Hew]

>> The first two are between hinting on and off for Type 1.  Notice how
>> the base glyphs of accented characters shift about regardless.
>
> Interesting.  It seems to show that the problem is not in the hinting
> but at a more fundamental level.

Ugh. This was a really simple mistake, and I'd missed it completely. I
had set the origin point wrongly in `seac' for the base character.
Fixed.

>> The third is for CFF converted to Type 1.  Notice how the line
>> spacing changes in discrete steps above a certain font size.  For
>> 26~29pt, it shifts downwards one step, and for 30pt it seems to
>> shift a little bit more.
>
> Ditto.

The cause for this was harder to find. It turns out that, at least for
the Source Sans font, when converted to Type 1, the OS/2 table was
lost, which makes the line spacing wrong. I think that needs .afm
output, which this converter doesn't seem to support.

Trying with what font Hin-Tak provided didn't give any extra clues
unfortunately, and the hints in that one appear to be broken too -
they didn't show up in the interpreter debug trace.

I feel that the cause for the line spacing lies with the font
converter, and there's no other way to obtain the same vertical
advance without those tables.

Ewald