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

[Werner LEMBERG]

>> 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.

Good!

> 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.

OK.

> 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.

A call to `t1disasm' from the `t1utils' package might give clues if
you compare the Type1 file hints with the ones created by the `ttx'
disassembler.

> 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.

The AFM specification can be found in Adobe Technical Note #5004.

  http://www.adobe.com/content/dam/Adobe/en/devnet/font/pdfs/5004.AFM_Spec.pdf

FontForge is able to output AFM files also while exporting Type 1
fonts; maybe this helps.

I suppose that the Type1->CFF engine transition in FreeType is not
affected by AFM handling (via `FT_Attach_File'), right?


    Werner