Re: [ft] Freetype vs. FontLab values for Linegap

[George Williams]

On Sun, 2006-06-04 at 03:19, Юлиана Зигангирова wrote:
> As far as I understand, Type 1 fonts theoretically do not
> have any OS/2 table; 
The Type1 spec does not provide any way of specifying line spacing
information. There is no concept of line gap.
> but if I open a type 1 font in FontLab
> I still see the "sTypoAscender", "sTypoDescender" and "sTypoLineGap"
> values under FontInfo / Metrics and Dimensions / True-Type-specific 
> metrics / os/2.
> For examples, for URW-Fonts which comes with Ghostscript I see 
> values like 
> TypoAscender     624
> TypoDescender    -205 
> LineGap          62   
> or similar numbers.
> Ascender and Descender corresponds to the values which I get from
> .afm file, but where on earth does FontLab take the value for LineGap from  -
> like 59, 62, 67 etc.?
It is guessing. Perhaps one tenth of the ascent?

> How else could the value for line gap for Type 1 font be calculated?
> I hope very much on your help,
You must guess too.