Re: [ft-devel] [patch] TrueType GX/AAT validator

[George Williams]

On Mon, 2005-08-22 at 23:17, address@hidden wrote:
> As written in README,
> some of TrueType GX tables (mort, feat, prop) are widely used,
> others (lcar, opbd) are very rare, and there are a few tables
> (kern format1) we cannot find samples.
I have one example font containing a kern format 1 table (which David
Opstad, formerly at Apple, made for me). He did not say I should not
distribute it so I shall pass it on to you (off list).

The table specifies kerning for the three glyphs "F", "." and
"quotedouble".
   Given the string 'F."' then 
        the "F." pair is kerned by -382
        the '."' pair is kerned by 0
   Otherwise given '."'
        the pair is kerned by -526
   Otherwise given "F."
        the pair is kerned by -382

(the final bit of a kerning offset in the ValueTable marks the end of
the value list, so the kerning offset has a resolution of 2 FUnits
rather than 1, thus the -382 above actually appears as -381)
As with the ligature state machine, the offsets are applied as the
glyphs are popped off the stack (which appears backwards). So in the F."
case, first the " glyph is popped (with an offset of 0) and then the .
glyph is popped (with an offset of -381).