[Dev-luatex] Luatex 0.44.0 announcement

Khaled Hosny khaledhosny at eglug.org
Sun Nov 1 14:00:25 CET 2009

On Fri, Oct 30, 2009 at 09:02:30AM +0100, Taco Hoekwater wrote:
> Hi,
> Khaled Hosny wrote:
> > On Tue, Oct 27, 2009 at 12:06:09PM +0100, Taco Hoekwater wrote:
> >> * Math delimiters and large operators in new MATH fonts no
> >>   longer apply the italic correction (this fixes placements
> >>   of super- and subscripts on such items for those fonts).
> > 
> > This doesn't sound the correct way to me. The described algorithm in
> > MATH specification is to set subscripts immediately after the base
> > (without italic correction) and shift superscripts horizontally by the
> > amount of italic correction, then apply math kerning if present, this
> > way fonts with no math kerning will still give acceptable output and
> > need for math kerning will be minimized.
> Well, I am clearly doing something wrong, because both the old and
> new outputs look crappy. I'll rethink this.

Office 2007 seems to handle sub/superscripts of big operators
differently; superscript is placed immediately after base glyph while a
negative kern equal to italic correction is inserted between base and
subscript i.e. the reverse of what is described in the spec, and math
kerning is ignored completely.
So I think the current positioning of superscripts is correct, only
subscripts need to be fixed, though I'm not really sure about any of
those conclusions :)


 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer
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