[HarfBuzz] How to increase harfbuzz numerical precision

[Kelvin Ma]

I thought ppem was dependent on UPEM and font scale, is it not?

On Tue, Jun 28, 2016 at 7:12 PM, Khaled Hosny <khaledhosny at eglug.org> wrote:

> Device tables depend on ppem, so despite the scale being set
> on the font, you should still set the exact ppem.
>
> On Tue, Jun 28, 2016 at 06:43:58PM -0400, Kelvin Ma wrote:
> > so that’s the only way huh…
> > doesn’t that kind of defeat the purpose of hb.font_create() and having
> many
> > scaled versions of the same font? You would only ever need one font of
> each
> > face, scaled to the UPEM, if the fontsize was to be applied externally
> > after shaping already occurred.
> >
> > On Tue, Jun 28, 2016 at 5:51 PM, Behdad Esfahbod <behdad at behdad.org>
> wrote:
> >
> > > HarfBuzz coordinates work in a int32 space.  You are free to set
> whatever
> > > scales you want on the font.  For example, use 6 or 8 or 10 or 16 bits
> of
> > > sub-pixel precision by multiplying your scale by a number.
> > >
> > > On Tue, Jun 28, 2016 at 4:57 PM, Kelvin Ma <kelvinsthirteen at gmail.com>
> > > wrote:
> > >
> > >> It appears that harfbuzz rounds all decimals to integers when giving
> > >> glyph advances and offsets. This is causing some ugly misalignment
> problems
> > >> in arabic shaping, as well as latin cursive fonts. (see pictures)
> > >>
> > >> [image: Inline image 1]
> > >>
> > >> [image: Inline image 2]
> > >>
> > >> [image: Inline image 3]
> > >> How do I get harfbuzz to preserve the floats?
> > >>
> > >> _______________________________________________
> > >> HarfBuzz mailing list
> > >> HarfBuzz at lists.freedesktop.org
> > >> https://lists.freedesktop.org/mailman/listinfo/harfbuzz
> > >>
> > >>
> > >
> > >
> > > --
> > > behdad
> > > http://behdad.org/
> > >
>
>
>
>
>
> > _______________________________________________
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> > HarfBuzz at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/harfbuzz
>
>
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