Re: [ft-devel] Improved Arabic auto-hinting

[Khaled Hosny]

On Fri, Aug 07, 2015 at 05:24:17PM +0200, Werner LEMBERG wrote:
> 
> >> I've verified that the vertical position for the joining glyphs are
> >> the same in his font...
> >> 
> >>> I can't reproduce any improvements so far.
> >>> This effect:
> >>>
> >>>   https://www.flickr.com/photos/behdad/34769511/
> >>>
> >>> still happens in my limited testing.
> >> 
> >> ... and apparently this doesn't work as universally as I've hoped.
> >> Please send me the font privately and tell me how to reproduce this
> >> image.
> > 
> > With this font:
> > 
> > https://github.com/googlei18n/noto-fonts/blob/master/unhinted/NotoNaskhArabic-Regular.ttf
> > 
> > and this command-line:
> > 
> > $ hb-view ./NotoNaskhArabic-Regular.ttf نستعلیق \
> >           --font-size 400 --background 000 --foreground ffffff \
> >           | display
> 
> Thanks.  IMHO, this is not a bug in the autohinter; it's a font bug:
> The overlapping of glyphs isn't constructed correctly, which makes
> repeated drawing of the overlapping parts problematic, as described in
> your blog entry.
> 
> For comparison, here an image using a font by Titus with the same
> hb-view command.  Another image shows how the joining parts are
> designed to avoid (or to reduce the effects of) exactly this problem.

Per (old?) Microsoft recommendation [1], both approaches are incorrect.

Regards,
Khaled

1. https://www.microsoft.com/typography/cursivescriptguidelines.mspx