W3C home > Mailing lists > Public > www-xsl-fo@w3.org > June 2011

Re: fonts

From: Liam R E Quin <liam@w3.org>
Date: Sun, 12 Jun 2011 13:19:27 -0400
To: Dave Pawson <dave.pawson@gmail.com>
Cc: www-xsl-fo@w3.org
Message-ID: <1307899167.2776.45.camel@desktop.barefootcomputing.com>
On Sun, 2011-06-12 at 12:04 -0400, Dave Pawson wrote:
> On 12 June 2011 16:38, Liam R E Quin <liam@w3.org> wrote:
> > On Sun, 2011-06-12 at 12:24 +0100, Dave Pawson wrote:
> >> http://new.myfonts.com/fonts/dstype/esta/ligatures/ shows
> >> a variant of a font, this file containing ligatures.
> >>
> >> How might this be used in xsl-fo?

> . You'd probably have to tell the
> > fo renderer that it was a different font family.
> Which seems wrong somehow Liam? It is the same font-family.
> Just an odd variant. Perhaps font-forge and add them there, somehow.

No, you really don't want to do that :-)
The reason is that this font tells lies.  It says that it supports the
character "a" but then draws it as an fj ligature.

To use it as part of the same font family, first re-encode the glyphs to
the private use area in Unicode. Then you won't have an "a" that's in
both the Roman (Normal) and the Roman (normal, crazyligatures) and you
can then have CSS glyph selection working.

> > The newer "approved" way for this to wor is via a single OpenType font
> > with an opentype feature such as "CrazyLigatures" enabled, but FO 1 has
> > no way to turn on such a feature except via implementation extensions.
> I must admit I can't think of a reasonable syntax to use these,
> or any other 'same font' inclusions.

If it was all in one OpenType font, e.g. like Mrs Eaves Pro, you'd
enable contextual ligatures for the font, e.g.
<fo:inline font-features="+contextual-ligatures">...
(proposed for FO 2.0) or for HTML with CSS it'd be <span
style="font-variant-contextual-ligatures: on">... I think, I forget the
status of the draft right now. The result would be that when you had an
f followed by a j, you'd get the fj ligature.  This would require the
formatter to understand opentype shaping of course, as the ligature
would quite likely have a different set width than the glyphs for the
individual characters.


Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/
Received on Sunday, 12 June 2011 17:19:27 UTC

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