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From Manuel Mall ...@arcus.com.au>
Subject Re: Implementing OpenType font support, how hard?
Date Thu, 03 Aug 2006 13:19:15 GMT
On Thursday 03 August 2006 21:04, Simon Pepping wrote:
> On Wed, Aug 02, 2006 at 06:44:28PM +0200, Vincent Hennebert wrote:
<snip/>
> > >>
> > >> 3b) Modify the chars-to-metrics mapping to handle things like
> > >> automatic ligatures, where several chars map to a single glyph
> > >
> > >Here I think you can profit from my work on kerning to handle
> > > special cases.
> >
> > The only problem I see with ligatures is when a word may be
> > hyphenated between two characters for which there is a ligature: if
> > it ends up being hyphenated the separate glyphs should be used,
> > otherwise the ligature glyph should be used. I don't think this can
> > be easily represented in the current Knuth glue/box/penalty model
> > which is used to break lines into paragraphs.
>
> I think it can be done, and is similar to things that have been done
> in FOP.
>
> The main problem with all these smart font features is that you
> cannot implement them in rendering without also implementing them in
> the linebreaking code. The linebreaking code must be able to
> correctly predict the metrics of the characters that are going to be
> rendered.
>

That comment does not only apply to line breaking, justification, 
hyphenation, word spacing, are all affected. That is layout needs to 
know the exact metrics the renderer is going to use.

<snip/>
>
> Regards, Simon

Manuel

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