True Type Instructions

Andrew Tween amtween at
Tue May 16 22:02:46 UTC 2006

"Boris Gaertner" <Boris.Gaertner at> wrote in message
news:000801c67921$9e28e640$fce661c2 at Standard...
> "Noname Myname" <gcdart_squeak at> wrote:
> > One more Question , shud the true type instructions in the
> > Open Type files definitely be executed ?
> > Or are they supported currently in SQUEAK ?
> > Well if they are ... then wud'nt
> > the display of characters be terribly slow ?
> Squeak does not execute glyph instructions (hints).
> Most TTF fonts can be used without hinting. The well-known
> exception is MingLiU, a font for chinese. The glyphs of that
> font are defined as glyph instructions that assemble collections
> of strokes into hanzi ideographs. To render such these glyphs,
> you have to execute the glyph instructions. But I think MingLiU
> is a rare exception in the universe of True Type Fonts.
> > Becuz you have to create an intrepreter inside another
> > interpreter("SQUEAK")
> > to understand the instructions and execute them.
> I think it would be doable to write an interpreter for glyph
> instructions, but it would be difficult - if not impossible - to
> incorporate it into an open software project like Squeak.
> You have to bear in mind that some aspects of glyph hinting
> are protected by patents (hold by Apple). It is therefore not
> possible to freely distribute a complete implementation of
> glyph hinting. There is a well-known work-around: FreeType.
> The late Henrik Gedenryd has done some impressive work
> in this direction, but at this moment I feel unable to explain you
> details about that admireable work.

Henrik implemented an interface to FreeType, mainly through FFI. He also
implemented sub-pixel anti-aliasing.
An alternative interface to FreeType was developed by Arjen van Elteren, and
subsequently modified by Ned Konz, (see Freetype/2 Font Demo package on
SqueakMap). This interface is built as a plugin, and has been utilised in the
Sophie project.
I am currently working on gathering some of this FreeType stuff into a form
suitable for use with, and possible inclusion in, 3.9 (or later).

FreeType is distributed, in source form, with a complete implementation of the
patent protected glyph hinting. So, following that lead, it would probably be ok
to distribute a Squeak Smalltalk implementation of the same, provided it is only
distributed as source code. The onus would be on the user of the code to ensure
that they were acting legally (e.g. by using the code in a country where the
patent does not apply, or by purchasing a license from Apple). I'm not
volunteering to write such a thing, but someone else might get a kick out of
doing it .


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