Re: [ft] Tahoma rendering differently on Freetype & Windows

[Todd Bateman]

Hi Werner,

> > If this isn't a bug, is there a way for me to 'tune' the hinting to
> > match the results produced by Windows XP's native rendering?
> 
> The direct answer is: Sorry, no, there is no possibility to do that.
> The indirect answer is: You might privately modify Tahoma's bytecode
> so that point 25 is moved by only 0.15px to the right, say, thus
> avoiding a drop-out mode case.  However, this is nothing for the
> faint-hearted :-)

Not for the faint-hearted indeed!  Thank you for breaking this one
down so masterfully.  Simply observing the process by which this
behavior can be debugged is elucidating in its own right.  It would
seem I've fallen down quite the rabbit hole with this whole business
of putting text to screen.

Mounting an attempt at the bytecode certainly is tempting, though it
may be best to leave well enough alone unless I am planning a
professional career in this sort of thing.

Rather than fiddle with the TTF instructions, I thought I might first
try adding a cleaned up version of Tahoma at 16ppem into the original
TTF as an embedded bitmap.  Not the most elegant of patch jobs, but at
least one that is within reach of a mere mortal such as myself.

As it turns out, this gives mixed results.  Some applications will
prefer the embedded bitmap strikes over their proportional
counterparts while others seem to willfully ignore their existence.
In terms as which glyphs get rendered onscreen, there is no getting
around the fact that the application has the final say in the matter
with flags like FT_LOAD_NO_BITMAP remaining at its disposal.

So, my solution is about as robust as it is elegant.  It seems all
that remains is the bytecode but that hill looks pretty steep.

While the TTF format supports embedded bitmaps and I've managed to
produce such a font, I can't say I've yet come across any other fonts
that make use of this feature.  Can you cite any examples of fonts
that embed bitmap strikes?  Are such fonts even known to exist?  If
so, are they generally provided in place of, rather than in addition
to the hints?

Much obliged,

.lewis