[Fontinst] letterspacing

[Philipp Lehman]

Am Montag, 18. April 2005 14:57 schrieb Lars Hellström:

> Mind you, there could be an error of policy here. letterspacing has
> always been documented as an _encoding_ variable, which is why it
> isn't used in the metric files, but that could be the wrong
> approach. It is certainly a rather metric quantity, and for glyphs
> like SSspaced it needs to be fixed already at the metric stage.
> That issue thus needs to be reexamined.

On I related note: I wonder if "SS" and "germandbls" should be 
affected by the "ligaturing" variable. Granted, they are not 
ligatures on the Tex level, but they are usually one glyph in the 
font.

The problem is that, if you uppercase "ß" and it gets resolved to 
"SS", "SS" is treated as a sequence of two independent letters in 
German. When applying letterspacing, it should be spaced out just 
like FF or FFI. Unless I'm missing something, you have to redefine 
the glyph explicitly right now:

\resetglyph{SS}
  \glyph{S}{1000}
  \movert{\int{letterspacing}}
  \glyph{S}{1000}
\endsetglyph

Or, with t1c.etx:

\resetglyph{SSspaced}
  \glyph{S}{1000}
  \movert{\int{letterspacing}}
  \glyph{S}{1000}
\endsetglyph

I believe it should be sufficient to set letterspacing=value and 
ligaturing=0. That's also in-line with monowidth fonts in which SS 
should be two letters wide.

I suppose this applies to IJ/ij as well, but I'm not sure about Œ/œ 
and Æ/æ. Certainly not as far as the glyph width in monowidth fonts 
is concerned, but are these ligatures broken up if letterspacing is 
applied? This could get tricky.

-- 
Philipp Lehman <lehman at gmx.net>