Intolerable difference in glyph width: font=vnbx12

[Werner LEMBERG]

>> In other words, the metrics change for the advance width of 'u
>> horn' to be identical to 'u' was done in the vnbx12 sources and/or
>> the TFM files but apparently forgotten in `vnbx12.pfb` (see
>> attached images).
> 
> yes this seems the root of the problem.  The pfb files were
> converted using a number of tools and I honestly cannot recall
> exactly how it was done.  Fortunately there is a tugboat article
> https://www.tug.org/TUGboat/tb24-1/thanh.pdf about it.

Interesting, thanks!

> From the article it looks likely that all [uoUo]horn letters (plus
> their accented variants) from vnr fonts will have this problem, and
> it will take quite a lot of time/work to fix.  I wish I had the time
> to fix this problem, but I have other things that have higher
> priority on my todo list.

As mentioned already in a private mail, the following might be a route
that shouldn't take too long:

* Find out whether there are more glyph width differences in the vnr
  family (dvipdfmx shows that).

* Fix the widths by using `t1disasm` + manual editing + `t1asm`.  A
  skilled user might even write a script to automate the manual
  editing part, i.e., taking the width of the 'u' glyph from the
  disassembled output and replacing the widths of all other
  occurrences of 'u + accent(s)'.

* Use FontForge to mechanically convert the Type1 fonts to CFF.  An
  advantage of FontForge is that this process can be scripted, too.

* Do a round-trip conversion using `ttx` (from the `fonttools`
  package) for better normalization and even more compact results.

There are alternatives, for example using Adobe's FDK or other font
editors – especially if you want to create OpenType fonts using the
more compact CFF2 as the font format (which FontForge doesn't support
yet AFAIK).  However, I have never used these tools, so I can't give
any advice how to proceed.

> If someone would like to work on this, I will do my best to make all
> info and tools available.

Yes, so: volunteers, please step forward!


    Werner