[luatex] [tex-live] Ignored italic correction with lua(la)tex format

[Philipp Stephani]

2011/10/8 Taco Hoekwater <taco at elvenkind.com>:
> On 10/08/2011 09:18 AM, Philipp Stephani wrote:
>>
>>> Cambria has minimal italic correction so the
>>> difference is not so visible and its sub/superscripts are handled with
>>> math kerning so the difference is even more invisible. XITS renders fine
>>> in Word.
>>
>> For Cambria, the test looks better without italic correction. The
>> OpenType math document allows math italic correction to be applied
>> after a run of italic characters, but does not specify how to tell
>> italic and upright characters apart.
>
> I believe the fix here should be for luatex not to
> apply italic corrections in math mode at all, so:
>
>   if (is_new_mathfont(cur_f)) {
>       *delta = 0;     /* no italic correction  */
>   }

This would be allowed according to the OpenType specification and
remove the category code issues, but in our case XITS actually should
have italic correction, otherwise the characters would bump into each
other even in ConTeXt. I think we should find a better solution.
Maybe you can implement a set (hash table or whatever) of characters
that should be treated as italic. Users should be able to set this set
using tex.set_italic_characters({123, 456}) or similar.