[NTG-context] special case to disable italic correction

[Hans Hagen]

On 1/26/2014 8:24 PM, Pablo Rodriguez wrote:
> Hi Hans,
>
> after reading the relevant part for italic correction in fonts-mkiv.pdf
> and enabling it in my documents, I have found a case in which the italic
> correction could be improved.
>
> My settings are:
>
>    \definefontfeature[default][default][itlc=yes]
>    \setupitaliccorrection[global,always]
>
> If I get it right, the italic correction should be avoided before points
> and commas (these are all the exceptions I can imagine for this case).
> The explanation is simple: the space is already at the base line, since
> at the glyph base, the inclination of the italic or slanted glyph makes
> the right side-bearing larger at the baseline. The issue with italic
> correction is mainly with ascenders or at the cap height, but I think it
> isn’t at the base line (or the descenders). Because of that I think it
> is important to disable italic correction before points and commas.
>
> The sample shows the issue:
>
> \setuppagenumbering[location=]
> \definefontfeature[default][default][itlc=yes]
> \setupitaliccorrection[global,always]
> \starttext
> \startTEXpage[offset=1ex]
> Abf. {\em Abf}.\\
> Abf, {\em Abf},\\
> Abf. {\it Abf}.\\
> Abf, {\it Abf},
> \stopTEXpage
> \stoptext
>
> I think it might be worth considering.
>
> Many thanks for your help and your excellent work,

Hard coded char checking is talking all punctuation is tricky, so i now 
use a threshold instead (enabled by default).

\disabledirectives[typesetters.threshold]

% % % % test:

\definefontfeature
   [default]
   [default]
   [itlc=yes]

\setupitaliccorrection
   [global,always]

% \enabletrackers[typesetters.italics]

\starttext
     \startTEXpage[offset=1ex]
         f. {\em f}.\par f, {\em f},\par f. {\it f}.\par f, {\it f},\par 
f: {\it f}:\par f; {\it f};\par
         x. {\em x}.\par x, {\em x},\par x. {\it x}.\par x, {\it x},\par 
x: {\it x}:\par x; {\it x};\par
     \stopTEXpage
\stoptext


Will be in next beta.

Hans


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