Re: [NTG-context] Adjust kern for one character

26 Dec 2019

      ...
Okay, I have progressed further but have run into something (else) I 
cannot understand. Consider the following example:
\definefontfeature   [myserif] [mode=node,kern=yes,xkern=yes]
    \definefontfeature   [mysans]  [mode=node,kern=yes,xkern=no]
    \definefontfeature   [none]    [mode=node]
    \definefontfamily    [mykerns] [serif] [Baskervaldx]    [features=myserif]
    \definefontfamily    [mykerns] [sans]  [Dejavusans]     [features=mysans]
    \definefontfamily    [default] [serif] [Baskervaldx]    [features=default]
    \definefontfamily    [default] [sans]  [Dejavusans]     [features=default]
    \definefontfamily    [nokerns] [serif] [Baskervaldx]    [features=none]
    \definefontfamily    [nokerns] [sans]  [Dejavusans]     [features=none]
    \definefontfamily    [legends] [mono]  [Dejavusansmono] [features=default]
\startluacode
       fonts.handlers.otf.addfeature {
           name = "kern",
           type = "kern",
           data = {
               ["x"] = { ["x"] = -300 },
               [" "] = { ["A"] = 1000 }
           }
       }
       fonts.handlers.otf.addfeature {
           name = "xkern",
           type = "kern",
           data = {
               ["x"] = { ["x"] = 500 },
               [" "] = { ["J"] = 500 }
           }
       }
    \stopluacode
\startbuffer[Sample]
       g, Jaxxb AJon
    \stopbuffer
\define[2]\Test{
       {\switchtobodyfont[#1]#2\getbuffer[Sample]}}
\setupbodyfont[legends]
\starttext
    \starttabulate[|l|l|l|]
    \NC test     \NC  Serif                \NC  Sans                 \NC \NR
    \NC nokerns  \NC  \Test{nokerns}{\tf}  \NC  \Test{nokerns}{\ss}  \NC \NR
    \NC default  \NC  \Test{default}{\tf}  \NC  \Test{default}{\ss}  \NC \NR
    \NC mykerns  \NC  \Test{mykerns}{\tf}  \NC  \Test{mykerns}{\ss}  \NC \NR
    \stoptabulate
    \stoptext
It shows, as far as I see, that the kern feature type supports " ", but 
only when it is named kern. When it is named xkern, as here, it does not 
support spaces, but does support other characters.
Indeed it's currently bound to 'kern' (mostly for convenience and a
On 12/26/2019 1:41 PM, Rik Kabel wrote:

little for performance) but it's not that hard to make it a bit more 
flexible (but not today).

Hans

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