Re: Adjust kern for one character

[Rik Kabel <ConTeXt@rik.users.panix.com>]

On 12/22/2019 21:34, Henri Menke wrote:
>
>
> On 12/23/19 3:33 PM, Henri Menke wrote:
>> On 12/23/19 2:30 PM, Rik Kabel wrote:
>>>
>>> On 12/22/2019 17:40, mf wrote:
>>>> Il 22/12/19 22:19, Rik Kabel ha scritto:
>>>>> List,
>>>>>
>>>>> Is there a way in ConTeXt to adjust the left-side kern for one
>>>>> character? The cap J in the font I am using is being set too close to
>>>>> the preceding characters and I would rather not insert a thinspace
>>>>> before each. (Inserting a thinspace is sufficient, but finer control
>>>>> is welcome.)
>>>>>
>>>> \definecharacterspacing[distantJ]
>>>> \setupcharacterspacing[distantJ]["004A][left=.15,alternative=1] % 004A
>>>> is the unicode hex index of letter J
>>>> \starttext
>>>>     normal: AJB\par
>>>>     \setcharacterspacing[distantJ] more space on the left: AJB\par
>>>>     \resetcharacterspacing normal again: AJB\par
>>>> \stoptext
>>>>
>>> Thank you for that, Massi.
>>>
>>> Unfortunately, that is too blunt an instrument in this case -- in
>>> addition to the body font where the problem exists, it works on the
>>> heading and titling font, which does not share the problem.
>>>
>>> As Henri's answer hints, I was a bit unclear in my request. It is a 
>>> kern
>>> between a word space and the cap J that is the issue. Perhaps a font
>>> feature file is the place to do such a thing.
>>
>> \startluacode
>> fonts.handlers.otf.addfeature {
>>       name = "kern",
>>       type = "kern",
>>       data = {
>>           [" "] = {
>>               ["J"] = 1000 % exaggerated value
>
> Should of course be a Lua comment
>
>             ["J"] = 1000 -- exaggerated value
>
>>           }
>>       }
>> }
>> \stopluacode
>>
>> \setupbodyfont[modern] % have to reload the font
>>
>> \starttext
>>
>> No Jokes!
>>
>> \stoptext
>>
Henri,

This looks very promising. It works, mostly. That is, all fonts that use 
default fontfeatures pick up the change. So, for example, the companion 
sansserif for my body font also gets it even though that is not what I want.

I can remove kerning from the default fontfeatures and add it back just 
for the problematic font, but that means no kerning for the sans font.

Is there a way to apply this to one font only (serif upright, bold, 
italic, ...) or even a single face (upright), perhaps by giving it a 
unique name? I have tried a few variations but had no success. The 
fonts-mkiv manual has very little on this, and the cld manual nothing.

-- 
Rik

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