[NTG-context] Re: Zigzag left margin with italics

[Wolfgang Schuster <wolfgang.schuster.lists@gmail.com>]

Hans Hagen schrieb am 04.11.2024 um 18:54:
> On 11/4/2024 6:39 PM, Rik Kabel wrote:
>>
>> On 2024-11-04 10:55, Wolfgang Schuster wrote:
>>> Mikael Sundqvist schrieb am 04.11.2024 um 07:35:
>>>> Hi,
>>>>
>>>> You can try this below (from test suite), but then, as you see, also
>>>> upright T will move out. Not sure how/if you can control that.
>>>>
>>>> \startluacode
>>>>
>>>> local classes = fonts.protrusions.classes
>>>> local vectors = fonts.protrusions.vectors
>>>>
>>>> classes.rik = {
>>>>      vector = 'rik',
>>>>      factor = 1,
>>>> }
>>>>
>>>> vectors.rik = table.merged (
>>>>      vectors.quality,
>>>>      {
>>>>        [0x0054] = { 0.35, 0 }, -- T
>>>>      })
>>>>
>>>> \stopluacode
>>>>
>>>> \definefontfeature
>>>>    [default]
>>>>    [default]
>>>>    [protrusion=rik,expansion=quality]
>>>
>>> Define a feature which sets only the custom protrusion values:
>>>
>>> \definefontfeature [rik] [protrusion=quality]
>>>
>>> and create a new typeface where you apply the new feature to the 
>>> italic/slanted style:
>>>
>>> \definefontfamily [riktimes] [rm] [TeX Gyre Termes] [sl=features: 
>>> {default,rik}]
>>>
>>> Afterwards use \seupbodyfont[riktimes] to access the new typeface.
>>>
>>> Wolfgang
>>> ___________________________________________________________________________________ 
>>>
>>
>> Looking a bit more, the problem is not protrusion but the bounding 
>> box. Look at the left side of the italic T and W, and to a lesser 
>> degree C, O, and Q, produced by the following.
>>
>>     \usetypescript[libertinus]
>>     \setupbodyfont[libertinus]
>>     \starttext
>>     ¦\doloopoverlist{a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z}
>>     {\it\recursestring\tf¦}\par
>>     ¦\doloopoverlist{a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z}
>>     {\recursestring¦}
>>
>>     ¦\doloopoverlist{a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z}
>>     {\WORD{\it\recursestring}\tf¦}\par
>>     ¦\doloopoverlist{a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z}
>>     {\WORD{\recursestring}¦}
>>     \stoptext
>>
>> This may be an issue for the font maintainer, but is there anything 
>> that could be done within context?
> 
> you can make a font goodie file where you patch properties of a specific 
> glyph but then you also need to keep an eye on when the font gets fixed

A simple solution is to use \shapecorrection which moves the slanted 
glyphs closer the margins of the text block.

%%%% begin example
\setuppapersize[A5]

\startbuffer
H\crlf
{\it T}
\blank
H\crlf
{\shapecorrection[both]\it T}
\stopbuffer

\showframe

\starttext

\subject{Latin Modern}
\getbuffer

\setupbodyfont[times]
\subject{Times}
\getbuffer

\setupbodyfont[libertinus]
\subject{Libertinus}
\getbuffer

\stoptext
%%%% end example

Wolfgang
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