disabling specific ligatures

disabling specific ligatures

[Csikos Bela]

Dear context users:

Is it possible to disable a specific ligature in a whole document in mkiv?
I would like to disable fi ligature.
Does it make a difference if I use a true type font installed on my
system?

Thank you in advance,

bcsikos
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Re: disabling specific ligatures

[Hans Hagen]

On 3/21/2017 5:44 PM, Csikos Bela wrote:
> Dear context users:
>
> Is it possible to disable a specific ligature in a whole document in mkiv?
> I would like to disable fi ligature.
> Does it make a difference if I use a true type font installed on my
> system?

normally that is done by setting a language feature in the font

you can also cook up a new feature, like

     fonts.handlers.otf.addfeature {
         name    = "nofiligature1",
         type    = "chainsubstitution",
         nocheck = true,
         prepend = true,
         lookups = {
             {
                 type = "multiple",
                 data = {
                     ["f"] = { "f", 0x200C },
                  -- ["i"] = { "i" },
                 },
             },
         },
         data = {
             rules = {
                 {
                  -- current = { { "f" }, { "i" } },
                  -- lookups = { 1, 1 },
                     current = { { "f" } },
                     after   = { { "i" } },
                     lookups = { 1 },
                 },
             },
         }
     }

     fonts.handlers.otf.addfeature {
         name    = "nofiligature2",
         type    = "chainsubstitution",
         nocheck = true,
         append  = true,
         lookups = {
             {
                 type = "ligature",
                 data = {
                     ["f"] = { "f", 0x200C },
                 },
             },
          -- {
          --     type = "substitution",
          --     data = {
          --         ["i"] = "i"
          --     },
          -- },
         },
         data = {
             rules = {
                 {
                  -- current = { { "f" }, { 0x200C }, { "i" } },
                  -- lookups = { 1, 2 },
                     current = { { "f" }, { 0x200C } },
                     after   = { { "i" } },
                     lookups = { 1 },
                 },
             },
         }
     }

Here the two step approach is needed to make sure you get proper kerning 
(given that a font has it, e.g pagella has between fe but not between 
ffe so ...).

Anyway, I've added a helper to the upcoming so that it's a bit easier:

\blockligatures[fi,ff]
\blockligatures[fl]

\definefontfeature
   [default]
   [default]
   [blockligatures=yes]

\setupbodyfont[pagella]

The only thing you need to keep in mind is that the \blockligature 
commands have to come before fonts get defined (has to do with shared 
resources and optimizations and such) and of course that you need to
enable the feature.

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
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Re: Disabling specific ligatures

[Aditya Mahajan]

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On Sun, 18 Sep 2011, Wolfgang Schuster wrote:

>
> Am 18.09.2011 um 03:13 schrieb Aditya Mahajan:
>
>> On Sun, 18 Sep 2011, Khaled Hosny wrote:
>>
>>> On Sat, Sep 17, 2011 at 08:02:43PM -0400, Aditya Mahajan wrote:
>>>> In MkII, one can disable ligatures by inserting {} at the
>>>> appropriate place. For example `self{}ish` disables the ligature
>>>> between f and i. What is the equivalent way to disable ligatures in
>>>> MkIV?
>>>
>>> Inserting a empty box? self\null ish seems to work.
>>
>> \null works but it disable hyphenation.
>>
>>> The "Unicode way"
>>> would be inserting U+200C (ZWNJ)
>>
>> Thank you. This works perfectly.

Actually it does not. The word cannot hypenate wher \zwnj is inserted.

> When you don’t mind the extra space you can use “|*|”.

This works well. But why is the * discretionary defined to insert the 
extra 0.05em space? (I can overwrite it in my document, but I just curious 
about the reason for the original definition).

Aditya

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Re: Disabling specific ligatures

[Wolfgang Schuster]

Am 18.09.2011 um 03:13 schrieb Aditya Mahajan:

> On Sun, 18 Sep 2011, Khaled Hosny wrote:
> 
>> On Sat, Sep 17, 2011 at 08:02:43PM -0400, Aditya Mahajan wrote:
>>> In MkII, one can disable ligatures by inserting {} at the
>>> appropriate place. For example `self{}ish` disables the ligature
>>> between f and i. What is the equivalent way to disable ligatures in
>>> MkIV?
>> 
>> Inserting a empty box? self\null ish seems to work.
> 
> \null works but it disable hyphenation.
> 
>> The "Unicode way"
>> would be inserting U+200C (ZWNJ)
> 
> Thank you. This works perfectly.

When you don’t mind the extra space you can use “|*|”.

Wolfgang
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Re: Disabling specific ligatures

[Aditya Mahajan]

On Sun, 18 Sep 2011, Khaled Hosny wrote:

> On Sat, Sep 17, 2011 at 08:02:43PM -0400, Aditya Mahajan wrote:
>> In MkII, one can disable ligatures by inserting {} at the
>> appropriate place. For example `self{}ish` disables the ligature
>> between f and i. What is the equivalent way to disable ligatures in
>> MkIV?
>
> Inserting a empty box? self\null ish seems to work.

\null works but it disable hyphenation.

> The "Unicode way"
> would be inserting U+200C (ZWNJ)

Thank you. This works perfectly.

Aditya
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Re: Disabling specific ligatures

[Khaled Hosny]

On Sat, Sep 17, 2011 at 08:02:43PM -0400, Aditya Mahajan wrote:
> In MkII, one can disable ligatures by inserting {} at the
> appropriate place. For example `self{}ish` disables the ligature
> between f and i. What is the equivalent way to disable ligatures in
> MkIV?

Inserting a empty box? self\null ish seems to work. The "Unicode way"
would be inserting U+200C (ZWNJ)

\starttext
self{}ish\par
self\null ish\par
self\zwnj ish
\stoptext

Regards,
 Khaled

-- 
 Khaled Hosny
 Egyptian
 Arab
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Disabling specific ligatures

[Aditya Mahajan]

In MkII, one can disable ligatures by inserting {} at the appropriate 
place. For example `self{}ish` disables the ligature between f and i. What 
is the equivalent way to disable ligatures in MkIV?

Thanks,
Aditya
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maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
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