Re: [NTG-context] ligatures/substituation at word boundaries
On 7/30/2017 11:39 AM, Ulrike Fischer wrote:
Am Fri, 28 Jul 2017 23:21:18 +0200 schrieb Hans Hagen:
Is it possible to refer in fonts.handlers.otf.addfeature to the word
boundary? The luatex manual speaks of a virtual "left_boundary"
char, but I couldn't find a way to use it.
It is possible to check against spaces in contextual lookups. There
isn't something like left boundary. I added some test code to the beta
but keep in mind that this will only work with self-made features.
Thanks. It seems to work quite good and after some playing around I
also got the knack of the syntax.
A few questions:
1. "lookups = { 1 }," refers to the first lookup. Is it possible to
name the lookups and to refer to this name?.
no, because order matters
2. 0xFFFC refers more or less to the begin and end of line, right?
Why doesn't it interfere with hyphenations? I tried to get
ab-
ab
and the second wasn't replaced (as wanted) and I wondered how it
worked.
0xFFFC is just the same as "anything other than glyph or discretionary"
3. Why is in the following example "abcd" not replaced by "12"?
i'll have a look at this (advancing in somewhat messy defined)
\startluacode
fonts.handlers.otf.addfeature {
name= "test-a",
type= "chainsubstitution",
lookups = {
{
type = "ligature",
data = {
['1'] = { "a", "b" },
['2'] = { "c", "d" },
},
},
},
data = {
rules = {
{
before = { { " ", 0xFFFC } },
current = { { "a" }, { "b" } },
lookups = { 1 },
},
{
current = { { "c" }, { "d" } },
after = { { 0xFFFC, " " } },
lookups = { 1 },
},
},
},
}
\stopluacode
\definefontfeature[test-a][test-a=yes]
\startbuffer
xxx abcd abxcd xxx
\stopbuffer
\starttext
\typebuffer
\definedfont[file:dejavu-serif.ttf*default] \getbuffer \blank
\definedfont[file:dejavu-serif.ttf*default,test-a] \getbuffer \blank
\stoptext
--
-
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: [NTG-context] ligatures/substituation at word boundaries
Am Fri, 28 Jul 2017 23:21:18 +0200 schrieb Hans Hagen:
>> Is it possible to refer in fonts.handlers.otf.addfeature to the word
>> boundary? The luatex manual speaks of a virtual "left_boundary"
>> char, but I couldn't find a way to use it.
> It is possible to check against spaces in contextual lookups. There
> isn't something like left boundary. I added some test code to the beta
> but keep in mind that this will only work with self-made features.
Thanks. It seems to work quite good and after some playing around I
also got the knack of the syntax.
A few questions:
1. "lookups = { 1 }," refers to the first lookup. Is it possible to
name the lookups and to refer to this name?.
2. 0xFFFC refers more or less to the begin and end of line, right?
Why doesn't it interfere with hyphenations? I tried to get
ab-
ab
and the second wasn't replaced (as wanted) and I wondered how it
worked.
3. Why is in the following example "abcd" not replaced by "12"?
\startluacode
fonts.handlers.otf.addfeature {
name= "test-a",
type= "chainsubstitution",
lookups = {
{
type = "ligature",
data = {
['1'] = { "a", "b" },
['2'] = { "c", "d" },
},
},
},
data = {
rules = {
{
before = { { " ", 0xFFFC } },
current = { { "a" }, { "b" } },
lookups = { 1 },
},
{
current = { { "c" }, { "d" } },
after = { { 0xFFFC, " " } },
lookups = { 1 },
},
},
},
}
\stopluacode
\definefontfeature[test-a][test-a=yes]
\startbuffer
xxx abcd abxcd xxx
\stopbuffer
\starttext
\typebuffer
\definedfont[file:dejavu-serif.ttf*default] \getbuffer \blank
\definedfont[file:dejavu-serif.ttf*default,test-a] \getbuffer \blank
\stoptext
--
Ulrike Fischer
http://www.troubleshooting-tex.de/
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___
Re: [NTG-context] ligatures/substituation at word boundaries
On 7/27/2017 8:09 PM, Ulrike Fischer wrote:
Is it possible to refer in fonts.handlers.otf.addfeature to the word
boundary? The luatex manual speaks of a virtual "left_boundary"
char, but I couldn't find a way to use it.
\startluacode
fonts.handlers.otf.addfeature {
name = "ltest",
type = "ligature",
data = {
['1'] = { "a", "b" },
['2'] = { "d", "a" },
}
}
\stopluacode
%how to replace only the start a
\startluacode
fonts.handlers.otf.addfeature {
name = "wtest",
type = "ligature",
data = {
['1'] = { "left_boundary", "a" },
}
}
\stopluacode
\definefontfeature[wtest][wtest=yes]
\definefontfeature[ltest][ltest=yes]
\starttext
\definedfont[file:dejavu-serif.ttf*default]%
{\addff{ltest} ababa\par}
{\addff{wtest} ababa\par}
\stoptext
It is possible to check against spaces in contextual lookups. There
isn't something like left boundary. I added some test code to the beta
but keep in mind that this will only work with self-made features. (I
have to check performance impact because I don't like making contextual
lookups measurable slower due to some hardly used feature. First test
show that it behaves ok.) In the test code below 0xFFFC is the boundary
(this 0xFFFC check is the new thing). I adapted a few more things in the
loader so best check that out too.
I'll upload a beta.
Hans
\starttext
\startluacode
fonts.handlers.otf.addfeature {
name= "test-a",
type= "chainsubstitution",
lookups = {
{
type = "substitution",
data = {
["a"] = "A",
["b"] = "B",
["c"] = "C",
["d"] = "D",
},
},
{
type = "ligature",
data = {
['1'] = { "a", "b" },
['2'] = { "c", "d" },
},
},
},
data = {
rules = {
{
before = { { " ", 0xFFFC } },
current = { { "a" }, { "b" } },
lookups = { 2 },
},
{
current = { { "c" }, { "d" } },
after = { { 0xFFFC, " " } },
lookups = { 2 },
},
{
current = { { "a" } },
after = { { "b" } },
lookups = { 1 },
},
{
current = { { "c" } },
after = { { "d" } },
lookups = { 1 },
},
},
},
}
fonts.handlers.otf.addfeature {
name= "test-b",
type= "chainsubstitution",
lookups = {
{
type = "ligature",
data = {
['1'] = { "a", "b" },
['2'] = { "c", "d" },
},
},
},
data = {
rules = {
{
-- the space is redundant as 0xFFFC contains it
before = { { " ", 0xFFFC } },
current = { { "a" }, { "b" } },
lookups = { 1 },
},
{
current = { { "c" }, { "d" } },
-- the space is redundant as 0xFFFC contains it
after = { { 0xFFFC, " " } },
lookups = { 1 },
},
},
},
}
fonts.handlers.otf.addfeature {
name= "test-c",
type= "chainsubstitution",
lookups = {
{
type = "ligature",
data = {
['1'] = { "a", "b" },
['2'] = { "c", "d" },
},
},
},
data = {
rules = {
{
before = { { " " } },
current = { { "a" }, { "b" } },
lookups = { 1 },
},
{
current = { { "c" }, { "d" } },
after = { { " " } },
lookups = { 1 },
},
},
},
}
\stopluacode
\definefontfeature[test-a][test-a=yes]
\definefontfeature[test-b][test-b=yes]
\definefontfeature[test-c][test-c=yes]
\startbuffer
abababcdcd abababcdcd abababcdcd
\stopbuffer
\typebuffer
\definedfont[file:dejavu-serif.ttf*default,test-a] \getbuffer \blank
\definedfont[file:dejavu-serif.ttf*default,test-b] \getbuffer \blank
\definedfont[file:dejavu-serif.ttf*default,test-c] \getbuffer \blank
\stoptext
-
Hans Hagen | PRAGMA ADE
[NTG-context] ligatures/substituation at word boundaries
Is it possible to refer in fonts.handlers.otf.addfeature to the word
boundary? The luatex manual speaks of a virtual "left_boundary"
char, but I couldn't find a way to use it.
\startluacode
fonts.handlers.otf.addfeature {
name = "ltest",
type = "ligature",
data = {
['1'] = { "a", "b" },
['2'] = { "d", "a" },
}
}
\stopluacode
%how to replace only the start a
\startluacode
fonts.handlers.otf.addfeature {
name = "wtest",
type = "ligature",
data = {
['1'] = { "left_boundary", "a" },
}
}
\stopluacode
\definefontfeature[wtest][wtest=yes]
\definefontfeature[ltest][ltest=yes]
\starttext
\definedfont[file:dejavu-serif.ttf*default]%
{\addff{ltest} ababa\par}
{\addff{wtest} ababa\par}
\stoptext
--
Ulrike Fischer
http://www.troubleshooting-tex.de/
___
If your question is of interest to others as well, please add an entry to the
Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___
