using lua fonts

using lua fonts

[Ulrike Fischer]

I'm trying to run one of the examples of fonts-mkiv.pdf

I copied the code from 4.5 Lua fonts to a file
"fonts-demo-rule.lua". This lua file is in the same directory as my
test file.

Then I tried

\definefont
[MyRuleFont]
[file:fonts-demo-rule.lua*default sa 1]

\starttext

{\MyRuleFont So when we use it we get text }

\stoptext

but I get in the log

fonts > defining > forced type 'lua' of 'fonts-demo-rule' not found
fonts > defining > font with asked name 'fonts-demo-rule' is not
found using lookup 'file'
fonts > defining > unknown font 'fonts-demo-rule', loading aborted
fonts > defining > unable to define 'fonts-demo-rule.lua' as
'MyRuleFont--0'

The file itself is found (I can see its path later on). What is
going on here?

-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/

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Re: using lua fonts

[Hans Hagen]

On 5/3/2018 8:26 PM, Ulrike Fischer wrote:
> I'm trying to run one of the examples of fonts-mkiv.pdf
> 
> I copied the code from 4.5 Lua fonts to a file
> "fonts-demo-rule.lua". This lua file is in the same directory as my
> test file.
> 
> Then I tried
> 
> \definefont
> [MyRuleFont]
> [file:fonts-demo-rule.lua*default sa 1]
> 
> \starttext
> 
> {\MyRuleFont So when we use it we get text }
> 
> \stoptext
> 
> but I get in the log
> 
> fonts > defining > forced type 'lua' of 'fonts-demo-rule' not found
> fonts > defining > font with asked name 'fonts-demo-rule' is not
> found using lookup 'file'
> fonts > defining > unknown font 'fonts-demo-rule', loading aborted
> fonts > defining > unable to define 'fonts-demo-rule.lua' as
> 'MyRuleFont--0'
> 
> The file itself is found (I can see its path later on). What is
> going on here?
i have no clue as it works ok here

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: using lua fonts

[Ulrike Fischer]

Am Tue, 8 May 2018 10:43:00 +0200 schrieb Hans Hagen:

> i have no clue as it works ok here

;-(. 

Where is the fonts-demo-rule.lua on your system? I don't think that
it is actually loaded in my test file. I can write nonsense in it
and get no error.


-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/

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Re: using lua fonts

[Hans Hagen]

On 5/8/2018 4:01 PM, Ulrike Fischer wrote:
> Am Tue, 8 May 2018 10:43:00 +0200 schrieb Hans Hagen:
> 
>> i have no clue as it works ok here
> 
> ;-(.
> 
> Where is the fonts-demo-rule.lua on your system? I don't think that
> it is actually loaded in my test file. I can write nonsense in it
> and get no error.

current directory

-----------------------------------------------------------------
                                           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: using lua fonts

[Ulrike Fischer]

Am Thu, 3 May 2018 20:26:20 +0200 schrieb Ulrike Fischer:

> I'm trying to run one of the examples of fonts-mkiv.pdf
> 
> I copied the code from 4.5 Lua fonts to a file
> "fonts-demo-rule.lua". This lua file is in the same directory as my
> test file.
> 
...
> 
> but I get in the log
> 
> fonts > defining > forced type 'lua' of 'fonts-demo-rule' not found

For the record: It was a silly error. As the lua file is not in the
sources I had to copy & paste from the fonts-mkiv.pdf and overlooked
that the code has a last "end" on the next page. After adding it to
the lua everything worked as expected.

-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/

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Re: using lua fonts

[Henri Menke]

Dear list,

this is a follow-up on Ulrike's post, so I'm just hijacking the thread.

How can I use the Lua fonts in Plain?  It works fine if I just remove 
ConTeXt-specific actualtext bits but as soon as I add features to the 
font, the name resolution fails with something like

! Font 
\mainfont=file:fonts-demo-rule.lua:original=file:texgyrepagella-regular.
otf not loadable: metric data not found or bad.

MWE is below as always.

Cheers, Henri

----------- test.tex -----------

\input luaotfload.sty

\font\mainfont="file:fonts-demo-rule.lua":original=file:texgyrepagella-regular.otf
\mainfont

This code is stored in fonts-demo-rule.lua and we can load that font in 
the usual way,
by specifying a filename.

\bye

----------- fonts-demo-rule.lua -----------

return function(specification)
     local features = specification.features.normal
     local name = features.original or "dejavu-serif"
     local option = features.option -- we only support "line"
     local size = specification.size -- always set
     local detail = specification.detail -- e.g. default
     if detail then
         name = name .. "*" .. detail
     end
     local f, id = fonts.constructors.readanddefine(name,size)
     if f then
         f.properties.name = specification.name
         f.properties.virtualized = true
         f.fonts = {
             { id = id },
         }
         for s in string.gmatch("aeuioy",".") do
             local n = utf.byte(s)
             local c = f.characters[n]
             if c then
                 local w = c.width or 0
                 local h = c.height or 0
                 local d = c.depth or 0
                 if option == "line" then
                     f.characters[n].commands = {
                         { "rule", option == "line" and size/10, w },
                     }
                 else
                     f.characters[n].commands = {
                         { "down", d },
                         { "rule", h + d, w },
                     }
                 end
             else
                 -- probably a real bad font
             end
         end
     end
     return f
end

On 04/05/18 06:26, Ulrike Fischer wrote:
> I'm trying to run one of the examples of fonts-mkiv.pdf
> 
> I copied the code from 4.5 Lua fonts to a file
> "fonts-demo-rule.lua". This lua file is in the same directory as my
> test file.
> 
> Then I tried
> 
> \definefont
> [MyRuleFont]
> [file:fonts-demo-rule.lua*default sa 1]
> 
> \starttext
> 
> {\MyRuleFont So when we use it we get text }
> 
> \stoptext
> 
> but I get in the log
> 
> fonts > defining > forced type 'lua' of 'fonts-demo-rule' not found
> fonts > defining > font with asked name 'fonts-demo-rule' is not
> found using lookup 'file'
> fonts > defining > unknown font 'fonts-demo-rule', loading aborted
> fonts > defining > unable to define 'fonts-demo-rule.lua' as
> 'MyRuleFont--0'
> 
> The file itself is found (I can see its path later on). What is
> going on here?
> 
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___________________________________________________________________________________

Re: using lua fonts

[Hans Hagen]

On 5/9/2018 3:02 AM, Henri Menke wrote:
> Dear list,
> 
> this is a follow-up on Ulrike's post, so I'm just hijacking the thread.
> 
> How can I use the Lua fonts in Plain?  It works fine if I just remove 
> ConTeXt-specific actualtext bits but as soon as I add features to the 
> font, the name resolution fails with something like
> 
> ! Font 
> \mainfont=file:fonts-demo-rule.lua:original=file:texgyrepagella-regular.
> otf not loadable: metric data not found or bad.
> 
> MWE is below as always.

(1) This lua font stuff was mostly written for demonstration purposes so 
anything done like should really use the mechanisms available in the 
macro package used

(2) If you use plain and want to play with the font interface you can 
better use the plain code that comes with context because that is what I 
can run here (this plain version has always been present btw).

(3) Examples coming from the font manual can use feaures only present in 
context (for instance because it uses other code present in context or 
because i didn't bother to make in generic).

(4) File lookup is macro package specific.

So, say that you have:

\font\mainfont="file:fonts-demo-rule.lua":original=texgyrepagellaregular;

\mainfont

This code is stored in fonts-demo-rule.lua and we can load that font in 
the usual way, by specifying a filename.

\bye

and then in that lua file

     if detail then
         name = name .. ":" .. detail
     end

watch how i replaced the * by : because only context has the * syntax 
while you use/want the xetex syntax

   mtxrun --script plain yourtexfile

should work gven that you made a format with

   mtxrun --script plain --make

(mtxrun --script font --reload --simple will make a plain database if 
needed)

It uses luatex-plain that ships with context as format (there's also a 
luatex-test file that shows some font stuff).

Fwiw, the latest version also supports font effects at the font level 
but one needs luatex 1.08 (which is the current garden version).

> Cheers, Henri
> 
> ----------- test.tex -----------
> 
> \input luaotfload.sty
> 
> \font\mainfont="file:fonts-demo-rule.lua":original=file:texgyrepagella-regular.otf 
> 
> \mainfont
> 
> This code is stored in fonts-demo-rule.lua and we can load that font in 
> the usual way,
> by specifying a filename.
> 
> \bye
> 
> ----------- fonts-demo-rule.lua -----------
> 
> return function(specification)
>      local features = specification.features.normal
>      local name = features.original or "dejavu-serif"
>      local option = features.option -- we only support "line"
>      local size = specification.size -- always set
>      local detail = specification.detail -- e.g. default
>      if detail then
>          name = name .. "*" .. detail
>      end
>      local f, id = fonts.constructors.readanddefine(name,size)
>      if f then
>          f.properties.name = specification.name
>          f.properties.virtualized = true
>          f.fonts = {
>              { id = id },
>          }
>          for s in string.gmatch("aeuioy",".") do
>              local n = utf.byte(s)
>              local c = f.characters[n]
>              if c then
>                  local w = c.width or 0
>                  local h = c.height or 0
>                  local d = c.depth or 0
>                  if option == "line" then
>                      f.characters[n].commands = {
>                          { "rule", option == "line" and size/10, w },
>                      }
>                  else
>                      f.characters[n].commands = {
>                          { "down", d },
>                          { "rule", h + d, w },
>                      }
>                  end
>              else
>                  -- probably a real bad font
>              end
>          end
>      end
>      return f
> end
> 
> On 04/05/18 06:26, Ulrike Fischer wrote:
>> I'm trying to run one of the examples of fonts-mkiv.pdf
>>
>> I copied the code from 4.5 Lua fonts to a file
>> "fonts-demo-rule.lua". This lua file is in the same directory as my
>> test file.
>>
>> Then I tried
>>
>> \definefont
>> [MyRuleFont]
>> [file:fonts-demo-rule.lua*default sa 1]
>>
>> \starttext
>>
>> {\MyRuleFont So when we use it we get text }
>>
>> \stoptext
>>
>> but I get in the log
>>
>> fonts > defining > forced type 'lua' of 'fonts-demo-rule' not found
>> fonts > defining > font with asked name 'fonts-demo-rule' is not
>> found using lookup 'file'
>> fonts > defining > unknown font 'fonts-demo-rule', loading aborted
>> fonts > defining > unable to define 'fonts-demo-rule.lua' as
>> 'MyRuleFont--0'
>>
>> The file itself is found (I can see its path later on). What is
>> going on here?
>>
> ___________________________________________________________________________________ 
> 
> 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
> ___________________________________________________________________________________


-- 

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

Re: using lua fonts

[Ulrike Fischer]

Am Wed, 9 May 2018 09:56:50 +0200 schrieb Hans Hagen:

> watch how i replaced the * by : because only context has the * syntax

Thank you very much for this explanation. I was wondering about the
same thing and replacing this made the code going. 

Perhaps a general remark: I and certainly Henry too are quite aware
that some of the code is context specific. But it is often quite
difficult to see the boundaries -- which part of the examples are
generic and which rely on context (and on how much in context). It
is also not easy to decide which (lua) functions are "public" and
won't break at the next update of the font handler.


Henri: As you are interested in these things too, do you think it
would be a good idea to setup a github repository where we collect
such (plain and latex and context) examples? 


-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/

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___________________________________________________________________________________

Re: using lua fonts

[Hans Hagen]

On 5/9/2018 12:40 PM, Ulrike Fischer wrote:
> Am Wed, 9 May 2018 09:56:50 +0200 schrieb Hans Hagen:
> 
>> watch how i replaced the * by : because only context has the * syntax
> 
> Thank you very much for this explanation. I was wondering about the
> same thing and replacing this made the code going.
> 
> Perhaps a general remark: I and certainly Henry too are quite aware
> that some of the code is context specific. But it is often quite
> difficult to see the boundaries -- which part of the examples are
> generic and which rely on context (and on how much in context). It
> is also not easy to decide which (lua) functions are "public" and
> won't break at the next update of the font handler.

normally function that are part of the generic loader code are publis 
(one can argue about the low level helpers as these are only loaded for 
the code to work i.e. i have no clue how useful these are outside 
context) .. that code doesn't change that much nowadays (just assume 
that i also use it in modules sometimes and i don't want to change that 
too often)

then there is the wrapper code (that hooks into callbacks) which is also 
mostly stable (unless we add something fundamental)

for instance, the effects feature has a sort of sub syntax that suits 
context feature definitions, so for latex you probably need to map onto 
that somehow ... i happily leave that to others to figure out as i don't 
want to impose something (the same is true for variable fonts)

the big font manual is a context one so there can be examples that 
assume the context user interface and there is not much we can do about 
that (and i don't know much about latex apart from what i occasionally 
see at some tex meeting) ... wrrt the font loader: the luatex-plain 
version is sort of the generic reference ... anything written on top of 
that is specific for a macro package

another difference is the font database ... i'm pretty sure that the 
context one is quite generic but latex folks wanted their own so ...

> Henri: As you are interested in these things too, do you think it
> would be a good idea to setup a github repository where we collect
> such (plain and latex and context) examples?

anyway, if something doesn't work at some point we can always see why 
and provide a compatibility hack in luatex-fonts-hacks or so

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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