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/

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?

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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 -----------------------------------------------------------------