[NTG-context] font features

[Thomas A. Schmitz]

On 11/3/22 13:27, Henning Hraban Ramm via ntg-context wrote:
> If it works for you, then it’s a problem of my installation, otherwise a 
> regression in current LMTX...

No, I get the same error message, this looks promising but doesn't work.

And at the risk of sounding grumpy, but all of this is too much manual 
intervention; I would like to have a completely automated script. So 
I'll show what I have and add a few comments:

local Feature_Table = { }
local Parsed_Features = { }

local My_Font = environment.arguments["font"]

local Font_Features = os.resultof("otfinfo -f " .. My_Font)

for Feature_Sigla, Feature_Name in
   string.gmatch(Font_Features, "(%S-)\t(.-)\n") do
   Feature_Table[Feature_Sigla] = Feature_Name
end

COMMENTS

Expectation: this should return a list of all features and their 
descriptions as a lua table. If you run the file as

context test.cld --font="/path/to/font"

this works, and you get a table

Feature_Table={
  ["aalt"]="Access All Alternates",
  ["c2sc"]="Small Capitals From Capitals"} etc.

CODE

for name, _ in pairs(Feature_Table) do
   Context_Name = "f:" .. name
   Parsed_Features[name] = Context_Name
   context.definefontfeature( { Context_Name }, { name="yes" } )
end

COMMENTS

This should produce a lua table with ConTeXt fontfeatures and define 
those features. The table appears to be correct:

Parsed_Features={
  ["aalt"]="f:aalt",
  ["c2sc"]="f:c2sc"} etc.

So I expected that this should be equivalent to

\definefontfeature [f:aalt] [aalt=yes]

and return a list of defined features.

CODE

local Test_String = [[
ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 1234567890 1/4 2/8 
3/9 ffi ft fi fl ffl
]]

local Font_Name =  os.resultof("otfinfo -a " .. My_Font)

context.definefontfamily( { "Test" }, { "serif" }, { Font_Name }, {} )

context.setupbodyfont{ "Test, 12pt" }

COMMENTS

Again, this works; the font is set as bodyfont.

CODE

context.starttext()

for name, feature in pairs(Feature_Table) do
   context.start ()
   context.addfeature { Parsed_Features[name] }
   context.midaligned (feature)
   context.bold (Parsed_Features[name])
   context.par ()
   context.blank{ "medium" }
   context(Test_String)
   context.par ()
   context.stop ()
end

context.stoptext()

COMMENTS

And this doesn't work: the names are picked up, but the font features 
are not defined; the sample text does not reflect any features. So this 
is what I've got... maybe one of the wizards can help.

Thomas