make font definition callback wrapper work with current tfm object structure

2 files changed, 91 insertions, 63 deletions

diff --git a/luaotfload-deferred.lua b/luaotfload-deferred.lua
index a3026c9..bfbf644 100644
--- a/luaotfload-deferred.lua
+++ b/luaotfload-deferred.lua
@@ -1,6 +1,33 @@
 --- TODO integrate into luaotfload.dtx
+
+local type, next = type, next
+
+local stringfind = string.find
 --- this part is loaded after luatexbase
-local loadmodule = luaotfload.loadmodule
+local loadmodule      = luaotfload.loadmodule
+local luatexbase      = luatexbase
+local generic_context = generic_context --- from fontloader
+
+local add_to_callback, create_callback =
+      luatexbase.add_to_callback, luatexbase.create_callback
+local reset_callback, call_callback =
+      luatexbase.reset_callback, luatexbase.call_callback
+
+--[[doc--
+We do our own callback handling with the means provided by luatexbase.
+
+Note: \verb|pre_linebreak_filter| and \verb|hpack_filter| are coupled
+in \CONTEXT\ in the concept of \emph{node processor}.
+--doc]]--
+
+add_to_callback("pre_linebreak_filter",
+                generic_context.callback_pre_linebreak_filter,
+                "luaotfload.node_processor",
+                1)
+add_to_callback("hpack_filter",
+                generic_context.callback_hpack_filter,
+                "luaotfload.node_processor",
+                1)
 
 loadmodule("lib-dir.lua")    -- required by font-nms; will change with lualibs update
 loadmodule("font-nms.lua")
@@ -8,31 +35,55 @@ loadmodule("font-clr.lua")
 --loadmodule("font-ovr.lua")
 loadmodule("font-ltx.lua")
 
-luatexbase.create_callback("luaotfload.patch_font", "simple", function() end)
+local dummy_function = function ( ) end --- upvalue more efficient than lambda
+create_callback("luaotfload.patch_font", "simple", dummy_function)
 
-local function def_font(...)
-    local fontdata = fonts.define.read(...)
-    if type(fontdata) == "table" and fontdata.shared then
-        local otfdata = fontdata.shared.otfdata
-        if otfdata.metadata.math then
-            local mc = { }
-            for k,v in next, otfdata.metadata.math do
-                if k:find("Percent") then
+--[[doc--
+This is a wrapper for the imported font loader.
+As of 2013, everything it does appears to be redundand, so we won’t use
+it.
+Nevertheless, it has been adapted to work with the current structure of
+font data objects and will stay here for reference / until somebody
+reports breakage.
+
+TODO
+This one also enables patching fonts.
+The current fontloader apparently comes with a dedicated mechanism for
+that already: enhancers.
+How those work remains to be figured out.
+--doc]]--
+local define_font_wrapper = function (...)
+    --- we use “tfmdata” (not “fontdata”) for consistency with the
+    --- font loader
+    local tfmdata = fonts.definers.read(...)
+    if type(tfmdata) == "table" and tfmdata.shared then
+        local metadata = tfmdata.shared.rawdata.metadata
+        local mathdata = metadata.math --- do all fonts have this field?
+        if mathdata then
+            local mathconstants = { } --- why new hash, not modify in place?
+            local units_per_em  = metadata.units_per_em
+            local size          = tfmdata.size
+            for k,v in next, mathdata do
+                --- afaics this is alread taken care of by
+                --- definers.read
+                if stringfind(k, "Percent") then
                     -- keep percent values as is
-                    mc[k] = v
+                    print(k,v)
+                    mathconstants[k] = v
                 else
-                    mc[k] = v / fontdata.units * fontdata.size
+                    mathconstants[k] = v / units_per_em * size
                 end
             end
-            -- for \overwithdelims
-            mc.FractionDelimiterSize             = 1.01 * fontdata.size
-            mc.FractionDelimiterDisplayStyleSize = 2.39 * fontdata.size
-
-            fontdata.MathConstants = mc
+            --- for \overwithdelims
+            --- done by definers.read as well
+            mathconstants.FractionDelimiterSize             = 1.01 * size
+            --- fontloader has 2.4 × size
+            mathconstants.FractionDelimiterDisplayStyleSize = 2.39 * size
+            tfmdata.MathConstants = mathconstants
         end
-        luatexbase.call_callback("luaotfload.patch_font", fontdata)
+        call_callback("luaotfload.patch_font", tfmdata)
     end
-    return fontdata
+    return tfmdata
 end
 fonts.mode = "node"
 
@@ -45,35 +96,21 @@ function attributes.private(name)
     return number
 end
 
---luaotfload.loadmodule("font-otc.lua") -- broken
+reset_callback("define_font")
 
---luatexbase.create_callback("luaotfload.patch_font", "simple", function() end)
-
---local function def_font(...)
-    --local fontdata = fonts.define.read(...)
-    --if type(fontdata) == "table" and fontdata.shared then
-        --local otfdata = fontdata.shared.otfdata
-        --if otfdata.metadata.math then
-            --local mc = { }
-            --for k,v in next, otfdata.metadata.math do
-                --if k:find("Percent") then
-                    ---- keep percent values as is
-                    --mc[k] = v
-                --else
-                    --mc[k] = v / fontdata.units * fontdata.size
-                --end
-            --end
-            ---- for \overwithdelims
-            --mc.FractionDelimiterSize             = 1.01 * fontdata.size
-            --mc.FractionDelimiterDisplayStyleSize = 2.39 * fontdata.size
-
-            --fontdata.MathConstants = mc
-        --end
-        --luatexbase.call_callback("luaotfload.patch_font", fontdata)
-    --end
-    --return fontdata
---end
---fonts.mode = "node"
+if luaotfload.old_font_definer  then
+  add_to_callback("define_font",
+                  old_define_font_wrapper,
+                  "luaotfload.define_font",
+                  1)
+else -- use default font loader
+  add_to_callback("define_font",
+                  generic_context.callback_define_font,
+                  "luaotfload.define_font",
+                  1)
+end
+
+--luaotfload.loadmodule("font-otc.lua") -- broken
 
 --local register_base_sub = fonts.otf.features.register_base_substitution
 --local gsubs = {
@@ -86,19 +123,9 @@ end
 --for _,v in next, gsubs do
     --register_base_sub(v)
 --end
---luatexbase.add_to_callback("pre_linebreak_filter",
-                            --nodes.simple_font_handler,
-                           --"luaotfload.pre_linebreak_filter")
---luatexbase.add_to_callback("hpack_filter",
-                            --nodes.simple_font_handler,
-                           --"luaotfload.hpack_filter")
---luatexbase.reset_callback("define_font")
---luatexbase.add_to_callback("define_font",
-                            --def_font,
-                           --"luaotfload.define_font", 1)
---luatexbase.add_to_callback("find_vf_file",
-                            --fonts.vf.find,
-                           --"luaotfload.find_vf_file")
+--add_to_callback("find_vf_file",
+                 --fonts.vf.find,
+                --"luaotfload.find_vf_file")
 --local function set_sscale_diments(fontdata)
     --local mc = fontdata.MathConstants
     --if mc then
diff --git a/luaotfload.lua b/luaotfload.lua
index 5550c79..1bfca79 100644
--- a/luaotfload.lua
+++ b/luaotfload.lua
@@ -29,9 +29,11 @@ luaotfload.module = {
     license       = "CC0"
 }
 
+luaotfload.old_font_definer = false --- toggle wrapper for font loader
+
 local fl_prefix = "otfl" -- “luatex” for luatex-plain
 
---- these will be overloaded later by luatexbase
+--- these will be provided by luatexbase some time
 local error = function(...) print("err", string.format(...)) end
 local log   = function(...) print("log", string.format(...)) end
 
@@ -98,7 +100,7 @@ luaotfload.loadmodule = loadmodule --- required in deferred code
   that’s it, go thank Hans!
 --]]--
 
---[[doc
+--[[doc--
 We treat the fontloader as a black box so behavior is consistent
 between formats.
 The wrapper file is |otfl-fonts.lua| which we imported from
@@ -145,7 +147,6 @@ _G.non_generic_context = { luatex_fonts = {
 
 loadmodule("fonts.lua")
 
---- now load luatexbase (from the TEX end)
 --- then continue in luaotfload-deferred.lua
 
 -- vim:tw=71:sw=2:ts=2:expandtab