diff options
| -rw-r--r-- | luaotfload-letterspace.lua | 45 |
1 files changed, 27 insertions, 18 deletions
diff --git a/luaotfload-letterspace.lua b/luaotfload-letterspace.lua index aa89651..da78864 100644 --- a/luaotfload-letterspace.lua +++ b/luaotfload-letterspace.lua @@ -62,14 +62,11 @@ kernfont.keeptogether = false --- node-ini ----------------------------------------------------------------------- -nodes = nodes or { } --- should be present with luaotfload -local bothways = function (t) return table.swapped (t, t) end - -local kerncodes = bothways({ - [0] = "fontkern", - [1] = "userkern", - [2] = "accentkern", -}) +local bothways = function (t) return table.swapped (t, t) end +local kerncodes = bothways { [0] = "fontkern" + , [1] = "userkern" + , [2] = "accentkern" + } kerncodes.kerning = kerncodes.fontkern --- idiosyncrasy local kerning_code = kerncodes.kerning @@ -144,7 +141,7 @@ if not parameters then return parameters end end) - fonthashes.parameters = parameters + --fonthashes.parameters = parameters end if not chardata then @@ -179,7 +176,7 @@ if not quaddata then return quad end end) - fonthashes.quads = quaddata + --fonthashes.quads = quaddata end ---=================================================================--- @@ -408,14 +405,12 @@ kerncharacters = function (head) return head, done end -kernfont.handler = kerncharacters - ---=================================================================--- --- integration ---=================================================================--- --- kernfont_callback : fontwise ---- · callback: kernfont.handler +--- · callback: kerncharacters --- · enabler: enablefontkerning --- · disabler: disablefontkerning @@ -447,7 +442,7 @@ end --- now for the simplistic variant --- unit -> bool local enablefontkerning = function ( ) - return add_processor( kernfont.handler + return add_processor( kerncharacters , "typesetters.kernfont" , "pre_linebreak_filter" , "hpack_filter") @@ -458,15 +453,29 @@ local disablefontkerning = function ( ) return remove_processor "typesetters.kernfont" end ---- fontwise kerning uses a font property for passing along the ---- letterspacing factor +--[[doc-- + + Fontwise kerning is enabled via the “kernfactor” option at font + definition time. Unlike the Context implementation which relies on + Luatex attributes, it uses a font property for passing along the + letterspacing factor of a node. + + The callback is activated the first time a letterspaced font is + requested and stays active until the end of the run. Since the font + is a property of individual glyphs, every glyph in the entire + document must be checked for the kern property. This is quite + inefficient compared to Context’s attribute based approach, but Xetex + compatibility reduces our options significantly. + +--doc]]-- + local fontkerning_enabled = false --- callback state --- fontobj -> float -> unit local initializefontkerning = function (tfmdata, factor) if factor ~= "max" then - factor = tonumber(factor) or 0 + factor = tonumber (factor) or 0 end if factor == "max" or factor ~= 0 then local fontproperties = tfmdata.properties @@ -475,7 +484,7 @@ local initializefontkerning = function (tfmdata, factor) fontproperties.kerncharacters = factor end if not fontkerning_enabled then - fontkerning_enabled = enablefontkerning() + fontkerning_enabled = enablefontkerning () end end end |