2018-07-17 17:32:00

1 files changed, 196 insertions, 0 deletions

diff --git a/tex/context/base/mkiv/lpdf-fnt.lua b/tex/context/base/mkiv/lpdf-fnt.lua
new file mode 100644
index 000000000..601e20de3
--- /dev/null
+++ b/tex/context/base/mkiv/lpdf-fnt.lua
@@ -0,0 +1,196 @@
+if not modules then modules = { } end modules ['lpdf-fnt'] = {
+    version   = 1.001,
+    comment   = "companion to lpdf-ini.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- This is experimental code.
+
+local match, gmatch = string.match, string.gmatch
+local tonumber = tonumber
+
+local pdfreserveobject = lpdf.reserveobject
+local pdfincludechar   = lpdf.includechar
+local pdfincludefont   = lpdf.includefont
+local pdfreference     = lpdf.reference
+
+local pdfe = lpdf.epdf
+
+local tobemerged   = { }
+local trace_merge  = false  trackers.register("graphics.fonts",function(v) trace_merge = v end)
+local report_merge = logs.reporter("graphics","fonts")
+
+local function register(usedname,cleanname)
+    local cleanname = cleanname or fonts.names.cleanname(usedname)
+    local fontid    = fonts.definers.internal { name = cleanname }
+    if fontid then
+        local objref = pdfreserveobject()
+        pdfincludefont(fontid)
+        if trace_merge then
+            report_merge("registering %a with name %a, id %a and object %a",usedname,cleanname,fontid,objref)
+        end
+        return {
+            id        = fontid,
+            reference = objref,
+            indices   = { },
+            cleanname = cleanname,
+        }
+    end
+    return false
+end
+
+function lpdf.registerfont(usedname,cleanname)
+    local v = register(usedname,cleanname)
+    tobemerged[usedname] = v
+    return v
+end
+
+table.setmetatableindex(tobemerged,function(t,k)
+    return lpdf.registerfont(k)
+end)
+
+local function finalizefont(v)
+    local indextoslot = fonts.helpers.indextoslot
+    if v then
+        local id = v.id
+        local n  = 0
+        for i in next, v.indices do
+            local u = indextoslot(id,i)
+            pdfincludechar(id,u)
+            n = n + 1
+        end
+        v.n = n
+    end
+end
+
+statistics.register("merged fonts", function()
+    if next(tobemerged) then
+        local t = { }
+        for k, v in table.sortedhash(tobemerged) do
+            t[#t+1] = string.formatters["%s (+%i)"](k,v.n)
+        end
+        return table.concat(t," ")
+    end
+end)
+
+function lpdf.finalizefonts()
+    for k, v in next, tobemerged do
+        finalizefont(v)
+    end
+end
+
+callback.register("font_descriptor_objnum_provider",function(name)
+    local m = rawget(tobemerged,name)
+    if m then
+     -- finalizefont(m)
+        local r = m.reference or 0
+        if trace_merge then
+            report_merge("using object %a for font descriptor of %a",r,name)
+        end
+        return r
+    end
+    return 0
+end)
+
+local function getunicodes1(str,indices)
+    for s in gmatch(str,"beginbfrange%s*(.-)%s*endbfrange") do
+        for first, last, offset in gmatch(s,"<([^>]+)>%s+<([^>]+)>%s+<([^>]+)>") do
+            for i=tonumber(first,16),tonumber(last,16) do
+                indices[i] = true
+            end
+        end
+    end
+    for s in gmatch(str,"beginbfchar%s*(.-)%s*endbfchar") do
+        for old, new in gmatch(s,"<([^>]+)>%s+<([^>]+)>") do
+            indices[tonumber(old,16)] = true
+        end
+    end
+end
+
+local function getunicodes2(widths,indices)
+    for i=1,#widths,2 do
+        local start =  widths[i]
+        local count = #widths[i+1]
+        if start and count then
+            for i=start,start+count-1 do
+                indices[i] = true
+            end
+        end
+    end
+end
+
+local function checkedfonts(pdfdoc,xref,copied,page)
+    local list = page.Resources.Font
+    local done = { }
+    for k, somefont in pdfe.expanded(list) do
+        if somefont.Subtype == "Type0" and somefont.Encoding == "Identity-H" then
+            local descendants = somefont.DescendantFonts
+            if descendants then
+                for i=1,#descendants do
+                    local d = descendants[i]
+                    if d then
+                        local subtype = d.Subtype
+                        if subtype == "CIDFontType0" or subtype == "CIDFontType2" then
+                            local basefont = somefont.BaseFont
+                            if basefont then
+                                local fontname = match(basefont,"^[A-Z]+%+(.+)$")
+                                local fontdata = tobemerged[fontname]
+                                if fontdata then
+                                    local descriptor = d.FontDescriptor
+                                    if descriptor then
+                                        local okay   = false
+                                        local widths = d.W
+                                        if widths then
+                                            getunicodes2(widths,fontdata.indices)
+                                            okay = true
+                                        else
+                                            local tounicode = somefont.ToUnicode
+                                            if tounicode then
+                                                getunicodes1(tounicode(),fontdata.indices)
+                                                okay = true
+                                            end
+                                        end
+                                        if okay then
+                                            local r = xref[descriptor]
+                                            done[r] = fontdata.reference
+                                        end
+                                    end
+                                end
+                            end
+                        end
+                    end
+                end
+            end
+        end
+    end
+    return next(done) and done
+end
+
+if pdfincludefont then
+
+    function lpdf.epdf.plugin(pdfdoc,xref,copied,page)
+        local done = checkedfonts(pdfdoc,xref,copied,page)
+        if done then
+            return {
+                FontDescriptor = function(xref,copied,object,key,value,copyobject)
+                    local r = value[3]
+                    local d = done[r]
+                    if d then
+                        return pdfreference(d)
+                    else
+                        return copyobject(xref,copied,object,key,value)
+                    end
+                end
+            }
+        end
+    end
+
+else
+
+    function lpdf.epdf.plugin() end
+
+end
+
+lpdf.registerdocumentfinalizer(lpdf.finalizefonts)