[fontloader] sync Context as of 2016-04-07

1 files changed, 236 insertions, 0 deletions

diff --git a/src/fontloader/misc/fontloader-font-gbn.lua b/src/fontloader/misc/fontloader-font-gbn.lua
new file mode 100644
index 0000000..f81c877
--- /dev/null
+++ b/src/fontloader/misc/fontloader-font-gbn.lua
@@ -0,0 +1,236 @@
+if not modules then modules = { } end modules ['font-gbn'] = {
+    version   = 1.001,
+    comment   = "companion to luatex-*.tex",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- generic [base|node] mode handler
+
+if context then
+    texio.write_nl("fatal error: this module is not for context")
+    os.exit()
+end
+
+local fonts = fonts
+local nodes = nodes
+
+local nuts        = nodes.nuts -- context abstraction of direct nodes
+
+local traverse_id = nuts.traverse_id
+local free_node   = nuts.free
+local remove_node = nuts.remove
+
+local glyph_code  = nodes.nodecodes.glyph
+local disc_code   = nodes.nodecodes.disc
+
+local tonode      = nuts.tonode
+local tonut       = nuts.tonut
+
+local getfont     = nuts.getfont
+local getchar     = nuts.getchar
+local getid       = nuts.getid
+local getprev     = nuts.getprev
+local getnext     = nuts.getnext
+local getdisc     = nuts.getdisc
+local setchar     = nuts.setchar
+local setlink     = nuts.setlink
+
+-- from now on we apply ligaturing and kerning here because it might interfere with complex
+-- opentype discretionary handling where the base ligature pass expect some weird extra
+-- pointers (which then confuse the tail slider that has some checking built in)
+
+local n_ligaturing = node.ligaturing
+local n_kerning    = node.kerning
+
+local ligaturing   = nuts.ligaturing
+local kerning      = nuts.kerning
+
+local basemodepass = true
+
+local function l_warning() texio.write_nl("warning: node.ligaturing called directly") l_warning = nil end
+local function k_warning() texio.write_nl("warning: node.kerning called directly")    k_warning = nil end
+
+function node.ligaturing(...)
+    if basemodepass and l_warning then
+        l_warning()
+    end
+    return n_ligaturing(...)
+end
+
+function node.kerning(...)
+    if basemodepass and k_warning then
+        k_warning()
+    end
+    return n_kerning(...)
+end
+
+function nodes.handlers.setbasemodepass(v)
+    basemodepass = v
+end
+
+function nodes.handlers.nodepass(head)
+    local fontdata = fonts.hashes.identifiers
+    if fontdata then
+        local nuthead   = tonut(head)
+        local usedfonts = { }
+        local basefonts = { }
+        local prevfont  = nil
+        local basefont  = nil
+        local variants  = nil
+        local redundant = nil
+        for n in traverse_id(glyph_code,nuthead) do
+            local font = getfont(n)
+            if font ~= prevfont then
+                if basefont then
+                    basefont[2] = getprev(n)
+                end
+                prevfont = font
+                local used = usedfonts[font]
+                if not used then
+                    local tfmdata = fontdata[font] --
+                    if tfmdata then
+                        local shared = tfmdata.shared -- we need to check shared, only when same features
+                        if shared then
+                            local processors = shared.processes
+                            if processors and #processors > 0 then
+                                usedfonts[font] = processors
+                            elseif basemodepass then
+                                basefont = { n, nil }
+                                basefonts[#basefonts+1] = basefont
+                            end
+                        end
+                        local resources = tfmdata.resources
+                        variants = resources and resources.variants
+                        variants = variants and next(variants) and variants or false
+                    end
+                else
+                    local tfmdata = fontdata[prevfont]
+                    if tfmdata then
+                        local resources = tfmdata.resources
+                        variants = resources and resources.variants
+                        variants = variants and next(variants) and variants or false
+                    end
+                end
+            end
+            if variants then
+                local char = getchar(n)
+                if char >= 0xFE00 and (char <= 0xFE0F or (char >= 0xE0100 and char <= 0xE01EF)) then
+                    local hash = variants[char]
+                    if hash then
+                        local p = getprev(n)
+                        if p and getid(p) == glyph_code then
+                            local variant = hash[getchar(p)]
+                            if variant then
+                                setchar(p,variant)
+                                if not redundant then
+                                    redundant = { n }
+                                else
+                                    redundant[#redundant+1] = n
+                                end
+                            end
+                        end
+                    end
+                end
+            end
+        end
+        if redundant then
+            for i=1,#redundant do
+                local n = redundant[i]
+                remove_node(nuthead,n)
+                free_node(n)
+            end
+        end
+        for d in traverse_id(disc_code,nuthead) do
+            local _, _, r = getdisc(d)
+            if r then
+                for n in traverse_id(glyph_code,r) do
+                    local font = getfont(n)
+                    if font ~= prevfont then
+                        prevfont = font
+                        local used = usedfonts[font]
+                        if not used then
+                            local tfmdata = fontdata[font] --
+                            if tfmdata then
+                                local shared = tfmdata.shared -- we need to check shared, only when same features
+                                if shared then
+                                    local processors = shared.processes
+                                    if processors and #processors > 0 then
+                                        usedfonts[font] = processors
+                                    end
+                                end
+                            end
+                        end
+                    end
+                end
+            end
+        end
+        if next(usedfonts) then
+            for font, processors in next, usedfonts do
+                for i=1,#processors do
+                    head = processors[i](head,font,0) or head
+                end
+            end
+        end
+        if basemodepass and #basefonts > 0 then
+            for i=1,#basefonts do
+                local range = basefonts[i]
+                local start = range[1]
+                local stop  = range[2]
+                if start then
+                    local front = nuthead == start
+                    local prev, next
+                    if stop then
+                        next = getnext(stop)
+                        start, stop = ligaturing(start,stop)
+                        start, stop = kerning(start,stop)
+                    else
+                        prev  = getprev(start)
+                        start = ligaturing(start)
+                        start = kerning(start)
+                    end
+                    if prev then
+                        setlink(prev,start)
+                    end
+                    if next then
+                        setlink(stop,next)
+                    end
+                    if front and nuthead ~= start then
+                        head = tonode(start)
+                    end
+                end
+            end
+        end
+        return head, true
+    else
+        return head, false
+    end
+end
+
+function nodes.handlers.basepass(head)
+    if not basemodepass then
+        head = n_ligaturing(head)
+        head = n_kerning(head)
+    end
+    return head, true
+end
+
+local nodepass    = nodes.handlers.nodepass
+local basepass    = nodes.handlers.basepass
+local injectpass  = nodes.injections.handler
+local protectpass = nodes.handlers.protectglyphs
+
+function nodes.simple_font_handler(head)
+    if head then
+        head = nodepass(head)
+        head = injectpass(head)
+        if not basemodepass then
+            head = basepass(head)
+        end
+        protectpass(head)
+        return head, true
+    else
+        return head, false
+    end
+end