1 files changed, 122 insertions, 0 deletions
diff --git a/tex/context/base/mkxl/typo-fkr.lmt b/tex/context/base/mkxl/typo-fkr.lmt
new file mode 100644
index 000000000..3491c9eff
--- /dev/null
+++ b/tex/context/base/mkxl/typo-fkr.lmt
@@ -0,0 +1,122 @@
+if not modules then modules = { } end modules ['typo-fkr'] = {
+    version   = 1.001,
+    comment   = "companion to typo-fkr.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+local nuts          = nodes.nuts
+local getid         = nuts.getid
+local getnext       = nuts.getnext
+local getattr       = nuts.getattr
+local isglyph       = nuts.isglyph
+
+local nodecodes     = nodes.nodecodes
+local glyph_code    = nodecodes.glyph
+
+local fontdata      = fonts.hashes.identifiers
+local getkernpair   = fonts.handlers.otf.getkern
+
+local insertbefore  = nuts.insertbefore
+local new_kern      = nuts.pool.fontkern
+
+local enableaction  = nodes.tasks.enableaction
+
+local a_extrakern   = attributes.private("extrafontkern")
+
+-- 0=none 1=min 2=max 3=mixed
+
+typesetters.fontkerns = { }
+
+function typesetters.fontkerns.handler(head)
+    local current   = head
+    local lastfont  = nil
+    local lastchar  = nil
+    local lastdata  = nil
+    while current do
+        local char, font = isglyph(current)
+        if char then
+            local a = getattr(current,a_extrakern)
+            if a then
+                if font ~= lastfont then
+                    if a > 0 and lastchar then
+                        if not lastdata then
+                            lastdata = fontdata[lastfont]
+                        end
+                        local kern  = nil
+                        local data  = fontdata[font]
+                        local kern1 = getkernpair(lastdata,lastchar,char)
+                        local kern2 = getkernpair(data,lastchar,char)
+                        if a == 1 then
+                            kern = kern1 > kern2 and kern2 or kern1 -- min
+                        elseif a == 2 then
+                            kern = kern1 > kern2 and kern1 or kern2 -- max
+                        else -- 3
+                            kern = (kern1 + kern2)/2                -- mixed
+                        end
+                        if kern ~= 0 then
+                            head = insertbefore(head,current,new_kern(kern))
+                        end
+                        lastdata = data
+                    else
+                        lastdata = nil
+                    end
+                elseif lastchar then
+                    if not lastdata then
+                        lastdata = fontdata[lastfont]
+                    end
+                    local kern = getkernpair(lastdata,lastchar,char)
+                    if kern ~= 0 then
+                        head = insertbefore(head,current,new_kern(kern))
+                    end
+                end
+                lastchar = char
+                lastfont = font
+            elseif lastfont then
+                lastfont = nil
+                lastchar = nil
+                lastdata = nil
+            end
+        elseif lastfont then
+            lastfont = nil
+            lastchar = nil
+            lastdata = nil
+        end
+        current = getnext(current)
+    end
+    return head
+end
+
+do
+
+    local variables    = interfaces.variables
+    local unsetvalue   = attributes.unsetvalue
+    local enabled      = false
+    local setattribute = tex.setattribute
+
+    local values       = {
+        [variables.none ] = 0,
+        [variables.min  ] = 1,
+        [variables.max  ] = 2,
+        [variables.mixed] = 3,
+        [variables.reset] = unsetvalue,
+    }
+
+    local function setextrafontkerns(str)
+        if not enabled then
+            enableaction("processors","typesetters.fontkerns.handler")
+            enabled = true
+        end
+        setattribute(a_extrakern,str and values[str] or unsetvalue)
+    end
+
+    interfaces.implement {
+        name      = "setextrafontkerns",
+        public    = true,
+        protected = true,
+        arguments = "optional",
+        actions   = setextrafontkerns,
+    }
+
+end