From a4e07f30e880ab27c2918f81f136e257475b7729 Mon Sep 17 00:00:00 2001
From: Hans Hagen <pragma@wxs.nl>
Date: Thu, 15 Mar 2018 16:04:31 +0100
Subject: 2018-03-15 15:36:00

---
 tex/context/base/mkiv/typo-ovl.lua | 183 +++++++++++++++++++++++++++++++++++++
 1 file changed, 183 insertions(+)
 create mode 100644 tex/context/base/mkiv/typo-ovl.lua

(limited to 'tex/context/base/mkiv/typo-ovl.lua')

diff --git a/tex/context/base/mkiv/typo-ovl.lua b/tex/context/base/mkiv/typo-ovl.lua
new file mode 100644
index 000000000..09cf5e129
--- /dev/null
+++ b/tex/context/base/mkiv/typo-ovl.lua
@@ -0,0 +1,183 @@
+if not modules then modules = { } end modules ['typo-ovl'] = {
+    version   = 1.001,
+    comment   = "companion to typo-ovl.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- This is dubious code. If you needed it your source is probably bad. We only used
+-- in when we had to mark bad content but when cleaning up some project code I decided
+-- that it is easier to maintain in the distribution then in a project style. After all,
+-- we have hardly any private code. For convenience I hooked it into the existing
+-- replacement module (as it used the same code anyway). I did some cleanup.
+
+local next = next
+
+local context      = context
+
+local nuts         = nodes.nuts
+local tonut        = nodes.tonut
+local tonode       = nodes.tonode
+
+local nodecodes    = nodes.nodecodes
+local glyph_code   = nodecodes.glyph
+local disc_code    = nodecodes.disc
+
+local getnext      = nuts.getnext
+local getid        = nuts.getid
+local getdisc      = nuts.getdisc
+local getattr      = nuts.getattr
+local setattr      = nuts.setattr
+local getattrlist  = nuts.getattrlist
+local setattrlist  = nuts.setattrlist
+local getfield     = nuts.getfield
+local setfont      = nuts.setfont
+
+local unsetvalue   = attributes.unsetvalue
+local prvattribute = attributes.private
+
+local texgetbox    = tex.getbox
+local currentfont  = font.current
+
+local a_overloads  = attributes.private("overloads")
+local n_overloads  = 0
+local t_overloads  = { }
+
+local overloaded   = { }
+
+local function markasoverload(a)
+    local n = prvattribute(a)
+    if n then
+        overloaded[n] = a
+    end
+end
+
+attributes.markasoverload = markasoverload
+
+markasoverload("color")
+markasoverload("colormodel")
+markasoverload("transparency")
+markasoverload("case")
+markasoverload("negative")
+markasoverload("effect")
+markasoverload("ruled")
+markasoverload("shifted")
+markasoverload("kernchars")
+markasoverload("kern")
+markasoverload("noligature")
+markasoverload("viewerlayer")
+
+local function tooverloads(n)
+    local current = tonut(n)
+    local a = getattrlist(current)
+    local s = { }
+    while a do
+        local n = getfield(a,"number")
+        local o = overloaded[n]
+        if o then
+            local v = getfield(a,"value")
+            if v ~= unsetvalue then
+                s[n] = v
+             -- print(o,n,v)
+            end
+        end
+        a = getnext(a)
+    end
+    return s
+end
+
+attributes.tooverloads = tooverloads
+
+function attributes.applyoverloads(specification,start,stop)
+    local current   = tonut(start)
+    local processor = specification.processor
+    local overloads = specification.processor or getattr(current,a_overloads)
+    if overloads and overloads ~= unsetvalue then
+        overloads = t_overloads[overloads]
+        if not overloads then
+            return
+        end
+    else
+        return
+    end
+
+    local last    = stop and tonut(stop)
+    local oldlist = nil
+    local newlist = nil
+    local newfont = overloads.font
+
+    local function apply()
+        local a = getattrlist(current)
+        if a == oldlist then
+            setattrlist(current,newlist)
+        else
+            oldlist = getattrlist(current)
+            for k, v in next, overloads do
+                setattr(current,k,v)
+            end
+            newlist = current -- getattrlist(current)
+        end
+        if newfont then
+            setfont(current,newfont)
+        end
+    end
+
+    while current do
+        local id = getid(current)
+        if id == glyph_code then
+            apply()
+        elseif id == disc_code then
+            apply()
+            if pre then
+                while pre do
+                    if getid(pre) == glyph_code then
+                        apply()
+                    end
+                    pre = getnext(pre)
+                end
+            end
+            if post then
+                while post do
+                    if getid(post) == glyph_code then
+                        apply()
+                    end
+                    post = getnext(post)
+                end
+            end
+            if replace then
+                while replace do
+                    if getid(replace) == glyph_code then
+                        apply()
+                    end
+                    replace = getnext(replace)
+                end
+            end
+        end
+        if current == last then
+            break
+        end
+        current = getnext(current)
+    end
+end
+
+-- we assume the same highlight so we're global
+
+interfaces.implement {
+    name      = "overloadsattribute",
+    arguments = { "string", "integer", "integer" },
+    actions   = function(name,font,box)
+        local samplebox = texgetbox(box)
+        local sample    = samplebox and samplebox.list
+        local overloads = sample and tooverloads(sample)
+        if overloads then
+            overloads.font = font > 0 and font or false
+            n_overloads = n_overloads + 1
+            t_overloads[n_overloads] = overloads
+            t_overloads[name] = overloads
+            context(n_overloads)
+        else
+            context(unsetvalue)
+        end
+    end
+}
-- 
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