From f3af2599da855edcead7e48f828438e4c705c484 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcel=20Fabian=20Kr=C3=BCger?= <zauguin@gmail.com>
Date: Sun, 7 Jun 2020 13:10:33 +0200
Subject: [PATCH] Legacy PDF outline support

---
 luametalatex-back-pdf.lua    |  6 ++++--
 luametalatex-pdf-outline.lua | 31 ++++++++++++++++++++++++++-----
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/luametalatex-back-pdf.lua b/luametalatex-back-pdf.lua
index ea39983..7e03f8a 100644
--- a/luametalatex-back-pdf.lua
+++ b/luametalatex-back-pdf.lua
@@ -572,14 +572,16 @@ token.luacmd("pdfextension", function(_, imm)
       local actionobj = scan_action()
       action = pfile:indirect(nil, get_action_attr(pfile, actionobj))
     end
+    local outline = get_outline()
     if token.scan_keyword'level' then
       local level = token.scan_int()
       local open = token.scan_keyword'open'
-      local outline = get_outline()
       local title = token.scan_string()
       outline:add(pdf_string(title), action, level, open, attr)
     else
-      error[[Legacy outline not yet supported]]
+      local count = token.scan_keyword'count' and token.scan_int() or 0
+      local title = token.scan_string()
+      outline:add_legacy(pdf_string(title), action, count, attr)
     end
   elseif token.scan_keyword"dest" then
     local id
diff --git a/luametalatex-pdf-outline.lua b/luametalatex-pdf-outline.lua
index 62b6f69..fe252c6 100644
--- a/luametalatex-pdf-outline.lua
+++ b/luametalatex-pdf-outline.lua
@@ -1,8 +1,3 @@
-local outline = {
-  { title = "title 1", attr = "", open = true, level = 5,
-    { ... },
-  }
-}
 local function add_outline(outline, title, action, level, open, attr)
   local entry = {title = title, action = action, attr = attr, open = open, level = level}
   -- Now find the right nesting level. We have to deal with non-continuous
@@ -15,6 +10,31 @@ local function add_outline(outline, title, action, level, open, attr)
   until not outline or outline.level >= level
   parent[#parent + 1] = entry 
 end
+local function add_legacy(outline, title, action, count, attr)
+  local state = outline.legacy
+  if not state then
+    state = {}
+    outline.legacy = state
+  end
+  local level = #state
+  if level ~= 0 then
+    state[level] = state[level] - 1
+  end
+  local open
+  if count and count ~= 0 then
+    open = count > 0
+    if not open then
+      count = -count
+    end
+    state[level+1] = count
+  else
+    open = false -- Doesn't matter without children
+    while state[#state] == 0 do
+      state[#state] = nil
+    end
+  end
+  return outline:add(title, action, level, open, attr)
+end
 local function assign_objnum(pdf, outline)
   local objnum = pdf:getobj()
   outline.objnum = objnum
@@ -94,6 +114,7 @@ end
 local meta = {__index = {
   write = write_outline,
   add = add_outline,
+  add_legacy = add_legacy,
 }}
 return function()
   return setmetatable({}, meta)