Named destinations and improved outline interface

There is no support for PDFTeX's outline command yet, but the new one is
much easier to use.

luametalatex-back-pdf.lua

@@ -1,6 +1,7 @@
 local pdf = pdf
 local writer = require'luametalatex-nodewriter'
 local newpdf = require'luametalatex-pdf'
+local nametree = require'luametalatex-pdf-nametree'
 local pdfname, pfile
 local fontdirs = setmetatable({}, {__index=function(t, k)t[k] = pfile:getobj() return t[k] end})
 local usedglyphs = {}
@@ -23,6 +24,13 @@ local function get_pfile()
   end
   return pfile
 end
+local outline
+local function get_outline()
+  if not outline then
+    outline = require'luametalatex-pdf-outline'()
+  end
+  return outline
+end
 local properties = node.direct.properties
 token.luacmd("shipout", function()
   local pfile = get_pfile()
@@ -44,6 +52,7 @@ token.luacmd("shipout", function()
   token.scan_token()
 end, 'force', 'protected')
 local infodir = ""
+local namesdir = ""
 local catalogdir = ""
 local creationdate = os.date("D:%Y%m%d%H%M%S%z"):gsub("+0000$", "Z"):gsub("%d%d$", "'%0")
 local function write_infodir(p)
@@ -87,7 +96,26 @@ callback.register("stop_run", function()
   end
   pfile.root = pfile:getobj()
   pfile.version = string.format("%i.%i", pdf.variable.majorversion, pdf.variable.minorversion)
+  local destnames = {}
+  for k,obj in next, dests do
+    if pfile:written(obj) then
+      if type(k) == 'string' then
+        destnames[k] = obj .. ' 0 R'
+      end
+    else
+      texio.write_nl("Warning: Undefined destination %q", tostring(k))
+    end
+  end
+  if next(destnames) then
+    namesdir = string.format("/Dests %i 0 R%s", nametree(destnames, pfile), namesdir or '')
+  end
+  if namesdir then
+    catalogdir = string.format("/Names<<%s>>%s", namesdir, catalogdir)
+  end
   local pages = #pfile.pages
+  if outline then
+    catalogdir = string.format("/Outlines %i 0 R%s", outline:write(pfile), catalogdir)
+  end
   pfile:indirect(pfile.root, string.format([[<</Type/Catalog/Version/%s/Pages %i 0 R%s>>]], pfile.version, pfile:writepages(), catalogdir))
   pfile.info = write_infodir(pfile)
   local size = pfile:close()
@@ -151,10 +179,10 @@ local function projected(m, x, y, w)
   return x*m[1] + y*m[3] + w*m[5], x*m[2] + y*m[4] + w*m[6]
 end
 
-local function get_action_attr(p, action)
+local function get_action_attr(p, action, is_link)
   local action_type = action.action_type
   if action_type == 3 then return action.data end
-  local action_attr = "/Subtype/Link/A<<"
+  local action_attr = is_link and "/Subtype/Link/A<<" or "<<"
   local file = action.file
   if file then
     action_attr = action_attr .. '/F' .. pdf_string(file)
@@ -190,7 +218,7 @@ end
 local function write_link(p, link)
   local quads = link.quads
   local minX, maxX, minY, maxY = math.huge, -math.huge, math.huge, -math.huge
-  local attr = link.attr .. get_action_attr(p, link.action)
+  local attr = link.attr .. get_action_attr(p, link.action, true)
   assert(#quads%8==0)
   local quadStr = {}
   for i=1,#quads,8 do
@@ -421,7 +449,7 @@ end
 local function maybe_gobble_cmd(cmd)
   local t = token.scan_token()
   if t.command ~= cmd then
-    token.put_next(cmd)
+    token.put_next(t)
   end
 end
 token.luacmd("pdffeedback", function()
@@ -500,6 +528,8 @@ token.luacmd("pdfextension", function(_, imm)
     infodir = infodir .. token.scan_string()
   elseif token.scan_keyword"catalog" then
     catalogdir = catalogdir .. ' ' .. token.scan_string()
+  elseif token.scan_keyword"names" then
+    namesdir = namesdir .. ' ' .. token.scan_string()
   elseif token.scan_keyword"obj" then
     local pfile = get_pfile()
     if token.scan_keyword"reserveobjnum" then
@@ -532,6 +562,25 @@ token.luacmd("pdfextension", function(_, imm)
         handle = do_refobj,
       })
     node.write(whatsit)
+  elseif token.scan_keyword"outline" then
+    local pfile = get_pfile()
+    local attr = token.scan_keyword'attr' and token.scan_string() or ''
+    local action
+    if token.scan_keyword"useobjnum" then
+      action = token.scan_int()
+    else
+      local actionobj = scan_action()
+      action = pfile:indirect(nil, get_action_attr(pfile, actionobj))
+    end
+    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]]
+    end
   elseif token.scan_keyword"dest" then
     local id
     if token.scan_keyword'num' then

luametalatex-pdf-nametree.lua

@@ -0,0 +1,53 @@
+local min = math.min
+local format = string.format
+local concat = table.concat
+local move = table.move
+local function write(pdf, tree, escaped, step)
+  local nextcount = (#tree-1)//6+1
+  for i=1, nextcount do
+    if #tree > 6 then
+      tree[i] = pdf:indirect(nil, format('<</Limits[%s %s]/Kids[%s 0 R]>>', escaped[step*(i-1)+1], escaped[step*i] or escaped[#escaped], concat(tree, ' 0 R ', 6*i-5, min(#tree, 6*i))))
+    else
+      return pdf:indirect(nil, format('<</Kids[%s 0 R]>>', concat(tree, ' 0 R ', 6*i-5, #tree)))
+    end
+  end
+  move(tree, #tree+1, 2*#tree-nextcount, nextcount+1)
+  return write(pdf, tree, escaped, step*6)
+end
+local function pdf_string(s)
+  -- Emulate other engines here: If  looks like an escaped string, treat it as such. Otherwise, add parenthesis.
+  return s:match("^%(.*%)$") or s:match("^<.*>$") or '(' .. s .. ')'
+end
+local serialized = {}
+return function(values, pdf)
+  local tree = {}
+  for k in next, values do
+    if type(k) ~= "string" then
+      error[[Invalid entry in nametree]] -- Might get ignored in a later version
+    end
+    tree[#tree+1] = k
+  end
+  table.sort(tree)
+  local total = #tree
+  local newtree = {}
+  for i=0,(total-1)//6 do
+    for j=1, 6 do
+      local key = tree[6*i+j]
+      if key then
+        local value = values[key]
+        key = pdf_string(key)
+        tree[6*i+j] = key
+        serialized[2*j-1] = key
+        serialized[2*j] = value
+      else
+        serialized[2*j-1], serialized[2*j] = nil, nil
+      end
+    end
+    if total > 6 then
+      newtree[i+1] = pdf:indirect(nil, format('<</Limits[%s %s]/Names[%s]>>', tree[6*i+1], tree[6*i+6] or tree[total], concat(serialized, ' ')))
+    else
+      return pdf:indirect(nil, format('<</Names[%s]>>', concat(serialized, ' ')))
+    end
+  end
+  return write(pdf, newtree, tree, 36)
+end

luametalatex-pdf-outline.lua

@@ -0,0 +1,100 @@
+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
+  -- levels, so we search the last entry which still had a smaller level
+  -- and append under that
+  local parent
+  repeat
+    parent = outline
+    outline = outline[#outline]
+  until not outline or outline.level >= level
+  parent[#parent + 1] = entry 
+end
+local function assign_objnum(pdf, outline)
+  local objnum = pdf:getobj()
+  outline.objnum = objnum
+  local cur
+  for i=1,#outline do
+    local prev = cur
+    cur = outline[i]
+    cur.parent = objnum
+    assign_objnum(pdf, cur)
+    if prev then
+      cur.prev = prev.objnum
+      prev.next = cur.objnum
+    end
+  end
+  if outline[1] then
+    outline.first, outline.last = outline[1].objnum, outline[#outline].objnum
+  end
+end
+local function get_count(pdf, outline)
+  local count = 0
+  for i=1,#outline do
+    local child = outline[i]
+    local sub = get_count(pdf, child)
+    local open = child.open
+    child.count = sub ~= 0 and (open and sub or -sub) or nil
+    count = count + 1 + (open and sub or 0)
+  end
+  return count
+end
+local function write_objects(pdf, outline)
+  local content = "<<"
+  local title = outline.title
+  if title then
+    content = string.format("%s/Title%s", content, title)
+  end
+  local parent = outline.parent
+  if parent then
+    content = string.format("%s/Parent %i 0 R", content, parent)
+  end
+  local prev = outline.prev
+  if prev then
+    content = string.format("%s/Prev %i 0 R", content, prev)
+  end
+  local next = outline.next
+  if next then
+    content = string.format("%s/Next %i 0 R", content, next)
+  end
+  local first = outline.first
+  if first then
+    content = string.format("%s/First %i 0 R", content, first)
+  end
+  local last = outline.last
+  if last then
+    content = string.format("%s/Last %i 0 R", content, last)
+  end
+  local action = outline.action
+  if action then
+    content = string.format("%s/A %i 0 R", content, action)
+  end
+  local count = outline.count
+  if count then
+    content = string.format("%s/Count %i", content, count)
+  end
+  content = content .. (outline.attr or '') .. ">>"
+  pdf:indirect(outline.objnum, content)
+  for i=1,#outline do
+    write_objects(pdf, outline[i])
+  end
+end
+local function write_outline(outline, pdf)
+  assign_objnum(pdf, outline)
+  local count = get_count(pdf, outline)
+  outline.count = count == #outline and count or nil
+  write_objects(pdf, outline)
+  return outline.objnum
+end
+local meta = {__index = {
+  write = write_outline,
+  add = add_outline,
+}}
+return function()
+  return setmetatable({}, meta)
+end