luametalatex/luametalatex-pdf-pagetree.lua

66 lines
1.8 KiB
Lua

local min = math.min
local format = string.format
local concat = table.concat
local pdfvariable = pdf.variable
local function write(pdf, tree, total, max)
tree = tree or pdf.pages
if #tree == 0 then
local id = pdf:getobj()
pdf:indirect(id, '<</Type/Pages/Kids[]/Count 0>>')
return id
end
max = max or 6 -- These defaults only work on the lowest level
total = total or #tree
local remaining = total
-- if #tree == 1 then
-- retur
local newtree = {}
local parent = ""
for i=0,(#tree-1)//6 do
local id = tree[-i]
newtree[i+1] = id
if 0 == i % 6 and #tree > 6 then
local parentid = pdf:getobj()
newtree[-(i//6)] = parentid
parent = format("/Parent %i 0 R", parentid)
elseif #tree <= 6 then
parent = pdfvariable.pagesattr
end
pdf:indirect(id, format('<</Type/Pages%s/Kids[%s 0 R]/Count %i>>', parent, concat(tree, ' 0 R ', 6*i+1, min(#tree, 6*i+6)), min(remaining, max)))
remaining = remaining - max
end
if newtree[0] then
return write(pdf, newtree, total, max*6)
end
return newtree[1]
end
local function newpage(pdf)
local pages = pdf.pages
local pagenumber = #pages+1
local pageid = pages.reserved and pages.reserved[pagenumber] or pdf:getobj()
pages.reserved[pagenumber] = nil
pages[pagenumber] = pageid
if 1 == pagenumber % 6 then
pages[-((pagenumber-1)//6)] = pdf:getobj()
end
return pageid, pages[-((pagenumber-1)//6)]
end
local function reservepage(pdf, num)
local pages = pdf.pages
if pages[num] then return pages[num] end
local reserved = pages.reserved
if reserved then
if reserved[num] then return reserved[num] end
else
reserved = {}
pages.reserved = reserved
end
reserved[num] = pdf:getobj()
return reserved[num]
end
return {
write = write,
newpage = newpage,
reservepage = reservepage,
}