Re: OT: Pdf info

[Hans Hagen <pragma@wxs.nl>]

On 20-7-2011 2:02, Hartmut Henkel wrote:
>> 2011/7/20 Procházka Lukáš Ing. - Pontex s. r. o.<LPr@pontex.cz>:
>>> Hello,
>>>
>>> this question in not straightly related to Context, but Context users
>> may
>>> have solved it and Ctx may be used to solve it.
>>>
>>> I would need to get the following information from .pdf file(s):
>>>
>>> - number of pages,
>>> - common width and height of pages (provided that they are the same;
>>> otherwise the dimension can be e.g. zero).
>>>
>>> The final goal is to use Ctx as a .pdf joining engine - to provide this,
>> I
>>> need to know whether the .pdf to be inserted is portrait or landscape
>>> oriented, what is its size (so if to be scaled or not) etc.
>>>
>>> So Lua inside Ctx may be used to get the required .pdf info, if
>> necessary.
>>>
>>> If an external program was used, it should be non-interactive
>> (command-line
>>> oriented), free and working under Windows.
>>>
>>> Does anyone have any experience with such a task?
>> You can use some macros (see Taco), and for external programs
>> google for  mupdf and  xpdf
>>
>> Tthe lua pdf library with mkiv should be also useful, but I've still
>> to play with it.
>
> luatex's epdf library (= poppler Lua bindings, maybe that's what Luigi meant) allows to extract all this info from a pdf file, with a bit of Lua programming.

indeed (although we still need to fill in some gaps)

anyhow:

local MyDocument = lpdf.epdf.load("sometext.pdf")

context.starttext()

local pages    = MyDocument.pages
local dummy    = MyDocument.pages[1] -- we need lua 5.2 in order to 
avoid this

local nofpages = #MyDocument.pages

context.starttabulate { "|c|c|c|" }

context.NC() context("page")
context.NC() context("width")
context.NC() context("height") context.NR()

for i=1, nofpages do
     local page = pages[i]
     local bbox = page.CropBox or page.MediaBox
     context.NC() context(i)
     context.NC() context(bbox[4]-bbox[2])
     context.NC() context(bbox[3]-bbox[1]) context.NR()
end

context.stoptabulate()

context.stoptext()



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