[poppler] Direct Poppler access without frontend allowed?

[jose.aliste at gmail.com]

Hi,

On Thu, May 12, 2011 at 12:36 AM, Andreas Butti <andreasbutti at gmail.com> wrote:
> Ok, I can provide my code, but I need some help to complete integrate with
> Poppler.
>
> What I did now:
> I have two PDFs, one for background and one for the foreground, like two
> slides on a overhead projector, the second slide is on top of the first
> slide. Sometimes there are two pages, 1 foreground and one background,
> sometimes there is only one PDF.
> Not all source PDFs are used always, and sometimes PDF Pages are used twice.
>
>
> My code does the following:
>
> Extract the contents stream of the pages
> Append the stream from one page to the other page
>
> update all references, e.g. images and fonts, because /F1 in one document is
> may not the same font than /F1 in the other document
>
> Write outlines to the document (they have to be created by the application,
> because if there are pages inserted / deleted, I cannot use the original
> outlines)
> Write metadata (Creator, Autor, Creationdate etc.)
There is a patch to poppler-glib bindings to add write/edit  metadata
in bugzilla. The patch is not ready yet, but help with that would be
appreciated I think.

> Writeout the document to a file
>
> Create new XREF table
> compress the contents of the pages with GZ
>
> My application is mostly written in C++, but I use GTK (no discussion about
> this combination;-)).
>
> So I first used the GLib frontend, but there I had problems with searching,
> and I cannot access the underlying poppler objects.
So I guess it makes sense to use the glib frontend as you are using
GTK. If there are things that the glib frontend does not support, then
you should feel free to file bugs and attach patches to implement the
api you are missing. Normally, you need to divide your patches in two
parts, first, a core part if the functionality you want to add is not
already present in the core poppler, and two the glib part that gives
you access to this functionality from the glib frontend.

>
>
> The Question is now which frontend I should use.
>
>
> In my opinion, the best solution is may to create a new frontend, e.g. a
> PDF-editing frontend?
>
> Because then it's possible to change some behaviour, and add other things,
> like:
>
> Edit text within PDF documents (not add, add is no problem with merging)
> Delete objects from a PDF (e.g. select a rectangle and delete all objects
> within this rectangle)
> Copy objects

as I pointed above, the best thing is to submit bugs/attach patches to
poppler-core/ and poppler-glib to make this happen. As Albert pointed
out, you don't really need a new frontend, but instead to add some API
to the poppler-glib one. For instance, the poppler-glib frontend
already supports adding annotations, and as I mentioned, there is a
patch to support editing the metadata.

Greetings,

José

>
> Currently there is no easy to use application which support these 3
> operations for Linux.
>
> If poppler would have such a frontend I'll may append this functionality to
> Xournal++ (in the future, not now).
>
>
> What do you think about this?
>
>
>
>
> Andreas
>
> Am 11.05.2011 21:43, schrieb Albert Astals Cid:
>
> A Wednesday, May 11, 2011, Andreas Butti va escriure:
>
> Hello everybody
>
> Hi
>
> I'm working on a new Xournal version (Xournal++, not yet present on a
> webpage, only in the SVN).
>
> I used Poppler to display PDF and also for PDF export, to implement the
> PDF export (merging two PDFs together) I access Poppler without any
> frontend.
>
> I'm working on Ubuntu, which contain all necessary headers, but other
> distributions don't.
>
> Now there is a discussion if it's allowed to access Poppler without
> frontend, or not.
>
> I thought it should be allowed, because on the poppler Wiki are also two
> projects listed which access poppler without frontent,
>
> But now I need a clear answer if it's allowed or not, and if not if
> there is another way for me to implement this without breaking any rules.
>
> It is not encouraged since we reserve the right to change the API (and do
> so)
> at any release (minor versions included) while our API in the frontends is
> much more stable.
>
> If you tell us what you are missing from the public frontend API we might
> add
> it, or you might even contribute the code you have that uses the internal
> API
> so we add it to our frontend ;-)
>
> Albert
>
> Thank you for the answer.
>
>
> Andreas
>
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