[poppler] PDF with layers

[Valerio Messina]

On 4/4/23 8:09 PM, Pablo Rodríguez wrote:
> Your statement is extremely broad and it might be false, since OCGs are
> supported in poppler.

OK, sorry, maybe it is related to poppler-utils only


> In the merge you provided at the GitLab report, OCGs aren‘t merged in a
> single OCG.
> 
> What might be the case here is that OCGs from the second document are
> simply being ignored.
> 
> Since you provided two documents with exactly the same OCG names, it is
> impossible to see that OCGs from the second document are simply ignored
> (not their content).
> 
> This explains the behavior you describe in your bug report.

no, the pdfunite output has no layers, see below


> If you allow me one more comment, please create two minimal files with
> one OCG each and merge them and explains what happens in the issue at
> GitLab.

OK, I admit that three test files from open bug date 5 years ago are 
confusing.


Lets focus on PDFlayers_tst3* files only, the last posted i the report, 
that are minimal and simple:

File 1, 4 layers: Level 1, Background 1, Level 2, Background 2
gray circle on Level 1
black rectangle on Background 1
Level 2 and Background 2 are empty
https://gitlab.freedesktop.org/poppler/poppler/uploads/40f9db4e9a18bbade826f99d3036019b/PDFlayers_tst3_pg1.pdf


File 2, 4 layers: Level 1, Background 1, Level 2, Background 2
black circle on Level 2
gray rectangle on Background 2
Level 1 and Background 1 are empty
https://gitlab.freedesktop.org/poppler/poppler/uploads/b91f5ea252ed31b2eb6be756f5789040/PDFlayers_tst3_pg2.pdf


The merged, 2 pages file generated by 'pdfunite' is:
File 3, NO layers: All contents merged to one layer in both pag.1 and 2
https://gitlab.freedesktop.org/poppler/poppler/uploads/96c05c385c3ab7f2d1e7db7520715ad4/PDFlayers_tst3_pdfunite22.03.0.pdf


The reference (expected) output shuold be:
File 4, 4 layers: Level 1, Background 1, Level 2, Background 2
gray circle on Level 1 pag.1
black rectangle on Background 1 pag.1
black circle on Level 2 pag.2
gray rectangle on Background 2 pag.2
https://gitlab.freedesktop.org/poppler/poppler/uploads/c10e8f6a1064e27b323ecc1583dc28f2/PDFlayers_tst3_Scribus1.5.3.pdf


All 4 files are already linked in gitlab, last my two posts from past year.


> But if part of the issue you mention is guessing what is misbehaving in
> poppler, this won’t help to speed up the potential fix.

yes, my knowledge of english is poor, so I cannot explain as I want, 
again sorry.

-- 
Valerio