Bug concerning PDF "Optional Content" feature...

[Albert Astals Cid]

El dimecres, 15 de maig de 2019, a les 9:40:41 CEST, Édouard Canot va escriure:
> Hi,
> 
> The attached PDF file, "Labels_and_Languages_3_OC.pdf", clearly reveals 
> a bug in okular: some graphic objects are not erased when switching 
> between mutually exclusive Optional Contents (implemented via the 
> RadioButton group).

Can you please open a bug in bugs.kde.org so we can keep proper track of this?

Cheers,
  Albert

> 
> This PDF demonstrates the "Optional Content" feature... When opening it 
> with any browser, you can open the layers and choose one language among 
> three available ones (there are mutually exclusive). Most of PDF 
> browsers (Adobe Acrobat Reader under Windows, Evince under linux, ...) 
> behave well. The problem comes when using okular: when switching from 
> one language to another, the old active PDF object is not erased, and 
> all texts are overwritten on the display.
> 
> This bug appeared for me since Ubuntu-17.10 (therefore for 
> okular-1.1.3). Previously (under Ubuntu-17.04, okular-1.0.3), it was 
> correct. The bug is still present in okular-1.6.3 under Ubuntu-19.04.
> 
> The PDF has been generated by my own graphic library Muesli. You can 
> open it with any text editor since it uses only ASCII characters. To my 
> knowledge, it is standard compliant: 'mupdf' doesn't claim about any 
> errors, and the "PDF Tools Online" validator 
> (https://www.pdf-online.com/osa/validate.aspx) returns nothing special 
> about it:
> /Validating file "Labels_and_Languages_3_OC.pdf" for conformance level 
> pdf1.5//
> //    The document does conform to the PDF 1.5 standard.//
> //    Done./
> 
> Regards,
> Édouard Canot
> 
>