Wrong rendering of PDF files in Okular

[Darkmaster006]

Hello! I hope someone can help me with this or direct me to where I can report this “bug”. Basically, I have seen a problem in Okular (and, for a fact, in some other PDF readers), where some files cannot be rendered “properly”, or at least in the most “readable” way. What do I mean by this? Well, let’s show some comparisons:

Default PDF viewer from Linux Mint: https://images2.imgbox.com/bd/8b/qFzQQ3cP_o.png

Okular: https://images2.imgbox.com/35/e0/SiEpq6OO_o.png

Default PDF viewer: https://images2.imgbox.com/6d/44/0Cf4ul3p_o.png

Okular: https://images2.imgbox.com/70/bc/uM6JJmUR_o.png

As you can see clearly, Ganshof’s book is difficult to see (looks even worse on the actual file and not the screencap); while MALLIMACI’s is outright unreadable. I can provide both these files if there’s a need to test this. Files for testing: aHR0cHM6Ly9tZWdhLm56L2ZpbGUvTmlGV0FBSWEjU09xZTgtdmJUSm02YWVETkQyMU1GU3pHcWdabnl1R2tuS2xyX0JsbVA5MA== aHR0cHM6Ly9tZWdhLm56L2ZpbGUva2lrMjFTWUEjd2xYUFlRQXNQYjdwckN1Umdvdk9jVUt1NE1FMFdPUmx2NUdPUlkyOWh2aw== b64. Any help is appreciated, thank you.

[Paul_Brown]

You can report bugs to

https://bugs.kde.org

[dzon]

Why the base64. Anywho, out of curiosity…I ran this in okular, onlyoffice and libreoffice.

The , by far, both slowest and worst quality: Libreoffice.

Second, Okular.

Best quality and fastest…onlyoffice.

Okular was…ok-ish as far as I can tell.

[Darkmaster006]

Hmm, that looks similar to mine in the Default Mint PDF viewer, I wonder what could have changed?

[dzon]

I have no idea. I tested a geometrical circular and…well, it’s pretty obvious.

In onlyoffice and some web browser:

And Okular:

[medin]

What you see as good quality is just some extra smoothing added on top of bitmap image, the images inside that pdf file are originally of poor quality.

MasterPDF Editor - Without bitmap smoothing:

MasterPDF Editor - With bitmap smoothing:

So the problem is that Okular image antialiasing even if enabled is simply broken.