I installed Lubuntu 20.04 LTS and I did the upgrade of system (sudo apt upgrade).
But this function don’t work. I installed Evince and I setting as default PDF reader, but don’t work.
As you see in image above, the pdf thumbnail don’t show. I installed Nautilus and the thumbnails work well, just PCManFM that don’t work.
I tried with official Ubuntu 20.04 LTS on live mode and thumbnails work well. I installed PCManFM-qt on Ubuntu and worked too! See the picture:
Thanks for response. I finally understood how thumbnails are produced.
The guy of your link use graphicsmagick to generate thumbnails, but in my tests its so slow to execute. Evince was more fast.
I tested against a book of 828 MB six times:
time gm convert -quality 100 -thumbnail 128 -flatten Biology.pdf[0] 1.png
real 0m15,729s
real 0m7,861s
real 0m10,055s
real 0m8,773s
real 0m8,416s
real 0m11,417s
# File generated had 23,6 KiB
time evince-thumbnailer -s 128 Biology.pdf 2.png
real 0m0,250s
real 0m0,250s
real 0m0,273s
real 0m0,249s
real 0m0,251s
real 0m0,249s
# File generated had 25,4KiB
Evince takes less 1 second to generate the thumbnail whereas graphicsmagick takes 10 seconds in average.
Do you know some alternative of thumbnailer for LXQt as fast as Evince ?
I really liked of qpdf and I want takes just one PDF reader in my machine, but I think that feature is essential when you have a lot of pdf documents to check in the work.
Another problem that I found is that evince-thumbnailer just work in Lubuntu 18/20.04 if I disable apparmor.
I did and restart:
In my tests here, neither graphicsmagick nor pdftoppm can generate thumbnails on top of the SMB protocol. Evince-thumbnailer can if apparmor had disabled.
I will continue using pdftoppm, but if someone need this feature over SMB those people will have to change to Evince.