Basically, I want a viewer which has a night mode or a dark mode so that I can change a pdf with a white background and black text to a dark background and light coloured text.
This method is only for text only documents. Otherwise the image colors will be inverted.
You can install Evince document viewer from this link and open it.Then goto the options on the top right corner as seen in the picture.
Then select Inverted colors. This will help you to read white text on a black background. In Evince document viewer 3.30.1+ select Night Mode.
Simply inverting colors doesn't provide the best readability (being limited to very bright white text on very dark black background), although it can improve it a lot in a dark environment.
Evince, Okular and also pdfstudioviewer can do that, which will result in something like this (in both image and text pdfs):
PDF readers that can change both page and text color in both text and image (scanned text) pdf files are:
I think this is more readable:
Adobe Reader 9, which can still be used in Linux, can change both text and background color but only in text-based pdf files. More here.
See my linked answer on Foxit Reader, which can match Adobe Reader but has no dark GUI and no full-screen.
Calibre Ebook Reader (like many ebook readers) can edit colors of font and page, but it can also open text-based pdfs.
I found all these answer are usefull then finally found this
xcalib -i -a
This inverts all the screen , everywhere. So no need to find if a particular software have this feature or not. I can set a hotkey and now whenever I want dark mode I just need to press the Hotkey, works even for browser.
sudo apt-get install xcalib
i was searching for X software too and i could not find one my bad solution...using vim with a plugin ( Plug 'makerj/vim-pdf') let you do it just make sure your terminal is readable and you book as no real image and your set here a link to the "plugin" https://github.com/makerj/vim-pdf
how about Foxit Reader? ( a big name on Windows - although the Linux version seems like minimal version )
It allows us to view a PDF in many better ways than Inverted Colors so you can choose what is suit for you ( and your eyes)
thanks @bodqhrohro for the image
Get it officially here: http://www.foxitsoftware.com/products/pdf-reader/