When Okular is setted in dark mode by OS theme or in Okular settings, in addition to the interface being dark, the PDF should turn black aswell, white background becomes black and white text becomes white/greyish, and picture white background becomes black, and for non B&W text/BG/picture you decide between invert color, let as is or modify only if it's too near to B&W (to not experience invisible picture), or maybe a liiiiitle white border around picture borders. And to not disapoint the user you make appear a banner to ask if the user wants to continue to use this PDF dark mode or to view this document in original colors or to always view original document color
black text*
invisible contents*
liiiiitle white/greyish border*
And neededless to say, you create an entry in the parameters to toggle this function manually and maybe to customize it a little
Are you aware of the “Change Colors” feature (Settings -> Configure Okular -> Accessibility)? It provides “Invert Colors”, but without any intelligence concerning pictures. Can you describe what you wish additionally to that?
The defaultness depending of the OS/Okular color settings, the banner, maybe the "picture intelligence" (or maybe not if you prefer to charge the user for transparency of pictures), turn grey instead of white for text (less aggressive), if picture border is adopted grey too
Are you basically asking for this "dark/inverted colors mode" to be invoked automatically when the system is using a dark theme or color scheme?
Yeah
Could make sense. Kate now does this, and it's been very well received by users. Perhaps we could use the "change light and dark colors" feature, and plug in appropriate colors from the color scheme. We would probably want to make it optional though.