Ubuntu 20.04 LTS, with KDE installed on top.
Problem: When using a dark theme, text file thumbnails in dolphin use a light color for the text, but do not change the background, leading to white-on-white text, which is all but invisible. (The same problem was present under Kubuntu; I suspect it's common to all KDE Plasma sessions.)
My previous solution was to mess around with the color scheme until I found the right color ("View Text"), then switch it to a color that was visible on both light or dark background. But that's not ideal because it also controls the color of a lot of other system fonts.
This time, though, I want to do it the right way and find a way to:
A) Change the background of text file thumbnails to a darker theme color, so the white text on top is visible.
B) Change the color used for the text file text to either be hardcoded as black (since the background seems to be hardcoded), or to use one of the darker theme colors.
C) Maybe actually contribute this change as a change to the repository, since many other people are surely dealing with it ... though they may not realize or care.
To do this, though, I'll really need to get into the weeds of how Dolphin (or KDE itself) generates thumbnails for text files. Can anybody point me in that direction? What package in particular actually generates the thumbnails? Does it have a config file somewhere? Is it part of Dolphin, or part of KDE in general?
I'm not the best coder, but I think this would be within my abilities to change ... if I could find the code that actually does it. I've been poking around the Dolphin Github, but haven't found anything promising so far. If I could find the code there that calls the thumbnail-generating code, maybe I could follow the trail from there.
