Submitted by def..@..ce.net
Created attachment 287116 the proposed alternative view mode
The problem is that it's hard to read black letters on white background for a long time, at least for some people, which was described at https://bugzilla.gnome.org/show_bug.cgi?id=321823. The existing solution, to invert colors, usually leads to excessive contrast, and colors become, well, inverted, which is not always satisfactory.
Some people use xcalib to solve that (http://askubuntu.com/questions/191579/how-to-change-pdf-background-color-in-evince), but it's more like a hack. Some document viewers provide monochrome document view mode, with altered colors, but that leads to loss of colors, and is not that nice again (though that's what I was using before).
So, now I've solved it for myself by converting image data into HSV, inverting V (like GIMP's "value invert"), then tweaking V a little more, and decreasing S, which results in what is pictured on the attached snapshot, and want to commit such functionality into Evince. But need to find out if such a commit would be welcome, and to figure out how exactly to add it, as long as I see at least three options:
- Replace the current inversion with that.
- Add it as another option, and maybe a few more presets - so users will be able to choose what works best for them.
- Add Guile support for such tweaks, so users will be able to tweak colors as they want.
The third option could cause a performance drop, and would be a relatively big change, but otherwise it should be the most user-friendly, I guess.
Was not able to attach additional snapshots, so here are links to all three (original, inverted, and proposed) view modes: http://paste.uberspace.net/evince-original.png http://paste.uberspace.net/evince-inverted.png http://paste.uberspace.net/evince-new.png