[Enhancement] Make Editor file preview background color customizable

[João Victor Bohrer Munhoz]

I've recently transitioned to dark mode on Calibre due to eye-strain issues.

While the different color scheme took a while to get accustomed to, there is a jarring flaw to the dark mode philosophy in which the Calibre Editor file preview still has a default white background, even though there is no CSS setting any background color.

It would be interesting having the option to customize the file preview default background and font colors. Those default colors would obviously be overwritten by the colors coded through CSS, if any.

While my goal is setting the background color to black and font color to white while on dark mode, the more choices you give to the user, the better.

[Kovid Goyal (kovid)]

Fixed in branch master. The fix will be in the next release. calibre is usually released every alternate Friday.

 status fixreleased

[Jon Wolf (jswolf)]

I find the new change to not be good. I preferred to see the preview as it would be in most cases. Please either put it back or give us an option to put it back but default it to the light view. I would have changed from dark mode had the preview been dark.

[Kovid Goyal (kovid)]

If you dont like dark things, dont use dark mode.

[João Victor Bohrer Munhoz (jvmunhoz)]

Thanks for getting to this so fast Kovid Goyal. Dark mode feels much better.

While I do agree that an option to change it back to light mode would be interesting to users, this dark background makes much more sense being the default one on dark mode.

[Simone fusi (simone-fusi)]

I agree with jswolf. I prefer for the editor the dark mode interface but I think the preview is much more useful and easy when mimicking an actual ebook reader - ie with a clear background.
While the fonts used in the main program and editor are easy on the eye in dark mode, the ones used in ebooks are not so. Maybe it's totally subjective, but I find reading the preview really tiring.
Replying to Kovid, It's not that I don't like dark things (I prefer dark mode configuration in Calibre), it's that non everything is better - the preview certainly not.
Moreover, it's buggy; while

body {
background-color:rgb(128,128,128);
}

works flawlessly in the sylesheet in light mode, in dark mode is overridden and the background is fixed.