I want gdm, lightdm, something--anything--other than the default one in KDE. I'm not talking about the login manager or anything, that I have set to gdm. I'm talking about the lock screen with the ugly background that gets messed up visually with any theme and doesn't look cool to begin with unless you like the stock kde look. Any ideas?
I think changing only lock screen, not the login manager (i.e diplay manager) would be littl hard. But as you told in the question, you can change the lock screen background.
Simplest way to do that would be overwrite the
/usr/share/wallpaper/Elarun/content/images/1366×768.png image with your custom one with same name.
But there is another and safer way to do that.
Not that here
~/.kde4 may be diffrent according to you kde version
mkdir -p ~/.kde4/share/wallpapers/MyWallpaper/contents/images cp yourImage.png ~/.kde4/share/wallpapers/MyWallpaper/contents/images/1366x768.png
Now create a file
~/.kde4/share/wallpapers/MyWallpaper/metadata.desktop with following contents
[Desktop Entry] Name=MyWallpaper X-KDE-PluginInfo-Name=MyWallpaper
Now modify your plasma theme metadata fiel to use this file.
~/.kde4/share/apps/desktoptheme/< your_Theme_Name >/metadata.desktop
(if this file is not present, create one) and fillowing contents.
[Wallpaper] defaultWallpaperTheme=MyWallpaper defaultFileSuffix=.png defaultWidth=1366 defaultHeight=768
defaultHeight according to your resolution.