Plymouth

Plymouth is used to show splash screens during system boot and shutdown. It is a more modern alternative to fbsplash and provides flicker-free animated boot splashes with support for progress bars, solar flares, and other nifty things. In addition to OpenRC, it also has full systemd support. Since it a boot splash tool, Plymouth does not provide background eye-candy for the ttys in the way fbsplash does (meaning it shows no decoration on your consoles after the system has booted).

Installation
can be installed using

Themes
After emerging Plymouth number of themes will be pulled in automatically, however you can download more Plymouth themes from the internet and install them manually. You can extract new themes to the default Plymouth install directory:

Make sure each new theme you add is contained in its own folder just like the other themes that are installed.

Once you have extracted any new, additional themes, you can check your work by requesting Plymouth to generate a list of all themes can be found. You do this by using the  command:

Assuming you want to select the solar theme as the default theme:

Kernel Configuration
You will most likely need to recompile your kernel in order to get Plymouth working properly. Use the  command (or equivalent) in order to modify your kernel configuration.

It’s highly advised that you disable Linux logo. On some systems it seems to cause problems:

Be sure you enable kernel modesetting for your respective graphics card.

For Nvidia graphic cards using the closed source official Nvidia drivers
To use the official Nvidia drivers see the wiki's official Nvidia article.

Genkernel-Next
At this point normal genkernel cannot create an initramfs with a Plymouth theme included. Therefore, in order to proceed, you will need to select either dracut or to build your initramfs with a Plymouth theme included. From this point onward this configuration guide will continue presumming you've genkernel-next since it is marked stable in the Portage tree and is essentially a drop in replacement for "normal" genkernel, however plans for dracut The "plymouth" use flag needs to be enabled in.

Dracut
The Dracut portion of this article is a work in progress. More information will be added soon.

OpenRC Configuration
Use your text editor of choice to enable Plymouth and the Plymouth theme in genkernel-next's configuration file:

Additionally, you will need to edit to make RC non-interactive:

Regenerate the initramfs using the  command:

Make an update to your Grub2 configuration to enable the splash screen during early boot. Append the options "quiet splash" to the GRUB_CMDLINE_LINUX_DEFAULT variable, adjust the resolution in the GRUB_GFXMODE variable to match your desired resolution for your primary screen, and set GRUB_GFXPAYLOAD_LINUX to "keep" in order to preserve the graphics mode during the entire boot.

Finally, run the  command to update Grub2's boot configuration. This will set Grub2 to be sure to include the changes you made when you updated file above.

You are done! Congratulations on your new boot splash!

Systemd Configuration
Plymouth automatically registers itself with systemd to show a splash screen during shutdown/restart.

External Resources
Plymouth Main Project Page

Plymouth Source Code Page

An Early Gentoo Guide for Plymouth

Wikipedia Page