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 is a boot splash tool, Plymouth does not provide background eye-candy for the ttys way fbsplash does (meaning it shows no decoration on the consoles after the system has booted).

Emerge
The package can be installed by running:

Kernel
Specific kernel options must be altered in order to get Plymouth working properly. Use the genkernel --menuconfig all command (or equivalent) in order to modify the kernel configuration.

Bootup logo
It is highly advised to disable the Linux bootup logo. On some systems having the bootup logo displayed seems to cause problems.

KMS for Nvidia cards (official drivers)
To use the official Nvidia drivers see the wiki's official Nvidia-drivers article.

Initramfs generators
There are currently two initramfs generators that support Plymouth. Either one will produce essentially the same result. Determining which to use, is entirely the choice of the user. This article does not go into detail on troubleshooting failed results. So, choosing the more comfortable initramfs would be a wise choice. Using genkernel-next is recommended, since many users are already familiar with using genkernel.

At this point in time, normal genkernel cannot create an initramfs with a Plymouth theme included. Therefore, in order to proceed, either dracut or will need to be selected, in order to build an initramfs capable of including a Plymouth theme. From this point onward, this configuration guide will continue presuming genkernel-next has been selected, since it is marked stable in the Portage tree and is essentially a drop in replacement for normal genkernel. Instructions for Dracut will be provided, although they are far from a full configuration.

Genkernel-Next
Continue by enabling the  USE flag in  in order for Portage to emerge genkernel-next properly:

When using genkernel-next, skip the Dracut section that immediately follows this section.

Dracut
Dracut is an alternative initram generator created by the Fedora development team. Before reading the rest of Dracut guide, here is a fun fact: both Plymouth and Dracut are cities in Massachusetts. This is speculation. However, it would appear, the creators of these programs might have taken this into consideration.

Follow this link for Dracut installation instructions.

Dracut must be configured to be used with Plymouth.

Add  as a module to the  file:

Generate a new initramfs using Dracut:

Configure GRUB2 to use Dracut initramfs:

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

Additionally, edit the file to make RC non-interactive:

Regenerate the initramfs using the genkernel command:

Systemd
Plymouth automatically registers itself with systemd to show splash screens during shutdown and restart. No additional configuration is required.

GRUB2
When using GRUB2, an update to GRUB2's configuration file must be made in order to enable the splash screen during early boot. Append the options  to the   variable, adjust the resolution in the   variable to match the desired resolution for the monitor, and set   to "keep" in order to preserve the graphics mode during the entire boot.

This all can be performed by modifying the configuration file:

Be sure to run the grub2-mkconfig command to update GRUB2's boot configuration. This will instruct GRUB2 to look at the changes made to the file above and output a configuration file accordingly:

All done! Congratulations on creating a system with a Plymouth boot splash screen! May the splash be present always!

Themes
After emerging Plymouth a number of themes will be pulled in automatically, however more Plymouth themes can be downloaded from the web and installed manually. Extract the downloaded themes to the Plymouth theme directory:

Make sure each new theme is contained in its own folder (just like the default themes that are installed) or they will not be detected by Plymouth.

Once the themes have been extracted verify successful extraction by requesting Plymouth to generate a list of all available themes. Do this using the plymouth-set-default-theme command:

Assuming the solar theme is desired as the system's theme, run:

Theme creation
It is possible to create themes for Plymouth. See the Theme creation article for more information.

External resources

 * http://dev.gentoo.org/~aidecoe/doc/en/plymouth.xml - An early Gentoo guide for Plymouth.