Changing bootsplash

Question

I've been attempting to change the bootsplash. I've followed the instructions I've found for ubuntu 14.04 thinking they would work since it's based on that distro. I created my own theme which I'll paste the code below. Are there any special instructions since elementary OS is very heavily rebuilt?

dell.plymouth:

[Plymouth Theme]
Name=dell
Description=Dell Bootsplash
ModuleName=script

[script]
ImageDir=/lib/plymouth/themes/dell
ScriptFile=/lib/plymouth/themes/dell/dell.script

dell.script:

wallpaper_image = Image(“wallpaper.png”);
screen_width = Window.GetWidth();
screen_height = Window.GetHeight();
resized_wallpaper_image = wallpaper_image.Scale(screen_width,screen_height);
wallpaper_sprite = Sprite(resized_wallpaper_image);
wallpaper_sprite.SetZ(-100);

Answer 1

In order to use your theme you need to add and set an alternative for the default plymouth theme, and update the initrd image.

sudo update-alternatives --install /lib/plymouth/themes/default.plymouth default.plymouth /lib/plymouth/themes/dell/dell.plymouth 75
sudo update-alternatives --set default.plymouth /lib/plymouth/themes/dell/dell.plymouth
sudo update-initramfs -u

You can also test your theme without rebooting by using plymouthd and plymouth.

sudo apt-get install plymouth-x11
sudo plymouthd
sudo plymouth show-splash

Edit: Here's the slightly modified dell.script that I used for testing:

Window.SetBackgroundTopColor(0.91, 0.92, 0.91);
Window.SetBackgroundBottomColor(0.80, 0.80, 0.80);

screen.width = Window.GetWidth();
screen.height = Window.GetHeight();

dell.image = Image("wallpaper.png");
dell.width = dell.image.GetWidth();
dell.height = dell.image.GetHeight();

if(dell.width < dell.height) {
  dell.ratio = screen.height / dell.height;
  dell.x = Math.Abs(screen.width - (dell.width * dell.ratio)) / 2;
  dell.y = 0;
} else {
  dell.ratio = screen.width / dell.width;
  dell.x = 0;
  dell.y = Math.Abs(screen.height - (dell.height * dell.ratio)) / 2;
}

dell.scaled = dell.image.Scale(dell.width * dell.ratio, dell.height * dell.ratio);
dell.sprite = Sprite(dell.scaled);
dell.sprite.SetX(dell.x);
dell.sprite.SetY(dell.y);