Optifine loading screen
Optifine is not officially supported by ItemsAdder, but if you want to get more customization you can read these tutorials.
Please don't ask support about Optifine features. Thanks!
If you want you can use the alternative method which doesn't require Optifine.
Vanilla loading screen
Custom loading screen
How to do that?
Minecraft 1.15 and lower versions
You can get a GIMP template here.
Edit my file:
contents/loading_screen/resourcepack/minecraft/textures/gui/title/mojang.pngSave the file in the same location
Minecraft 1.16+
Warning: a known issue is that the logo is bugged when you use /iazip or /iatexture to apply the texture ingame.
The logo will be shown with no issue only on server join for some reason, probably an Optifine bug.
A little bit difficult: basically you have to split your image in half like I did, so you have to know how to use image editing programs (Photoshop, GIMP or Paint.net). You can get a GIMP template here.
Edit my file:
contents\loading_screen\resourcepack\minecraft\textures\gui\title\mojangstudios.pngSave the file in the same location
IMPORTANT The position of the parts needs to be precise. The left side of the texture needs to touch the top-right corner of the canvas while the right side needs to touch the center-left side of the canvas.
This is always the case, no matter the size of the actual texture!
How to change the background color (1.16+ only)
Create a new file (or edit the already provided one): contents/loading_screen/resourcepack/minecraft/optifine/color.properties
Put this content:
You can edit the colors using a HEX color picker
Do not include the # at the start of the color code!