fedimoji

A system to display custom emojis in Minecraft, using a server-provided resource pack. It works with completely Vanilla clients, as long as they accept the resource pack.

On the server side, it currently requires use of the Styled Chat fabric mod with some configuration. Of course, the server must also be configured to present the resource pack to clients.

A companion server-only mod is planned, which will add some commands for searching and previewing the available emoji without having to send one in chat just to see it. That mod will probably not remove the need for Styled Chat, as that would be much more of a hassle and isn't really needed.

There's a limit in this implementation of 65534 emoji. Technically it could be increased to 137468 but I don't see that as necessary.

Some notes

The notation \u0000 seems to work correctly in the chars array for the normal Private Use Area (part of the BMP) but not the higher Private Use Planes. I advise you to always just use the character in question directly (e.g. when editing config files). (I put \uF0000 rather than 󰀀 in the resource pack and a bunch of other random chars on the screen became half a neofox lol)

How it works

TL;DR: We assign a codepoint in Unicode's Private Use Areas to each emoji, and put all the emoji images in one image file so Minecraft can use it. We add to the definition of the default Minecraft font so that it displays these characters using the emoji. Styled Chat is configured to allow people to type (for example) :neofox: and have it be mapped to the correct special character when sent.

This repository contains a tool to take a bunch of emoji packs as input and output all the files needed to actually put it in Minecraft.

It resizes all the emoji to 64x64 pixels (chosen by seeing how small I can make a neofox before it looks bad) to save space (clients need to download this when joining, remember) - and combines them into one image. This font bitmap is 1 glyph wide (though the Minecraft default fonts use a 16-glyph wide one - I don't know if this matters) and as many tall as is needed.

To each emoji it assigns a unique Unicode codepoint in the range U+F0000 to U+FFFFD. We're only using the Supplementary Private Use Area-A because I wanted to use one continuous region of Unicode, but wanted more than the 6400 possible codepoints in the ordinary Private Use Area.

It then makes a set of strings that tell Minecraft which codepoints map to where in the provided image. Each string represents a new row in the image, and each character is what character is to use the glyph in the corresponding position in the image. Blank parts of the image are \u0000, as each string must define the same number of glyphs.

How to use it

At the moment, this process isn't fully automated. You can't just provide a few URLs or zip files of emoji packs and have it just work. Maybe in the future.

Note: This may use a lot of RAM, given it loads all the files into memory and processes them there.

For now, here are the steps:

Just dump a bunch of PNGs (non-square images will be shrunk to fit) in ./emoji/ with the file names being the names they'll be used as in-game.
Run the program. cargo run --release (--release for performance reasons) should do. If it gives any errors or advice, take note of those. If you are modifying an existing pack you've made, point the --import argument at your old fedimoji.json to keep the codepoints for existing emoji. This ensures signs people have already written using the emoji continue to render correctly. If you've renamed some emoji, make the changes to the names in this fedimoji.json so the import works right.
Arrange the output files in the following way.

I've provided a template for the resource pack (./template-resource-pack/), containing everything that isn't specific to your input. Make a copy of that (or don't). You'll be putting some of the generated files in there to make it yours. Further docs assume it's been copied to ./pack/, such that ./pack/pack.mcmeta exists.

The following files will be output into ./out/, and existing files there will be overwritten.

`emoji.png`

This is the font bitmap, an atlas of all the custom glyphs.

It is copied to ./pack/assets/fedimoji/textures/font/emoji.png.

`emoji.json`

This is the definition of the font provider, which tells Minecraft how to display the custom glyphs.

It is copied to ./pack/assets/fedimoji/font/include/emoji.json.

`fedimoji.json`

This tells the Styled Chat mod how to map emoji names (like :neofox:) to character codepoints.

You will need to perform some configuration of Styled Chat.

First, copy fedimoji.json from the output directory to config/fedimoji.json in your Minecraft server.

Next, add an emoticon entry to your Styled Chat config:

Assuming you're using the default style (adapt this yourself if not), add the entry "$default:from_file:fedimoji.json": "${emoji}" to default.emoticons.
I would also recommend changing auto_completion.emoticons to true so that people can tab-complete the emoji names in chat.
I'd also remove the "$emojibase:builtin:joypixels" entry under emoticons, and perhaps all the others if you want, so that people can only use the emoji you've added. They'll look way better, anyway.

Here's a JSON snippet of those changes, for clarity:

{
    "auto_completion": {
        "emoticons": true
    },
    "default": {
        "emoticons": {
            "$default:from_file:fedimoji.json": "${emoji}"
        }
    }
}

Resource Pack Preparation

You need to turn the ./pack/ dir (or whatever you used) into a ZIP file, and configure your server to give it to clients.

Before you do that, however, you can make any changes you want to the pack. Here's my recommendations:

Edit the LICENSE file I have in there in the template, crediting all the artists whose work you're redistributing. Remember, you'll be serving this resource pack file to everyone who joins your server.
Edit the description key in pack.mcmeta to something you want.
Change the pack.png.

Conclusion

Sorry for the lacklustre documentation (and general UX), I'm mostly making this for myself. It got enough fedi interaction, though, that I thought I should at least write something about how to use it. And besides, I'm assuming anyone doing this knowns enough about doing admin stuff that they can figure it out.

Seercat3160 / fedimoji