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Modding Library

A declarative, reactive UI component library for Minecraft 1.21.4 Fabric mods, written in Java 21. Build screens by composing components instead of subclassing Screen and writing imperative init() / render() boilerplate.

import static org.triggersstudio.moddinglib.client.ui.api.Components.*;
import static org.triggersstudio.moddinglib.client.ui.styling.Styles.*;

State<Integer> counter = State.of(0);

UIScreen screen = Screen(Column(
        padding(20).backgroundColor(0xFF_1A_1A_1A).build(),

        Text(counter.map(v -> "Counter: " + v),
             fontSize(16).textColor(WHITE).build()),

        Button("+1", height(28)
                .onClick((x, y, btn) -> counter.set(counter.get() + 1))
                .build())
));

MinecraftClient.getInstance().setScreen(screen);

What's inside

• Composition API — Components.Row(...), Components.Column(...), vararg children or Consumer<ContainerScope> builders.
• Reactive state — State<T> with map, combine, bindBidirectional, automatic threading hop to the render thread.
• Rich components — Text, Button, Image, TextField, TextArea, Sliders (5 numeric types), ProgressBar, Pagination, Accordion, ComboBox, SelectList, Calendar, ColorPicker, Skeleton, Spinner, Tooltip, Toast, Charts (Line/Bar/Pie), PlayerRender.
• Animations — Tween (time-based) and Spring (physics) interpolators, full Penner easing family, Bezier and step curves, ColorTween for ARGB. FadeIn, FadeOut, SlideIn shortcuts.
• Styling — Style.Builder with size, padding, margin, background, border, radius, opacity, font, alignment, click handler.
• Client↔server channel — typed plugin-messaging on top of a shared Envelope codec, with a companion moddinglib-spigot plugin that exposes a simple register(pluginId, action, handler) / send(player, ...) API to other Spigot plugins. See Networking.

Project layout

The repo is split into three Gradle modules so the Fabric mod and the Spigot server plugin can share a single source of truth for the wire format without dragging each other's runtime deps along:

Module	Artifact	What it ships
:common	moddinglib-common	Pure-Java protocol: Envelope record, VarInts codec, channel name. No MC / Fabric / Bukkit imports.
:fabric	moddinglib	The mod itself — every UI component, animation primitive, video player, etc. Bundles :common via Loom include.
:spigot	moddinglib-spigot	Server-side companion plugin exposing ModdingLibApi for downstream plugins.

Read next

• Getting Started — install + your first screen.
• Concepts — UIComponent, State<T>, lifecycle, focus, layout flow.
• Styling — Style.Builder, helpers, color constants.
• Components — index of every component, organized by family.
• Animations — Tween, Spring, Easing, ColorTween.
• Networking — Envelope protocol and the Spigot-side ModdingLibApi.
• Devmode & Examples — /demomenu subcommands and bundled example screens.

Status

• Minecraft: 1.21.4
• Fabric Loader: 0.17.2
• Java: 21

For the canonical roadmap (shipped / on side branch / planned / under discussion), see FEATURES.md in the main repo.