Lumina UI

Lumina UI is a library for building beautiful, fast and flexible interfaces in Minecraft mods.
It is a dependency for other mods: on its own it adds only a small demo (/lumina demo).

Supports Forge 1.20.1 and NeoForge 1.21.1 with the same API, so UI code written once works on both.

Why Lumina

• Looks modern out of the box. Rounded corners, borders, soft shadows, glow and gradients are drawn by an SDF shader, crisp at any GUI scale.
• Fast. Layout and styles are cached, invisible elements are skipped, nothing runs while the UI is idle, and frames render with almost no allocations.
• Flexible. Every widget, layout, style property and event can be replaced or extended with plain Java code. No reflection, no annotations.
• Reactive. Bind widgets to signals and they update themselves.

Features

• Layout: flexbox (gap, grow/shrink, justify, align), stack layers, grid, absolute positioning, responsive breakpoints, UI scale.
• Styling: themes with tokens (change the accent color or corner radius and the whole UI follows smoothly), multiple style classes, hover/pressed/focused/disabled states, per-property transitions.
• Colors: RGB, HSV, HSL, OKLCH; linear, radial and conic gradients with up to 8 stops; blend modes; backdrop blur.
• Animations: keyframes, sequences, loops, yoyo, 23 easing curves and springs.
• HTML and CSS: describe screens with markup and stylesheets, bind logic right in the markup, hot reload with F3+T, override with resource packs.
• 60+ widgets: buttons, text and number fields, sliders, toggles, checkboxes, radio groups, dropdowns, key bind fields, date and color pickers, tabs, side navigation, windows, context and radial menus, tooltips, tables, trees, virtual lists for tens of thousands of rows, charts, forms with validation, wizards, Markdown and books with syntax highlighting.
• Game widgets: inventory slots with drag and drop, mobs and the player in 3D, 3D items and block structures, world preview, minimap and world map.
• In-game HUD: bars, gauges, timers, boss bars, toasts and a notification feed, bound to live game data.
• Server-synced container screens: your own chests and machines with a Lumina UI, synced like vanilla menus.
• Config screens generated from a simple description, saved as TOML.
• Vanilla effects in the UI: fire, explosions, falling TNT, snow, rain and particles.
• Live language switching: the open screen is translated instantly, no rebuild needed.
• Accessibility: color-blindness correction, high-contrast themes, text scale, reduced motion, focus narration.
• Developer tools: UI inspector, gamepad navigation, theme editor.

Quick example

Signal<Integer> clicks = Signal.of(0);

Panel window = Panel.column().gap(10).add(
        new Label("Lumina UI").scale(1.5f),
        Label.bound(clicks.map(c -> "Clicks: " + c)),
        new Button("Press me", () -> clicks.update(c -> c + 1)));

Minecraft.getInstance().setScreen(new LuminaScreen(Component.literal("Example"),
        screen -> new UiRoot(Panel.box(StackLayout.centered()).fill().add(window))));

For developers

The developer guide covers adding the dependency, your first screen, the whole API and how to extend it: Wiki: Developer Guide.

License

Lumina UI is licensed under the GNU LGPL 3.0: you can use it in any mod, including closed-source ones; modified versions of the library itself must stay open under the same license.

For players

Install Lumina UI only if another mod requires it. Put the jar for your loader into the mods folder.