LowFrame Screen API

A lightweight, styled screen and widget toolkit for Minecraft Fabric mods.

LowFrame Screen API handles the repetitive parts of custom Minecraft interfaces—screen lifecycle, widget rendering, mouse and keyboard dispatch, tooltips, and consistent styling—so you can focus on what your screen actually does.

This is a developer library. Installing it by itself does not add menus or gameplay features. It is required by mods that build their interfaces with LowFrame Screen API.

Features

• Lightweight client-side API
• Styled buttons, text fields, toggles, and sliders
• Simple base class for custom screens
• Automatic widget rendering and input dispatch
• Hover detection and tooltips
• Screen-level mouse, keyboard, character, drag, and scroll hooks
• Helpers for panels, rectangles, outlines, text, and colors
• Support for custom widgets through LFWidget
• No Fabric API dependency

Compatibility

Requirement	Version
Minecraft	1.21.11
Mod loader	Fabric
Fabric Loader	0.19.3 or newer
Java	21 or newer
Environment	Client

Minecraft changes its GUI methods between versions. Only use a Screen API release made for your exact Minecraft version.

Installation for players

1. Install Fabric Loader for Minecraft 1.21.11.
2. Download LowFrame Screen API.
3. Place the JAR in your Minecraft mods folder.
4. Install a mod that requires LowFrame Screen API.

Installation for developers

Download the JAR and place it in your project's libs directory:

dependencies {
    modImplementation files("libs/lowframe-screen-api-1.0.0.jar")
}

Add the dependency to your fabric.mod.json:

{
  "depends": {
    "fabricloader": ">=0.19.3",
    "minecraft": "~1.21.11",
    "lowframe_screen_api": ">=1.0.0"
  }
}

Quick example

import dev.lowframe.gui.api.LFButton;
import dev.lowframe.gui.api.LFScreen;
import dev.lowframe.gui.api.LFTextField;
import net.minecraft.client.gui.screen.Screen;

public final class ExampleScreen extends LFScreen {
    private final Screen parent;
    private LFTextField name;

    public ExampleScreen(Screen parent) {
        super("Example Screen");
        this.parent = parent;
    }

    @Override
    protected void build() {
        int panelWidth = 220;
        int x = (width - panelWidth) / 2;
        int y = height / 2 - 30;

        name = add(new LFTextField(x, y, panelWidth, 20, "Player name"));

        LFButton save = add(new LFButton(
            x, y + 28, panelWidth, 20, "Save",
            () -> System.out.println(name.getText())
        ));

        save.accent();
        save.tooltip = "Save the entered name";
    }

    @Override
    public void close() {
        client.setScreen(parent);
    }
}

Open the screen from client-side code:

MinecraftClient client = MinecraftClient.getInstance();
client.setScreen(new ExampleScreen(client.currentScreen));

Included widgets

• LFButton — clickable buttons with labels, actions, tooltips, and accent styling
• LFTextField — lightweight single-line text input
• LFToggle — boolean on/off control using getter and setter functions
• LFSlider — numeric slider using getter and setter functions
• LFWidget — base class for creating your own widgets
• LFScreen — base screen with rendering, lifecycle, input, and tooltip handling

Important rendering note

Minecraft 1.21.11 may apply menu blur before rendering your screen. Do not call vanilla renderBackground(...) again from an LFScreen, because Minecraft can crash with:

IllegalStateException: Can only blur once per frame

Use super.renderScreen(...) or draw your own background fill instead.

Documentation and source

• Full documentation is included in wiki/index.html in the source repository.
• Source repository: https://github.com/Astro-Tech-Inc/LowFrame-ScreenAPI/tree/main
• Issue tracker: https://github.com/Astro-Tech-Inc/LowFrame-ScreenAPI/issues

License

LowFrame Screen API uses the LowFrame Attribution-ShareAlike License 1.0.

You may use, modify, redistribute, sublicense, and sell it for any purpose. If you distribute the API or a substantially derived work, you must:

1. Give reasonable credit to Astro Tech Inc.
2. Use the same license and include its license text.

Private modifications do not need to be published.