GUI Maker Fabric (1.21.1)

Java-only Fabric conversion of the original GUI Maker datapack:

• Target: Minecraft 1.21.1 + Fabric
• No internal mcfunction usage
• Multiplayer-safe persistent server state

What is implemented

• Persistent GUI profiles/pages in Java (PersistentState)
• Virtual chest-style GUIs opened directly from Fabric code
• Multiplayer-safe per-player caching for:
  • Item Holders
  • Toggle Buttons
• GUI export/import as a custom barrel item
• Datapack-like slot metadata parsing from item custom_data.gui
• Server commands for creating, editing, deleting, exporting, importing and opening GUIs
• Java callback registry for button functions
• Java item-modifier registry for dynamic item rendering

Core commands

Create/list/delete

• /guimaker profile create
• /guimaker profile list
• /guimaker profile delete <guiId>

Capture pages from a container block below the player

• /guimaker page capture <guiId>
• /guimaker page capture <guiId> <name...>
• /guimaker page list <guiId>
• /guimaker page rename <guiId> <page> <name...>
• /guimaker page delete <guiId> <page>

Open GUI for players

• /guimaker open <targets> <guiId>
• /guimaker open <targets> <guiId> <page>

Special items

• /guimaker items

This gives:

• Item Holder [UNCACHED]
• Item Holder [CACHED]
• Toggle Button [UNCACHED]
• Toggle Button [CACHED]
• Data Driven Item Button
• Data Driven Page Creator

Edit slot config

• /guimaker slot icon <guiId> <page> <slot> (copies mainhand item)
• /guimaker slot type <guiId> <page> <slot> <simple|holder|toggle|data_button|data_page_creator>
• /guimaker slot cached <guiId> <page> <slot> <true|false>
• /guimaker slot togglelist <guiId> <page> <slot> (captures states from container below player)
• /guimaker slot clear <guiId> <page> <slot>

Edit slot actions

• /guimaker slot action clear <guiId> <page> <slot>
• /guimaker slot action command <guiId> <page> <slot> <command...>
• /guimaker slot action function <guiId> <page> <slot> <namespace:id>
• /guimaker slot action itemmodifier <guiId> <page> <slot> <namespace:id>
• /guimaker slot action sound <guiId> <page> <slot> <namespace:id>
• /guimaker slot action changemenu <guiId> <page> <slot> <targetGuiId> <targetPage>

Import / export

• /guimaker export <guiId>
• /guimaker export <guiId> <targets>
• /guimaker import

Hold the exported barrel in your main hand and run /guimaker import.

Java extension points

Button callback registry

Register callbacks through GuiMakerApi.registerButtonCallback(...).

Built-ins:

• guimaker:close
• guimaker:refresh
• guimaker:message

Item modifier registry

Register item modifiers through GuiMakerApi.registerItemModifier(...).

Built-in:

• guimaker:noop

Notes

• This mod intentionally replaces the datapack's command-function backend with Java logic.
• The chest GUI is virtual; it is not implemented through marker entities + tick polling.
• data_driven_button and data_driven_page_creator are recognized and preserved, but their advanced datapack behavior is left as extension points for future Java-side expansion.
• The workspace environment used to generate this project does not include Java 21, so the project was prepared but not built inside the sandbox.

Build

Use Java 21.

./gradlew build