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Version: 26.1.2 (Latest)

Updating from 1.21.1 to 26.1.2

This update changes how book styling is defined.

Summary​

If your 1.21.1 book used custom textures, colors, layout offsets, or other book styling fields, you will need to migrate that styling into a separate theme.json file and update how the textures are organised.

The main change is:

  • book.json now focuses on book content and structure.
  • theme.json now contains book appearance, layout, sprites, and palette data.
  • Instead of the old manual texture atlases (book_overview.png, book_content.png, ...) each sprite now lives in its own file under resources/assets/<modid>/textures/gui/sprites/modonomicon/themes/<themeid>/.../. Minecraft then automatically assembles an atlas. This allows more flexible override of modonomicon textures and fully supports the .mcmeta format for e.g. texture tile, nine_slice or stretch instructions.

See also:

What changed​

theme.json is now required for custom styling​

Book appearance data is no longer stored inline in book.json.

This includes old styling values such as:

  • frame and content textures
  • crafting and recipe textures
  • frame overlays
  • text and title colors
  • text and button offsets
  • category icon scale
  • single page texture overrides

If you had a styled book on 1.21.1, that styling now belongs in theme.json.

Datagen API changed​

If you generate books in code, the datagen API changed as well.

The old BookModel styling setters were replaced by a theme-based setup. Use a theme model and attach it with withTheme(...) instead of configuring textures and palette values directly on the book model.

Theme system and registry were added​

Themes are now backed by a dedicated runtime theme system.

For normal custom themes, use your own theme id together with the default theme type and place your files into the correct theme folder. Only use a custom theme type if you also register a custom Java theme implementation.

The old atlases were split into individual sprites​

The old manual atlases such as book_overview.png, book_content.png, and similar shared GUI sheets were split into many individual sprite files under the theme folder. Minecraft now assembles the atlas automatically from those sprite files.

This makes it easier to override only the parts you care about, and it also adds proper .mcmeta support for things like tile, nine_slice, and stretch.

If you previously maintained custom versions of the old manual atlases, see the automation section below for help splitting and converting them.

Partial theme overrides now work well​

You can override only the individual files you want to change. If a theme file is missing, Modonomicon falls back to the default built-in theme asset for that file.

Regenerate generated data​

After migrating, rerun datagen so the generated book resources include the new theme output.

How to update​

Datapack / JSON users​

  1. Visit the Demo Book and review how book.json and theme.json are set up.
  2. Keep your book structure in book.json.
  3. Move old visual styling into a new theme.json next to the book data.
  4. Set the correct theme id and usually keep type as modonomicon:default.
  5. Place any custom theme textures into the matching theme asset folder.
  6. Test the book in game and confirm buttons, backgrounds, node connectors, and recipe visuals render correctly.

Datagen users​

  1. Visit the Demo Book Datagen and review how it sets up the book model.
  2. Remove old inline styling calls from your BookModel setup and instead delegate to .withTheme(...).
  3. Optionally register your own theme class (see Theme.json) if you want to override rendering behaviour or use sprites with custom sizes.
  4. Run datagen again.

Need help converting old custom styling?​

If you had a heavily customized 1.21.1 book, the conversion can be tedious.

Join the Discord and ask about the script that can automate conversion of old custom styling data:

https://dsc.gg/klikli

  • open the book in game
  • verify the overview screen styling
  • verify entry backgrounds and node connections
  • verify recipe page backgrounds
  • verify frame overlays and text colors
  • rerun datagen if generated resources are missing