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README.md

KTX: FreeType asynchronous font loading utilities

A tiny modules that makes it easier to use gdx-freetype library along with the coroutines-based AssetStorage from ktx-async.

Why?

gdx-freetype requires quite a bit of setup before it can be fully integrated with LibGDX AssetStorage due to how LibGDX AssetManager loaders are implemented. This module aims to limit the boilerplate necessary to load FreeType fonts in LibGDX applications.

See also ktx-freetype.

Guide

This module consists of the following functions:

  • Extension method AssetStorage.registerFreeTypeFontLoaders allows to register all loaders required to load FreeType font assets. It should be called right after constructing a AssetStorage instance and before loading any assets.
  • Extension method AssetStorage.loadFreeTypeFont allows to easily configure loaded BitmapFont instances with Kotlin DSL.

Since it depends on the ktx-freetype module, it also comes with the following functions:

  • ktx.freetype.freeTypeFontParameters function is a Kotlin DSL for customizing font loading parameters.
  • FreeTypeFontGenerator.generateFont extension function allows to generate BitmapFont instances using a FreeTypeFontGenerator with Kotlin DSL.

Usage examples

Creating AssetStorage with registered FreeType font loaders:

import ktx.async.assets.AssetStorage
import ktx.async.enableKtxCoroutines
import ktx.freetype.async.*

fun initiateAssetStorage(): AssetStorage {
  // Coroutines have to be enabled. AssetStorage uses an asynchronous executor,
  // so concurrency level has to be above 0. See ktx-async documentation.
  enableKtxCoroutines(asynchronousExecutorConcurrencyLevel = 1)
  
  val assetStorage = AssetStorage()
  // Calling registerFreeTypeFontLoaders is necessary in order to load TTF/OTF files.
  assetStorage.registerFreeTypeFontLoaders()
  return assetStorage
}

Registering BitmapFont loaders for custom file extensions:

import ktx.freetype.async.*

assetStorage.registerFreeTypeFontLoaders(fileExtensions = arrayOf(".custom"))

Replacing default BitmapFont loader with FreeType font loader:

import ktx.freetype.async.*

assetStorage.registerFreeTypeFontLoaders(replaceDefaultBitmapFontLoader = true)

Loading a FreeType font using AssetStorage in a coroutine:

import ktx.async.ktxAsync
import ktx.freetype.async.*

ktxAsync {
  val font = assetStorage.loadFreeTypeFont("font.ttf")
  // font is BitmapFont
}

Loading a FreeType font with custom parameters using AssetStorage:

import ktx.freetype.async.*

val font = assetStorage.loadFreeTypeFont("font.ttf") {
  size = 14
  borderWidth = 1.5f
  color = Color.ORANGE
  borderColor = Color.BLUE
}

Accessing a fully loaded font:

import com.badlogic.gdx.graphics.g2d.BitmapFont

val font = assetStorage.get<BitmapFont>("font.ttf")

Loading a FreeTypeFontGenerator:

import com.badlogic.gdx.graphics.g2d.freetype.FreeTypeFontGenerator

val generator = assetStorage.load<FreeTypeFontGenerator>("font.ttf")

Creating a FreeTypeFontLoaderParameter with customized font parameters:

import com.badlogic.gdx.graphics.g2d.freetype.FreetypeFontLoader.FreeTypeFontLoaderParameter
import ktx.freetype.*

fun getFontParameters(): FreeTypeFontLoaderParameter = freeTypeFontParameters("font.ttf") {
  size = 14
  borderWidth = 1.5f
  color = Color.ORANGE
  borderColor = Color.BLUE
}

Generating a new BitmapFont using LibGDX FreeTypeFontGenerator:

import com.badlogic.gdx.graphics.g2d.freetype.FreeTypeFontGenerator
import ktx.freetype.*

val generator: FreeTypeFontGenerator = getGenerator()
// Default parameters:
val fontA = generator.generateFont()
// Customized:
val fontB = generator.generateFont {
  size = 42
}

Alternatives

FreeType font loaders can be registered manually. See this article. setLoader method can be used to add new LibGDX loaders to an AssetStorage.

Additional documentation