expo-native-fonts v0.0.6

expo-native-fonts

Load fonts on iOS and Android using native code.

Traditionally, loading fonts in an Expo project requires using the expo-fonts library. While this has historically been a great solution, it has to load the fonts at runtime which necessitates you to show the splash screen.

With expo-native-fonts, font files are loaded via native code. What does that mean?

Fonts will be available immediately at runtime.

No more long splash screens!

You can change the font family, weight, and style individually.

No more fontFamily: 'Raleway-BoldItalic'!

Installation

1. Install the package:

   yarn add expo-native-fonts

2. Add your font files to a directory (we recommend assets/fonts):

   app/
   assets/
   |- fonts/
      |- Raleway-Black.ttf
      |- Raleway-BlackItalic.ttf
      |- ...

3. Add the plugin to your app.json config:

   {
     "expo": {
       "plugins": [
         [
           "expo-native-fonts",
           {
             "Raleway": [
               {
                 "path": "./assets/fonts/Raleway-Black.ttf",
                 "weight": 900
               },
               {
                 "path": "./assets/fonts/Raleway-BlackItalic.ttf",
                 "weight": 900,
                 "style": "italic"
               }
               // ...
             ]
           }
         ]
       ]
     }
   }

4. Rebuild your app as described in the "Adding custom native code" guide

5. Start using the newly-defined font in your style objects:

   const styles = StyleSheet.create({
     text: {
       fontFamily: "Raleway",
       fontWeight: "900",
       fontStyle: "italic",
     },
   });

Gotchas

Supported Font Files

This plugin has only been tested with .ttf and .otf files.

The use of other file types may not work!

Font Family Name

The key you use to define a family in the plugin config must exactly match the actual font family name defined in the font files.

To find the family name:

1. Install the lcdf-typetools package:

   brew install lcdf-typetools

2. Run the following on one of the font files:

   otfinfo --family Raleway-Regular.ttf

3. The printed value is the family name to use.

   For example, if the command printed Matter, you should format your config like so:

   {
     "expo": {
       "plugins": [
         [
           "expo-native-fonts",
           {
             "Matter": [
               // ...
             ]
           }
         ]
       ]
     }
   }

Contributing

Check out our Contributing guide for more information on reporting issues, submitting feedback, or contributing code.

Setup

To set up the repository locally on your machine, follow these steps:

1. Install the project dependencies:

   yarn

2. Create a new build:

   yarn build

Testing

To test that the project works, set up an example project app using create-expo-app and follow these steps:

1. In this repo, link the project:

   yarn link

2. In your example project repo, link the dependency:

   yarn link expo-native-fonts

3. In your example project repo, run the prebuild command:

   yarn expo prebuild --clean

Credits

Major props to @jsamr for their documentation on supporting fonts natively: https://github.com/jsamr/react-native-font-demo