This plugin adds font settings button in the GitBook website.

This is a default plugin and it can be disabled using a book.json configuration:

{
    plugins: ["-fontsettings"]
}

This plugin can be configured in the book.json:

Default configuration is:

{
    "pluginsConfig": {
        "fontsettings": {
            "theme": 'white', // 'sepia', 'night' or 'white',
            "family": 'sans', // 'serif' or 'sans',
            "size": 2         // 1 - 4
        }
    }
}

This plugin exposes the following API to easily allow new themes to manage the plugin behavior.

All API functions are called using the prefix gitbook.fontsettings., for instance gitbook.fontsettings.enlargeFontSize().

Increases the font size of the document by one. Max value is 4.

Decreases the font size of the document by one. Min value is 1.

Each font family should be described as:

var fontFamily = {
    config: 'sans',  // name of the font family in book.json for your theme
    text: 'Sans',    // display name of the font family in menu
    id: 0            // the id appended to the CSS class for this font-family
};

The text property will be used to display the font-family name in the fontsettings dropdown menu.

The config property allows you to let the users of your theme choose a default font family in their book.json. You will have to handle setting the chosen font family in your theme's frontend JavaScript.

For instance:

// book.json
{
    plugins: ["my-theme"],
    pluginsConfig: {
        "my-theme": {
            "font-family": "sans"
        }
    }
}

// my-theme.js
require('gitbook', function(gitbook) {
    var FONT_FAMILIES = [
        {
            config: 'sans',
            text: 'Sans',
            id: 0
        },
        {
            config: 'serif',
            text: 'Serif',
            id: 1
        }
    ];

    gitbook.events.on('start', function(e, config) {
        // Read configuration
        var themeConfig = config['my-theme'],
            defaultFont = themeConfig['font-family'];

        // Initialize new font families
        gitbook.fontsettings.setFamilies(FONT_FAMILIES);
        // Set to configured font-family
        gitbook.fontsettings.setFamily(defaultFont);
    });
});

The id property lets you define a specific id to use for your CSS rules as explained below.

The CSS class font-family-<id> will be applied to the theme book's root element <div class="book"> when a font family is selected in the menu.

The CSS rules for the font-family can then easily be defined using the parent selector .book.font-family-<id>:

.book.font-family-<id> {
  font-family: 'My Awesome Font';
}

Returns the currently set font families.

By default, the font families are:

// Default font families
var FAMILIES = [
    {
        config: 'serif',
        text: 'Serif',
        id: 0
    },
    {
        config: 'sans',
        text: 'Sans',
        id: 1
    }
];

Set the new font families configuration, as an array of font family objects, used by the plugin-fontsettings in the form:

var FONT_FAMILIES = [
    {
        config: 'sans',
        text: 'Sans',
        id: 0
    },
    {
        config: 'serif',
        text: 'Serif',
        id: 1
    }
];

gitbook.fontsettings.setFamilies(FONT_FAMILIES);

This will recreate the fontsettings menu to reflect the changes.

Takes a font-family config key as an argument and updates the font-family used for this book.

This will basically apply the CSS class with the corresponding family id: .font-family-<id>.

Setting and manipulating color themes follow the exact same rules as font families.

Here are the default value for the color themes in the plugin:

// Default themes
var THEMES = [
    {
        config: 'white',
        text: 'White',
        id: 0
    },
    {
        config: 'sepia',
        text: 'Sepia',
        id: 1
    },
    {
        config: 'night',
        text: 'Night',
        id: 2
    }
];

The applied CSS classes for color themes will be in the form: .color-theme-<id>.

Caution: No CSS class for color theme with id: 0 will be applied. Basically, the first color theme corresponds to your default theme's colors.

For instance, using the default color themes:

gitbook.fontsettings.setTheme('night');

will result in the following HTML state for the root element:

<div class="book color-theme-2">

While:

gitbook.fontsettings.setTheme('white');

will reset the HTML state for the root element:

<div class="book">

Returns the currently set color themes.

By default, the font families are:

// Default themes
var THEMES = [
    {
        config: 'white',
        text: 'White',
        id: 0
    },
    {
        config: 'sepia',
        text: 'Sepia',
        id: 1
    },
    {
        config: 'night',
        text: 'Night',
        id: 2
    }
];

Set the new color themes configuration, as an array of font family objects, used by the plugin-fontsettings in the form:

var COLOR_THEMES = [
    {
        config: 'light',
        text: 'Light',
        id: 0
    },
    {
        config: 'dark',
        text: 'Dark',
        id: 1
    }
];

gitbook.fontsettings.setThemes(COLOR_THEMES);

This will recreate the fontsettings menu to reflect the changes.

Takes a color theme config key as an argument and updates the color theme used for this book.

This will basically apply the CSS class with the corresponding theme id: .color-theme-<id>, or remove the applied CSS class if the selected theme id is 0.