docs(*): add gitbook related a11y guide

_book/gitbook/gitbook-plugin-fontsettings/fontsettings.js

@@ -0,0 +1,240 @@
+require(['gitbook', 'jquery'], function(gitbook, $) {
+    // Configuration
+    var MAX_SIZE       = 4,
+        MIN_SIZE       = 0,
+        BUTTON_ID;
+
+    // Current fontsettings state
+    var fontState;
+
+    // Default themes
+    var THEMES = [
+        {
+            config: 'white',
+            text: 'White',
+            id: 0
+        },
+        {
+            config: 'sepia',
+            text: 'Sepia',
+            id: 1
+        },
+        {
+            config: 'night',
+            text: 'Night',
+            id: 2
+        }
+    ];
+
+    // Default font families
+    var FAMILIES = [
+        {
+            config: 'serif',
+            text: 'Serif',
+            id: 0
+        },
+        {
+            config: 'sans',
+            text: 'Sans',
+            id: 1
+        }
+    ];
+
+    // Return configured themes
+    function getThemes() {
+        return THEMES;
+    }
+
+    // Modify configured themes
+    function setThemes(themes) {
+        THEMES = themes;
+        updateButtons();
+    }
+
+    // Return configured font families
+    function getFamilies() {
+        return FAMILIES;
+    }
+
+    // Modify configured font families
+    function setFamilies(families) {
+        FAMILIES = families;
+        updateButtons();
+    }
+
+    // Save current font settings
+    function saveFontSettings() {
+        gitbook.storage.set('fontState', fontState);
+        update();
+    }
+
+    // Increase font size
+    function enlargeFontSize(e) {
+        e.preventDefault();
+        if (fontState.size >= MAX_SIZE) return;
+
+        fontState.size++;
+        saveFontSettings();
+    }
+
+    // Decrease font size
+    function reduceFontSize(e) {
+        e.preventDefault();
+        if (fontState.size <= MIN_SIZE) return;
+
+        fontState.size--;
+        saveFontSettings();
+    }
+
+    // Change font family
+    function changeFontFamily(configName, e) {
+        if (e && e instanceof Event) {
+            e.preventDefault();
+        }
+
+        var familyId = getFontFamilyId(configName);
+        fontState.family = familyId;
+        saveFontSettings();
+    }
+
+    // Change type of color theme
+    function changeColorTheme(configName, e) {
+        if (e && e instanceof Event) {
+            e.preventDefault();
+        }
+
+        var $book = gitbook.state.$book;
+
+        // Remove currently applied color theme
+        if (fontState.theme !== 0)
+            $book.removeClass('color-theme-'+fontState.theme);
+
+        // Set new color theme
+        var themeId = getThemeId(configName);
+        fontState.theme = themeId;
+        if (fontState.theme !== 0)
+            $book.addClass('color-theme-'+fontState.theme);
+
+        saveFontSettings();
+    }
+
+    // Return the correct id for a font-family config key
+    // Default to first font-family
+    function getFontFamilyId(configName) {
+        // Search for plugin configured font family
+        var configFamily = $.grep(FAMILIES, function(family) {
+            return family.config == configName;
+        })[0];
+        // Fallback to default font family
+        return (!!configFamily)? configFamily.id : 0;
+    }
+
+    // Return the correct id for a theme config key
+    // Default to first theme
+    function getThemeId(configName) {
+        // Search for plugin configured theme
+        var configTheme = $.grep(THEMES, function(theme) {
+            return theme.config == configName;
+        })[0];
+        // Fallback to default theme
+        return (!!configTheme)? configTheme.id : 0;
+    }
+
+    function update() {
+        var $book = gitbook.state.$book;
+
+        $('.font-settings .font-family-list li').removeClass('active');
+        $('.font-settings .font-family-list li:nth-child('+(fontState.family+1)+')').addClass('active');
+
+        $book[0].className = $book[0].className.replace(/\bfont-\S+/g, '');
+        $book.addClass('font-size-'+fontState.size);
+        $book.addClass('font-family-'+fontState.family);
+
+        if(fontState.theme !== 0) {
+            $book[0].className = $book[0].className.replace(/\bcolor-theme-\S+/g, '');
+            $book.addClass('color-theme-'+fontState.theme);
+        }
+    }
+
+    function init(config) {
+        // Search for plugin configured font family
+        var configFamily = getFontFamilyId(config.family),
+            configTheme = getThemeId(config.theme);
+
+        // Instantiate font state object
+        fontState = gitbook.storage.get('fontState', {
+            size:   config.size || 2,
+            family: configFamily,
+            theme:  configTheme
+        });
+
+        update();
+    }
+
+    function updateButtons() {
+        // Remove existing fontsettings buttons
+        if (!!BUTTON_ID) {
+            gitbook.toolbar.removeButton(BUTTON_ID);
+        }
+
+        // Create buttons in toolbar
+        BUTTON_ID = gitbook.toolbar.createButton({
+            icon: 'fa fa-font',
+            label: 'Font Settings',
+            className: 'font-settings',
+            dropdown: [
+                [
+                    {
+                        text: 'A',
+                        className: 'font-reduce',
+                        onClick: reduceFontSize
+                    },
+                    {
+                        text: 'A',
+                        className: 'font-enlarge',
+                        onClick: enlargeFontSize
+                    }
+                ],
+                $.map(FAMILIES, function(family) {
+                    family.onClick = function(e) {
+                        return changeFontFamily(family.config, e);
+                    };
+
+                    return family;
+                }),
+                $.map(THEMES, function(theme) {
+                    theme.onClick = function(e) {
+                        return changeColorTheme(theme.config, e);
+                    };
+
+                    return theme;
+                })
+            ]
+        });
+    }
+
+    // Init configuration at start
+    gitbook.events.bind('start', function(e, config) {
+        var opts = config.fontsettings;
+
+        // Generate buttons at start
+        updateButtons();
+
+        // Init current settings
+        init(opts);
+    });
+
+    // Expose API
+    gitbook.fontsettings = {
+        enlargeFontSize: enlargeFontSize,
+        reduceFontSize:  reduceFontSize,
+        setTheme:        changeColorTheme,
+        setFamily:       changeFontFamily,
+        getThemes:       getThemes,
+        setThemes:       setThemes,
+        getFamilies:     getFamilies,
+        setFamilies:     setFamilies
+    };
+});
+
+