Add Font Size dropdown to the toolbar (#790)

* Update quill_dropdown_button.dart

* Update toolbar.dart

* Update quill_dropdown_button.dart

* Update quill_dropdown_button.dart

* Update toolbar.dart

* Update quill_dropdown_button.dart

* Update toolbar.dart

* Update toolbar.dart

* Update toolbar.dart

* Update toolbar.dart

* Update toolbar.dart

* Update quill_dropdown_button.dart

* Update toolbar.dart

* Update quill_dropdown_button.dart

* Update toolbar.dart

lib/src/widgets/toolbar.dart

@@ -21,6 +21,7 @@ import 'toolbar/select_header_style_button.dart';
 import 'toolbar/toggle_check_list_button.dart';
 import 'toolbar/toggle_style_button.dart';
 import 'toolbar/video_button.dart';
+import 'toolbar/quill_dropdown_button.dart';
 
 export 'toolbar/clear_format_button.dart';
 export 'toolbar/color_button.dart';
@@ -72,6 +73,7 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
     double toolbarSectionSpacing = 4,
     WrapAlignment toolbarIconAlignment = WrapAlignment.center,
     bool showDividers = true,
+    bool showFontSize = true,
     bool showBoldButton = true,
     bool showItalicButton = true,
     bool showSmallButton = false,
@@ -108,6 +110,10 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
     WebImagePickImpl? webImagePickImpl,
     WebVideoPickImpl? webVideoPickImpl,
 
+    ///List of font sizes in [int]
+    List? fontSizeValues,
+    int? initialFontSizeValue,
+      
     ///The theme to use for the icons in the toolbar, uses type [QuillIconTheme]
     QuillIconTheme? iconTheme,
 
@@ -121,6 +127,7 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
     Key? key,
   }) {
     final isButtonGroupShown = [
+      showFontSize ||  
       showBoldButton ||
           showItalicButton ||
           showSmallButton ||
@@ -143,6 +150,20 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
       showLink
     ];
 
+    //default font size values
+    final fontSizes = fontSizeValues ?? [
+      10,
+      12,
+      14,
+      16,
+      18,
+      20,
+      24,
+      28,
+      32,
+      48
+    ];
+      
     return QuillToolbar(
       key: key,
       toolbarHeight: toolbarIconSize * 2,
@@ -167,6 +188,25 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
             undo: false,
             iconTheme: iconTheme,
           ),
+        if (showFontSize)
+            QuillDropdownButton(
+              iconTheme: iconTheme,
+              height:toolbarIconSize*2,
+              items:[
+                for (var fontSize in fontSizes)
+                PopupMenuItem<int>(
+                  value: fontSize,
+                  child: Text(fontSize.toString()),
+                ),
+              ],
+              onSelected:(newSize){
+                if (newSize != null)
+                  {
+                    controller.formatSelection(Attribute.fromKeyValue('size', newSize));
+                  }
+                },
+              initialValue: fontSizes[initialFontSizeValue ?? 0],
+            ),          
         if (showBoldButton)
           ToggleStyleButton(
             attribute: Attribute.bold,

lib/src/widgets/toolbar/quill_dropdown_button.dart

@@ -1,10 +1,8 @@
 import 'package:flutter/material.dart';
 import '../../models/themes/quill_icon_theme.dart';
 
-@Deprecated('Not being used')
 class QuillDropdownButton<T> extends StatefulWidget {
   const QuillDropdownButton({
-    required this.child,
     required this.initialValue,
     required this.items,
     required this.onSelected,
@@ -20,7 +18,6 @@ class QuillDropdownButton<T> extends StatefulWidget {
   final Color? fillColor;
   final double hoverElevation;
   final double highlightElevation;
-  final Widget child;
   final T initialValue;
   final List<PopupMenuEntry<T>> items;
   final ValueChanged<T> onSelected;
@@ -32,6 +29,14 @@ class QuillDropdownButton<T> extends StatefulWidget {
 
 // ignore: deprecated_member_use_from_same_package
 class _QuillDropdownButtonState<T> extends State<QuillDropdownButton<T>> {
+  
+  int _currentValue = 0;
+
+  @override
+  void initState(){
+      _currentValue = widget.initialValue as int;
+  }
+  
   @override
   Widget build(BuildContext context) {
     return ConstrainedBox(
@@ -81,18 +86,21 @@ class _QuillDropdownButtonState<T> extends State<QuillDropdownButton<T>> {
         // if (widget.onCanceled != null) widget.onCanceled();
         return null;
       }
-      widget.onSelected(newValue);
+      setState(() {
+        _currentValue = newValue as int;
+        widget.onSelected(newValue);
+      });
     });
   }
 
   Widget _buildContent(BuildContext context) {
     return ConstrainedBox(
-      constraints: const BoxConstraints.tightFor(width: 110),
+      constraints: const BoxConstraints.tightFor(width: 60),
       child: Padding(
         padding: const EdgeInsets.symmetric(horizontal: 8),
         child: Row(
           children: [
-            widget.child,
+            Text(_currentValue.toString()),
             Expanded(child: Container()),
             const Icon(Icons.arrow_drop_down, size: 15)
           ],