feat: Add TabView.addIconBuilder (#1047)

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 * feat: Added `DatePicker.fieldFlex` to control the width proportion of each field.
 * fix: `Slider` thumb is correct rendered when it's on the edges.
+* feat: Added `TabView.addIconBuilder` ([#1047](https://github.com/bdlukaa/fluent_ui/pull/1047))
 
 ## 4.8.6
 

lib/src/controls/navigation/tab_view.dart

@@ -61,6 +61,7 @@ class TabView extends StatefulWidget {
     required this.tabs,
     this.onNewPressed,
     this.addIconData = FluentIcons.add,
+    this.addIconBuilder,
     this.shortcutsEnabled = true,
     this.onReorder,
     this.showScrollButtons = true,
@@ -91,6 +92,13 @@ class TabView extends StatefulWidget {
 
   /// The icon of the new button
   final IconData addIconData;
+
+  /// The builder for the add icon. 
+  ///
+  /// This does not build the add button, only its icon.
+  ///
+  /// When null, the add icon is rendered.
+  final Widget Function(Widget addIcon)? addIconBuilder;
 
   /// Whether the following shortcuts are enabled:
   ///
@@ -562,7 +570,10 @@ class _TabViewState extends State<TabView> {
                       ),
                       child: _buttonTabBuilder(
                         context,
-                        Icon(widget.addIconData, size: 12.0),
+                        widget.addIconBuilder?.call(
+                              Icon(widget.addIconData, size: 12.0),
+                            ) ??
+                            Icon(widget.addIconData, size: 12.0),
                         widget.onNewPressed!,
                         localizations.newTabLabel,
                       ),