feat: add customizabilty for biometrics button

lib/src/config/login_options.dart

@@ -178,6 +178,7 @@ class LoginBiometricsOptions {
     this.onBiometricsSuccess,
     this.onBiometricsError,
     this.onBiometricsFail,
+    this.biometricsIconBuilder,
   });
 
   /// Ask the user to login with biometrics instead of email and password.
@@ -200,6 +201,14 @@ class LoginBiometricsOptions {
 
   /// The callback function to be called when the biometrics login errors.
   final OptionalAsyncCallback? onBiometricsError;
+
+  /// Function to provide the icon to be displayed
+  /// as the biometrics login button.
+  /// If null, a default icon will be used based on the platform.
+  ///
+  /// The function provides the onPressed callback and the size of the button
+  final Widget Function(VoidCallback onPressed, Size size)?
+      biometricsIconBuilder;
 }
 
 /// Translations for all the texts in the component

lib/src/widgets/email_password_login.dart

@@ -206,9 +206,15 @@ class _EmailPasswordLoginFormState extends State<EmailPasswordLoginForm> {
       ),
     );
 
-    var biometricsButton = BiometricsButton(
-      onPressed: () async => LocalAuthService().authenticate(options),
-    );
+    var biometricsButton =
+        widget.options.biometricsOptions.biometricsIconBuilder != null
+            ? widget.options.biometricsOptions.biometricsIconBuilder!(
+                () async => _localAuthService.authenticate(options),
+                BiometricsButton.buttonSize,
+              )
+            : BiometricsButton(
+                onPressed: () async => LocalAuthService().authenticate(options),
+              );
 
     return Scaffold(
       backgroundColor: options.loginBackgroundColor,

pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_login
 description: Flutter Login Component
-version: 7.3.0
+version: 7.4.0
 
 publish_to: https://forgejo.internal.iconica.nl/api/packages/internal/pub