feat(firebaseai): ImageConfig and FinishReasons

packages/firebase_ai/firebase_ai/example/lib/pages/image_generation_page.dart

@@ -39,6 +39,8 @@ class _ImageGenerationPageState extends State<ImageGenerationPage> {
   final FocusNode _textFieldFocus = FocusNode();
   final List<MessageData> _messages = <MessageData>[];
   bool _loading = false;
+  ImageAspectRatio? _selectedAspectRatio;
+  ImageSize? _selectedImageSize;
 
   @override
   void initState() {
@@ -80,7 +82,19 @@ class _ImageGenerationPageState extends State<ImageGenerationPage> {
     _scrollDown();
 
     try {
-      final response = await _model.generateContent([Content.text(prompt)]);
+      final response = await _model.generateContent(
+        [Content.text(prompt)],
+        generationConfig: GenerationConfig(
+          responseModalities: [
+            ResponseModalities.text,
+            ResponseModalities.image,
+          ],
+          imageConfig: ImageConfig(
+            aspectRatio: _selectedAspectRatio,
+            imageSize: _selectedImageSize,
+          ),
+        ),
+      );
 
       String? textResponse = response.text;
       Uint8List? imageBytes;
@@ -162,31 +176,100 @@ class _ImageGenerationPageState extends State<ImageGenerationPage> {
               ),
             ),
             Padding(
-              padding: const EdgeInsets.symmetric(vertical: 25, horizontal: 15),
-              child: Row(
+              padding: const EdgeInsets.symmetric(vertical: 15, horizontal: 15),
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
                 children: [
-                  Expanded(
-                    child: TextField(
-                      autofocus: true,
-                      focusNode: _textFieldFocus,
-                      controller: _textController,
-                      decoration: const InputDecoration(
-                        hintText: 'Enter image prompt...',
+                  Row(
+                    children: [
+                      Expanded(
+                        child: DropdownButtonFormField<ImageAspectRatio?>(
+                          initialValue: _selectedAspectRatio,
+                          decoration: const InputDecoration(
+                            labelText: 'Aspect Ratio',
+                            border: OutlineInputBorder(),
+                            contentPadding: EdgeInsets.symmetric(
+                              horizontal: 10,
+                              vertical: 10,
+                            ),
+                          ),
+                          items: [
+                            const DropdownMenuItem(
+                              child: Text('Default'),
+                            ),
+                            ...ImageAspectRatio.values.map(
+                              (e) => DropdownMenuItem(
+                                value: e,
+                                child: Text('${e.name} (${e.toJson()})'),
+                              ),
+                            ),
+                          ],
+                          onChanged: (value) {
+                            setState(() {
+                              _selectedAspectRatio = value;
+                            });
+                          },
+                        ),
                       ),
-                      onSubmitted: _generateImage,
-                    ),
+                      const SizedBox(width: 15),
+                      Expanded(
+                        child: DropdownButtonFormField<ImageSize?>(
+                          initialValue: _selectedImageSize,
+                          decoration: const InputDecoration(
+                            labelText: 'Image Size',
+                            border: OutlineInputBorder(),
+                            contentPadding: EdgeInsets.symmetric(
+                              horizontal: 10,
+                              vertical: 10,
+                            ),
+                          ),
+                          items: [
+                            const DropdownMenuItem(
+                              child: Text('Default'),
+                            ),
+                            ...ImageSize.values.map(
+                              (e) => DropdownMenuItem(
+                                value: e,
+                                child: Text('${e.name} (${e.toJson()})'),
+                              ),
+                            ),
+                          ],
+                          onChanged: (value) {
+                            setState(() {
+                              _selectedImageSize = value;
+                            });
+                          },
+                        ),
+                      ),
+                    ],
                   ),
-                  const SizedBox(width: 15),
-                  if (!_loading)
-                    IconButton(
-                      onPressed: () => _generateImage(_textController.text),
-                      icon: Icon(
-                        Icons.send,
-                        color: Theme.of(context).colorScheme.primary,
+                  const SizedBox(height: 15),
+                  Row(
+                    children: [
+                      Expanded(
+                        child: TextField(
+                          autofocus: true,
+                          focusNode: _textFieldFocus,
+                          controller: _textController,
+                          decoration: const InputDecoration(
+                            hintText: 'Enter image prompt...',
+                          ),
+                          onSubmitted: _generateImage,
+                        ),
                       ),
-                    )
-                  else
-                    const CircularProgressIndicator(),
+                      const SizedBox(width: 15),
+                      if (!_loading)
+                        IconButton(
+                          onPressed: () => _generateImage(_textController.text),
+                          icon: Icon(
+                            Icons.send,
+                            color: Theme.of(context).colorScheme.primary,
+                          ),
+                        )
+                      else
+                        const CircularProgressIndicator(),
+                    ],
+                  ),
                 ],
               ),
             ),

packages/firebase_ai/firebase_ai/lib/firebase_ai.dart

@@ -66,6 +66,7 @@ export 'src/error.dart'
         QuotaExceeded,
         UnsupportedUserLocation;
 export 'src/firebase_ai.dart' show FirebaseAI;
+export 'src/image_config.dart' show ImageConfig, ImageAspectRatio, ImageSize;
 export 'src/imagen/imagen_api.dart'
     show
         ImagenSafetySettings,

packages/firebase_ai/firebase_ai/lib/src/api.dart

@@ -14,6 +14,7 @@
 
 import 'content.dart';
 import 'error.dart';
+import 'image_config.dart';
 import 'schema.dart';
 import 'tool.dart' show Tool, ToolConfig;
 
@@ -790,9 +791,45 @@ enum FinishReason {
   /// The candidate content was flagged for malformed function call reasons.
   malformedFunctionCall('MALFORMED_FUNCTION_CALL'),
 
-  /// The model produced an unexpected tool call.
+  /// Token generation was stopped because the response contained forbidden terms.
+  blocklist('BLOCKLIST'),
+
+  /// Token generation was stopped because the response contained potentially prohibited content.
+  prohibitedContent('PROHIBITED_CONTENT'),
+
+  /// Token generation was stopped because of Sensitive Personally Identifiable Information (SPII).
+  spii('SPII'),
+
+  /// Token generation stopped because generated images contain safety violations.
+  imageSafety('IMAGE_SAFETY'),
+
+  /// Image generation stopped because generated images have other prohibited content.
+  imageProhibitedContent('IMAGE_PROHIBITED_CONTENT'),
+
+  /// Image generation stopped because of other miscellaneous issues.
+  imageOther('IMAGE_OTHER'),
+
+  /// The model was expected to generate an image, but none was generated.
+  noImage('NO_IMAGE'),
+
+  /// Image generation stopped due to recitation.
+  imageRecitation('IMAGE_RECITATION'),
+
+  /// The response candidate content was flagged for using an unsupported language.
+  language('LANGUAGE'),
+
+  /// Model generated a tool call but no tools were enabled in the request.
   unexpectedToolCall('UNEXPECTED_TOOL_CALL'),
 
+  /// Model called too many tools consecutively, thus the system exited execution.
+  tooManyToolCalls('TOO_MANY_TOOL_CALLS'),
+
+  /// Request has at least one thought signature missing.
+  missingThoughtSignature('MISSING_THOUGHT_SIGNATURE'),
+
+  /// Finished due to malformed response.
+  malformedResponse('MALFORMED_RESPONSE'),
+
   /// Unknown reason.
   other('OTHER');
 
@@ -813,8 +850,21 @@ enum FinishReason {
       'RECITATION' => FinishReason.recitation,
       'OTHER' => FinishReason.other,
       'MALFORMED_FUNCTION_CALL' => FinishReason.malformedFunctionCall,
+      'BLOCKLIST' => FinishReason.blocklist,
+      'PROHIBITED_CONTENT' => FinishReason.prohibitedContent,
+      'SPII' => FinishReason.spii,
+      'IMAGE_SAFETY' => FinishReason.imageSafety,
+      'IMAGE_PROHIBITED_CONTENT' => FinishReason.imageProhibitedContent,
+      'IMAGE_OTHER' => FinishReason.imageOther,
+      'NO_IMAGE' => FinishReason.noImage,
+      'IMAGE_RECITATION' => FinishReason.imageRecitation,
+      'LANGUAGE' => FinishReason.language,
       'UNEXPECTED_TOOL_CALL' => FinishReason.unexpectedToolCall,
-      _ => throw FormatException('Unhandled FinishReason format', jsonObject),
+      'TOO_MANY_TOOL_CALLS' => FinishReason.tooManyToolCalls,
+      'MISSING_THOUGHT_SIGNATURE' => FinishReason.missingThoughtSignature,
+      'MALFORMED_RESPONSE' => FinishReason.malformedResponse,
+      'UNKNOWN' => FinishReason.unknown,
+      _ => FinishReason.unknown,
     };
   }
 
@@ -1220,6 +1270,7 @@ final class GenerationConfig extends BaseGenerationConfig {
     this.responseSchema,
     this.responseJsonSchema,
     this.thinkingConfig,
+    this.imageConfig,
   }) : assert(responseSchema == null || responseJsonSchema == null,
             'responseSchema and responseJsonSchema cannot both be set.');
 
@@ -1268,6 +1319,9 @@ final class GenerationConfig extends BaseGenerationConfig {
   /// support thinking.
   final ThinkingConfig? thinkingConfig;
 
+  /// Configuration options for generating images with Gemini models.
+  final ImageConfig? imageConfig;
+
   @override
   Map<String, Object?> toJson() => {
         ...super.toJson(),
@@ -1282,6 +1336,8 @@ final class GenerationConfig extends BaseGenerationConfig {
           'responseJsonSchema': responseJsonSchema,
         if (thinkingConfig case final thinkingConfig?)
           'thinkingConfig': thinkingConfig.toJson(),
+        if (imageConfig case final imageConfig?)
+          'imageConfig': imageConfig.toJson(),
       };
 }
 

packages/firebase_ai/firebase_ai/lib/src/image_config.dart

@@ -0,0 +1,110 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/// Configuration options for generating images with Gemini models.
+final class ImageConfig {
+  /// Initializes configuration options for generating images with Gemini.
+  const ImageConfig({this.aspectRatio, this.imageSize});
+
+  /// The aspect ratio of generated images.
+  final ImageAspectRatio? aspectRatio;
+
+  /// The size of the generated images.
+  final ImageSize? imageSize;
+
+  /// Convert to json format.
+  Map<String, Object?> toJson() => {
+        if (aspectRatio case final aspectRatio?)
+          'aspectRatio': aspectRatio.toJson(),
+        if (imageSize case final imageSize?) 'imageSize': imageSize.toJson(),
+      };
+}
+
+/// An aspect ratio for generated images.
+enum ImageAspectRatio {
+  /// Square (1:1) aspect ratio.
+  square1x1('1:1'),
+
+  /// Portrait widescreen (9:16) aspect ratio.
+  portrait9x16('9:16'),
+
+  /// Widescreen (16:9) aspect ratio.
+  landscape16x9('16:9'),
+
+  /// Portrait full screen (3:4) aspect ratio.
+  portrait3x4('3:4'),
+
+  /// Fullscreen (4:3) aspect ratio.
+  landscape4x3('4:3'),
+
+  /// Portrait (2:3) aspect ratio.
+  portrait2x3('2:3'),
+
+  /// Landscape (3:2) aspect ratio.
+  landscape3x2('3:2'),
+
+  /// Portrait (4:5) aspect ratio.
+  portrait4x5('4:5'),
+
+  /// Landscape (5:4) aspect ratio.
+  landscape5x4('5:4'),
+
+  /// Portrait (1:4) aspect ratio.
+  portrait1x4('1:4'),
+
+  /// Landscape (4:1) aspect ratio.
+  landscape4x1('4:1'),
+
+  /// Portrait (1:8) aspect ratio.
+  portrait1x8('1:8'),
+
+  /// Landscape (8:1) aspect ratio.
+  landscape8x1('8:1'),
+
+  /// Ultrawide (21:9) aspect ratio.
+  ultrawide21x9('21:9');
+
+  const ImageAspectRatio(this._jsonString);
+  final String _jsonString;
+
+  /// Convert to json format.
+  String toJson() => _jsonString;
+
+  @override
+  String toString() => name;
+}
+
+/// The size of images to generate.
+enum ImageSize {
+  /// 512px (0.5K) image size.
+  size512('512'),
+
+  /// 1K image size.
+  size1K('1K'),
+
+  /// 2K image size.
+  size2K('2K'),
+
+  /// 4K image size.
+  size4K('4K');
+
+  const ImageSize(this._jsonString);
+  final String _jsonString;
+
+  /// Convert to json format.
+  String toJson() => _jsonString;
+
+  @override
+  String toString() => name;
+}