add new option to parse metadata for animated images

Author: huandu

packages/command/pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_gen
 description: The Flutter code generator for your assets, fonts, colors, … — Get rid of all String-based APIs.
-version: 5.10.0
+version: 5.11.0
 homepage: https://github.com/FlutterGen/flutter_gen
 repository: https://github.com/FlutterGen/flutter_gen
 documentation: https://github.com/FlutterGen/flutter_gen
@@ -13,7 +13,8 @@ executables:
   fluttergen: flutter_gen_command
 
 dependencies:
-  flutter_gen_core: 5.10.0
+  flutter_gen_core: 5.11.0
+
   args: ^2.0.0
 
 dev_dependencies:

packages/core/lib/generators/assets_generator.dart

@@ -63,6 +63,7 @@ Future<String> generateAssets(
       ImageIntegration(
         config.packageParameterLiteral,
         parseMetadata: config.flutterGen.parseMetadata,
+        parseAnimation: config.flutterGen.parseAnimation,
       ),
     if (config.flutterGen.integrations.flutterSvg)
       SvgIntegration(

packages/core/lib/generators/integrations/image_integration.dart

@@ -1,6 +1,7 @@
 import 'dart:io';
 
 import 'package:flutter_gen_core/generators/integrations/integration.dart';
+import 'package:image/image.dart' as img;
 import 'package:image_size_getter/file_input.dart';
 import 'package:image_size_getter/image_size_getter.dart';
 
@@ -11,9 +12,12 @@ import 'package:image_size_getter/image_size_getter.dart';
 class ImageIntegration extends Integration {
   ImageIntegration(
     String packageName, {
+    required this.parseAnimation,
     super.parseMetadata,
   }) : super(packageName);
 
+  final bool parseAnimation;
+
   String get packageParameter => isPackage ? ' = package' : '';
 
   String get keyName =>
@@ -32,6 +36,9 @@ class ImageIntegration extends Integration {
     this._assetName, {
     this.size,
     this.flavors = const {},
+    this.isAnimation = false,
+    this.duration = Duration.zero,
+    this.frames = 1,
   });
 
   final String _assetName;
@@ -40,6 +47,9 @@ ${isPackage ? "\n  static const String package = '$packageName';" : ''}
 
   final Size? size;
   final Set<String> flavors;
+  final bool isAnimation;
+  final Duration duration;
+  final int frames;
 
   Image image({
     Key? key,
@@ -116,12 +126,20 @@ ${isPackage ? "\n  static const String package = '$packageName';" : ''}
 
   @override
   String classInstantiate(AssetType asset) {
-    final info = parseMetadata ? _getMetadata(asset) : null;
+    final info = parseMetadata || parseAnimation ? _getMetadata(asset) : null;
     final buffer = StringBuffer(className);
     buffer.write('(');
     buffer.write('\'${asset.posixStylePath}\'');
     if (info != null) {
-      buffer.write(', size: Size(${info.width}, ${info.height})');
+      buffer.write(', size: const Size(${info.width}, ${info.height})');
+
+      if (info.animation case final animation?) {
+        buffer.write(', isAnimation: ${animation.frames > 1}');
+        buffer.write(
+          ', duration: const Duration(milliseconds: ${animation.duration.inMilliseconds})',
+        );
+        buffer.write(', frames: ${animation.frames}');
+      }
     }
     if (asset.flavors.isNotEmpty) {
       buffer.write(', flavors: {');
@@ -161,11 +179,47 @@ ${isPackage ? "\n  static const String package = '$packageName';" : ''}
         FileInput(File(asset.fullPath)),
       );
       final size = result.size;
-      return ImageMetadata(size.width.toDouble(), size.height.toDouble());
+      final animation = parseAnimation ? _parseAnimation(asset) : null;
+
+      return ImageMetadata(
+        width: size.width.toDouble(),
+        height: size.height.toDouble(),
+        animation: animation,
+      );
     } catch (e) {
       stderr
           .writeln('[WARNING] Failed to parse \'${asset.path}\' metadata: $e');
     }
     return null;
   }
+
+  ImageAnimation? _parseAnimation(AssetType asset) {
+    final decoder = switch (asset.mime) {
+      'image/gif' => img.GifDecoder(),
+      'image/webp' => img.WebPDecoder(),
+      _ => null,
+    };
+
+    if (decoder == null) {
+      return null;
+    }
+
+    final file = File(asset.fullPath);
+    final bytes = file.readAsBytesSync();
+    final image = decoder.decode(bytes);
+
+    if (image == null) {
+      return null;
+    }
+
+    return ImageAnimation(
+      frames: image.frames.length,
+      duration: Duration(
+        milliseconds: image.frames.fold(
+          0,
+          (duration, frame) => duration + frame.frameDuration,
+        ),
+      ),
+    );
+  }
 }

packages/core/lib/generators/integrations/integration.dart

@@ -55,8 +55,24 @@ const String deprecationMessagePackage =
 /// Currently only contains the width and height, but could contain more in
 /// future.
 class ImageMetadata {
-  const ImageMetadata(this.width, this.height);
+  const ImageMetadata({
+    required this.width,
+    required this.height,
+    this.animation,
+  });
 
   final double width;
   final double height;
+  final ImageAnimation? animation;
+}
+
+/// Metadata about the parsed animation file when [parseAnimation] is true.
+class ImageAnimation {
+  const ImageAnimation({
+    required this.frames,
+    required this.duration,
+  });
+
+  final int frames;
+  final Duration duration;
 }

packages/core/lib/generators/integrations/svg_integration.dart

@@ -132,7 +132,10 @@ ${isPackage ? "\n  static const String package = '$packageName';" : ''}
       // but it's also the same way it will be eventually rendered by Flutter.
       final svg = File(asset.fullPath).readAsStringSync();
       final vec = parseWithoutOptimizers(svg);
-      return ImageMetadata(vec.width, vec.height);
+      return ImageMetadata(
+        width: vec.width,
+        height: vec.height,
+      );
     } catch (e) {
       stderr.writeln(
         '[WARNING] Failed to parse SVG \'${asset.path}\' metadata: $e',

packages/core/lib/settings/config_default.dart

@@ -8,6 +8,8 @@ flutter_gen:
   line_length: 80
   # Optional
   parse_metadata: false
+  # Optional
+  parse_animation: false
 
   # Optional
   integrations:

packages/core/lib/settings/pubspec.dart

@@ -56,6 +56,7 @@ class FlutterGen {
     required this.output,
     required this.lineLength,
     required this.parseMetadata,
+    required this.parseAnimation,
     required this.assets,
     required this.fonts,
     required this.integrations,
@@ -73,6 +74,9 @@ class FlutterGen {
   @JsonKey(name: 'parse_metadata', required: true)
   final bool parseMetadata;
 
+  @JsonKey(name: 'parse_animation', required: true)
+  final bool parseAnimation;
+
   @JsonKey(name: 'assets', required: true)
   final FlutterGenAssets assets;
 

packages/core/lib/settings/pubspec.g.dart

@@ -1,2 +1,2 @@
 /// DO NOT MODIFY BY HAND, Generated by version_gen
-String packageVersion = '5.10.0';
+String packageVersion = '5.11.0';

packages/core/lib/version.gen.dart

@@ -1,6 +1,6 @@
 name: flutter_gen_core
 description: The Flutter code generator for your assets, fonts, colors, … — Get rid of all String-based APIs.
-version: 5.10.0
+version: 5.11.0
 homepage: https://github.com/FlutterGen/flutter_gen
 repository: https://github.com/FlutterGen/flutter_gen
 documentation: https://github.com/FlutterGen/flutter_gen
@@ -16,20 +16,21 @@ dependencies:
   meta: ^1.7.0
   path: ^1.8.0
   yaml: ^3.0.0
-  mime: '>=1.0.0 <3.0.0'
+  mime: ">=1.0.0 <3.0.0"
   xml: ^6.0.0
   dartx: ^1.0.0
   color: ^3.0.0
   collection: ^1.15.0
   json_annotation: ^4.4.0
   glob: ^2.0.0
 
-  dart_style: '>=2.3.7 <4.0.0'
-  archive: '>=3.4.0 <5.0.0'
+  dart_style: ">=2.3.7 <4.0.0"
+  archive: ">=3.4.0 <5.0.0"
   args: ^2.0.0
   pub_semver: ^2.0.0
   vector_graphics_compiler: ^1.1.9
   image_size_getter: ^2.4.0
+  image: ^4.5.4
 
 dev_dependencies:
   lints: any # Ignoring the version to allow editing across SDK versions.