feat(import-export): add state history minification and optimize memo…

…ry usage (#322)

- Added `import_history_5_0_0_minified.dart` for example state history import with minified format
- Implemented key minifier in `key_minifier.dart` to reduce export data size
- Enhanced state history handling to consume less RAM during in-app usage
- Updated affected models, layers, and editors for compatibility with the minified export format
- Reorganized test structure, moving modules into `features` and `shared` directories
- Introduced new tests for minified keys to ensure reliability

example/lib/features/import_export_example.dart

@@ -4,7 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:google_fonts/google_fonts.dart';
 import 'package:pro_image_editor/pro_image_editor.dart';
 
-import '/core/constants/import_history_demo_data.dart';
+import '/core/constants/history_demo/import_history_5_0_0_minified.dart';
 import '/core/mixin/example_helper.dart';
 
 /// The import export example
@@ -66,6 +66,8 @@ class _ImportExportExampleState extends State<ImportExportExample>
                                 onPressed: () async {
                                   var history = await editor.exportStateHistory(
                                     configs: const ExportEditorConfigs(
+                                        historySpan:
+                                            ExportHistorySpan.currentAndBackward
                                         // configs...
                                         ),
                                   );
@@ -101,8 +103,8 @@ class _ImportExportExampleState extends State<ImportExportExample>
 
                   /// The `widgetLoader` is optional and only required if you
                   /// add `exportConfigs` with an id to the widget layers.
-                  /// Refer to the [sticker-example] for details on how this
-                  /// works in the sticker editor.
+                  /// Refer to the [sticker-example](https://github.com/hm21/pro_image_editor/blob/stable/example/lib/features/stickers_example.dart)
+                  /// for details on how this works in the sticker editor.
                   ///
                   /// If you add widget layers directly to the editor,
                   /// you can pass the parameters as shown below:

lib/core/models/editor_configs/text_editor_configs.dart

@@ -48,6 +48,7 @@ class TextEditorConfigs {
     this.minScale = double.negativeInfinity,
     this.maxScale = double.infinity,
     this.customTextStyles,
+    this.defaultTextStyle = const TextStyle(),
     this.initialBackgroundColorMode = LayerBackgroundMode.backgroundAndColor,
     this.safeArea = const EditorSafeArea(),
     this.style = const TextEditorStyle(),
@@ -94,6 +95,11 @@ class TextEditorConfigs {
   /// Allow users to select a different font style
   final List<TextStyle>? customTextStyles;
 
+  /// The default text style to be used in the text editor.
+  ///
+  /// This style will be applied to the text if no other style is specified.
+  final TextStyle defaultTextStyle;
+
   /// The minimum scale factor from the layer.
   final double minScale;
 
@@ -145,6 +151,7 @@ class TextEditorConfigs {
     double? minFontScale,
     LayerBackgroundMode? initialBackgroundColorMode,
     List<TextStyle>? customTextStyles,
+    TextStyle? defaultTextStyle,
     double? minScale,
     double? maxScale,
     bool? enableSuggestions,
@@ -171,6 +178,7 @@ class TextEditorConfigs {
       initialBackgroundColorMode:
           initialBackgroundColorMode ?? this.initialBackgroundColorMode,
       customTextStyles: customTextStyles ?? this.customTextStyles,
+      defaultTextStyle: defaultTextStyle ?? this.defaultTextStyle,
       minScale: minScale ?? this.minScale,
       maxScale: maxScale ?? this.maxScale,
       enableSuggestions: enableSuggestions ?? this.enableSuggestions,

lib/core/models/history/state_history.dart

@@ -13,15 +13,15 @@ class EditorStateHistory {
   ///
   /// All parameters are required.
   EditorStateHistory({
-    required this.blur,
-    required this.layers,
-    required this.filters,
-    required this.tuneAdjustments,
-    required this.transformConfigs,
+    this.blur,
+    this.layers = const [],
+    this.filters = const [],
+    this.tuneAdjustments = const [],
+    this.transformConfigs,
   });
 
   /// The blur factor.
-  final double blur;
+  final double? blur;
 
   /// The list of layers.
   final List<Layer> layers;
@@ -33,5 +33,5 @@ class EditorStateHistory {
   final List<TuneAdjustmentMatrix> tuneAdjustments;
 
   /// The transformation from the crop/ rotate editor.
-  TransformConfigs transformConfigs;
+  TransformConfigs? transformConfigs;
 }

lib/core/models/layers/emoji_layer.dart

@@ -32,17 +32,24 @@ class EmojiLayer extends Layer {
 
   /// Factory constructor for creating an EmojiLayer instance from a Layer
   /// and a map.
-  factory EmojiLayer.fromMap(Layer layer, Map<String, dynamic> map) {
+  factory EmojiLayer.fromMap(
+    Layer layer,
+    Map<String, dynamic> map, {
+    Function(String key)? keyConverter,
+  }) {
+    keyConverter ??= (String key) => key;
+
     /// Constructs and returns an EmojiLayer instance with properties
     /// derived from the layer and map.
     return EmojiLayer(
+      id: layer.id,
       flipX: layer.flipX,
       flipY: layer.flipY,
       enableInteraction: layer.enableInteraction,
       offset: layer.offset,
       rotation: layer.rotation,
       scale: layer.scale,
-      emoji: map['emoji'],
+      emoji: map[keyConverter('emoji')],
     );
   }
 
@@ -57,6 +64,14 @@ class EmojiLayer extends Layer {
       'type': 'emoji',
     };
   }
+
+  @override
+  Map<String, dynamic> toMapFromReference(Layer layer) {
+    return {
+      ...super.toMapFromReference(layer),
+      if ((layer as EmojiLayer).emoji != emoji) 'emoji': emoji,
+    };
+  }
 }
 
 // TODO: Remove in version 8.0.0
@@ -81,6 +96,7 @@ class EmojiLayerData extends EmojiLayer {
     /// Constructs and returns an EmojiLayerData instance with properties
     /// derived from the layer and map.
     return EmojiLayerData(
+      id: layer.id,
       flipX: layer.flipX,
       flipY: layer.flipY,
       enableInteraction: layer.enableInteraction,

lib/core/models/layers/layer.dart

@@ -1,6 +1,7 @@
 // Flutter imports:
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:pro_image_editor/shared/services/import_export/utils/key_minifier.dart';
 
 import '/shared/services/import_export/types/widget_loader.dart';
 import '../../utils/parser/double_parser.dart';
@@ -38,6 +39,7 @@ class Layer {
     bool? flipX,
     bool? flipY,
     bool? enableInteraction,
+    bool? isDeleted,
   }) {
     key = GlobalKey();
     // Initialize properties with provided values or defaults.
@@ -48,6 +50,7 @@ class Layer {
     this.flipX = flipX ?? false;
     this.flipY = flipY ?? false;
     this.enableInteraction = enableInteraction ?? true;
+    this.isDeleted = isDeleted ?? false;
   }
 
   /// Factory constructor for creating a Layer instance from a map and a list
@@ -56,31 +59,36 @@ class Layer {
     Map<String, dynamic> map, {
     List<Uint8List>? widgetRecords,
     WidgetLoader? widgetLoader,
+    String? id,
     Function(EditorImage editorImage)? requirePrecache,
+    EditorKeyMinifier? minifier,
   }) {
+    var keyConverter = minifier?.convertLayerKey ?? (String key) => key;
+
     /// Creates a base Layer instance with default or map-provided properties.
     Layer layer = Layer(
-      flipX: map['flipX'] ?? false,
-      flipY: map['flipY'] ?? false,
-      enableInteraction: map['enableInteraction'] ?? true,
+      id: id,
+      flipX: map[keyConverter('flipX')] ?? false,
+      flipY: map[keyConverter('flipY')] ?? false,
+      enableInteraction: map[keyConverter('enableInteraction')] ?? true,
       offset: Offset(safeParseDouble(map['x']), safeParseDouble(map['y'])),
-      rotation: safeParseDouble(map['rotation']),
-      scale: safeParseDouble(map['scale'], fallback: 1),
+      rotation: safeParseDouble(map[keyConverter('rotation')]),
+      scale: safeParseDouble(map[keyConverter('scale')], fallback: 1),
     );
 
     /// Determines the layer type from the map and returns the appropriate
     /// LayerData subclass.
-    switch (map['type']) {
+    switch (map[keyConverter('type')]) {
       case 'text':
         // Returns a TextLayer instance when type is 'text'.
-        return TextLayer.fromMap(layer, map);
+        return TextLayer.fromMap(layer, map, keyConverter: keyConverter);
       case 'emoji':
         // Returns an EmojiLayer instance when type is 'emoji'.
-        return EmojiLayer.fromMap(layer, map);
+        return EmojiLayer.fromMap(layer, map, keyConverter: keyConverter);
       case 'paint':
       case 'painting':
         // Returns a PaintLayer instance when type is 'paint'.
-        return PaintLayer.fromMap(layer, map);
+        return PaintLayer.fromMap(layer, map, minifier: minifier);
       case 'sticker':
       case 'widget':
         // Returns a WidgetLayer instance when type is 'widget' or 'sticker',
@@ -91,6 +99,7 @@ class Layer {
           widgetRecords: widgetRecords ?? [],
           widgetLoader: widgetLoader,
           requirePrecache: requirePrecache,
+          keyConverter: keyConverter,
         );
       default:
         // Returns the base Layer instance when type is unrecognized.
@@ -114,6 +123,9 @@ class Layer {
   /// Flag to enable or disable the user interaction with the layer.
   late bool enableInteraction;
 
+  /// Flag which indicates to the history that the layer is removed.
+  late bool isDeleted;
+
   /// A unique identifier for the layer.
   late String id;
 
@@ -130,8 +142,56 @@ class Layer {
       'scale': scale,
       'flipX': flipX,
       'flipY': flipY,
+      if (isDeleted) 'isDeleted': isDeleted,
       'enableInteraction': enableInteraction,
       'type': 'default',
     };
   }
+
+  /// Converts the current layer to a map representation, comparing it with a
+  /// reference layer.
+  ///
+  /// The resulting map will contain only the properties that differ from the
+  /// reference layer.
+  Map<String, dynamic> toMapFromReference(Layer layer) {
+    return {
+      'id': layer.id,
+      if (layer.offset.dx != offset.dx) 'x': offset.dx,
+      if (layer.offset.dy != offset.dy) 'y': offset.dy,
+      if (layer.rotation != rotation) 'rotation': rotation,
+      if (layer.scale != scale) 'scale': scale,
+      if (layer.flipX != flipX) 'flipX': flipX,
+      if (layer.flipY != flipY) 'flipY': flipY,
+      if (isDeleted) 'isDeleted': isDeleted,
+      if (layer.enableInteraction != enableInteraction)
+        'enableInteraction': enableInteraction,
+    };
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+
+    return other is Layer &&
+        other.id == id &&
+        other.offset == offset &&
+        other.rotation == rotation &&
+        other.scale == scale &&
+        other.flipX == flipX &&
+        other.flipY == flipY &&
+        other.enableInteraction == enableInteraction &&
+        other.isDeleted == isDeleted;
+  }
+
+  @override
+  int get hashCode {
+    return id.hashCode ^
+        offset.hashCode ^
+        rotation.hashCode ^
+        scale.hashCode ^
+        flipX.hashCode ^
+        flipY.hashCode ^
+        enableInteraction.hashCode ^
+        isDeleted.hashCode;
+  }
 }

lib/core/models/layers/paint_layer.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/widgets.dart';
 
+import '../../../shared/services/import_export/utils/key_minifier.dart';
 import '../../utils/parser/double_parser.dart';
 import '../paint_editor/painted_model.dart';
 import 'layer.dart';
@@ -41,22 +42,32 @@ class PaintLayer extends Layer {
 
   /// Factory constructor for creating a PaintLayer instance from a
   /// Layer and a map.
-  factory PaintLayer.fromMap(Layer layer, Map<String, dynamic> map) {
+  factory PaintLayer.fromMap(
+    Layer layer,
+    Map<String, dynamic> map, {
+    EditorKeyMinifier? minifier,
+  }) {
+    var keyConverter = minifier?.convertLayerKey ?? (String key) => key;
+
     /// Constructs and returns a PaintLayer instance with properties
     /// derived from the layer and map.
     return PaintLayer(
+      id: layer.id,
       flipX: layer.flipX,
       flipY: layer.flipY,
       enableInteraction: layer.enableInteraction,
       offset: layer.offset,
       rotation: layer.rotation,
       scale: layer.scale,
-      opacity: safeParseDouble(map['opacity'], fallback: 1.0),
+      opacity: safeParseDouble(map[keyConverter('opacity')], fallback: 1.0),
       rawSize: Size(
-        safeParseDouble(map['rawSize']?['w'], fallback: 0),
-        safeParseDouble(map['rawSize']?['h'], fallback: 0),
+        safeParseDouble(map[keyConverter('rawSize')]?['w'], fallback: 0),
+        safeParseDouble(map[keyConverter('rawSize')]?['h'], fallback: 0),
+      ),
+      item: PaintedModel.fromMap(
+        map[keyConverter('item')] ?? {},
+        keyConverter: minifier?.convertPaintKey,
       ),
-      item: PaintedModel.fromMap(map['item'] ?? {}),
     );
   }
 
@@ -85,6 +96,21 @@ class PaintLayer extends Layer {
       'type': 'paint',
     };
   }
+
+  @override
+  Map<String, dynamic> toMapFromReference(Layer layer) {
+    var paintLayer = layer as PaintLayer;
+    return {
+      ...super.toMapFromReference(layer),
+      if (paintLayer.item != item) 'item': item.toMap(),
+      if (paintLayer.rawSize != rawSize)
+        'rawSize': {
+          'w': rawSize.width,
+          'h': rawSize.height,
+        },
+      if (paintLayer.opacity != opacity) 'opacity': opacity,
+    };
+  }
 }
 
 // TODO: Remove in version 8.0.0
@@ -109,6 +135,7 @@ class PaintLayerData extends PaintLayer {
   /// Layer and a map.
   factory PaintLayerData.fromMap(Layer layer, Map<String, dynamic> map) {
     return PaintLayerData(
+      id: layer.id,
       flipX: layer.flipX,
       flipY: layer.flipY,
       enableInteraction: layer.enableInteraction,