Add currency text formatter and donut chart type

- CurrencyTextInputFormatterModel (formatter type currency) with a
  bindable currencyCode, for amount fields that group as you type.
- ChartType.donut with donutThickness, sliceGap and startAngle, and
  selectOnHover for every chart type.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015oUVftgvTVsZQJ5PqZ7Lkh

Author: claude

lib/src/api/models/text_input_formatter_model.dart

@@ -12,6 +12,9 @@ enum TextInputFormatterType {
 
   /// A formatter that uses a regular expression to match the text.
   regex,
+
+  /// Groups an amount as it is typed, in a currency's format.
+  currency,
 }
 
 /// Text formatters that can be applied to the text field input to restrict the
@@ -37,13 +40,16 @@ sealed class TextInputFormatterModel with Equatable, SerializableMixin {
       TextInputFormatterType.regex => RegexTextInputFormatterModel.fromJson(
         json,
       ),
+      TextInputFormatterType.currency =>
+        CurrencyTextInputFormatterModel.fromJson(json),
     };
   }
 
   /// A list of all available text field formatters.
   static const List<TextInputFormatterModel> formatters = [
     NoneTextInputFormatterModel(),
     ...RegexTextInputFormatterModel.formatters,
+    CurrencyTextInputFormatterModel(),
   ];
 
   /// A list of all available text field formatter names.
@@ -202,3 +208,37 @@ class RegexTextInputFormatterModel extends TextInputFormatterModel {
     allow,
   ];
 }
+
+
+/// Formats an amount while it is typed, the way [currencyCode] writes
+/// money: digits grouped (`12,345.6`, `12.345,6` for EUR), decimals capped
+/// at the currency's (none for JPY), "." accepted as the decimal mark of a
+/// comma currency. [currencyCode] may be a variable or formula
+/// (`${account.currency}`), so the field follows the selected account.
+class CurrencyTextInputFormatterModel extends TextInputFormatterModel {
+  /// ISO code, e.g. USD, EUR, GBP, JPY; or a `${...}` binding.
+  final String currencyCode;
+
+  const CurrencyTextInputFormatterModel({this.currencyCode = 'USD'})
+    : super(name: 'Currency Amount', type: TextInputFormatterType.currency);
+
+  CurrencyTextInputFormatterModel copyWith({String? currencyCode}) =>
+      CurrencyTextInputFormatterModel(
+        currencyCode: currencyCode ?? this.currencyCode,
+      );
+
+  factory CurrencyTextInputFormatterModel.fromJson(Map json) =>
+      CurrencyTextInputFormatterModel(
+        currencyCode: json['currencyCode'] as String? ?? 'USD',
+      );
+
+  @override
+  Map toJson() => {
+    'name': name,
+    'type': type.name,
+    if (currencyCode != 'USD') 'currencyCode': currencyCode,
+  };
+
+  @override
+  List<Object?> get props => [...super.props, currencyCode];
+}

lib/src/api/models/text_input_formatter_model.g.dart

@@ -27,13 +27,18 @@ enum ChartType {
 
   /// One horizontal band of colored segments over a numeric domain, e.g. a
   /// machine's states across a shift.
-  timeline;
+  timeline,
+
+  /// A ring of slices, one per data item, sized by the first series' field
+  /// and colored by its colorField (e.g. spending by category).
+  donut;
 
   /// Display name.
   String get prettify => switch (this) {
     ChartType.bar => 'Bar',
     ChartType.line => 'Line',
     ChartType.timeline => 'Timeline',
+    ChartType.donut => 'Donut',
   };
 }
 
@@ -420,6 +425,21 @@ class ChartProperties extends CustomProperties with FieldsHolder {
   /// Timeline: divisions marked with ticks (e.g. hours).
   int divisions;
 
+  /// Donut: ring width as a fraction of the chart's diameter.
+  double donutThickness;
+
+  /// Donut: gap between slices, in degrees.
+  double sliceGap;
+
+  /// Donut: where the first slice starts, in degrees clockwise from 12
+  /// o'clock.
+  double startAngle;
+
+  /// Hovering a category (bar group, line point or slice) selects it, as a
+  /// tap does, and leaving the chart clears the selection (-1); bind
+  /// selectedIndex to show what is under the pointer.
+  bool selectOnHover;
+
   /// Creates [ChartProperties].
   ChartProperties({
     this.chartType = ChartType.bar,
@@ -469,6 +489,10 @@ class ChartProperties extends CustomProperties with FieldsHolder {
       a: 1,
     ),
     this.divisions = 8,
+    this.donutThickness = 0.15,
+    this.sliceGap = 1.5,
+    this.startAngle = 0,
+    this.selectOnHover = false,
   });
 
   /// Duplicates these properties with the given overrides.
@@ -505,6 +529,10 @@ class ChartProperties extends CustomProperties with FieldsHolder {
     ColorRGBA? nowColor,
     ColorRGBA? trackColor,
     int? divisions,
+    double? donutThickness,
+    double? sliceGap,
+    double? startAngle,
+    bool? selectOnHover,
   }) => ChartProperties(
     chartType: chartType ?? this.chartType,
     series: series ?? this.series,
@@ -538,11 +566,33 @@ class ChartProperties extends CustomProperties with FieldsHolder {
     nowColor: nowColor ?? this.nowColor,
     trackColor: trackColor ?? this.trackColor,
     divisions: divisions ?? this.divisions,
+    donutThickness: donutThickness ?? this.donutThickness,
+    sliceGap: sliceGap ?? this.sliceGap,
+    startAngle: startAngle ?? this.startAngle,
+    selectOnHover: selectOnHover ?? this.selectOnHover,
   );
 
   @override
   FieldsMap generateFields() => {
     ...super.generateFields(),
+    'donutThickness': NumFieldAccess<double>(
+      'Ring Width',
+      'Donut ring width as a fraction of the diameter',
+      () => donutThickness,
+      (v) => donutThickness = v,
+    ),
+    'sliceGap': NumFieldAccess<double>(
+      'Slice Gap',
+      'Gap between donut slices in degrees',
+      () => sliceGap,
+      (v) => sliceGap = v,
+    ),
+    'selectOnHover': BoolFieldAccess(
+      'Select On Hover',
+      'Hovering a category selects it',
+      () => selectOnHover,
+      (v) => selectOnHover = v,
+    ),
     'labelField': StringFieldAccess(
       'Label Field',
       'Field holding x-axis labels',
@@ -627,6 +677,10 @@ class ChartProperties extends CustomProperties with FieldsHolder {
     nowColor,
     trackColor,
     divisions,
+    donutThickness,
+    sliceGap,
+    startAngle,
+    selectOnHover,
   ];
 
   /// Creates [ChartProperties] from JSON.