### SplineElement start property API details

Source: https://pub.dev/documentation/graphic/latest/graphic/SplineElement/start

Detailed API documentation for the `start` property of the `SplineElement` class, including its type, description, and modifiers, as part of the `graphic` package.

```APIDOC
SplineElement class (from graphic package 2.6.0):
  Property: start
    Type: Offset (https://api.flutter.dev/flutter/dart-ui/Offset-class.html)
    Description: The start point of this spline.
    Modifiers: final
```

--------------------------------

### APIDOC LineElement.start Property Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/LineElement/start

Detailed API documentation for the `start` property of the `LineElement` class, including its type, modifiers, and purpose.

```APIDOC
LineElement.start property:
  Type: Offset
  Modifiers: final
  Description: The start point of this line.
```

--------------------------------

### Generic Abstract Method Signature for Convert

Source: https://pub.dev/documentation/graphic/latest/graphic/ScaleConv/convert

A generic code example demonstrating the abstract method signature for a conversion function, as seen in the `ScaleConv` class implementation details.

```Dart
O convert(I input);
```

--------------------------------

### Dart LineElement operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/LineElement/operator_equals

An example implementation of the `operator ==` method for a `LineElement` class in Dart. This override demonstrates how to check for type compatibility, leverage the superclass's equality, and compare specific properties (`start`, `end`) to determine if two `LineElement` objects are considered equal. This method is typically overridden in conjunction with the `hashCode` method.

```Dart
@override
bool operator ==(Object other) =>
    other is LineElement &&
    super == other &&
    start == other.start &&
    end == other.end;
```

--------------------------------

### TooltipGuide Constructor Dart Implementation Details

Source: https://pub.dev/documentation/graphic/latest/graphic/TooltipGuide/TooltipGuide

Shows the internal Dart implementation of the TooltipGuide constructor, including how parameters are initialized and validated using assertions.

```Dart
TooltipGuide({
  this.selections,
  this.followPointer,
  this.anchor,
  this.layer,
  this.mark,
  this.align,
  this.offset,
  this.padding,
  this.backgroundColor,
  this.radius,
  this.elevation,
  this.textStyle,
  this.multiTuples,
  this.variables,
  this.constrained,
  this.renderer,
})  : assert(isSingle([renderer, align], allowNone: true)),
      assert(isSingle([renderer, offset], allowNone: true)),
      assert(isSingle([renderer, padding], allowNone: true)),
      assert(isSingle([renderer, backgroundColor], allowNone: true)),
      assert(isSingle([renderer, radius], allowNone: true)),
      assert(isSingle([renderer, elevation], allowNone: true)),
      assert(isSingle([renderer, textStyle], allowNone: true)),
      assert(isSingle([renderer, multiTuples], allowNone: true)),
      assert(isSingle([renderer, constrained], allowNone: true)),
      assert(isSingle([renderer, variables], allowNone: true));
```

--------------------------------

### CrosshairGuide Constructor API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/CrosshairGuide/CrosshairGuide

Documents the parameters available for initializing a CrosshairGuide object, used for creating interactive crosshairs in graphic visualizations.

```APIDOC
CrosshairGuide({
  Set<String>? selections,
  List<PaintStyle?>? styles,
  List<LabelStyle?>? labelStyles,
  List<PaintStyle?>? labelBackgroundStyles,
  List<double>? labelPaddings,
  List<bool>? showLabel,
  List<String? Function(dynamic)?>? formatter,
  List<bool>? followPointer,
  int? layer,
  int? mark,
  List<bool>? expandEdges
})
```

--------------------------------

### Dart LineElement start property declaration

Source: https://pub.dev/documentation/graphic/latest/graphic/LineElement/start

Declaration of the `start` property within the `LineElement` class, specifying it as a final `Offset` type.

```Dart
final Offset start;
```

--------------------------------

### SplineElement start property declaration

Source: https://pub.dev/documentation/graphic/latest/graphic/SplineElement/start

Declaration of the `start` property within the `SplineElement` class, showing its type as `Offset` and its immutability with the `final` keyword.

```Dart
final Offset start;
```

--------------------------------

### TooltipGuide Constructor API Signature

Source: https://pub.dev/documentation/graphic/latest/graphic/TooltipGuide/TooltipGuide

Describes the public API signature and available parameters for the TooltipGuide constructor in the graphic package, used for creating tooltips.

```APIDOC
TooltipGuide({
  Set<String>? selections,
  List<bool>? followPointer,
  Offset anchor(Size)?,
  int? layer,
  int? mark,
  Alignment? align,
  Offset? offset,
  EdgeInsets? padding,
  Color? backgroundColor,
  Radius? radius,
  double? elevation,
  TextStyle? textStyle,
  bool? multiTuples,
  List<String>? variables,
  bool? constrained,
  TooltipRenderer? renderer,
})

Purpose: Creates a tooltip.
```

--------------------------------

### Basic Bar Chart Example with Flutter Graphic

Source: https://pub.dev/documentation/graphic/latest/graphic/graphic-library

Demonstrates how to create a simple bar chart using the `graphic` library's `Chart` widget, defining data, variables, marks, and axes for visualization.

```Dart
Chart(
  data: [
    { 'genre': 'Sports', 'sold': 275 },
    { 'genre': 'Strategy', 'sold': 115 },
    { 'genre': 'Action', 'sold': 120 },
    { 'genre': 'Shooter', 'sold': 350 },
    { 'genre': 'Other', 'sold': 150 },
  ],
  variables: {
    'genre': Variable(
      accessor: (Map map) => map['genre'] as String,
    ),
    'sold': Variable(
      accessor: (Map map) => map['sold'] as num,
    ),
  },
  marks: [IntervalMark()],
  axes: [
    Defaults.horizontalAxis,
    Defaults.verticalAxis,
  ],
)
```

--------------------------------

### AxisGuide<V> Constructor API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/AxisGuide/AxisGuide

Documents the parameters and their types for the AxisGuide constructor, which is used to create an axis with various customizable properties.

```APIDOC
AxisGuide<V> constructor:
  AxisGuide<V>({
    Dim? dim,
    String? variable,
    double? position,
    bool? flip,
    PaintStyle? line,
    TickLine? tickLine,
    TickLineMapper? tickLineMapper,
    LabelStyle? label,
    LabelMapper? labelMapper,
    PaintStyle? grid,
    GridMapper? gridMapper,
    PaintStyle? labelBackground,
    LabelBackgroundMapper? labelBackgroundMapper,
    int? layer,
    int? gridZIndex
  })
  
  Description: Creates an axis.
  
  Parameters:
    dim: Dim?
    variable: String?
    position: double?
    flip: bool?
    line: PaintStyle?
    tickLine: TickLine?
    tickLineMapper: TickLineMapper?
    label: LabelStyle?
    labelMapper: LabelMapper?
    grid: PaintStyle?
    gridMapper: GridMapper?
    labelBackground: PaintStyle?
    labelBackgroundMapper: LabelBackgroundMapper?
    layer: int?
    gridZIndex: int?
```

--------------------------------

### PartitionMark.new Constructor Dart Implementation

Source: https://pub.dev/documentation/graphic/latest/graphic/PartitionMark/PartitionMark

Dart implementation of the PartitionMark constructor, showing how it initializes its superclass with the provided parameters to construct a partition mark.

```Dart
PartitionMark({
  ColorEncode? color,
  ElevationEncode? elevation,
  GradientEncode? gradient,
  LabelEncode? label,
  Varset? position,
  ShapeEncode<S>? shape,
  SizeEncode? size,
  List<Modifier>? modifiers,
  int? layer,
  Selected? selected,
  StreamController<Selected?>? selectionStream,
  Transition? transition,
  Set<MarkEntrance>? entrance,
  String? Function(Tuple)? tag,
}) : super(
        color: color,
        elevation: elevation,
        gradient: gradient,
        label: label,
        position: position,
        shape: shape,
        size: size,
        modifiers: modifiers,
        layer: layer,
        selected: selected,
        selectionStream: selectionStream,
        transition: transition,
        entrance: entrance,
        tag: tag,
      );
```

--------------------------------

### Dart Modifier.operator == Example Implementation

Source: https://pub.dev/documentation/graphic/latest/graphic/Modifier/operator_equals

An example of overriding the `operator ==` method in a Dart class, demonstrating a common pattern for equality checks by delegating to an `equalTo` method.

```Dart
@override
bool operator ==(Object other) => equalTo(other);
```

--------------------------------

### Dart SymmetricModifier operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/SymmetricModifier/operator_equals

A concrete Dart code example demonstrating how the `operator ==` method can be implemented for the `SymmetricModifier` class. This specific implementation checks if the `other` object is an instance of `SymmetricModifier`.

```Dart
@override
bool operator ==(Object other) => other is SymmetricModifier;
```

--------------------------------

### PartitionShape Class API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/PartitionShape-class

Detailed API documentation for the abstract `PartitionShape` class, including its constructors, properties, methods, and operators, along with inheritance and implementers.

```APIDOC
PartitionShape class [abstract]
  Description: The shape for the partition mark.
  See also: PartitionMark

Inheritance:
  - Object
  - Shape
  - PartitionShape

Implementers:
  - PolygonShape

Constructors:
  - PartitionShape.new()

Properties:
  - defaultSize: double
    Description: The default size of the shape if Attributes.size is null.
    Modifiers: no setter, override
  - hashCode: int
    Description: The hash code for this object.
    Modifiers: no setter, inherited
  - runtimeType: Type
    Description: A representation of the runtime type of the object.
    Modifiers: no setter, inherited

Methods:
  - drawGroupLabels(List<Attributes> group, CoordConv coord, Offset origin): List<MarkElement<ElementStyle>>
    Description: Renders label elements of all tuples of a group.
    Modifiers: inherited
  - drawGroupPrimitives(List<Attributes> group, CoordConv coord, Offset origin): List<MarkElement<ElementStyle>>
    Description: Renders primitive elements of all tuples of a group.
    Modifiers: inherited
  - equalTo(Object other): bool
    Description: Checks the equlity of two specs.
    Modifiers: inherited
  - noSuchMethod(Invocation invocation): dynamic
    Description: Invoked when a nonexistent method or property is accessed.
    Modifiers: inherited
  - representPoint(List<Offset> position): Offset
    Description: Gets the represent point of Attributes.position points.
    Modifiers: inherited
  - toString(): String
    Description: A string representation of this object.
    Modifiers: inherited

Operators:
  - operator ==(Object other): bool
    Description: The equality operator.
    Modifiers: inherited
```

--------------------------------

### PointMark Constructor Dart Implementation

Source: https://pub.dev/documentation/graphic/latest/graphic/PointMark/PointMark

Provides the Dart source code for the `PointMark` constructor, illustrating how it initializes its properties by passing them directly to the superclass constructor. This implementation ensures proper inheritance and setup of mark attributes.

```Dart
PointMark({
  ColorEncode? color,
  ElevationEncode? elevation,
  GradientEncode? gradient,
  LabelEncode? label,
  Varset? position,
  ShapeEncode<PointShape>? shape,
  SizeEncode? size,
  List<Modifier>? modifiers,
  int? layer,
  Selected? selected,
  StreamController<Selected?>? selectionStream,
  Transition? transition,
  Set<MarkEntrance>? entrance,
  String? Function(Tuple)? tag,
}) : super(
        color: color,
        elevation: elevation,
        gradient: gradient,
        label: label,
        position: position,
        shape: shape,
        size: size,
        modifiers: modifiers,
        layer: layer,
        selected: selected,
        selectionStream: selectionStream,
        transition: transition,
        entrance: entrance,
        tag: tag,
      );
```

--------------------------------

### Dart LabelElement operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/LabelElement/operator_equals

Example implementation of the `operator ==` method for the `LabelElement` class in Dart. It checks if the `other` object is a `LabelElement`, then compares the superclass equality and the `text` property.

```Dart
@override
bool operator ==(Object other) =>
    other is LabelElement && super == other && text == other.text;
```

--------------------------------

### CrosshairGuide Constructor Implementation

Source: https://pub.dev/documentation/graphic/latest/graphic/CrosshairGuide/CrosshairGuide

Shows the internal implementation of the CrosshairGuide constructor, assigning provided parameters to instance variables.

```Dart
CrosshairGuide({
  this.selections,
  this.styles,
  this.labelStyles,
  this.labelBackgroundStyles,
  this.labelPaddings,
  this.showLabel,
  this.formatter,
  this.followPointer,
  this.layer,
  this.mark,
  this.expandEdges
});
```

--------------------------------

### Dart Implementation of LineElement.lerpFrom

Source: https://pub.dev/documentation/graphic/latest/graphic/LineElement/lerpFrom

The Dart code demonstrating the internal logic of the `lerpFrom` method. It shows how properties like `start`, `end`, `style`, `rotation`, and `rotationAxis` are interpolated using `Offset.lerp` and `lerpDouble`.

```Dart
@override
LineElement lerpFrom(covariant LineElement from, double t) => LineElement(
      start: Offset.lerp(from.start, start, t)!,
      end: Offset.lerp(from.end, end, t)!,
      style: style.lerpFrom(from.style, t),
      rotation: lerpDouble(from.rotation, rotation, t),
      rotationAxis: Offset.lerp(from.rotationAxis, rotationAxis, t),
      tag: tag,
    );
```

--------------------------------

### Dart `ElementStyle` `operator ==` Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/ElementStyle/operator_equals

A practical example demonstrating how to override the `operator ==` method for the `ElementStyle` class in Dart. This specific implementation checks if the `other` object is an instance of `ElementStyle`.

```Dart
@override
bool operator ==(Object other) => other is ElementStyle;
```

--------------------------------

### FunctionMark.new Constructor API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/FunctionMark/FunctionMark

Defines the signature and parameters for creating a new FunctionMark instance, specifying various encoding and styling options.

```APIDOC
FunctionMark<S extends FunctionShape>({
  ColorEncode? color,
  ElevationEncode? elevation,
  GradientEncode? gradient,
  LabelEncode? label,
  Varset? position,
  ShapeEncode<S>? shape,
  SizeEncode? size,
  List<Modifier>? modifiers,
  int? layer,
  Selected? selected,
  StreamController<Selected?>? selectionStream,
  Transition? transition,
  Set<MarkEntrance>? entrance,
  String? Function(Tuple)? tag
})
```

--------------------------------

### Dart MoveSegment operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/MoveSegment/operator_equals

Example implementation of the `operator ==` method for the `MoveSegment` class, demonstrating how to check for type, call the superclass's equality, and compare specific properties like `end`.

```Dart
@override
bool operator ==(Object other) =>
    other is MoveSegment && super == other && end == other.end;
```

--------------------------------

### Dart LinearScale operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/LinearScale/operator_equals

An example implementation of the `operator ==` method for the `LinearScale` class in Dart, demonstrating a common pattern for overriding the equality operator to compare instances based on their type and superclass equality.

```dart
@override
bool operator ==(Object other) => other is LinearScale && super == other;
```

--------------------------------

### LineMark Constructor Implementation

Source: https://pub.dev/documentation/graphic/latest/graphic/LineMark/LineMark

The internal implementation of the `LineMark` constructor, showing how it initializes its properties by calling the superclass constructor with the provided arguments.

```Dart
LineMark({
  ColorEncode? color,
  ElevationEncode? elevation,
  GradientEncode? gradient,
  LabelEncode? label,
  Varset? position,
  ShapeEncode<LineShape>? shape,
  SizeEncode? size,
  List<Modifier>? modifiers,
  int? layer,
  Selected? selected,
  StreamController<Selected?>? selectionStream,
  Transition? transition,
  Set<MarkEntrance>? entrance,
  String? Function(Tuple)? tag,
}) : super(
        color: color,
        elevation: elevation,
        gradient: gradient,
        label: label,
        position: position,
        shape: shape,
        size: size,
        modifiers: modifiers,
        layer: layer,
        selected: selected,
        selectionStream: selectionStream,
        transition: transition,
        entrance: entrance,
        tag: tag,
      );
```

--------------------------------

### Dart Implementation of FunctionMark Constructor

Source: https://pub.dev/documentation/graphic/latest/graphic/FunctionMark/FunctionMark

Provides the Dart source code for the FunctionMark constructor, demonstrating how it initializes its superclass with the provided parameters.

```Dart
FunctionMark({
  ColorEncode? color,
  ElevationEncode? elevation,
  GradientEncode? gradient,
  LabelEncode? label,
  Varset? position,
  ShapeEncode<S>? shape,
  SizeEncode? size,
  List<Modifier>? modifiers,
  int? layer,
  Selected? selected,
  StreamController<Selected?>? selectionStream,
  Transition? transition,
  Set<MarkEntrance>? entrance,
  String? Function(Tuple)? tag,
}) : super(
        color: color,
        elevation: elevation,
        gradient: gradient,
        label: label,
        position: position,
        shape: shape,
        size: size,
        modifiers: modifiers,
        layer: layer,
        selected: selected,
        selectionStream: selectionStream,
        transition: transition,
        entrance: entrance,
        tag: tag,
      );
```

--------------------------------

### Dart CustomAnnotation operator == implementation example

Source: https://pub.dev/documentation/graphic/latest/graphic/CustomAnnotation/operator_equals

An example implementation of the `operator ==` method for the `CustomAnnotation` class in Dart. This override checks if the `other` object is also a `CustomAnnotation` and then delegates to the superclass's equality check.

```Dart
@override
bool operator ==(Object other) => other is CustomAnnotation && super == other;
```

--------------------------------

### SectorElement Constructor API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/SectorElement/SectorElement

Defines the signature and parameters for the `SectorElement` constructor, detailing required and optional inputs for creating a new sector element.

```APIDOC
SectorElement constructor:
  SectorElement({
    required Offset center,
    required double startRadius,
    required double endRadius,
    required double startAngle,
    required double endAngle,
    BorderRadius? borderRadius,
    required PaintStyle style,
    double? rotation,
    Offset? rotationAxis,
    String? tag
  })
  Description: Creates a sector element.
  Parameters:
    center: required Offset - The center point of the sector.
    startRadius: required double - The inner radius of the sector.
    endRadius: required double - The outer radius of the sector.
    startAngle: required double - The starting angle of the sector in radians.
    endAngle: required double - The ending angle of the sector in radians.
    borderRadius: BorderRadius? - Optional border radius for the sector.
    style: required PaintStyle - The paint style to use for the sector.
    rotation: double? - Optional rotation angle for the sector.
    rotationAxis: Offset? - Optional axis for rotation.
    tag: String? - Optional tag for the element.
```

--------------------------------

### Dart MarkElement operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/MarkElement/operator_equals

An example implementation of the `operator ==` method for the `MarkElement` class. This override checks if the `other` object is also a `MarkElement` and then compares specific properties like `style`, `rotation`, `rotationAxis`, and `tag` for equality.

```Dart
@override
bool operator ==(Object other) =>
    other is MarkElement &&
    style == other.style &&
    rotation == other.rotation &&
    rotationAxis == other.rotationAxis &&
    tag == other.tag;
```

--------------------------------

### PolylineElement.lerpFrom Method API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/PolylineElement/lerpFrom

API documentation for the `lerpFrom` method of the `PolylineElement` class, detailing its signature, parameters, return type, and a brief description of its purpose.

```APIDOC
PolylineElement.lerpFrom(
  from: covariant PolylineElement,
  t: double
) -> PolylineElement

Description: Linearly interpolate between this element and `from`.
```

--------------------------------

### ImageStyle operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/ImageStyle/operator_equals

Provides an example implementation of the `operator ==` for the `ImageStyle` class. This implementation checks if the `other` object is also an `ImageStyle`, calls the superclass's `==` method, and then compares the `blendMode` property for equality.

```Dart
@override
bool operator ==(Object other) =>
    other is ImageStyle && super == other && blendMode == other.blendMode;
```

--------------------------------

### Dart ContinuousScaleConv<V> operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/ContinuousScaleConv/operator_equals

Provides an example implementation of the `operator ==` method for the `ContinuousScaleConv` class in Dart. This override checks for type compatibility and equality of `min` and `max` properties, along with the superclass's equality.

```Dart
@override
bool operator ==(Object other) =>
    other is ContinuousScaleConv<V> &&
    super == other &&
    min == other.min &&
    max == other.max;
```

--------------------------------

### Selection Constructor API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/Selection/Selection

Documents the parameters and their types for the `Selection` class constructor, which is used to create a new selection instance with various configuration options.

```APIDOC
Selection constructor:
  Selection({
    Dim? dim,
    String? variable,
    Set<GestureType>? on,
    Set<GestureType>? clear,
    Set<PointerDeviceKind>? devices,
    int? layer
  })
Purpose: Creates a selection.
```

--------------------------------

### Dart AxisGuide Constructor Implementation

Source: https://pub.dev/documentation/graphic/latest/graphic/AxisGuide/AxisGuide

Shows the internal implementation of the AxisGuide constructor in Dart, including how parameters are assigned and the assertions used for validation.

```Dart
AxisGuide({
  this.dim,
  this.variable,
  this.position,
  this.flip,
  this.line,
  this.tickLine,
  this.tickLineMapper,
  this.label,
  this.labelMapper,
  this.grid,
  this.gridMapper,
  this.labelBackground,
  this.labelBackgroundMapper,
  this.layer,
  this.gridZIndex,
})  : assert(isSingle([tickLine, tickLineMapper], allowNone: true)),
      assert(isSingle([label, labelMapper], allowNone: true)),
      assert(isSingle([grid, gridMapper], allowNone: true)),
      assert(isSingle([labelBackground, labelBackgroundMapper],
          allowNone: true));
```

--------------------------------

### Dart Segment Class operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/Segment/operator_equals

Example implementation of the `operator ==` method for the `Segment` class in Dart. It checks if the `other` object is also a `Segment` and if their `tag` properties are equal, demonstrating a common pattern for value equality in Dart.

```dart
@override
bool operator ==(Object other) => other is Segment && tag == other.tag;
```

--------------------------------

### Dart operator == Method Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/Shape/operator_equals

This Dart code snippet provides a typical example of how to implement the `operator ==` method. It demonstrates overriding the default behavior to delegate equality comparison to a custom `equalTo` method, which is a common pattern for complex object equality.

```Dart
@override
bool operator ==(Object other) => equalTo(other);
```

--------------------------------

### TooltipGuide Class API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/TooltipGuide-class

Detailed API specification for the `TooltipGuide` class, including its configurable properties, available methods, and overloaded operators.

```APIDOC
TooltipGuide Class:
  Properties:
    align: Alignment?
      How this tooltip align to the anchor.
      getter/setter pair
    anchor: Offset Function(Size)?
      Indicates the anchor position of this tooltip directly.
      getter/setter pair
    backgroundColor: Color?
      The background color of this tooltip window.
      getter/setter pair
    constrained: bool?
      Whether the tooltip should be constrained within the chart widget border.
      getter/setter pair
    elevation: double?
      The shadow elevation of this tooltip window.
      getter/setter pair
    followPointer: List<bool>?
      Whether the position for each dimension follows the pointer or stick to selected points.
      getter/setter pair
    hashCode: int
      The hash code for this object.
      no setter inherited
    layer: int?
      The layer of this tooltip.
      getter/setter pair
    mark: int?
      Which mark series this tooltip reacts to.
      getter/setter pair
    multiTuples: bool?
      Whether to show multiple tuples or only single tuple in this tooltip.
      getter/setter pair
    offset: Offset?
      The offset of the tooltip form the anchor.
      getter/setter pair
    padding: EdgeInsets?
      The padding form the content to the window border of this tooltip.
      getter/setter pair
    radius: Radius?
      The border radius of this tooltip window.
      getter/setter pair
    renderer: TooltipRenderer?
      Indicates a custom render funcion of this tooltip.
      getter/setter pair
    runtimeType: Type
      A representation of the runtime type of the object.
      no setter inherited
    selections: Set<String>?
      The selections this crosshair reacts to.
      getter/setter pair
    textStyle: TextStyle?
      The text style of this tooltip content.
      getter/setter pair
    variables: List<String>?
      The variable values of tuples to show on in this tooltip.
      getter/setter pair
  Methods:
    noSuchMethod(invocation: Invocation) -> dynamic
      Invoked when a nonexistent method or property is accessed.
      inherited
    toString() -> String
      A string representation of this object.
      inherited
  Operators:
    operator ==(other: Object) -> bool
      The equality operator.
      override
```

--------------------------------

### TooltipGuide Class API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/TooltipGuide-class

Defines the `TooltipGuide` class, which specifies the structure and styling of tooltips. It allows for deep customization through its constructor parameters.

```APIDOC
class TooltipGuide:
  description: The specification of a tooltip.

  Constructors:
    TooltipGuide.new({
      selections: Set<String>?
      followPointer: List<bool>?
      anchor: Offset Function(Size)?
      layer: int?
      mark: int?
      align: Alignment?
      offset: Offset?
      padding: EdgeInsets?
      backgroundColor: Color?
      radius: Radius?
      elevation: double?
      textStyle: TextStyle?
      multiTuples: bool?
      variables: List<String>?
      constrained: bool?
      renderer: TooltipRenderer?
    })
      description: Creates a tooltip.
```

--------------------------------

### Dart Example: Custom Equality for ScaleConv Class

Source: https://pub.dev/documentation/graphic/latest/graphic/ScaleConv/operator_equals

A practical Dart code example demonstrating how to implement a custom `operator ==` for the `ScaleConv` class. This implementation checks if the `other` object is also a `ScaleConv` instance and then performs a deep comparison of their `ticks` properties using `deepCollectionEquals`.

```Dart
@override
bool operator ==(Object other) =>
    other is ScaleConv<V, SV> && deepCollectionEquals(ticks, other.ticks);
```

--------------------------------

### Chart Constructor

Source: https://pub.dev/documentation/graphic/latest/graphic/Chart-class

Creates a new Chart widget instance. This constructor requires a list of `data`, a map of `variables`, and a list of `marks`. It also accepts various optional parameters for layout (`padding`), guides (`axes`, `tooltip`, `crosshair`), annotations, selections, and event stream controllers for gestures, resizing, and data changes.

```APIDOC
Chart.new({
  Key? key,
  required List<D> data,
  bool? changeData,
  required Map<String, Variable<D, dynamic>> variables,
  List<VariableTransform>? transforms,
  required List<Mark<Shape>> marks,
  Coord? coord,
  EdgeInsets padding(Size)?,
  List<AxisGuide>? axes,
  TooltipGuide? tooltip,
  CrosshairGuide? crosshair,
  List<Annotation>? annotations,
  Map<String, Selection>? selections,
  bool? rebuild,
  StreamController<GestureEvent>? gestureStream,
  StreamController<ResizeEvent>? resizeStream,
  StreamController<ChangeDataEvent<D>>? changeDataStream
})
```

--------------------------------

### APIDOC Segment.lerpFrom Method Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/Segment/lerpFrom

Comprehensive API documentation for the `lerpFrom` method, including its parameters, return type, and a brief description of its functionality.

```APIDOC
Segment:
  lerpFrom(
    from: covariant Segment,
    t: double
  )
    Returns: Segment
    Description: Linearly interpolate between this segment and 'from'.
```

--------------------------------

### Dart DiscreteScaleConv operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/DiscreteScaleConv/operator_equals

An example implementation of the `operator ==` method for the `DiscreteScaleConv` class in Dart. This snippet demonstrates how to override the equality operator to compare specific properties of the class, utilize `super == other` for inherited equality, and use `deepCollectionEquals` for collection comparisons.

```Dart
@override
bool operator ==(Object other) =>
    other is DiscreteScaleConv<V, SP> &&
    super == other &&
    deepCollectionEquals(values, other.values) &&
    align == other.align &&
    band == other.band;
```

--------------------------------

### PartitionMark<S extends PartitionShape> Class API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/PartitionMark-class

Detailed API documentation for the abstract PartitionMark class, outlining its inheritance hierarchy, classes that implement it, and the parameters available in its constructor for creating new instances.

```APIDOC
PartitionMark<S extends PartitionShape> class [abstract]
  Description: The specification of a partition mark. Partitions separate a set of points into two or more subsets.
  Inheritance:
    - Object
    - Mark<S>
    - PartitionMark
  Implementers:
    - PolygonMark
  Constructors:
    PartitionMark.new({
      ColorEncode? color,
      ElevationEncode? elevation,
      GradientEncode? gradient,
      LabelEncode? label,
      Varset? position,
      ShapeEncode<S>? shape,
      SizeEncode? size,
      List<Modifier>? modifiers,
      int? layer,
      Selected? selected,
      StreamController<Selected?>? selectionStream,
      Transition? transition,
      Set<MarkEntrance>? entrance,
      String? tag(Tuple)?
    })
      Description: Creates a partition mark.
```

--------------------------------

### Dart CloseSegment operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/CloseSegment/operator_equals

A practical Dart code example demonstrating how to correctly override the `operator ==` method for a `CloseSegment` class. This implementation checks if the `other` object is also a `CloseSegment` and then delegates to the superclass's equality check, ensuring proper type-aware comparison.

```Dart
@override
bool operator ==(Object other) => other is CloseSegment && super == other;
```

--------------------------------

### Typedef: TooltipRenderer

Source: https://pub.dev/documentation/graphic/latest/graphic

Gets the elements of a tooltip.

```APIDOC
TooltipRenderer = List<MarkElement<ElementStyle>> Function(Size size, Offset anchor, Map<int, Tuple> selectedTuples)
Parameters:
  size: Size
  anchor: Offset
  selectedTuples: Map<int, Tuple>
```

--------------------------------

### PartitionMark.new Constructor API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/PartitionMark/PartitionMark

API documentation for the PartitionMark class constructor, outlining its generic type parameter and all optional named parameters with their respective types. This constructor is used to create a partition mark.

```APIDOC
PartitionMark<S extends PartitionShape>({
  ColorEncode? color,
  ElevationEncode? elevation,
  GradientEncode? gradient,
  LabelEncode? label,
  Varset? position,
  ShapeEncode<S>? shape,
  SizeEncode? size,
  List<Modifier>? modifiers,
  int? layer,
  Selected? selected,
  StreamController<Selected?>? selectionStream,
  Transition? transition,
  Set<MarkEntrance>? entrance,
  String? Function(Tuple)? tag
})
```

--------------------------------

### Label Class API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/Label-class

Detailed API documentation for the `Label` class, including its constructor, properties, methods, and operators. This reference outlines how to instantiate a Label object and interact with its various attributes and behaviors.

```APIDOC
class Label
  Description: Specification of a label. A label is a span of text with styles. In is used for LabelEncode, TagAnnotation, etc in the chart. If the text is null or empty, the label will render nothing.

  Constructors:
    Label.new(String? text, LabelStyle? style)
      Description: Creates a label.

  Properties:
    hashCode: int (read-only, inherited)
      Description: The hash code for this object.
    haveText: bool (read-only)
      Description: Whether the text is not null or empty;
    runtimeType: Type (read-only, inherited)
      Description: A representation of the runtime type of the object.
    style: LabelStyle (read/write)
      Description: The label style.
    text: String? (read/write)
      Description: The label text.

  Methods:
    noSuchMethod(Invocation invocation): dynamic (inherited)
      Description: Invoked when a nonexistent method or property is accessed.
    toString(): String (inherited)
      Description: A string representation of this object.

  Operators:
    operator ==(Object other): bool (override)
      Description: The equality operator.
```

--------------------------------

### Dart ElementAnnotation operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/ElementAnnotation/operator_equals

An example implementation of the `operator ==` method for the `ElementAnnotation` class in Dart. This override checks for type compatibility, calls the superclass's equality, and performs deep collection comparisons for `variables` and `values`, along with a direct comparison for `clip`.

```Dart
@override
bool operator ==(Object other) =>
    other is ElementAnnotation &&
    super == other &&
    deepCollectionEquals(variables, other.variables) &&
    deepCollectionEquals(values, values) &&
    clip == other.clip;
```

--------------------------------

### Dart LineAnnotation operator == Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/LineAnnotation/operator_equals

A concrete Dart example demonstrating how the `operator ==` method is implemented for the `LineAnnotation` class. It shows how to compare properties of the current object with those of another `LineAnnotation` instance to determine equality, ensuring type safety and proper inheritance chain comparison.

```Dart
@override
bool operator ==(Object other) =>
    other is LineAnnotation &&
    super == other &&
    dim == other.dim &&
    variable == other.variable &&
    value == other.value &&
    style == other.style;
```

--------------------------------

### ScaleConv.convert Abstract Method API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/ScaleConv/convert

API documentation for the `convert` abstract method of the `ScaleConv` class, detailing its signature, parameters, return type, and purpose.

```APIDOC
Class: ScaleConv<V, SV extends num>
Method: convert
  Description: Converts an input to output.
  Signature: SV convert(V input)
  Parameters:
    input: V - The input value to convert.
  Returns:
    SV - The converted output value.
```

--------------------------------

### Typedef: LabelMapper

Source: https://pub.dev/documentation/graphic/latest/graphic

Gets an axis label form an axis value text.

```APIDOC
LabelMapper = LabelStyle? Function(String? text, int index, int total)
Parameters:
  text: String?
  index: int
  total: int
```

--------------------------------

### OrdinalScaleConv Constructor Dart Implementation

Source: https://pub.dev/documentation/graphic/latest/graphic/OrdinalScaleConv/OrdinalScaleConv

Provides the Dart implementation details for the OrdinalScaleConv constructor, showing how it initializes the object by calling the superclass constructor with the provided arguments.

```Dart
OrdinalScaleConv(
  OrdinalScale spec,
  List<Tuple> tuples,
  String variable,
) : super(spec, tuples, variable);
```

--------------------------------

### Dart PaintStyle operator == Method Implementation Example

Source: https://pub.dev/documentation/graphic/latest/graphic/PaintStyle/operator_equals

An example implementation of the `operator ==` method for the `PaintStyle` class in Dart. This override checks if the 'other' object is also a `PaintStyle` instance and then performs a detailed comparison of various properties, including colors, gradients, blend mode, stroke properties, elevation, shadow color, and dash patterns, to determine equality.

```Dart
@override
bool operator ==(Object other) =>
    other is PaintStyle &&
    super == other &&
    fillColor == other.fillColor &&
    fillGradient == other.fillGradient &&
    // fillShader will not check.
    strokeColor == other.strokeColor &&
    strokeGradient == other.strokeGradient &&
    // strokeShader will not check
    gradientBounds == other.gradientBounds &&
    blendMode == other.blendMode &&
    strokeWidth == other.strokeWidth &&
    strokeCap == other.strokeCap &&
    strokeJoin == other.strokeJoin &&
    strokeMiterLimit == other.strokeMiterLimit &&
    elevation == other.elevation &&
    shadowColor == other.shadowColor &&
    deepCollectionEquals(dash, other.dash) &&
    dashOffset == other.dashOffset;
```

--------------------------------

### TooltipGuide.textStyle Property API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/TooltipGuide/textStyle

API documentation for the `textStyle` property of the `TooltipGuide` class, outlining its type, description, default behavior, and access methods.

```APIDOC
TooltipGuide class:
  Properties:
    textStyle:
      Type: TextStyle?
      Description: The text style of this tooltip content.
      Details: If null, a default TextStyle(color: Color(0xff595959), fontSize: 12,) is set.
      Access: getter/setter pair
```

--------------------------------

### Typedef: TickLineMapper

Source: https://pub.dev/documentation/graphic/latest/graphic

Gets an axis tick line form an axis value text.

```APIDOC
TickLineMapper = TickLine? Function(String? text, int index, int total)
Parameters:
  text: String?
  index: int
  total: int
```

--------------------------------

### Dart IntervalMark Constructor Implementation

Source: https://pub.dev/documentation/graphic/latest/graphic/IntervalMark/IntervalMark

Shows the Dart source code for the `IntervalMark` constructor, illustrating how it initializes the mark by passing all provided parameters to its superclass.

```Dart
IntervalMark({
  ColorEncode? color,
  ElevationEncode? elevation,
  GradientEncode? gradient,
  LabelEncode? label,
  Varset? position,
  ShapeEncode<IntervalShape>? shape,
  SizeEncode? size,
  List<Modifier>? modifiers,
  int? layer,
  Selected? selected,
  StreamController<Selected?>? selectionStream,
  Transition? transition,
  Set<MarkEntrance>? entrance,
  String? Function(Tuple)? tag,
}) : super(
        color: color,
        elevation: elevation,
        gradient: gradient,
        label: label,
        position: position,
        shape: shape,
        size: size,
        modifiers: modifiers,
        layer: layer,
        selected: selected,
        selectionStream: selectionStream,
        transition: transition,
        entrance: entrance,
        tag: tag,
      );
```

--------------------------------

### Typedef: LabelBackgroundMapper

Source: https://pub.dev/documentation/graphic/latest/graphic

Gets an axis labelBackground style form an axis value text.

```APIDOC
LabelBackgroundMapper = PaintStyle? Function(String? text, int index, int total)
Parameters:
  text: String?
  index: int
  total: int
```

--------------------------------

### AxisGuide<V> Class API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/AxisGuide-class

Detailed API documentation for the AxisGuide<V> class, including its constructor parameters, properties, and inherited methods, providing full control over axis appearance and behavior.

```APIDOC
Class: AxisGuide<V>
Description: The specification of an axis. There can be mutiple axes in one dimension.

Constructors:
  AxisGuide.new({
    Dim? dim,
    String? variable,
    double? position,
    bool? flip,
    PaintStyle? line,
    TickLine? tickLine,
    TickLineMapper? tickLineMapper,
    LabelStyle? label,
    LabelMapper? labelMapper,
    PaintStyle? grid,
    GridMapper? gridMapper,
    PaintStyle? labelBackground,
    LabelBackgroundMapper? labelBackgroundMapper,
    int? layer,
    int? gridZIndex
  })
    Description: Creates an axis.

Properties:
  dim: Dim?
    Description: The dimension where this axis lies.
    Access: getter/setter pair
  flip: bool?
    Description: Whether to flip tick lines and labels to the other side of the axis line.
    Access: getter/setter pair
  grid: PaintStyle?
    Description: The grid stroke style for all ticks.
    Access: getter/setter pair
  gridMapper: GridMapper?
    Description: Indicates how to get the grid stroke style for each tick.
    Access: getter/setter pair
  gridZIndex: int?
    Description: The layer of the grids.
    Access: getter/setter pair
  hashCode: int
    Description: The hash code for this object.
    Access: no setter inherited
  label: LabelStyle?
    Description: The label style for all ticks.
    Access: getter/setter pair
  labelBackground: PaintStyle?
    Description: The labelBackground style for all ticks.
    Access: getter/setter pair
  labelBackgroundMapper: LabelBackgroundMapper?
    Description: Indicates how to get the labelBackground style for each tick.
    Access: getter/setter pair
  labelMapper: LabelMapper?
    Description: Indicates how to get the label style for each tick.
    Access: getter/setter pair
  layer: int?
    Description: The layer of this axis.
    Access: getter/setter pair
  line: PaintStyle?
    Description: The stroke style for the axis line.
    Access: getter/setter pair
  position: double?
    Description: The position ratio in the crossing dimension where this axis line stands.
    Access: getter/setter pair
  runtimeType: Type
    Description: A representation of the runtime type of the object.
    Access: no setter inherited
  tickLine: TickLine?
    Description: The tick line settings for all ticks.
    Access: getter/setter pair
  tickLineMapper: TickLineMapper?
    Description: Indicates how to get the tick line setting for each tick.
    Access: getter/setter pair
  variable: String?
    Description: The variable this axis is binded to.
    Access: getter/setter pair

Methods:
  noSuchMethod(Invocation invocation): dynamic
    Description: Invoked when a nonexistent method or property is accessed.
    Access: inherited
  toString(): String
    Description: A string representation of this object.
    Access: inherited
```

--------------------------------

### Typedef: GridMapper

Source: https://pub.dev/documentation/graphic/latest/graphic

Gets an axis grid stroke style form an axis value text.

```APIDOC
GridMapper = PaintStyle? Function(String? text, int index, int total)
Parameters:
  text: String?
  index: int
  total: int
```

--------------------------------

### PolygonMark Constructor Dart Implementation

Source: https://pub.dev/documentation/graphic/latest/graphic/PolygonMark/PolygonMark

The Dart source code demonstrating the internal implementation of the PolygonMark constructor, showing how it passes parameters to its superclass for initialization.

```Dart
PolygonMark({
  ColorEncode? color,
  ElevationEncode? elevation,
  GradientEncode? gradient,
  LabelEncode? label,
  Varset? position,
  ShapeEncode<PolygonShape>? shape,
  SizeEncode? size,
  List<Modifier>? modifiers,
  int? layer,
  Selected? selected,
  StreamController<Selected?>? selectionStream,
  Transition? transition,
  Set<MarkEntrance>? entrance,
  String? Function(Tuple)? tag,
}) : super(
        color: color,
        elevation: elevation,
        gradient: gradient,
        label: label,
        position: position,
        shape: shape,
        size: size,
        modifiers: modifiers,
        layer: layer,
        selected: selected,
        selectionStream: selectionStream,
        transition: transition,
        entrance: entrance,
        tag: tag,
      );
```

--------------------------------

### Flutter GestureType: secondaryLongPressDown

Source: https://pub.dev/documentation/graphic/latest/graphic/GestureType

Fired when a pointer contacts the screen with a secondary button, potentially starting a long-press. Precedes secondaryLongPressStart or secondaryLongPressCancel.

```APIDOC
secondaryLongPressDown → const GestureType
:   The pointer has contacted the screen with a secondary button, which might
    be the start of a long-press.

    This triggers after the pointer down gesture.

    If the user completes the long-press, and this gesture wins,
    secondaryLongPressStart will be emitted after this gesture. Otherwise,
    secondaryLongPressCancel will be emitted after this gesture.

    A gesture of this type has details of LongPressDownDetails.
```

--------------------------------

### IntervalSelection Constructor API Reference

Source: https://pub.dev/documentation/graphic/latest/graphic/IntervalSelection/IntervalSelection

API signature and parameter details for the `IntervalSelection` constructor, outlining the types and names of arguments required to instantiate an interval selection.

```APIDOC
IntervalSelection.new constructor:
  Parameters:
    color: Color?
    dim: Dim?
    variable: String?
    clear: Set<GestureType>?
    devices: Set<PointerDeviceKind>?
    layer: int?
  Description: Creates an interval selection.
```

--------------------------------

### Define Varset for X and Y dimensions using cross operator

Source: https://pub.dev/documentation/graphic/latest/graphic/Varset-class

Example demonstrating how to assign 'name' to the x-dimension and 'score' to the y-dimension using the cross operator (*).

```Dart
Varset('name') * Varset('score')
```