SketchBoard class

SketchBoard is the main widget that renders a drawable canvas.

It supports two modes:

  • Draw Mode: where the user can draw handwriting directly on the canvas.
  • Move Mode: where the canvas can be zoomed and panned.

Features:

  • Renders handwriting using the Sketchcontroller.
  • Supports zoom and pan using InteractiveViewer.
  • Accepts overlay widgets (e.g., images or decorations) via overlayWidgets.
  • Wraps everything in a RepaintBoundary to support images export.

controller: Required controller that holds the drawing state. repaintKey: Key used to extract the widget as an images (PNG). overlayWidgets: Visual widgets (images, decorations, etc.) to be rendered below the drawing. boardColor: Background color of the drawing area. boardMinScale, boardMaxScale: Zoom scale limits when in move mode. backgroundColor: Scaffold background (outside the canvas). isPadDevice: Enable palm rejection by separating stylus and touch input.

Note:

  • All content, including overlay widgets and the canvas, will be captured when exporting as an images.
Inheritance

Constructors

SketchBoard({Key? key, required SketchController controller, GlobalKey<State<StatefulWidget>>? repaintKey, Color? boardColor, double? boardMaxScale, double? boardMinScale, Color? backgroundColor, Widget? overlayWidget, double? boardWidthSize, double? boardHeightSize, bool isPadDevice = false, bool multiTouchPanZoomEnabled = false})
Main widget for the sketch board.
const

Properties

backgroundColor → Color?
final
boardColor → Color?
final
boardHeightSize → double?
final
boardMaxScale → double?
final
boardMinScale → double?
final
boardWidthSize → double?
final
controller → SketchController
final
hashCode → int
The hash code for this object.
no setterinherited
isPadDevice → bool
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
multiTouchPanZoomEnabled → bool
final
overlayWidget → Widget?
final
repaintKey → GlobalKey<State<StatefulWidget>>?
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<StatefulWidget>
Creates the mutable state for this widget at a given location in the tree.
override
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String
A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, int wrapWidth = 65}) → String
Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String
Returns a one-line detailed description of the object.
inherited
toStringShort() → String
A short, textual description of this widget.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited