SignatureController class

class for interaction with signature widget manages points representing signature on canvas provides signature manipulation functions (export, clear)

Inheritance

Constructors

SignatureController.new({List<Point>? points, bool disabled = false, Color penColor = Colors.black, StrokeCap strokeCap = StrokeCap.butt, StrokeJoin strokeJoin = StrokeJoin.miter, double penStrokeWidth = 3.0, Color? exportBackgroundColor, Color? exportPenColor, VoidCallback? onDrawStart, VoidCallback? onDrawMove, VoidCallback? onDrawEnd})
constructor

Properties

canRedo → bool
check if there is any action to redo
no setter
canUndo → bool
check if there is any action to undo
no setter
defaultHeight → int?
Calculates a default height based on existing points. Will return null if there are no points.
no setter
defaultWidth → int?
Calculates a default width based on existing points. Will return null if there are no points.
no setter
disabled ↔ bool
If set to true canvas writting will be disabled.
getter/setter pair
exportBackgroundColor → Color?
background color to be used in exported png image
final
exportPenColor → Color?
color of a ginature line to be used in exported png image
final
hashCode → int
The hash code for this object.
no setterinherited
hasListeners → bool
Whether any listeners are currently registered.
no setterinherited
isEmpty → bool
check if canvas is empty (opposite of isNotEmpty method for convenience)
no setter
isNotEmpty → bool
check if canvas is not empty (opposite of isEmpty method for convenience)
no setter
maxXValue → double?
The biggest x value for all points. Will return null if there are no points.
no setter
maxYValue → double?
The biggest y value for all points. Will return null if there are no points.
no setter
minXValue → double?
The smallest x value for all points. Will return null if there are no points.
no setter
minYValue → double?
The smallest y value for all points. Will return null if there are no points.
no setter
onDrawEnd ↔ VoidCallback?
callback to notify when drawing has stopped
getter/setter pair
onDrawMove ↔ VoidCallback?
callback to notify when the pointer was moved while drawing.
getter/setter pair
onDrawStart ↔ VoidCallback?
callback to notify when drawing has started
getter/setter pair
penColor → Color
color of a signature line
final
penStrokeWidth → double
boldness of a signature line
final
points ↔ List<Point>
getter for points representing signature on 2D canvas
getter/setter pair
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
strokeCap → StrokeCap
shape of line ends
final
strokeJoin → StrokeJoin
shape of line joins
final
value ↔ List<Point>
The current value stored in this notifier.
getter/setter pairinherited

Methods

addListener(VoidCallback listener) → void
Register a closure to be called when the object changes.
inherited
addPoint(Point point) → void
add point to point collection
clear() → void
Clear the canvas
dispose() → void
Discards any resources used by the object. After this is called, the object is not in a usable state and should be discarded (calls to addListener will throw after the object is disposed).
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
notifyListeners() → void
Call all the registered listeners.
inherited
pointsToStrokes(double minDistanceBetweenPoints) → List<List<Point>>
Helper method to convert points to strokes
pushCurrentStateToUndoStack() → void
REMEMBERS CURRENT CANVAS STATE IN UNDO STACK
redo() → void
It will remove last reverted actions and add it into _latestActions Then, it will modify the real points with the last reverted action.
removeListener(VoidCallback listener) → void
Remove a previously registered closure from the list of closures that are notified when the object changes.
inherited
toImage({int? width, int? height}) → Future<Image?>
Convert to an ui.Image. Will return null if there are no points.
toPngBytes({int? height, int? width}) → Future<Uint8List?>
convert canvas to dart:ui ui.Image and then to PNG represented in Uint8List height and width should be at least as big as the drawings size Will return null if there are no points.
toRawSVG({int? width, int? height, double minDistanceBetweenPoints = 3}) → String?
Export the current content to a raw SVG string. Will return null if there are no points. width Canvas width to use height Canvas height to use minDistanceBetweenPoints Minimal distance between points to be included in svg. Used to reduce svg output size.
toString() → String
A string representation of this object.
inherited
toSVG({int? width, int? height, double minDistanceBetweenPoints = 3}) → SvgPicture?
Export the current content to a SVG graphic. Will return null if there are no points. width Canvas width to use height Canvas height to use minDistanceBetweenPoints Minimal distance between points to be included in svg. Used to reduce svg output size.
undo() → void
It will remove last action from _latestActions. The last action will be saved to _revertedActions that will be used to do redo-ing. Then, it will modify the real points with the last action.

Operators

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