SignatureController class
class for interaction with signature widget manages points representing signature on canvas provides signature manipulation functions (export, clear)
- Inheritance
-
- Object
- ChangeNotifier
- ValueNotifier<
List< Point> > - SignatureController
Constructors
-
SignatureController({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
- 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
-
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 returnnull
if there are no points. -
toRawSVG(
{int? width, int? height}) → String? -
Export the current content to a raw SVG string.
Will return
null
if there are no points. -
toString(
) → String -
A string representation of this object.
inherited
-
toSVG(
{int? width, int? height}) → SvgPicture? -
Export the current content to a SVG graphic.
Will return
null
if there are no points. -
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