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A Flutter plugin providing performance optimized signature canvas with ability to set custom style, boundaries and initial state.
A Flutter plugin providing performance optimized signature canvas with ability to set custom style, boundaries and initial state. This is native flutter implementation, so it supports all platforms.
In time of creation of this plugin, there was no available solution that had:
- required performance on wide range of devices
- ability to set canvas boundaries
- ability to initialize using previously saved state
Migration to 5.0.0+ #
- This version no longer wraps
Expandedwidget if you are using it without specifying dimensions
- This removes error
Incorrect use of ParentDataWidget, see this issue for more information.
- If you are passing dimensions to widget, you do not have to change anything.
- If you are using widget without dimensions inside
Flexwidgets, you have to wrap
- If you are using widget without dimensions, but not inside mentioned widgets you do not have change anything and error should dissapear from your logs :)
To use this plugin, add
signature as a dependency in your
// IMPORT PACKAGE import 'package:signature/signature.dart'; // Initialise a controller. It will contains signature points, stroke width and pen color. // It will allow you to interact with the widget final SignatureController _controller = SignatureController( penStrokeWidth: 5, penColor: Colors.red, exportBackgroundColor: Colors.blue, ); // INITIALIZE. RESULT IS A WIDGET, SO IT CAN BE DIRECTLY USED IN BUILD METHOD var _signatureCanvas = Signature( controller: _controller, width: 300, height: 300, backgroundColor: Colors.lightBlueAccent, ); // CLEAR CANVAS _controller.clear(); // EXPORT BYTES AS PNG // The exported image will be limited to the drawn area _controller.toPngBytes(); // isEmpty/isNotEmpty CAN BE USED TO CHECK IF SIGNATURE HAS BEEN PROVIDED _controller.isNotEmpty; //true if signature has been provided _controller.isEmpty; //true if signature has NOT been provided // EXPORT POINTS (2D POINTS ROUGHLY REPRESENTING WHAT IS VISIBLE ON CANVAS) var exportedPoints = _controller.points; //EXPORTED POINTS CAN BE USED TO INITIALIZE PREVIOUS CONTROLLER final SignatureController _controller = SignatureController(points: exportedPoints);
Contribution and Support #
- Contributions are welcome!
- If you want to contribute code please create a PR
- If you find a bug or want a feature, please fill an issue