scratcher

Scratch card widget which temporarily hides content from the user.

Features

• Supported platforms:
  • Android
  • iOS
  • Web (CanvasKit only)
• Cover content with full color or custom image
• Track the scratch progress and threshold
• Fully configurable

Getting started

1. First thing you need to do is adding the scratcher as a project dependency in pubspec.yaml:

dependencies:
 scratcher: "^2.5.0"

2. Now you can install it by running flutter pub get or through code editor.

Setting up

1. Import the library:

import 'package:scratcher/scratcher.dart';

2. Cover desired widget with the scratch card:

Scratcher(
  brushSize: 30,
  threshold: 50,
  color: Colors.red,
  onChange: (value) => print("Scratch progress: $value%"),
  onThreshold: () => print("Threshold reached, you won!"),
  child: Container(
    height: 300,
    width: 300,
    color: Colors.blue,
  ),
)

Properties

Property	Type	Description
child	Widget	Widget rendered under the scratch area.
enabled	bool	Whether new scratches can be applied.
threshold	double	Percentage level of scratch area which should be revealed to complete.
brushSize	double	Size of the brush. The bigger it is the faster user can scratch the card.
accuracy	ScratchAccuracy	Determines how accurate the progress should be reported. Lower accuracy means higher performance.
color	Color	Color used to cover the child widget.
image	Image	Image widget used to cover the child widget.
rebuildOnResize	bool	Determines if the scratcher should rebuild itself when space constraints change (resize).
onChange	Function	Callback called when new part of area is revealed (min 0.1% difference).
onThreshold	Function	Callback called when threshold is reached (only when defined).
onScratchStart	Function	Callback called when scratching starts.
onScratchUpdate	Function	Callback called during scratching.
onScratchEnd	Function	Callback called when scratching ends.

Programmatic access

You can control the Scratcher programmatically by assigning the GlobalKey to the widget.

final scratchKey = GlobalKey<ScratcherState>();

Scratcher(
  key: scratchKey,
  // remaining properties
)

After assigning the key, you can call any exposed methods e.g.:

RaisedButton(
  child: const Text('Reset'),
  onPressed: () {
    scratchKey.currentState.reset(duration: Duration(milliseconds: 2000));
  },
);

Method	Description
reset	Resets the scratcher state to the initial values.
reveal	Reveals the whole scratcher, so than only original child is displayed.

Example Project

There is a crazy example project in the example folder. Check it out to see most of the available options.

Resources

• https://www.youtube.com/watch?v=EM4D1pUpadA by The CS Guy