Scribble

Scribble is a lightweight library for freehand drawing in Flutter supporting pressure, variable line width and more!

Note: Scribble is still in development and will receive more features down the line!

Features

• Variable line width
• Image Export
• Pen and touch pressure support
• Choose which pointers can draw (touch, pen, mouse, etc.)
• Lines get slimmer when the pen is moved more quickly
• Line eraser support
• Full undo/redo support using history_state_notifier
• Sketches are fully serializable to JSON

Pipeline

• Load sketches
• PNG export

Usage

You can find a full working example in the example directory

You can create a drawing surface by adding the Scribble widget to your widget tree and passing in a ScribbleNotifier.

Where you manage this notifier is up to you, but since it is a StateNotifier, it works amazingly with riverpod for example.

import 'package:flutter_riverpod/flutter_riverpod.dart';

final scribbleStateProvider =
StateNotifierProvider.autoDispose<ScribbleNotifier, ScribbleState>(
      (ref) => ScribbleNotifier(),
);

You can then pass the notifier to the scribble widget.

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

class App extends ConsumerWidget {
  @override
  Widget build(BuildContext context, ScopedReader watch) {
    return Scaffold(
      body: Scribble(
        notifier: watch(scribbleStateProvider.notifier),
      ),
    );
  }
}

Use the public methods on ScribbleNotifier to control the behavior (for example from a button in the UI:

// Set color
notifier.setColor(Colors.black);

// Clear
notifier.clear();

// Undo
notifier.undo();

// Export to Image
notifier.renderImage(pixelRatio: 2.0);

// And more ... 

Additional information

As mentioned above, the package is still under development, but we already use it in the app we are currently developing.

Feel free to contribute, or open issues in our GitHub repo.