finger_painter 1.1.0

Painting package that let you finger paint with different brushes and different blend modes. The result can be read as a bitmap or list of Points to be used ie on a Map.

example/lib/main.dart

import 'dart:typed_data';
import 'dart:ui' as ui;

import 'package:finger_painter/finger_painter.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  Image? image;
  late PainterController painterController;

  @override
  void initState() {
    super.initState();
    painterController = PainterController()
      ..setStrokeColor(Colors.black)
      ..setMinStrokeWidth(3)
      ..setMaxStrokeWidth(15)
      ..setBlurSigma(0.0)
      ..setPenType(PenType.paintbrush2)
      ..setBlendMode(ui.BlendMode.srcOver);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Column(
          children: [
            const SizedBox(height: 30),
            Painter(
              controller: painterController,
              backgroundColor: const Color(0xFFF0F0F0),
              onDrawingEnded: (bytes) async {
                print('${painterController.getPoints()?.length} drawn points');
                setState(() {});
              },
              size: const Size(double.infinity, 250),
              // child: Image.asset('assets/map.png', fit: BoxFit.cover),
            ),
            const SizedBox(height: 30),
            Expanded(
              child: SingleChildScrollView(
                  child: Controls(
                pc: painterController,
                imgBytesList: painterController.getImageBytes(),
              )),
            ),
          ],
        ),
      ),
    );
  }
}

class Controls extends StatefulWidget {
  final PainterController? pc;
  final Uint8List? imgBytesList;

  const Controls({
    Key? key,
    this.pc,
    this.imgBytesList,
  }) : super(key: key);

  @override
  State<Controls> createState() => _ControlsState();
}

class _ControlsState extends State<Controls> {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            // display current drawing
            if (widget.imgBytesList != null)
              Container(
                decoration: BoxDecoration(
                  color: const Color(0x00FFFFFF),
                  border: Border.all(
                    color: const Color(0xFF000000),
                    style: BorderStyle.solid,
                    width: 4.0,
                  ),
                  borderRadius: BorderRadius.zero,
                  shape: BoxShape.rectangle,
                  boxShadow: const <BoxShadow>[
                    BoxShadow(
                      color: Color(0x66000000),
                      blurRadius: 10.0,
                      spreadRadius: 4.0,
                    )
                  ],
                ),
                child: Image.memory(
                  widget.imgBytesList!,
                  gaplessPlayback: true,
                  fit: BoxFit.scaleDown,
                  height: 140,
                ),
              ),

            const SizedBox(width: 30),

            // Pen types
            Column(
              children: [
                for (int i = 0; i < PenType.values.length; i++)
                  OutlinedButton(
                      child: Text(PenType.values[i].name),
                      style: ButtonStyle(
                          backgroundColor: widget.pc
                                      ?.getState()
                                      ?.penType
                                      .index ==
                                  i
                              ? MaterialStateProperty.all(
                                  Colors.greenAccent.withOpacity(0.5))
                              : MaterialStateProperty.all(Colors.transparent)),
                      onPressed: () {
                        if (widget.pc != null) {
                          widget.pc!.setPenType(PenType.values[i]);
                          setState(() {});
                        }
                      }),
              ],
            ),
          ],
        ),

        const SizedBox(height: 30),

        // Colors, background & delete
        Row(
          mainAxisSize: MainAxisSize.max,
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: [
            FloatingActionButton(
                backgroundColor: Colors.red,
                onPressed: () => widget.pc?.setStrokeColor(Colors.red)),
            FloatingActionButton(
                backgroundColor: Colors.yellowAccent,
                onPressed: () =>
                    widget.pc?.setStrokeColor(Colors.yellowAccent)),
            FloatingActionButton(
                backgroundColor: Colors.black,
                onPressed: () => widget.pc?.setStrokeColor(Colors.black)),
            FloatingActionButton(
                backgroundColor: Colors.green,
                onPressed: () => widget.pc?.setStrokeColor(Colors.green)),
            FloatingActionButton(
                backgroundColor: Colors.blue,
                child: const Icon(Icons.image),
                onPressed: () async {
                  Uint8List image = (await rootBundle.load('assets/dash.png'))
                      .buffer
                      .asUint8List();
                  widget.pc?.setBackgroundImage(image);
                  setState(() {});
                }),
            FloatingActionButton(
                backgroundColor: Colors.red,
                child: const Icon(Icons.delete_outline),
                onPressed: () => widget.pc
                    ?.clearContent(clearColor: const Color(0xfff0f0ff))),
          ],
        ),

        const SizedBox(height: 30),

        /// min stroke width
        Row(
          children: [
            Text('  min stroke '
                '${widget.pc?.getState()!.strokeMinWidth.toStringAsFixed(1)}'),
            Expanded(
              child: Slider.adaptive(
                  value: widget.pc?.getState()?.strokeMinWidth ?? 0,
                  min: 1,
                  max: 20,
                  onChanged: (value) {
                    if (widget.pc != null) {
                      widget.pc?.setMinStrokeWidth(value);
                      if (widget.pc!.getState()!.strokeMinWidth >
                          widget.pc!.getState()!.strokeMaxWidth) {
                        widget.pc?.setMinStrokeWidth(
                            widget.pc!.getState()!.strokeMaxWidth);
                      }
                      setState(() {});
                    }
                  }),
            ),
          ],
        ),

        /// max stroke width
        Row(
          children: [
            Text('  max stroke '
                '${widget.pc?.getState()!.strokeMaxWidth.toStringAsFixed(1)}'),
            Expanded(
              child: Slider.adaptive(
                  value: widget.pc?.getState()?.strokeMaxWidth ?? 0,
                  min: 1,
                  max: 40,
                  onChanged: (value) {
                    if (widget.pc != null) {
                      widget.pc!.setMaxStrokeWidth(value);
                      if (widget.pc!.getState()!.strokeMaxWidth <
                          widget.pc!.getState()!.strokeMinWidth) {
                        widget.pc!.setMaxStrokeWidth(
                            widget.pc!.getState()!.strokeMinWidth);
                      }
                      setState(() {});
                    }
                  }),
            ),
          ],
        ),

        /// blur
        Row(
          children: [
            Text('  blur '
                '${widget.pc?.getState()!.blurSigma.toStringAsFixed(1)}'),
            Expanded(
              child: Slider.adaptive(
                  value: widget.pc?.getState()?.blurSigma ?? 0,
                  min: 0.0,
                  max: 10.0,
                  onChanged: (value) {
                    if (widget.pc != null) {
                      widget.pc!.setBlurSigma(value);
                      setState(() {});
                    }
                  }),
            ),
          ],
        ),

        const SizedBox(height: 30),

        // blends modes
        Wrap(
          spacing: 4,
          alignment: WrapAlignment.center,
          crossAxisAlignment: WrapCrossAlignment.center,
          children: [
            const Text(' blend modes: '),
            for (int i = 0; i < ui.BlendMode.values.length; i++)
              OutlinedButton(
                  child: Text(ui.BlendMode.values[i].name),
                  style: ButtonStyle(
                      backgroundColor:
                          widget.pc?.getState()?.blendMode.index == i
                              ? MaterialStateProperty.all(
                                  Colors.greenAccent.withOpacity(0.5))
                              : MaterialStateProperty.all(Colors.transparent)),
                  onPressed: () {
                    widget.pc?.setBlendMode(ui.BlendMode.values[i]);
                    setState(() {});
                  }),
          ],
        ),
        const SizedBox(height: 30),
      ],
    );
  }
}