Dog camera step 3

dogcamera3.dart

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:camera/camera.dart';
import 'package:soundpool/soundpool.dart';
import 'dart:ui' as ui;
import 'dart:typed_data';
import 'package:image/image.dart' as imglib;

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key}) : super(key: key);
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  CameraController _controller;
  bool _cameraInitialized = false;
  bool _isDetecting = false;
  Soundpool _pool;
  int _soundId;
  CameraImage _savedImage;
  Uint8List _snapShot;
  bool _showSnapshot = false;

  @override
  void initState() {
    super.initState();
    SystemChrome.setEnabledSystemUIOverlays([SystemUiOverlay.bottom]);
    SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.dark);
    _initializeApp();
  }

  void _initializeApp() async {

    _pool = Soundpool(streamType: StreamType.notification);
    _soundId = await rootBundle
        .load("assets/178186__snapper4298__camera-click-nikon.wav")
        .then((ByteData soundData) {
      return _pool.load(soundData);
    });

    List<CameraDescription> cameras = await availableCameras();
    _controller = CameraController(cameras[0], ResolutionPreset.medium);
    _controller.initialize().then((_) async {
      _cameraInitialized = true;
      //    _isDetecting = false;
      await _controller
          .startImageStream((CameraImage image) => _processCameraImage(image));
      setState(() {});
    });
  }

  void _processCameraImage(CameraImage image) async {
    if (_isDetecting) return;
    _isDetecting = true;
    // Detecting a dog will be done here.
    setState(() {
      _savedImage = image;
    });
    _isDetecting = false;
  }

  @override
  void dispose() {
    _controller?.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: GestureDetector(
      onTapDown: (TapDownDetails details) async {
        double mediaHeight = MediaQuery.of(context).size.height;
        if (details.localPosition.dy < mediaHeight * 0.8) return;
        double mediaWidth = MediaQuery.of(context).size.width;
        double xTap = details.localPosition.dx;

        if (xTap < mediaWidth * 0.35) {
          print('Left button tapped.');

        } else if (xTap < mediaWidth * 0.65) {
          // White button tapped.
          if (_showSnapshot) {
            // Stop showing snapshot if tapped while doing so
            _showSnapshot = false;
            return;
          } else {
            _pool.play(_soundId);
            imglib.Image convertedImage = _convertCameraImage(_savedImage);
            imglib.Image fullImage = imglib.copyResize(convertedImage,
                height: mediaHeight.round());
            _snapShot = imglib.encodePng(fullImage);
            setState(() {_showSnapshot = true;});
            Future.delayed(const Duration(seconds: 4), () {
              setState(() {_showSnapshot = false;});
            });
          }
        } else {
          print('Right button tapped');
        }
      },
      child: Container(
        child: _cameraInitialized
            ? OverflowBox(
                maxWidth: double.infinity,
                child: AspectRatio(
                    aspectRatio: _controller.value.aspectRatio,
                    child: _showSnapshot
                        ? Stack(fit: StackFit.expand, children: <Widget>[
                            _snapShot != null
                                ? Image.memory(_snapShot)
                                : Text('wait'),
                            CustomPaint(painter: ButtonsPainter(null)),
                          ])
                        : Stack(fit: StackFit.expand, children: <Widget>[
                            CameraPreview(_controller),
                            CustomPaint(painter: ButtonsPainter(null)),
                          ])))
            : Text(
                ' Waiting for camera initialization',
                style: TextStyle(fontSize: 20),
              ),
      ),
    ));
  }

  static imglib.Image _convertCameraImage(CameraImage image) {
    int width = image.width;
    int height = image.height;
    // imglib -> Image package from https://pub.dartlang.org/packages/image
    var img = imglib.Image(width, height); // Create Image buffer
    const int hexFF = 0xFF000000;
    final int uvyButtonStride = image.planes[1].bytesPerRow;
    final int uvPixelStride = image.planes[1].bytesPerPixel;
    for (int x = 0; x < width; x++) {
      for (int y = 0; y < height; y++) {
        final int uvIndex =
            uvPixelStride * (x / 2).floor() + uvyButtonStride * (y / 2).floor();
        final int index = y * width + x;
        final yp = image.planes[0].bytes[index];
        final up = image.planes[1].bytes[uvIndex];
        final vp = image.planes[2].bytes[uvIndex];
        // Calculate pixel color
        int r = (yp + vp * 1436 / 1024 - 179).round().clamp(0, 255);
        int g = (yp - up * 46549 / 131072 + 44 - vp * 93604 / 131072 + 91)
            .round()
            .clamp(0, 255);
        int b = (yp + up * 1814 / 1024 - 227).round().clamp(0, 255);
        // color: 0x FF  FF  FF  FF
        //           A   B   G   R
        img.data[index] = hexFF | (b << 16) | (g << 8) | r;
      }
    }
    // Rotate 90 degrees to upright
    var img1 = imglib.copyRotate(img, 90);
    return img1;
  }
}

class ButtonsPainter extends CustomPainter {
  ui.Image buttonImage;
  ButtonsPainter(this.buttonImage);

  @override
  void paint(Canvas canvas, Size size) {
    var paint = Paint();
    // First paint black field around buttons with low opacity
    paint.color = Colors.black.withOpacity(0.1);
    Rect rect =
        Offset(0.0, size.height * 0.8) & Size(size.width, size.height * 0.2);
    canvas.drawRect(rect, paint);

    // Draw buttons at 10% from the bottom
    final double yButton = size.height * 0.9;
    paint.style = PaintingStyle.fill;
    paint.color = Colors.grey;
    final double canvasWidth = size.width;
    double xButton;
    var icon;

    // Paint left button if no  buttonImage supplied
    if (buttonImage == null) {
      xButton = canvasWidth * 0.3;
      icon = Icons.photo_library;
      canvas.drawCircle(Offset(xButton, yButton), 22.0, paint);
      var builder = ui.ParagraphBuilder(ui.ParagraphStyle(
        fontFamily: icon.fontFamily,
        fontSize: 25.0,
      ))
        ..addText(String.fromCharCode(icon.codePoint));
      var para = builder.build();
      para.layout(const ui.ParagraphConstraints(width: 100.0));
      canvas.drawParagraph(para, Offset(xButton - 12.5, yButton - 12.5));
    }

    //Paint middle button.
    xButton = canvasWidth * 0.5;
    canvas.drawCircle(Offset(xButton, yButton), 32.0, paint);
    paint.color = Colors.white;
    canvas.drawCircle(Offset(xButton, yButton), 28.0, paint);

    // Paint right button.
    xButton = canvasWidth * 0.7;
    icon = Icons.info_outline;
    paint.color = Colors.grey;
    canvas.drawCircle(Offset(xButton, yButton), 22.0, paint);
    var builder = ui.ParagraphBuilder(ui.ParagraphStyle(
      fontFamily: icon.fontFamily,
      fontSize: 25.0,
    ))
      ..addText(String.fromCharCode(icon.codePoint));
    var para = builder.build();
    para.layout(const ui.ParagraphConstraints(width: 100.0));
    canvas.drawParagraph(para, Offset(xButton - 12.5, yButton - 12.5));

    // Paint image on left button
    if (buttonImage != null) {
      xButton = canvasWidth * 0.3;
      // First set up a round clipping area.
      double radius = 22.0;
      double l, t, r, b;
      l = xButton - radius;
      r = xButton + radius;
      t = yButton - radius;
      b = yButton + radius;
      ui.Rect clippingRect = Rect.fromLTRB(l, t, r, b);
      RRect clippingArea =
          RRect.fromRectAndRadius(clippingRect, Radius.circular(radius));
      canvas.clipRRect(clippingArea);
      // Then draw the square button image over the round clipping area
      double x, y = 0.0;
      x = xButton - buttonImage.height / 2.0;
      y = yButton - buttonImage.width / 2.0;
      Offset buttonOffset = Offset(x, y);
      canvas.drawImage(buttonImage, buttonOffset, Paint());
    }
  }

  @override
  bool shouldRepaint(ButtonsPainter oldDelegate) =>
      oldDelegate.buttonImage != buttonImage;
}