image and image_picker example

import 'dart:io';
import 'dart:async';

import 'package:flutter/material.dart';
import 'package:image/image.dart' as img;
import 'package:image_picker/image_picker.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  File _originalImage;
  File _compressedImage;
  Size _originalResolution;
  Size _compressedResolution;
  img.Image image;
  void _loadImage() {
    //ImagePicker.pickImage(source: ImageSource.camera, maxWidth: 400.0 ).then((file) {
    ImagePicker.pickImage(source: ImageSource.camera).then((file) {
      setState(() {
        _originalImage = file;
        image = img.decodeJpg(file.readAsBytesSync());
        _originalResolution =
            Size(image.width.toDouble(), image.height.toDouble());
        image = img.copyResize(image, 400);
        _compressedResolution =
            Size(image.width.toDouble(), image.height.toDouble());
        _compressedImage = File('${_originalImage.parent.path}/compressed.jpg');
        _compressedImage.writeAsBytesSync(img.encodeJpg(image, quality: 60));
        // _compressedImage.open();
        image = null;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: SingleChildScrollView(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            FittedBox(
              child: Row(
                children: <Widget>[
                  _originalImage != null
                      ? Image.file(
                          _originalImage,
                          fit: BoxFit.scaleDown,
                        )
                      : Text("Load a new image to compress..."),
                  _compressedImage != null
                      ? Image.file(
                          _compressedImage,
                          fit: BoxFit.scaleDown,
                        )
                      : Text("Load a new image to compress..."),
                ],
              ),
            ),
            Text('Original Image Info:', style: TextStyle(fontSize: 30.0)),
            Text(
                'Resolution: ${_originalResolution?.width?.toInt()}x${_originalResolution?.height?.toInt()}'),
            Text('Path:${_originalImage?.path}'),
            FutureBuilder<int>(
              future: _originalImage?.length(),
              builder: (context, snapshot) {
                final size = (snapshot.data / 1024.0).toStringAsFixed(2);
                return Text('size: $size Kb');
              },
            ),
            Text('Compressed Image Info:', style: TextStyle(fontSize: 30.0)),
            Text(
                'Resolution: ${_compressedResolution?.width?.toInt()}x${_compressedResolution?.height?.toInt()}'),
            Text('Path:${_compressedImage?.path}'),
            FutureBuilder<int>(
              future: _compressedImage?.length(),
              builder: (context, snapshot) {
                final size = (snapshot.data / 1024.0).toStringAsFixed(2);
                return Text('size: $size Kb');
              },
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _loadImage,
        tooltip: 'ImportImage',
        child: Icon(Icons.photo_camera),
      ),
    );
  }
}