How to Crop Image in Flutter?

Question

I am using tflite for the recognition of image

For this image:

i have following result:

{rect: {w: 0.9337246417999268, x: 0.03002336621284485, h: 0.669991135597229, y: 0.31182175874710083}, confidenceInClass: 0.609375, detectedClass: person}

By using the above result I can make a rectangle around the object

How I can auto-crop a recognized rectangle and save it to memory.

Answer 1

if you want to crop an Image and not use Image_cropper. instead you can use the image package image: ^3.0.2.

image_package

you need to load the image and decode the image into a list, use copyCrop function to crop, and then encode it back

Answer 2

By using image_cropper.

Maybe this package helps - Flutter Image cropper
you just need to add this permission into AndroidManifest.xml.

<activity
    android:name="com.yalantis.ucrop.UCropActivity"
    android:screenOrientation="portrait"
    android:theme="@style/Theme.AppCompat.Light.NoActionBar"/>

And here is official example of using image_cropper

import 'package:flutter/material.dart';
import 'dart:async';
import 'dart:io';

import 'package:image_cropper/image_cropper.dart';
import 'package:image_picker/image_picker.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'ImageCropper',
      theme: ThemeData.light().copyWith(primaryColor: Colors.deepOrange),
      home: MyHomePage(
        title: 'ImageCropper',
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  final String title;

  MyHomePage({required this.title});

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

enum AppState {
  free,
  picked,
  cropped,
}

class _MyHomePageState extends State<MyHomePage> {
  late AppState state;
  File? imageFile;

  @override
  void initState() {
    super.initState();
    state = AppState.free;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: imageFile != null ? Image.file(imageFile!) : Container(),
      ),
      floatingActionButton: FloatingActionButton(
        backgroundColor: Colors.deepOrange,
        onPressed: () {
          if (state == AppState.free)
            _pickImage();
          else if (state == AppState.picked)
            _cropImage();
          else if (state == AppState.cropped) _clearImage();
        },
        child: _buildButtonIcon(),
      ),
    );
  }

  Widget _buildButtonIcon() {
    if (state == AppState.free)
      return Icon(Icons.add);
    else if (state == AppState.picked)
      return Icon(Icons.crop);
    else if (state == AppState.cropped)
      return Icon(Icons.clear);
    else
      return Container();
  }

  Future<Null> _pickImage() async {
    final pickedImage =
        await ImagePicker().getImage(source: ImageSource.gallery);
    imageFile = pickedImage != null ? File(pickedImage.path) : null;
    if (imageFile != null) {
      setState(() {
        state = AppState.picked;
      });
    }
  }

  Future<Null> _cropImage() async {
    File? croppedFile = await ImageCropper.cropImage(
        sourcePath: imageFile!.path,
        aspectRatioPresets: Platform.isAndroid
            ? [
                CropAspectRatioPreset.square,
                CropAspectRatioPreset.ratio3x2,
                CropAspectRatioPreset.original,
                CropAspectRatioPreset.ratio4x3,
                CropAspectRatioPreset.ratio16x9
              ]
            : [
                CropAspectRatioPreset.original,
                CropAspectRatioPreset.square,
                CropAspectRatioPreset.ratio3x2,
                CropAspectRatioPreset.ratio4x3,
                CropAspectRatioPreset.ratio5x3,
                CropAspectRatioPreset.ratio5x4,
                CropAspectRatioPreset.ratio7x5,
                CropAspectRatioPreset.ratio16x9
              ],
        androidUiSettings: AndroidUiSettings(
            toolbarTitle: 'Cropper',
            toolbarColor: Colors.deepOrange,
            toolbarWidgetColor: Colors.white,
            initAspectRatio: CropAspectRatioPreset.original,
            lockAspectRatio: false),
        iosUiSettings: IOSUiSettings(
          title: 'Cropper',
        ));
    if (croppedFile != null) {
      imageFile = croppedFile;
      setState(() {
        state = AppState.cropped;
      });
    }
  }

  void _clearImage() {
    imageFile = null;
    setState(() {
      state = AppState.free;
    });
  }
}

Or you can watch tutorials like:

• How to crop image in Flutter, by: Retro Portal Studio