flutter_image_compress

pub package GitHub GitHub stars

compress image with native code(objc kotlin)

This library can work on android/ios.

why

Q:Dart has image related libraries to compress. Why use native?

A:For reasons unknown, using dart language is not efficient, even in release version, using isolate can not solve the problem.

about android

maybe, you need update your kotlin version to 1.2.71 or higher.

about ios

No problems found at present.

use

dependencies:
  flutter_image_compress: ^0.2.3
import 'package:flutter_image_compress/flutter_image_compress.dart';

use:

see whole example code

  Future<List<int>> testCompressFile(File file) async {
    var result = await FlutterImageCompress.compressWithFile(
      file.absolute.path,
      minWidth: 2300,
      minHeight: 1500,
      quality: 94,
      rotate: 90,
    );
    print(file.lengthSync());
    print(result.length);
    return result;
  }

  Future<File> testCompressAndGetFile(File file, String targetPath) async {
    var result = await FlutterImageCompress.compressAndGetFile(
        file.absolute.path, targetPath,
        quality: 88,
        rotate: 180,
      );

    print(file.lengthSync());
    print(result.lengthSync());

    return result;
  }

  Future<List<int>> testCompressAsset(String assetName) async {
    var list = await FlutterImageCompress.compressAssetImage(
      assetName,
      minHeight: 1920,
      minWidth: 1080,
      quality: 96,
      rotate: 180,
    );

    return list;
  }

  Future<List<int>> testComporessList(List<int> list) async {
    var result = await FlutterImageCompress.compressWithList(
      list,
      minHeight: 1920,
      minWidth: 1080,
      quality: 96,
      rotate: 135,
    );
    print(list.length);
    print(result.length);
    return result;
  }

about List or Uint8List

you maybe need convert List<int> to 'Uint8List' to display image

use Uint8List need import package to your code like this

var u8 = Uint8List.fromList(list)
ImageProvider provider = MemoryImage(Uint8List.fromList(list));

use in Image Widget

    List<int> list = await testCompressFile(file);
    ImageProvider provider = MemoryImage(Uint8List.fromList(list));

    Image(
      image: provider ?? AssetImage("img/img.jpg"),
    ),

write to file

  void writeToFile(List<int> list, String filePath) {
    var file = File(filePath);
    file.writeAsBytes(list, flush: true, mode: FileMode.write);
  }

android build error

Caused by: org.gradle.internal.event.ListenerNotificationException: Failed to notify project evaluation listener.
        at org.gradle.internal.event.AbstractBroadcastDispatch.dispatch(AbstractBroadcastDispatch.java:86)
        ...
Caused by: java.lang.AbstractMethodError
        at org.jetbrains.kotlin.gradle.plugin.KotlinPluginKt.resolveSubpluginArtifacts(KotlinPlugin.kt:776)
        ...

see the flutter/flutter/issues#21473

you need edit your kotlin version to 1.2.71+

If flutter supports more platforms (windows, mac, linux, other) in the future and you use this library, propose issue / PR

ABOUT EXIF

Using this library, EXIF information will be removed.

Libraries

flutter_image_compress

Dart

dart:ui
Built-in types and core primitives for a Flutter application. [...]

Core

dart:async
Support for asynchronous programming, with classes such as Future and Stream. [...]
dart:collection
Classes and utilities that supplement the collection support in dart:core. [...]
dart:convert
Encoders and decoders for converting between different data representations, including JSON and UTF-8. [...]
dart:core
Built-in types, collections, and other core functionality for every Dart program. [...]
dart:developer
Interact with developer tools such as the debugger and inspector. [...]
dart:math
Mathematical constants and functions, plus a random number generator. [...]
dart:typed_data
Lists that efficiently handle fixed sized data (for example, unsigned 8 byte integers) and SIMD numeric types. [...]

VM

dart:io
File, socket, HTTP, and other I/O support for non-web applications. [...]
dart:isolate
Concurrent programming using isolates: independent workers that are similar to threads but don't share memory, communicating only via messages. [...]