Flutter图像处理插件flutter_image_process的使用

flutter_image_process 是一个用于在 Flutter 应用中进行图像处理的强大插件。它支持多种常见的图像处理操作，如裁剪、旋转、调整大小等。

安装插件

首先，在你的 pubspec.yaml 文件中添加 flutter_image_process 插件：

dependencies:
  flutter:
    sdk: flutter
  flutter_image_process: ^1.0.0  # 请根据最新版本进行更新

然后运行 flutter pub get 命令来获取该插件。

使用示例

以下是一个完整的示例，展示了如何使用 flutter_image_process 插件进行图像处理。

导入插件

在 Dart 文件中导入 flutter_image_process 包：

import 'package:flutter/material.dart';
import 'package:flutter_image_process/flutter_image_process.dart';

创建一个简单的图像处理应用

创建一个 Flutter 应用，其中包含一个按钮，点击按钮后可以加载并处理一张图片。

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Flutter 图像处理示例'),
        ),
        body: Center(
          child: ImageProcessorExample(),
        ),
      ),
    );
  }
}

class ImageProcessorExample extends StatefulWidget {
  @override
  _ImageProcessorExampleState createState() => _ImageProcessorExampleState();
}

class _ImageProcessorExampleState extends State<ImageProcessorExample> {
  final String imagePath = 'assets/images/example.jpg'; // 图片路径
  Uint8List? imageBytes;

  @override
  void initState() {
    super.initState();
    loadImage(imagePath);
  }

  Future<void> loadImage(String path) async {
    imageBytes = await rootBundle.loadByteArray(path);
    setState(() {});
  }

  void processImage() async {
    if (imageBytes == null) return;

    // 加载原始图像
    final originalImage = await decodeImageFromList(imageBytes!);

    // 裁剪图像
    final croppedImage = await FlutterImageProcess.crop(
      originalImage,
      rect: Rect.fromLTWH(50, 50, 100, 100),
    );

    // 保存处理后的图像
    final processedImagePath = await FlutterImageProcess.saveImage(croppedImage);

    // 显示处理后的图像
    setState(() {
      imageBytes = File(processedImagePath).readAsBytesSync();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        if (imageBytes != null)
          Image.memory(imageBytes!),
        SizedBox(height: 20),
        ElevatedButton(
          onPressed: processImage,
          child: Text('处理图像'),
        ),
      ],
    );
  }
}

解释代码

1. 导入包：

   import 'package:flutter/material.dart';
   import 'package:flutter_image_process/flutter_image_process.dart';
   

2. 主应用类：

   void main() {
     runApp(MyApp());
   }
   
   class MyApp extends StatelessWidget {
     @override
     Widget build(BuildContext context) {
       return MaterialApp(
         home: Scaffold(
           appBar: AppBar(
             title: Text('Flutter 图像处理示例'),
           ),
           body: Center(
             child: ImageProcessorExample(),
           ),
         ),
       );
     }
   }
   

3. 图像处理示例类：

   class ImageProcessorExample extends StatefulWidget {
     @override
     _ImageProcessorExampleState createState() => _ImageProcessorExampleState();
   }
   
   class _ImageProcessorExampleState extends State<ImageProcessorExample> {
     final String imagePath = 'assets/images/example.jpg'; // 图片路径
     Uint8List? imageBytes;
   
     @override
     void initState() {
       super.initState();
       loadImage(imagePath);
     }
   
     Future<void> loadImage(String path) async {
       imageBytes = await rootBundle.loadByteArray(path);
       setState(() {});
     }
   
     void processImage() async {
       if (imageBytes == null) return;
   
       // 加载原始图像
       final originalImage = await decodeImageFromList(imageBytes!);
   
       // 裁剪图像
       final croppedImage = await FlutterImageProcess.crop(
         originalImage,
         rect: Rect.fromLTWH(50, 50, 100, 100),
       );
   
       // 保存处理后的图像
       final processedImagePath = await FlutterImageProcess.saveImage(croppedImage);
   
       // 显示处理后的图像
       setState(() {
         imageBytes = File(processedImagePath).readAsBytesSync();
       });
     }
   
     @override
     Widget build(BuildContext context) {
       return Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: [
           if (imageBytes != null)
             Image.memory(imageBytes!),
           SizedBox(height: 20),
           ElevatedButton(
             onPressed: processImage,
             child: Text('处理图像'),
           ),
         ],
       );
     }
   }