Flutter图片裁剪插件 native_image_cropper_ios 的使用

native_image_cropper_ios 是用于iOS平台的图片裁剪插件，它是 native_image_cropper 插件的一部分。该插件提供了对iOS原生图片裁剪功能的支持。

使用方法

由于 native_image_cropper_ios 是一个被认可的联邦插件（endorsed federated plugin），你可以直接在Flutter项目中使用 native_image_cropper，而无需额外配置。当你在项目中添加依赖时，此插件会自动包含在你的应用中。

示例Demo

以下是一个完整的示例代码，展示了如何使用 native_image_cropper_ios 插件来裁剪图片：

import 'dart:async';
import 'dart:typed_data';

import 'package:flutter/cupertino.dart';
import 'package:flutter/services.dart';
import 'package:native_image_cropper_ios/native_image_cropper_ios.dart';
// 假设这些是自定义的UI组件和主题文件
// import 'package:native_image_cropper_ios_example/icon_button.dart';
// import 'package:native_image_cropper_ios_example/result.dart';
// import 'package:native_image_cropper_ios_example/slider.dart';
// import 'package:native_image_cropper_ios_example/themes.dart';

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

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  static const String imageName = 'sail-boat';

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final _nativeImageCropperIOSPlugin = NativeImageCropperIOS();
  ImageFormat _format = ImageFormat.jpg;

  @override
  Widget build(BuildContext context) {
    return CupertinoApp(
      theme: CustomThemes.theme,
      home: CupertinoPageScaffold(
        navigationBar: const CupertinoNavigationBar(
          heroTag: 'home',
          transitionBetweenRoutes: false,
          middle: Text(
            'Native Image Cropper iOS Example',
            style: TextStyle(color: CupertinoColors.white),
          ),
        ),
        child: FutureBuilder<Uint8List>(
          future: _getBytes(),
          builder: (context, snapshot) {
            if (snapshot.hasData) {
              final bytes = snapshot.data!;
              return Column(
                children: [
                  Image(
                    image: MemoryImage(bytes),
                    fit: BoxFit.contain,
                  ),
                  const SizedBox(
                    height: 20,
                  ),
                  Row(
                    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                    children: [
                      Flexible(
                        flex: 2,
                        child: ImageFormatSlider(
                          onValueChanged: (value) => setState(() {
                            _format = value;
                          }),
                        ),
                      ),
                      Flexible(
                        child: CupertinoIconButton(
                          icon: const Icon(
                            CupertinoIcons.crop,
                            color: CupertinoColors.black,
                          ),
                          onPressed: () => _crop(
                            context: context,
                            bytes: bytes,
                            method: _nativeImageCropperIOSPlugin.cropRect,
                          ),
                        ),
                      ),
                      Flexible(
                        child: CupertinoIconButton(
                          shape: BoxShape.circle,
                          icon: const Icon(
                            CupertinoIcons.crop,
                            color: CupertinoColors.black,
                          ),
                          onPressed: () => _crop(
                            context: context,
                            bytes: bytes,
                            method: _nativeImageCropperIOSPlugin.cropOval,
                          ),
                        ),
                      ),
                    ],
                  ),
                ],
              );
            }
            return const Center(
              child: CupertinoActivityIndicator(),
            );
          },
        ),
      ),
    );
  }

  Future<void> _crop({
    required BuildContext context,
    required Uint8List bytes,
    required Future<Uint8List> Function({
      required Uint8List bytes,
      required int x,
      required int y,
      required int width,
      required int height,
      required ImageFormat format,
    }) method,
  }) async {
    final croppedBytes = await method(
      bytes: bytes,
      x: 1200,
      y: 900,
      width: 600,
      height: 600,
      format: _format,
    );

    if (mounted) {
      Navigator.push<void>(
        context,
        CupertinoPageRoute(
          builder: (context) =>
              ResultPage(bytes: croppedBytes, format: _format),
        ),
      );
    }
  }

  Future<Uint8List> _getBytes() async {
    final byteData = await rootBundle.load('assets/${MyApp.imageName}.png');
    return byteData.buffer.asUint8List();
  }
}

请注意：

• 上述代码中的 CustomThemes, ImageFormatSlider, CupertinoIconButton, 和 ResultPage 是假设存在的自定义组件或页面，你需要根据实际情况替换为自己的实现。
• 确保在项目的 pubspec.yaml 文件中正确添加了 native_image_cropper 的依赖，并且在 assets 中声明了图片资源。例如：

dependencies:
  flutter:
    sdk: flutter
  native_image_cropper: ^latest_version

flutter:
  assets:
    - assets/sail-boat.png