feat: avatar cropping

lib/widgets/avatar_crop_dialog.dart

@@ -0,0 +1,70 @@
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+import 'package:crop_image/crop_image.dart';
+import 'package:fluffychat/l10n/l10n.dart';
+import 'package:flutter/material.dart';
+
+class AvatarCropDialog extends StatefulWidget {
+  final Uint8List image;
+
+  const AvatarCropDialog({super.key, required this.image});
+
+  @override
+  AvatarCropDialogController createState() => AvatarCropDialogController();
+}
+
+class AvatarCropDialogController extends State<AvatarCropDialog> {
+  final controller = CropController(
+    aspectRatio: 1,
+    defaultCrop: const Rect.fromLTWH(0.1, 0.1, 0.8, 0.8),
+  );
+
+  void onCancelAction() => Navigator.of(context).pop();
+
+  Future<void> onCropAction() async {
+    final image = await controller.croppedBitmap();
+    if (mounted) {
+      final data = await image.toByteData(format: ui.ImageByteFormat.png);
+      Navigator.of(context).pop(data?.buffer.asUint8List());
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) => AvatarCropDialogView(this);
+}
+
+class AvatarCropDialogView extends StatelessWidget {
+  final AvatarCropDialogController controller;
+
+  const AvatarCropDialogView(this.controller, {super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: Text(L10n.of(context).changeYourAvatar),
+      content: SizedBox(
+        width: 400,
+        height: 400,
+        child: CropImage(
+          controller: controller.controller,
+          image: Image.memory(controller.widget.image),
+          gridColor: Colors.white,
+          gridCornerSize: 20,
+          touchSize: 20,
+          alwaysShowThirdLines: true,
+        ),
+      ),
+      actions: [
+        TextButton(
+          onPressed: controller.onCancelAction,
+          child: Text(L10n.of(context).cancel),
+        ),
+        TextButton(
+          onPressed: controller.onCropAction,
+          child: Text(L10n.of(context).ok),
+        ),
+      ],
+    );
+  }
+}